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Question 1
Correct
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A 25-year-old regular gym attendee has been using growth hormone injections to enhance his muscle mass. What potential risks is he now more susceptible to?
Your Answer: Diabetes mellitus type II
Explanation:Excessive growth hormone can elevate the likelihood of developing type II diabetes mellitus. This is due to the hormone’s ability to release glucose from fat reserves, which raises its concentration in the bloodstream. As a result, the pancreas must produce more insulin to counteract the heightened glucose levels.
Additional indications of surplus growth hormone may involve thickened skin, enlarged extremities, a protruding jaw, carpal tunnel syndrome, fatigue, muscle frailty, and high blood pressure.
Understanding Growth Hormone and Its Functions
Growth hormone (GH) is a hormone produced by the somatotroph cells in the anterior pituitary gland. It plays a crucial role in postnatal growth and development, as well as in regulating protein, lipid, and carbohydrate metabolism. GH acts on a transmembrane receptor for growth factor, leading to receptor dimerization and direct or indirect effects on tissues via insulin-like growth factor 1 (IGF-1), which is primarily secreted by the liver.
GH secretion is regulated by various factors, including growth hormone releasing hormone (GHRH), fasting, exercise, and sleep. Conversely, glucose and somatostatin can decrease GH secretion. Disorders associated with GH include acromegaly, which results from excess GH, and GH deficiency, which can lead to short stature.
In summary, GH is a vital hormone that plays a significant role in growth and metabolism. Understanding its functions and regulation can help in the diagnosis and treatment of GH-related disorders.
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This question is part of the following fields:
- Endocrine System
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Question 2
Incorrect
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A 45-year-old woman visits her doctor for a follow-up appointment after commencing metformin treatment half a year ago. She expresses worry about the potential long-term impact of diabetes on her kidneys, based on information she read online.
What is the primary mechanism through which kidney damage occurs in this demographic of patients?Your Answer:
Correct Answer: Non-enzymatic glycosylation
Explanation:The non-enzymatic glycosylation of the basement membrane is responsible for the complications of diabetes nephropathy.
Understanding Diabetic Nephropathy: The Common Cause of End-Stage Renal Disease
Diabetic nephropathy is the leading cause of end-stage renal disease in the western world. It affects approximately 33% of patients with type 1 diabetes mellitus by the age of 40 years, and around 5-10% of patients with type 1 diabetes mellitus develop end-stage renal disease. The pathophysiology of diabetic nephropathy is not fully understood, but changes to the haemodynamics of the glomerulus, such as increased glomerular capillary pressure, and non-enzymatic glycosylation of the basement membrane are thought to play a key role. Histological changes include basement membrane thickening, capillary obliteration, mesangial widening, and the development of nodular hyaline areas in the glomeruli, known as Kimmelstiel-Wilson nodules.
There are both modifiable and non-modifiable risk factors for developing diabetic nephropathy. Modifiable risk factors include hypertension, hyperlipidaemia, smoking, poor glycaemic control, and raised dietary protein. On the other hand, non-modifiable risk factors include male sex, duration of diabetes, and genetic predisposition, such as ACE gene polymorphisms. Understanding these risk factors and the pathophysiology of diabetic nephropathy is crucial in the prevention and management of this condition.
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This question is part of the following fields:
- Renal System
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Question 3
Incorrect
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As a junior doctor in a GP surgery, you are requested to examine an 82-year-old man who has reported a tremor in his left hand. What additional symptoms could indicate the presence of Parkinson's disease?
Your Answer:
Correct Answer: Bradykinesia and rigidity
Explanation:Parkinson’s disease is characterized by three main symptoms: tremor at rest, bradykinesia, and rigidity. Nystagmus is not a typical feature of Parkinson’s disease, while chorea is more commonly associated with Huntington’s disease. Although ataxia may be present in Parkinson’s disease, it is more frequently seen in cases of cerebellar lesions.
Parkinson’s disease is a progressive neurodegenerative disorder that occurs due to the degeneration of dopaminergic neurons in the substantia nigra. This leads to a classic triad of symptoms, including bradykinesia, tremor, and rigidity, which are typically asymmetrical. The disease is more common in men and is usually diagnosed around the age of 65. Bradykinesia is characterized by a poverty of movement, shuffling steps, and difficulty initiating movement. Tremors are most noticeable at rest and typically occur in the thumb and index finger. Rigidity can be either lead pipe or cogwheel, and other features include mask-like facies, flexed posture, and drooling of saliva. Psychiatric features such as depression, dementia, and sleep disturbances may also occur. Diagnosis is usually clinical, but if there is difficulty differentiating between essential tremor and Parkinson’s disease, 123I‑FP‑CIT single photon emission computed tomography (SPECT) may be considered.
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This question is part of the following fields:
- Neurological System
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Question 4
Incorrect
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Which of the following carpal bones is a sesamoid bone in the tendon of flexor carpi ulnaris? Also, could you please adjust the age in the question slightly?
Your Answer:
Correct Answer: Pisiform
Explanation:The bone in question is a small one with only one articular facet. It protrudes from the triquetral bone on the ulnar side of the wrist, and is commonly considered a sesamoid bone located within the tendon of the flexor carpi ulnaris.
Carpal Bones: The Wrist’s Building Blocks
The wrist is composed of eight carpal bones, which are arranged in two rows of four. These bones are convex from side to side posteriorly and concave anteriorly. The trapezium is located at the base of the first metacarpal bone, which is the base of the thumb. The scaphoid, lunate, and triquetrum bones do not have any tendons attached to them, but they are stabilized by ligaments.
In summary, the carpal bones are the building blocks of the wrist, and they play a crucial role in the wrist’s movement and stability. The trapezium bone is located at the base of the thumb, while the scaphoid, lunate, and triquetrum bones are stabilized by ligaments. Understanding the anatomy of the wrist is essential for diagnosing and treating wrist injuries and conditions.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 5
Incorrect
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A 63-year-old man is being evaluated on the medical ward after undergoing surgery to remove a suspicious thyroid nodule. His vital signs are stable, his pain is adequately managed, and he is able to consume soft foods and drink oral fluids. He reports feeling generally fine, but has observed a hoarseness in his voice.
What is the probable reason for his hoarseness?Your Answer:
Correct Answer: Damage to recurrent laryngeal nerve
Explanation:Hoarseness is often linked to recurrent laryngeal nerve injury, which can affect the opening of the vocal cords by innervating the posterior arytenoid muscles. This type of damage can result from surgery, such as thyroidectomy, or compression from tumors. On the other hand, glossopharyngeal nerve damage is more commonly associated with swallowing difficulties. Since the patient is able to consume food orally, a dry throat is unlikely to be the cause of her hoarseness. While intubation trauma could cause vocal changes, the absence of pain complaints makes it less likely. Additionally, the lack of other symptoms suggests that an upper respiratory tract infection is not the cause.
The Recurrent Laryngeal Nerve: Anatomy and Function
The recurrent laryngeal nerve is a branch of the vagus nerve that plays a crucial role in the innervation of the larynx. It has a complex path that differs slightly between the left and right sides of the body. On the right side, it arises anterior to the subclavian artery and ascends obliquely next to the trachea, behind the common carotid artery. It may be located either anterior or posterior to the inferior thyroid artery. On the left side, it arises left to the arch of the aorta, winds below the aorta, and ascends along the side of the trachea.
Both branches pass in a groove between the trachea and oesophagus before entering the larynx behind the articulation between the thyroid cartilage and cricoid. Once inside the larynx, the recurrent laryngeal nerve is distributed to the intrinsic larynx muscles (excluding cricothyroid). It also branches to the cardiac plexus and the mucous membrane and muscular coat of the oesophagus and trachea.
Damage to the recurrent laryngeal nerve, such as during thyroid surgery, can result in hoarseness. Therefore, understanding the anatomy and function of this nerve is crucial for medical professionals who perform procedures in the neck and throat area.
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This question is part of the following fields:
- Neurological System
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Question 6
Incorrect
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A 65-year-old woman with a past medical history of heart failure presents to the emergency department complaining of palpitations. During the history-taking process, it is revealed that she takes ramipril and paracetamol regularly, but her cardiologist prescribed a new medication a week ago. She is unsure of the name of the medication but describes it as a 'water pill'. An electrocardiogram is performed, which shows abnormal tall T waves. What is the name of the 'water pill' that was recently prescribed?
Your Answer:
Correct Answer: Spironolactone (potassium-sparing diuretic)
Explanation:Spironolactone is a medication that works as an aldosterone antagonist in the cortical collecting duct. It is used to treat various conditions such as ascites, hypertension, heart failure, nephrotic syndrome, and Conn’s syndrome. In patients with cirrhosis, spironolactone is often prescribed in relatively large doses of 100 or 200 mg to counteract secondary hyperaldosteronism. It is also used as a NICE ‘step 4’ treatment for hypertension. In addition, spironolactone has been shown to reduce all-cause mortality in patients with NYHA III + IV heart failure who are already taking an ACE inhibitor, according to the RALES study.
However, spironolactone can cause adverse effects such as hyperkalaemia and gynaecomastia, although the latter is less common with eplerenone. It is important to monitor potassium levels in patients taking spironolactone to prevent hyperkalaemia, which can lead to serious complications such as cardiac arrhythmias. Overall, spironolactone is a useful medication for treating various conditions, but its potential adverse effects should be carefully considered and monitored.
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This question is part of the following fields:
- Renal System
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Question 7
Incorrect
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A 67-year-old man presents to the emergency department with chest pain. He describes this as crushing central chest pain which is associated with nausea and sweating.
Blood results are as follows:
Hb 148 g/L Male: (135-180)
Female: (115 - 160)
Platelets 268 * 109/L (150 - 400)
WBC 14.6 * 109/L (4.0 - 11.0)
Na+ 136 mmol/L (135 - 145)
K+ 4.7 mmol/L (3.5 - 5.0)
Urea 6.2 mmol/L (2.0 - 7.0)
Creatinine 95 µmol/L (55 - 120)
Troponin 4058 ng/L (< 14 ng/L)
An ECG is performed which demonstrates:
Current ECG Sinus rhythm, QRS 168ms, dominant S wave in V1
Previous ECG 12 months ago No abnormality
Which part of the heart's conduction system is likely to be affected?Your Answer:
Correct Answer: Purkinje fibres
Explanation:The Purkinje fibres have the highest conduction velocities in the heart, and a prolonged QRS (>120ms) with a dominant S wave in V1 may indicate left bundle branch block (LBBB). If a patient presents with chest pain, a raised troponin, and a previously normal ECG, LBBB should be considered as a possible cause and managed as an acute STEMI. LBBB is caused by damage to the left bundle branch and its associated Purkinje fibres.
Understanding the Cardiac Action Potential and Conduction Velocity
The cardiac action potential is a series of electrical events that occur in the heart during each heartbeat. It is responsible for the contraction of the heart muscle and the pumping of blood throughout the body. The action potential is divided into five phases, each with a specific mechanism. The first phase is rapid depolarization, which is caused by the influx of sodium ions. The second phase is early repolarization, which is caused by the efflux of potassium ions. The third phase is the plateau phase, which is caused by the slow influx of calcium ions. The fourth phase is final repolarization, which is caused by the efflux of potassium ions. The final phase is the restoration of ionic concentrations, which is achieved by the Na+/K+ ATPase pump.
Conduction velocity is the speed at which the electrical signal travels through the heart. The speed varies depending on the location of the signal. Atrial conduction spreads along ordinary atrial myocardial fibers at a speed of 1 m/sec. AV node conduction is much slower, at 0.05 m/sec. Ventricular conduction is the fastest in the heart, achieved by the large diameter of the Purkinje fibers, which can achieve velocities of 2-4 m/sec. This allows for a rapid and coordinated contraction of the ventricles, which is essential for the proper functioning of the heart. Understanding the cardiac action potential and conduction velocity is crucial for diagnosing and treating heart conditions.
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This question is part of the following fields:
- Cardiovascular System
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Question 8
Incorrect
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A 70-year-old male presents to the Emergency Department with a 3-hour history of tearing chest pain. He has a past medical history of poorly controlled hypertension. His observations show:
Respiratory rate of 20 breaths/min
Pulse of 95 beats/min
Temperature of 37.3ºC
Blood pressure of 176/148 mmHg
Oxygen saturations of 97% on room air
Auscultation of the heart identifies a diastolic murmur, heard loudest over the 2nd intercostal space, right sternal border.
What CT angiography findings would be expected in this patient's likely diagnosis?Your Answer:
Correct Answer: False lumen of the ascending aorta
Explanation:A false lumen in the descending aorta is a significant indication of aortic dissection on CT angiography. This condition is characterized by tearing chest pain, hypertension, and aortic regurgitation, which can be detected through a diastolic murmur over the 2nd intercostal space, right sternal border. The false lumen is formed due to a tear in the tunica intima of the aortic wall, which fills with a large volume of blood and is easily visible on angiographic CT.
Ballooning of the aortic arch is an incorrect answer as it refers to an aneurysm, which is a condition where the artery walls weaken and abnormally bulge out or widen. Aneurysms are prone to rupture and can have varying effects depending on their location.
Blurring of the posterior wall of the descending aorta is also an incorrect answer as it is a sign of a retroperitoneal, contained rupture of an aortic aneurysm. This condition may present with hypovolemic shock, hypotension, tachycardia, and tachypnea, leading to collapse.
Total occlusion of the left anterior descending artery is another incorrect answer as it would likely result in ST-elevation myocardial infarction (STEMI). Although chest pain is a symptom of both conditions, the nature of the pain and investigation findings make aortic dissection more likely. It is important to note that coronary arteries can only be viewed through coronary angiography, which involves injecting contrast directly into the coronary arteries using a catheter, and not through CT angiography.
Aortic dissection is classified according to the location of the tear in the aorta. The Stanford classification divides it into type A, which affects the ascending aorta in two-thirds of cases, and type B, which affects the descending aorta distal to the left subclavian origin in one-third of cases. The DeBakey classification divides it into type I, which originates in the ascending aorta and propagates to at least the aortic arch and possibly beyond it distally, type II, which originates in and is confined to the ascending aorta, and type III, which originates in the descending aorta and rarely extends proximally but will extend distally.
To diagnose aortic dissection, a chest x-ray may show a widened mediastinum, but CT angiography of the chest, abdomen, and pelvis is the investigation of choice. However, the choice of investigations should take into account the patient’s clinical stability, as they may present acutely and be unstable. Transoesophageal echocardiography (TOE) is more suitable for unstable patients who are too risky to take to the CT scanner.
The management of type A aortic dissection is surgical, but blood pressure should be controlled to a target systolic of 100-120 mmHg while awaiting intervention. On the other hand, type B aortic dissection is managed conservatively with bed rest and IV labetalol to reduce blood pressure and prevent progression. Complications of a backward tear include aortic incompetence/regurgitation and MI, while complications of a forward tear include unequal arm pulses and BP, stroke, and renal failure. Endovascular repair of type B aortic dissection may have a role in the future.
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This question is part of the following fields:
- Cardiovascular System
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Question 9
Incorrect
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What characteristic do Entamoeba histolytica and Aspergillus fungi have in common?
Your Answer:
Correct Answer: Membrane-bound nucleus
Explanation:Protozoa vs Fungi: the Differences
Protozoa and fungi are two distinct groups of organisms that share some similarities but also have significant differences. Protozoa are unicellular and mostly motile, while fungi are multicellular and mostly immobile. Both groups are eukaryotic, meaning they have a membrane-bound nucleus, but protozoa have an anal pore and pseudopods that are not found in fungi.
The anal pore in protozoa is used for excretion of substances, while pseudopods are projections of membrane used to engulf substances for uptake. These structures are not present in fungi, which have a cell wall instead. Aspergillus, for example, is a multicellular fungus with a cell wall, while most protozoa, including Entamoeba, do not have a cell wall.
the differences between protozoa and fungi is important for various fields, including medicine, agriculture, and ecology. For instance, protozoa can cause diseases such as malaria, while fungi can be used for food production or as biocontrol agents against pests. By studying the unique characteristics of these organisms, we can better appreciate their diversity and complexity in the natural world.
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This question is part of the following fields:
- Microbiology
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Question 10
Incorrect
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A woman in her early pregnancy has her kidney function assessed during a regular check-up. It is observed that her plasma urea and creatinine levels have decreased compared to her pre-pregnancy levels. What is the reason for this change?
Your Answer:
Correct Answer: Increased renal perfusion
Explanation:During pregnancy, plasma urea and creatinine levels decrease due to increased renal perfusion, which allows for more efficient clearing of these substances from the circulation. Additionally, the increased plasma volume dilutes these substances. This is a result of physiological changes in pregnancy, such as increased uterine size, cervical ectropion, and increased vaginal discharge. Cardiovascular and haemodynamic changes also occur, including increased plasma volume and decreased levels of albumin, urea, and creatinine. Progesterone-related effects, such as muscle relaxation, can lead to decreased blood pressure, constipation, and bladder relaxation. It is important to note that the foetus does not have functioning kidneys, and the mother filters the blood for it.
During pregnancy, a woman’s body undergoes various physiological changes. The cardiovascular system experiences an increase in stroke volume, heart rate, and cardiac output, while systolic blood pressure remains unchanged and diastolic blood pressure decreases in the first and second trimesters before returning to normal levels by term. The enlarged uterus may cause issues with venous return, leading to ankle swelling, supine hypotension, and varicose veins.
The respiratory system sees an increase in pulmonary ventilation and tidal volume, with oxygen requirements only increasing by 20%. This can lead to a sense of dyspnea due to over-breathing and a fall in pCO2. The basal metabolic rate also increases, potentially due to increased thyroxine and adrenocortical hormones.
Maternal blood volume increases by 30%, with red blood cells increasing by 20% and plasma increasing by 50%, leading to a decrease in hemoglobin levels. Coagulant activity increases slightly, while fibrinolytic activity decreases. Platelet count falls, and white blood cell count and erythrocyte sedimentation rate rise.
The urinary system experiences an increase in blood flow and glomerular filtration rate, with elevated sex steroid levels leading to increased salt and water reabsorption and urinary protein losses. Trace glycosuria may also occur.
Calcium requirements increase during pregnancy, with gut absorption increasing substantially due to increased 1,25 dihydroxy vitamin D. Serum levels of calcium and phosphate may fall, but ionized calcium levels remain stable. The liver experiences an increase in alkaline phosphatase and a decrease in albumin levels.
The uterus undergoes significant changes, increasing in weight from 100g to 1100g and transitioning from hyperplasia to hypertrophy. Cervical ectropion and discharge may increase, and Braxton-Hicks contractions may occur in late pregnancy. Retroversion may lead to retention in the first trimester but usually self-corrects.
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This question is part of the following fields:
- Reproductive System
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Question 11
Incorrect
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A 65-year-old man with a history of poorly-controlled type 2 diabetes presents to the emergency department with altered mental status. His daughter reports that he has been complaining of increased thirst and urination over the past few days and has been skipping his insulin injections. On examination, he is dehydrated with a GCS of 3. His vital signs are recorded, and he is intubated and given ventilatory support. An arterial blood gas shows mild metabolic acidosis and his capillary blood glucose is undetectable. What is the next most appropriate step in his treatment?
Your Answer:
Correct Answer: 0.9% sodium chloride
Explanation:In the ABCDE approach, the patient should be promptly given sodium chloride to restore their intravascular volume and maintain circulatory function. However, insulin is not recommended as an initial treatment for HHS. This is because glucose in the intravascular space helps maintain circulating volume, which is crucial for dehydrated patients. Administering insulin before fluid resuscitation can cause a reduction in intravascular volume and worsen hypotension. It may also worsen pre-existing hypokalaemia by driving potassium into the intracellular space. Potassium chloride should be administered only after fluid resuscitation and guided by potassium levels obtained from an arterial blood gas. Thiamine supplementation is not indicated at the moment as urgent resuscitation should be the priority.
Hyperosmolar hyperglycaemic state (HHS) is a serious medical emergency that can be challenging to manage and has a high mortality rate of up to 20%. It is typically seen in elderly patients with type 2 diabetes mellitus (T2DM) and is caused by hyperglycaemia leading to osmotic diuresis, severe dehydration, and electrolyte imbalances. HHS develops gradually over several days, resulting in extreme dehydration and metabolic disturbances. Symptoms include polyuria, polydipsia, lethargy, nausea, vomiting, altered consciousness, and focal neurological deficits. Diagnosis is based on hypovolaemia, marked hyperglycaemia, significantly raised serum osmolarity, and no significant hyperketonaemia or acidosis.
Management of HHS involves fluid replacement with IV 0.9% sodium chloride solution at a rate of 0.5-1 L/hour, depending on clinical assessment. Potassium levels should be monitored and added to fluids as needed. Insulin should not be given unless blood glucose stops falling while giving IV fluids. Patients are at risk of thrombosis due to hyperviscosity, so venous thromboembolism prophylaxis is recommended. Complications of HHS include vascular complications such as myocardial infarction and stroke.
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This question is part of the following fields:
- Endocrine System
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Question 12
Incorrect
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A 65-year-old farmer presents to the emergency department with weakness, fatigue and a dry mouth that has gradually developed over the past week. The weakness has progressed so that now he struggles to keep his head up and cannot lift his arms above the horizontal. On examination, he has reduced tone and power in his neck and arms. The biceps reflex is bilaterally absent. Neurological examination of the legs is unremarkable. Four weeks prior to this admission he cut his leg on some dirty machinery while working in the field and did not seek medical attention. The wound appears infected and swabs taken from the wound show anaerobic Gram-positive bacilli.
What is the underlying mechanism causing the weakness in this 65-year-old farmer?Your Answer:
Correct Answer: SNARE protein cleavage in the presynaptic terminal at the neuromuscular junction
Explanation:Botulinum toxin causes a flaccid paralysis by cleaving SNARE proteins in the presynaptic terminal at the neuromuscular junction. This is the correct mechanism of action and is consistent with the patient’s symptoms. The history of weakness progressing over the past week and the bilateral appearance suggest that this is not a stroke or the result of a spider bite. While tetanus toxin and alpha-latrotoxin also affect SNARE proteins, they cause spastic paralysis and are less likely in this case. Organophosphorus poisoning is also unlikely due to the lack of a clear exposure history.
Medical Uses of Botulinum Toxin
Botulinum toxin, commonly known as Botox, is not just used for cosmetic purposes. There are several licensed indications for its use in medical treatments. These include blepharospasm, hemifacial spasm, focal spasticity in patients with cerebral palsy, hand and wrist disability associated with stroke, spasmodic torticollis, severe hyperhidrosis of the axillae, and achalasia.
Blepharospasm is a condition where the eyelids twitch uncontrollably, while hemifacial spasm is a similar condition that affects one side of the face. Focal spasticity is a condition where certain muscles become stiff and difficult to move, often due to damage to the brain or spinal cord. Botulinum toxin can help relax these muscles and improve mobility.
Spasmodic torticollis is a condition where the neck muscles contract involuntarily, causing the head to twist or turn to one side. Severe hyperhidrosis of the axillae is excessive sweating in the armpits, which can be embarrassing and uncomfortable. Achalasia is a condition where the muscles in the esophagus do not work properly, making it difficult to swallow.
In all of these cases, botulinum toxin can be a useful treatment option. It works by blocking the signals that cause muscles to contract, leading to temporary muscle relaxation. While it is important to use botulinum toxin under the guidance of a medical professional, it can be a safe and effective treatment for a range of conditions.
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This question is part of the following fields:
- General Principles
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Question 13
Incorrect
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A 35-year-old man is diagnosed with a DVT in his right leg, which is determined to be caused by a genetic disorder. What is the most prevalent hereditary factor leading to DVT?
Your Answer:
Correct Answer: Factor V Leiden
Explanation:Deep vein thrombosis is a condition that occurs more frequently in Caucasians than in people of black African, Far East Asian, native Australian, and native American origin. The most common heritable causes of DVT, in descending order, are Factor V Leiden, Prothrombin G20210A variant, Protein C deficiency, Protein S deficiency, and Antithrombin deficiency. However, Von Willebrand disease and thalassaemia are not associated with DVT.
Understanding Factor V Leiden
Factor V Leiden is a common inherited thrombophilia, affecting around 5% of the UK population. It is caused by a mutation in the Factor V Leiden protein, resulting in activated factor V being inactivated 10 times more slowly by activated protein C than normal. This leads to activated protein C resistance, which increases the risk of venous thrombosis. Heterozygotes have a 4-5 fold risk of venous thrombosis, while homozygotes have a 10 fold risk, although the prevalence of homozygotes is much lower at 0.05%.
Despite its prevalence, screening for Factor V Leiden is not recommended, even after a venous thromboembolism. This is because a previous thromboembolism itself is a risk factor for further events, and specific management should be based on this rather than the particular thrombophilia identified.
Other inherited thrombophilias include Prothrombin gene mutation, Protein C deficiency, Protein S deficiency, and Antithrombin III deficiency. The table below shows the prevalence and relative risk of venous thromboembolism for each of these conditions.
Overall, understanding Factor V Leiden and other inherited thrombophilias can help healthcare professionals identify individuals at higher risk of venous thrombosis and provide appropriate management to prevent future events.
Condition | Prevalence | Relative risk of VTE
— | — | —
Factor V Leiden (heterozygous) | 5% | 4
Factor V Leiden (homozygous) | 0.05% | 10
Prothrombin gene mutation (heterozygous) | 1.5% | 3
Protein C deficiency | 0.3% | 10
Protein S deficiency | 0.1% | 5-10
Antithrombin III deficiency | 0.02% | 10-20 -
This question is part of the following fields:
- Haematology And Oncology
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Question 14
Incorrect
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A 35-year-old woman has come in with symptoms of loin pain and dysuria and has been diagnosed with pyelonephritis. She was treated with intravenous amoxicillin and gentamicin and has responded well. The consultant has decided to follow local guidelines and switch her to oral co-trimoxazole. What are the components of this medication?
Your Answer:
Correct Answer: Trimethoprim + sulfamethoxazole
Explanation:Understanding Sulfonamides and Their Adverse Effects
Sulfonamides are a type of drug that work by inhibiting dihydropteroate synthetase. This class of drugs includes antibiotic sulfonamides such as sulfamethoxazole, sulfadiazine, and sulfisoxazole. Co-trimoxazole, a combination of sulfamethoxazole and trimethoprim, is commonly used in the management of Pneumocystis jiroveci pneumonia. Non-antibiotic sulfonamides like sulfasalazine and sulfonylureas also exist.
However, the use of co-trimoxazole may lead to adverse effects such as hyperkalaemia, headache, and rash, including the potentially life-threatening Steven-Johnson Syndrome. It is important to understand the potential risks associated with sulfonamides and to consult with a healthcare professional before taking any medication.
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This question is part of the following fields:
- General Principles
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Question 15
Incorrect
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A 25-year-old man has a procedure to remove his testicle. During the surgery, the surgeon ties off the right testicular vein. Where does this vein typically drain into?
Your Answer:
Correct Answer: Inferior vena cava
Explanation:The drainage of the testicles starts in the septa, where the veins of the tunica vasculosa and the pampiniform plexus come together at the back of the testis. From there, the pampiniform plexus leads to the testicular vein, which then drains into either the left renal vein or the inferior vena cava, depending on which testicle it comes from.
Anatomy of the Scrotum and Testes
The scrotum is composed of skin and dartos fascia, with an arterial supply from the anterior and posterior scrotal arteries. It is also the site of lymphatic drainage to the inguinal lymph nodes. The testes are surrounded by the tunica vaginalis, a closed peritoneal sac, with the parietal layer adjacent to the internal spermatic fascia. The testicular arteries arise from the aorta, just below the renal arteries, and the pampiniform plexus drains into the testicular veins. The left testicular vein drains into the left renal vein, while the right testicular vein drains into the inferior vena cava. Lymphatic drainage occurs to the para-aortic nodes.
The spermatic cord is formed by the vas deferens and is covered by the internal spermatic fascia, cremasteric fascia, and external spermatic fascia. The cord contains the vas deferens, testicular artery, artery of vas deferens, cremasteric artery, pampiniform plexus, sympathetic nerve fibers, genital branch of the genitofemoral nerve, and lymphatic vessels. The vas deferens transmits sperm and accessory gland secretions, while the testicular artery supplies the testis and epididymis. The cremasteric artery arises from the inferior epigastric artery, and the pampiniform plexus is a venous plexus that drains into the right or left testicular vein. The sympathetic nerve fibers lie on the arteries, while the parasympathetic fibers lie on the vas. The genital branch of the genitofemoral nerve supplies the cremaster. Lymphatic vessels drain to lumbar and para-aortic nodes.
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This question is part of the following fields:
- Reproductive System
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Question 16
Incorrect
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What is the primary function of riboflavin (vitamin B2) in the human body?
Your Answer:
Correct Answer: Energy production
Explanation:The Importance of Riboflavin in the Body
Riboflavin, also known as vitamin B2, is a vital nutrient in the body. Its structure consists of a sugar molecule attached to a flavin ring structure, which gives it a yellow color. One of the main roles of riboflavin is to aid in energy production and cellular metabolism of fuels. This is achieved by the creation of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are essential for generating ATP from carbohydrates and other fuel sources. Additionally, riboflavin has antioxidant properties that help protect cells from damage caused by free radicals.
Riboflavin can be found in a variety of foods, including yeast and yeast extract, liver and kidney, wheat germ, milk and cheese, eggs, and some breakfast cereals and drinks that are fortified with riboflavin. It is important to ensure that you are getting enough riboflavin in your diet to support your body’s energy production and antioxidant functions.
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This question is part of the following fields:
- Clinical Sciences
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Question 17
Incorrect
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A 65-year-old woman visits her GP after experiencing painless frank haematuria. She reports that this happened two days ago and her urine looked like port wine. She has a smoking history of 30 pack-years and denies drinking alcohol.
The patient is urgently referred for cystoscopy, which reveals a 2x3cm ulcerated lesion adjacent to the left ureteric orifice. The lesion is biopsied and diagnosed as transitional cell carcinoma.
Which venous structure transmits blood from the tumour to the internal iliac veins?Your Answer:
Correct Answer: Vesicouterine plexus
Explanation:The vesicouterine plexus is responsible for draining the bladder in females.
Bladder Anatomy and Innervation
The bladder is a three-sided pyramid-shaped organ located in the pelvic cavity. Its apex points towards the symphysis pubis, while the base lies anterior to the rectum or vagina. The bladder’s inferior aspect is retroperitoneal, while the superior aspect is covered by peritoneum. The trigone, the least mobile part of the bladder, contains the ureteric orifices and internal urethral orifice. The bladder’s blood supply comes from the superior and inferior vesical arteries, while venous drainage occurs through the vesicoprostatic or vesicouterine venous plexus. Lymphatic drainage occurs mainly to the external iliac and internal iliac nodes, with the obturator nodes also playing a role. The bladder is innervated by parasympathetic nerve fibers from the pelvic splanchnic nerves and sympathetic nerve fibers from L1 and L2 via the hypogastric nerve plexuses. The parasympathetic fibers cause detrusor muscle contraction, while the sympathetic fibers innervate the trigone muscle. The external urethral sphincter is under conscious control, and voiding occurs when the rate of neuronal firing to the detrusor muscle increases.
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This question is part of the following fields:
- Renal System
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Question 18
Incorrect
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A 15-year-old girl presents with heavy menstrual bleeding and frequent nosebleeds. She also reports easy bruising. Upon investigation, the GP finds prolonged bleeding time and thrombocytopenia, leading to a diagnosis of Bernard-Soulier syndrome. What is the missing or defective component in this condition?
Your Answer:
Correct Answer: Platelet glycoprotein complex Ib-IX-V
Explanation:Bernard-Soulier syndrome is a bleeding disorder that occurs due to an autosomal recessive deficiency in the platelet glycoprotein complex Ib-IX-V. This complex is responsible for binding to von Willebrand factor (vWF) to allow platelet adherence. As a result of the deficiency, vWF cannot bind, leading to impaired platelet adhesion and the typical symptoms of coagulopathies such as abnormal bleeding and bruising.
It is important to note that von Willebrand factor is not deficient in Bernard-Soulier syndrome, but its function is impaired due to the lack of the platelet glycoprotein complex Ib-IX-V, which prevents it from binding to platelets.
Glanzmann’s disease is caused by a deficiency or dysfunction of platelet glycoprotein IIb/IIIa, which leads to impaired platelet aggregation as fibrinogen cannot bind to platelets.
Grey platelet syndrome, on the other hand, is characterized by alpha granule deficiency, where megakaryocytes fail to pack these granules into platelets and release them in the bone marrow. This results in a large number of agranulocytic platelets in blood smears, which is a diagnostic characteristic of the syndrome.
Finally, lack of fibrinogen is usually an acquired type of deficiency that may or may not present with clinical manifestations.
Understanding Bernard-Soulier Disease
Bernard-Soulier disease is a platelet disorder that is caused by a deficiency of the glycoprotein Ib/IX/V complex. This complex is responsible for acting as a receptor for von Willebrand factor. The disease is rare and inherited in an autosomal recessive manner. This means that an individual must inherit two copies of the mutated gene, one from each parent, to develop the disease. The lack of the glycoprotein Ib/IX/V complex leads to abnormal platelet function, which can result in bleeding tendencies and easy bruising. It is important for individuals with Bernard-Soulier disease to receive proper medical care and management to prevent complications.
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This question is part of the following fields:
- Haematology And Oncology
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Question 19
Incorrect
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A 31-year-old male visits his doctor with complaints of feeling unwell for several months. He reports a weight loss of 9kg and chronic diarrhea. During a skin examination, the doctor observes purple skin lesions on the tip of his nose, inside his mouth, and bleeding around his gums. The doctor suspects Kaposi's sarcoma and wonders which Human Herpes Virus (HHV) is responsible for this condition?
Your Answer:
Correct Answer: HHV-8
Explanation:Kaposi’s sarcoma is a type of cancer that is caused by the human herpes virus 8 (HHV-8). It is characterized by the appearance of purple papules or plaques on the skin or mucosa, such as in the gastrointestinal and respiratory tract. These skin lesions may eventually ulcerate, while respiratory involvement can lead to massive haemoptysis and pleural effusion. Treatment options for Kaposi’s sarcoma include radiotherapy and resection. It is commonly seen in patients with HIV.
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This question is part of the following fields:
- General Principles
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Question 20
Incorrect
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A 35-year-old woman has remarried and desires to have children with her new Caucasian husband. However, she already has a 5-year-old child with cystic fibrosis from her previous marriage. She is concerned about the likelihood of having another affected child with her new partner. Can you provide an estimated risk?
Your Answer:
Correct Answer: 1 in 100 chance
Explanation:Cystic Fibrosis Inheritance
Cystic fibrosis is a genetic disorder that is inherited in an autosomal recessive pattern. This means that both copies of the gene in each cell have mutations. Individuals with only one copy of the mutated gene are carriers and typically do not show signs or symptoms of the condition.
In the case of a female carrier for the CF gene, there is a 1 in 2 chance of producing a gamete carrying the CF gene. If her new partner is also a carrier, he has a 1 in 25 chance of having the CF gene and a 1 in 50 chance of producing a gamete with the CF gene. Therefore, the chance of producing a child with cystic fibrosis is 1 in 100.
It is important to understand the inheritance pattern of cystic fibrosis to make informed decisions about family planning and genetic testing. This knowledge can help individuals and families better understand the risks and potential outcomes of having children with this condition.
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This question is part of the following fields:
- Clinical Sciences
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Question 21
Incorrect
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Can you provide a definition for lipoprotein?
Your Answer:
Correct Answer: A lipid-rich core surrounded by a phospholipid monolayer
Explanation:Lipoproteins: Transporting Lipids in the Body
Lipoproteins are particles that move through the bloodstream and carry lipids throughout the body. The challenge with transporting lipids is that they are not soluble in blood. To overcome this, lipoproteins surround a lipid-rich core containing triglycerides and cholesterol esters with a phospholipid monolayer. This creates a hydrophilic outer layer that is soluble in water and a hydrophobic internal environment that is suitable for lipid storage and transport.
Apoproteins, which are proteins inserted into the phospholipid monolayer, play a role in binding lipoproteins to their receptors. Different types of lipoproteins have varying numbers and types of apoproteins. For example, chylomicrons, a type of lipoprotein, have several different apoproteins including apoA, B48, C, and E. Measuring the levels of apoA and B can be useful in diagnosing certain diseases.
Overall, lipoproteins are essential for transporting lipids throughout the body and maintaining proper lipid balance.
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This question is part of the following fields:
- Clinical Sciences
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Question 22
Incorrect
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A 43-year-old man is brought to the emergency department via ambulance after being found collapsed on the street. He is barely responsive and has a heart rate of 120 beats per minute, blood pressure of 80/40 mmHg, oxygen saturations of 92%, and a temperature of 39 ºC. During a full secondary survey, gas gangrene is discovered on his lower limbs. Biopsy results later confirm that the causative organism is Clostridium perfringens. What is the responsible toxin for this presentation?
Your Answer:
Correct Answer: Alpha toxin
Explanation:Gas gangrene is a severe infection caused by Clostridium perfringens, which produces alpha-toxin, a lecithinase. This toxin causes local haemolysis, leading to areas of hypoperfusion and subsequent hypoxia, creating an anaerobic environment that allows the bacteria to thrive and cause further damage.
Cereulide, Exfoliatin, and Exotoxin A are incorrect as they are produced by Bacillus cereus, Staphylococcus aureus, and Pseudomonas aeruginosa, respectively, and cause different illnesses or symptoms such as vomiting and diarrhoea, blistering of the skin, and inhibition of protein synthesis.
Exotoxins vs Endotoxins: Understanding the Differences
Exotoxins and endotoxins are two types of toxins produced by bacteria. Exotoxins are secreted by bacteria, while endotoxins are only released when the bacterial cell is lysed. Exotoxins are typically produced by Gram-positive bacteria, with some exceptions like Vibrio cholerae and certain strains of E. coli.
Exotoxins can be classified based on their primary effects, which include pyrogenic toxins, enterotoxins, neurotoxins, tissue invasive toxins, and miscellaneous toxins. Pyrogenic toxins stimulate the release of cytokines, resulting in fever and rash. Enterotoxins act on the gastrointestinal tract, causing either diarrheal or vomiting illness. Neurotoxins act on the nerves or neuromuscular junction, causing paralysis. Tissue invasive toxins cause damage to tissues, while miscellaneous toxins have various effects.
On the other hand, endotoxins are lipopolysaccharides that are released from Gram-negative bacteria like Neisseria meningitidis. These toxins can cause fever, sepsis, and shock. Unlike exotoxins, endotoxins are not actively secreted by bacteria but are instead released when the bacterial cell is lysed.
Understanding the differences between exotoxins and endotoxins is important in diagnosing and treating bacterial infections. While exotoxins can be targeted with specific treatments like antitoxins, endotoxins are more difficult to treat and often require supportive care.
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This question is part of the following fields:
- General Principles
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Question 23
Incorrect
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A 27-year-old patient, Sarah, suffered severe left-sided craniofacial trauma in a car accident. Following a period in the ICU, Sarah has been discharged to the ward and requires rehabilitation therapy due to suspected cranial nerve damage. Sarah experiences numbness on the left side of her face and struggles with chewing. However, she can still smile and reports no alteration in her sense of taste. The left eye lacks the corneal reflex, while the right eye has it. What other symptom is likely present in Sarah?
Your Answer:
Correct Answer: Jaw deviation to the left
Explanation:Tom’s jaw deviation towards the left is consistent with trigeminal nerve damage from his accident. The trigeminal nerve controls facial sensation and the muscles of mastication. His ability to smile and report no change in taste suggests that his facial nerve is intact, and he is not experiencing upper motor neuron lesion. Jaw deviation to the right, tongue deviation to the left or right, and inability to wrinkle the forehead are not consistent with trigeminal nerve palsy.
Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.
In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.
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This question is part of the following fields:
- Neurological System
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Question 24
Incorrect
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A 67-year-old man has been admitted to the surgical ward with abdominal pain and rectal bleeding. According to the notes, he has not had a bowel movement in five days. Additionally, he has begun vomiting and his abdomen is swollen.
What is the probable diagnosis?Your Answer:
Correct Answer: Large bowel obstruction
Explanation:Large bowel obstruction is the most likely diagnosis based on the pattern of symptoms, which include abdominal distension, absence of passing flatus or stool, and late onset or no vomiting.
Large bowel obstruction occurs when there is a blockage in the passage of food, fluids, and gas through the large intestines. The most common cause of this condition is a tumor, accounting for 60% of cases. Colonic malignancy is often the initial presenting complaint in approximately 30% of cases, especially in more distal colonic and rectal tumors due to their smaller lumen diameter. Other causes include volvulus and diverticular disease.
Clinical features of large bowel obstruction include abdominal pain, distention, and absence of passing flatus or stool. Nausea and vomiting may suggest a more proximal lesion, while peritonism may be present if there is associated bowel perforation. It is important to consider the underlying causes, such as recent symptoms suggestive of colorectal cancer.
Abdominal x-ray is still commonly used as a first-line investigation, with a diameter greater than the normal limits of 10-12 cm for the caecum, 8 cm for the ascending colon, and 6.5 cm for recto-sigmoid being diagnostic of obstruction. CT scan is highly sensitive and specific for identifying obstruction and its underlying cause.
Initial management of large bowel obstruction includes NBM, IV fluids, and nasogastric tube with free drainage. Conservative management for up to 72 hours can be trialed if the cause of obstruction does not require surgery, after which further management may be required if there is no resolution. Around 75% of cases will eventually require surgery. IV antibiotics are given if perforation is suspected or surgery is planned. Emergency surgery is necessary if there is any overt peritonitis or evidence of bowel perforation, involving irrigation of the abdominal cavity, resection of perforated segment and ischaemic bowel, and addressing the underlying cause of the obstruction.
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This question is part of the following fields:
- Gastrointestinal System
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Question 25
Incorrect
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A 32-year-old man arrives at the emergency department complaining of abdominal pain and diarrhoea that has been ongoing for 2 days. He mentions that he recently came to the UK from Vietnam to visit his family and has been here for 4 days.
Upon examination, there is no guarding or rebound tenderness, but an urticarial rash is visible on his abdomen. A slight wheeze is audible, and he has a fever. The patient also shows papulovesicular lesions on the soles of his feet.
Which helminths are most likely responsible for causing this man's symptoms?Your Answer:
Correct Answer: Strongyloides stercoralis
Explanation:Strongyloides stercoralis is a type of intestinal nematode that can cause Strongyloidiasis. Symptoms of this condition include abdominal pain and diarrhea, as well as the appearance of papulovesicular lesions on the soles of the feet and an urticarial rash. This parasitic infection is commonly found in tropical and subtropical regions around the world.
Pinworm, also known as Enterobius vermicularis, typically causes perianal itching that is particularly bothersome at night.
Onchocerca volvulus is known to cause blindness and hyperpigmentation of the skin.
Trichinella spiralis can lead to myositis, periorbital edema, and fever after consuming raw pork.
Helminths are a group of parasitic worms that can infect humans and cause various diseases. Nematodes, also known as roundworms, are one type of helminth. Strongyloides stercoralis is a type of roundworm that enters the body through the skin and can cause symptoms such as diarrhea, abdominal pain, and skin lesions. Treatment for this infection typically involves the use of ivermectin or benzimidazoles. Enterobius vermicularis, also known as pinworm, is another type of roundworm that can cause perianal itching and other symptoms. Diagnosis is made by examining sticky tape applied to the perianal area. Treatment typically involves benzimidazoles.
Hookworms, such as Ancylostoma duodenale and Necator americanus, are another type of roundworm that can cause gastrointestinal infections and anemia. Treatment typically involves benzimidazoles. Loa loa is a type of roundworm that is transmitted by deer fly and mango fly and can cause red, itchy swellings called Calabar swellings. Treatment involves the use of diethylcarbamazine. Trichinella spiralis is a type of roundworm that can develop after eating raw pork and can cause fever, periorbital edema, and myositis. Treatment typically involves benzimidazoles.
Onchocerca volvulus is a type of roundworm that causes river blindness and is spread by female blackflies. Treatment involves the use of ivermectin. Wuchereria bancrofti is another type of roundworm that is transmitted by female mosquitoes and can cause blockage of lymphatics and elephantiasis. Treatment involves the use of diethylcarbamazine. Toxocara canis, also known as dog roundworm, is transmitted through ingestion of infective eggs and can cause visceral larva migrans and retinal granulomas. Treatment involves the use of diethylcarbamazine. Ascaris lumbricoides, also known as giant roundworm, can cause intestinal obstruction and occasionally migrate to the lung. Treatment typically involves benzimidazoles.
Cestodes, also known as tapeworms, are another type of helminth. Echinococcus granulosus is a tapeworm that is transmitted through ingestion of eggs in dog feces and can cause liver cysts and anaphylaxis if the cyst ruptures
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This question is part of the following fields:
- General Principles
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Question 26
Incorrect
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A researcher is investigating the function of regulatory proteins in intracellular trafficking. He has discovered several intracellular proteins marked with significant ubiquitination.
To which organelles are these proteins targeted?Your Answer:
Correct Answer: Proteasome
Explanation:Proteins are marked with ubiquitin for degradation in both proteasomes and lysosomes.
Functions of Cell Organelles
The functions of major cell organelles can be summarized in a table. The rough endoplasmic reticulum (RER) is responsible for the translation and folding of new proteins, as well as the manufacture of lysosomal enzymes. It is also the site of N-linked glycosylation. Cells such as pancreatic cells, goblet cells, and plasma cells have extensive RER. On the other hand, the smooth endoplasmic reticulum (SER) is involved in steroid and lipid synthesis. Cells of the adrenal cortex, hepatocytes, and reproductive organs have extensive SER.
The Golgi apparatus modifies, sorts, and packages molecules that are destined for cell secretion. The addition of mannose-6-phosphate to proteins designates transport to lysosome. The mitochondrion is responsible for aerobic respiration and contains mitochondrial genome as circular DNA. The nucleus is involved in DNA maintenance, RNA transcription, and RNA splicing, which removes the non-coding sequences of genes (introns) from pre-mRNA and joins the protein-coding sequences (exons).
The lysosome is responsible for the breakdown of large molecules such as proteins and polysaccharides. The nucleolus produces ribosomes, while the ribosome translates RNA into proteins. The peroxisome is involved in the catabolism of very long chain fatty acids and amino acids, resulting in the formation of hydrogen peroxide. Lastly, the proteasome, along with the lysosome pathway, is involved in the degradation of protein molecules that have been tagged with ubiquitin.
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This question is part of the following fields:
- General Principles
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Question 27
Incorrect
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A 65-year-old male is recovering from a community acquired pneumonia in hospital. He has undergone some blood tests that morning which indicate that he is experiencing AKI stage 2. The results are as follows:
- Na+ 133 mmol/L (135 - 145)
- K+ 3.6 mmol/L (3.5 - 5.0)
- Bicarbonate 23 mmol/L (22 - 29)
- Urea 6.0 mmol/L (2.0 - 7.0)
- Creatinine 150 µmol/L (55 - 120)
Over the past 12 hours, he has only produced 360ml of urine. In light of this, what is the most crucial medication to discontinue from his drug chart?Your Answer:
Correct Answer: Diclofenac
Explanation:In cases of acute kidney injury (AKI), it is crucial to discontinue the use of nonsteroidal anti-inflammatory drugs (NSAIDs) as they can potentially worsen renal function. Ibuprofen, being an NSAID, falls under this category.
NSAIDs work by reducing the production of prostaglandins, which are responsible for vasodilation. Inhibiting their production can lead to vasoconstriction of the afferent arteriole, resulting in decreased renal perfusion and a decline in estimated glomerular filtration rate (eGFR).
To prevent further damage to the kidneys, all nephrotoxic medications, including NSAIDs, ACE inhibitors, gentamicin, vancomycin, and metformin (which should be discussed with the diabetic team), should be discontinued in cases of AKI.
Acute kidney injury (AKI) is a condition where there is a reduction in renal function following an insult to the kidneys. It was previously known as acute renal failure and can result in long-term impaired kidney function or even death. AKI can be caused by prerenal, intrinsic, or postrenal factors. Patients with chronic kidney disease, other organ failure/chronic disease, a history of AKI, or who have used drugs with nephrotoxic potential are at an increased risk of developing AKI. To prevent AKI, patients at risk may be given IV fluids or have certain medications temporarily stopped.
The kidneys are responsible for maintaining fluid balance and homeostasis, so a reduced urine output or fluid overload may indicate AKI. Symptoms may not be present in early stages, but as renal failure progresses, patients may experience arrhythmias, pulmonary and peripheral edema, or features of uraemia. Blood tests such as urea and electrolytes can be used to detect AKI, and urinalysis and imaging may also be necessary.
Management of AKI is largely supportive, with careful fluid balance and medication review. Loop diuretics and low-dose dopamine are not recommended, but hyperkalaemia needs prompt treatment to avoid life-threatening arrhythmias. Renal replacement therapy may be necessary in severe cases. Patients with suspected AKI secondary to urinary obstruction require prompt review by a urologist, and specialist input from a nephrologist is required for cases where the cause is unknown or the AKI is severe.
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This question is part of the following fields:
- Renal System
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Question 28
Incorrect
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A 46-year-old patient visits his doctor 5 days after his last appointment, worried about passing very small amounts of urine for the past 4 days. He was prescribed gentamicin for an infection during his last visit. The doctor suspects gentamicin-induced nephrotoxicity and conducts an examination, finding no abnormalities and normal blood pressure and temperature. The patient's fractional excretion of urine is greater than 4%, and a urine sample is sent to the lab for microscopy, culture, and sensitivity. What would be observed on microscopy if the doctor's suspicion is correct?
Your Answer:
Correct Answer: Brown granular casts
Explanation:The clinical significance of various laboratory findings is summarized in the table below:
Laboratory Finding Clinical Significance
Elevated creatinine and BUN Indicates impaired kidney function
Low serum albumin Indicates malnutrition or liver disease
Elevated liver enzymes Indicates liver damage or disease
Elevated glucose Indicates diabetes or impaired glucose tolerance
Elevated potassium Indicates kidney dysfunction or medication side effect
Elevated sodium Indicates dehydration or excessive sodium intake
Elevated nitrites Indicates urinary tract infection
Elevated white blood cells Indicates infection or inflammation
Elevated red blood cells Indicates dehydration or kidney disease
Elevated platelets Indicates clotting disorder or inflammationDifferent Types of Urinary Casts and Their Significance
Urine contains various types of urinary casts that can provide important information about the underlying condition of the patient. Hyaline casts, for instance, are composed of Tamm-Horsfall protein that is secreted by the distal convoluted tubule. These casts are commonly seen in normal urine, after exercise, during fever, or with loop diuretics. On the other hand, brown granular casts in urine are indicative of acute tubular necrosis.
In prerenal uraemia, the urinary sediment appears ‘bland’, which means that there are no significant abnormalities in the urine. Lastly, red cell casts are associated with nephritic syndrome, which is a condition characterized by inflammation of the glomeruli in the kidneys. By analyzing the type of urinary casts present in the urine, healthcare professionals can diagnose and manage various kidney diseases and disorders. Proper identification and interpretation of urinary casts can help in the early detection and treatment of kidney problems.
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This question is part of the following fields:
- Renal System
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Question 29
Incorrect
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A 75-year-old male is referred to the memory clinic due to a gradual decline in his memory. Over the past five months, he has been struggling to recall the names of his loved ones and has been found disoriented and confused on multiple occasions. After an evaluation, the patient is prescribed medication to slow down the advancement of the illness.
What is the primary enzyme inhibited by the initial medication for the suspected condition?Your Answer:
Correct Answer: Cholinesterase
Explanation:Patients with Alzheimer’s dementia, which is the most prevalent type, experience a decrease in cholinergic neurons. To address this, acetylcholine inhibitors (AChEI) are prescribed to increase the amount of AChEI in the synaptic cleft, resulting in amplified effects at the postsynaptic receptor. Donepezil, galantamine, and rivastigmine are examples of AChEI inhibitors.
Donepezil is the primary recommendation for treating Alzheimer’s disease, while memantine, an NMDA receptor antagonist, is the secondary recommendation.
Management of Alzheimer’s Disease
Alzheimer’s disease is a type of dementia that progressively affects the brain and is the most common form of dementia in the UK. There are both non-pharmacological and pharmacological management options available for patients with Alzheimer’s disease.
Non-pharmacological management involves offering activities that promote wellbeing and are tailored to the patient’s preferences. Group cognitive stimulation therapy, group reminiscence therapy, and cognitive rehabilitation are some of the options that can be considered.
Pharmacological management options include acetylcholinesterase inhibitors such as donepezil, galantamine, and rivastigmine for managing mild to moderate Alzheimer’s disease. Memantine, an NMDA receptor antagonist, is a second-line treatment option that can be used for patients with moderate Alzheimer’s who are intolerant of or have a contraindication to acetylcholinesterase inhibitors. It can also be used as an add-on drug to acetylcholinesterase inhibitors for patients with moderate or severe Alzheimer’s or as monotherapy in severe Alzheimer’s.
When managing non-cognitive symptoms, NICE does not recommend the use of antidepressants for mild to moderate depression in patients with dementia. Antipsychotics should only be used for patients at risk of harming themselves or others or when the agitation, hallucinations, or delusions are causing them severe distress.
It is important to note that donepezil is relatively contraindicated in patients with bradycardia, and adverse effects may include insomnia. Proper management of Alzheimer’s disease can improve the quality of life for patients and their caregivers.
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This question is part of the following fields:
- Neurological System
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Question 30
Incorrect
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A 45-year-old woman presents with a lesion in the cerebellopontine angle. Which cranial nerve is expected to be affected initially?
Your Answer:
Correct Answer: CN V
Explanation:An acoustic neuroma is the most probable type of lesion to develop in the cerebellopontine angle. The trigeminal nerve is typically affected first, with a wide base of involvement. The initial symptoms may be subtle, such as the loss of the corneal reflex on the same side. Additionally, hearing loss on the same side is likely to occur. If left untreated, the lesion may progress and eventually impact multiple cranial nerve roots in the area.
Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.
In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.
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This question is part of the following fields:
- Neurological System
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Question 31
Incorrect
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Which cell in the lung tissue is responsible for producing surfactant?
Your Answer:
Correct Answer: Type II pneumocyte
Explanation:The Roles of Different Lung Cells
The lungs are composed of various types of cells that perform different functions. Type 2 pneumocytes produce surfactant, which is essential for preventing the collapse of air-filled alveoli. Alveolar macrophages, on the other hand, are responsible for recognizing and destroying pathogens that enter the lungs. Endothelial cells have diverse functions depending on their location, while goblet cells produce mucous in the lungs. Finally, type 1 pneumocytes are involved in gas exchange in the alveoli.
In summary, the lungs are a complex organ composed of different types of cells that work together to ensure proper respiratory function. Each cell type has a specific role, from producing surfactant to recognizing and destroying pathogens. the functions of these cells is crucial in maintaining healthy lungs and preventing respiratory diseases.
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This question is part of the following fields:
- Clinical Sciences
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Question 32
Incorrect
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A 31-year-old man visits an ophthalmology clinic with a complaint of experiencing double vision while descending stairs. He reports a recent mountain biking accident that required him to seek emergency medical attention. Although he has recuperated, he mentions that he sustained a severe frontal head injury after colliding with a tree.
During the examination, his left eye is raised and deviated medially, and he experiences vertical diplopia when looking up and down.
Which cranial nerve is most likely affected in this individual?Your Answer:
Correct Answer: Trochlear nerve
Explanation:Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.
In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.
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This question is part of the following fields:
- Neurological System
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Question 33
Incorrect
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In an anatomy practical class, how can you differentiate between the right and left lungs based on their anatomical characteristics?
Your Answer:
Correct Answer: Has oblique and horizontal fissures
Explanation:Anatomy of the Lungs
The lungs are a vital organ responsible for breathing and oxygen exchange in the body. The right lung is divided into three lobes, namely the upper, middle, and lower lobes, by oblique and horizontal fissures. The left lung, on the other hand, has only two lobes, the upper and lower lobes, with a lingular segment that serves as its equivalent of the middle lobe.
It is worth noting that the right bronchus is wider and shorter than the left bronchus. Additionally, each lung has two pulmonary veins that return blood to the heart. the anatomy of the lungs is crucial in diagnosing and treating respiratory diseases and disorders. Proper care and maintenance of the lungs are essential for overall health and well-being.
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This question is part of the following fields:
- Clinical Sciences
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Question 34
Incorrect
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A 50-year-old man with type 2 diabetes mellitus, who is currently on metformin, visits for his diabetic check-up. His blood sugar levels are not well-controlled and the doctor decides to prescribe gliclazide in addition to his current medication. During the consultation, the doctor discusses the potential side effects of sulfonylureas. What is a possible side effect of sulfonylureas?
Your Answer:
Correct Answer: Hypoglycaemia
Explanation:Hypoglycaemia is a significant adverse effect of sulfonylureas, including gliclazide, which stimulate insulin secretion from the pancreas. Patients taking sulfonylureas should be educated about the possibility of hypoglycaemia and instructed on how to manage it if it occurs. Acarbose commonly causes flatulence, while PPAR agonists (glitazones) can lead to fluid retention, and metformin may cause nausea and diarrhoea.
Sulfonylureas are a type of medication used to treat type 2 diabetes mellitus. They work by increasing the amount of insulin produced by the pancreas, but only if the beta cells in the pancreas are functioning properly. Sulfonylureas bind to a specific channel on the cell membrane of pancreatic beta cells, known as the ATP-dependent K+ channel (KATP).
While sulfonylureas can be effective in managing diabetes, they can also cause some adverse effects. The most common side effect is hypoglycemia, which is more likely to occur with long-acting preparations like chlorpropamide. Another common side effect is weight gain. However, there are also rarer side effects that can occur, such as hyponatremia (low sodium levels) due to inappropriate ADH secretion, bone marrow suppression, hepatotoxicity (liver damage), and peripheral neuropathy.
It is important to note that sulfonylureas should not be used during pregnancy or while breastfeeding.
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This question is part of the following fields:
- Endocrine System
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Question 35
Incorrect
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A 67-year-old man complains of back pain that has been progressively worsening over the past 2 months. He also reports experiencing nocturia, urinary urgency, and frequency. The possibility of malignancy is being considered.
What is the embryological origin of the primary cancer that is most likely causing these symptoms in this patient?Your Answer:
Correct Answer: Urogenital sinus
Explanation:The prostate gland originates from the urogenital sinus, which also gives rise to the bulbourethral glands in males and Bartholin and Skene glands in females. The patient in question is likely suffering from prostate cancer, which has a tendency to spread to the vertebrae. The urethral fold gives rise to the ventral shaft of the penis in males and the labia minora in females, while the genital tubercle gives rise to the glans penis, corpus cavernosum, and spongiosum in males and the glans clitoris and vestibular bulbs in females. Finally, the labioscrotal swelling gives rise to the scrotum in males and the labia majora in females.
Urogenital Embryology: Development of Kidneys and Genitals
During embryonic development, the urogenital system undergoes a series of changes that lead to the formation of the kidneys and genitals. The kidneys develop from the pronephros, which is rudimentary and non-functional, to the mesonephros, which functions as interim kidneys, and finally to the metanephros, which starts to function around the 9th to 10th week. The metanephros gives rise to the ureteric bud and the metanephrogenic blastema. The ureteric bud develops into the ureter, renal pelvis, collecting ducts, and calyces, while the metanephrogenic blastema gives rise to the glomerulus and renal tubules up to and including the distal convoluted tubule.
In males, the mesonephric duct (Wolffian duct) gives rise to the seminal vesicles, epididymis, ejaculatory duct, and ductus deferens. The paramesonephric duct (Mullerian duct) degenerates by default. In females, the paramesonephric duct gives rise to the fallopian tube, uterus, and upper third of the vagina. The urogenital sinus gives rise to the bulbourethral glands in males and Bartholin glands and Skene glands in females. The genital tubercle develops into the glans penis and clitoris, while the urogenital folds give rise to the ventral shaft of the penis and labia minora. The labioscrotal swelling develops into the scrotum in males and labia majora in females.
In summary, the development of the urogenital system is a complex process that involves the differentiation of various structures from different embryonic tissues. Understanding the embryology of the kidneys and genitals is important for diagnosing and treating congenital abnormalities and disorders of the urogenital system.
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This question is part of the following fields:
- General Principles
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Question 36
Incorrect
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In the majority of cases of transfusion reaction caused by Rh antibodies, what is the probable Rh grouping of the mother, father, and child?
Your Answer:
Correct Answer: The mother is Rh-negative, the father Rh-positive, and the baby Rh-positive
Explanation:Transfusion Reactions and the Role of Rh Factor
A transfusion reaction can occur when Rh-positive blood is given to a person who is Rh-negative and has been previously exposed to Rh-positive blood. This exposure can result in the development of anti-Rh antibodies, which can cause a reaction when Rh-positive blood is introduced into the body. In addition to transfusions, the Rh factor can also play a role in pregnancy. If a mother is Rh-negative and the father and baby are Rh-positive, there is a risk of a transfusion reaction occurring in the fetus or newborn, leading to a condition known as hemolytic disease of the fetus and newborn (HDFN). It is important to take preventative measures to avoid transfusion reactions and HDFN, such as ensuring blood compatibility and administering Rh immune globulin to Rh-negative mothers during pregnancy. the role of the Rh factor can help prevent these potentially dangerous reactions.
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This question is part of the following fields:
- Haematology And Oncology
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Question 37
Incorrect
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A 35-year-old woman presents to the Emergency Department with progressive weakness of her lower limbs. Her symptoms started three days previously when she noticed her legs felt heavy when rising from a seated position. This weakness has progressed to the point now where she is unable to stand unassisted and has now started to affect some of the muscles of her abdominal wall and lower back. She is otherwise well, apart from suffering a diarrhoeal illness 12 days previously. Neurological examination of the lower limbs identifies generalised weakness, reduced tone and absent reflexes; sensory examination is unremarkable.
Which of the following organisms is most likely to have caused this patient's diarrhoeal symptoms?Your Answer:
Correct Answer: Campylobacter jejuni
Explanation:The correct answer for the trigger of Guillain-Barre syndrome is Campylobacter jejuni. The patient’s symptoms of ascending muscle weakness without sensory signs and absent reflexes and reduced tone suggest a lower motor neuron lesion, which is likely due to GBS. GBS is an autoimmune-mediated demyelinating disease of the peripheral nervous system that is often triggered by an infection, with Campylobacter jejuni being the classic trigger. None of the other options are associated with GBS. Bacillus cereus can cause food poisoning from rice, resulting in vomiting and diarrhoea. Escherichia coli is common among travellers and can cause watery stools and abdominal cramps. Shigella can cause bloody diarrhoea with vomiting and abdominal pain.
Understanding Guillain-Barre Syndrome and Miller Fisher Syndrome
Guillain-Barre syndrome is a condition that affects the peripheral nervous system and is often triggered by an infection, particularly Campylobacter jejuni. The immune system attacks the myelin sheath that surrounds nerve fibers, leading to demyelination. This results in symptoms such as muscle weakness, tingling sensations, and paralysis.
The pathogenesis of Guillain-Barre syndrome involves the cross-reaction of antibodies with gangliosides in the peripheral nervous system. Studies have shown a correlation between the presence of anti-ganglioside antibodies, particularly anti-GM1 antibodies, and the clinical features of the syndrome. In fact, anti-GM1 antibodies are present in 25% of patients with Guillain-Barre syndrome.
Miller Fisher syndrome is a variant of Guillain-Barre syndrome that is characterized by ophthalmoplegia, areflexia, and ataxia. This syndrome typically presents as a descending paralysis, unlike other forms of Guillain-Barre syndrome that present as an ascending paralysis. The eye muscles are usually affected first in Miller Fisher syndrome. Studies have shown that anti-GQ1b antibodies are present in 90% of cases of Miller Fisher syndrome.
In summary, Guillain-Barre syndrome and Miller Fisher syndrome are conditions that affect the peripheral nervous system and are often triggered by infections. The pathogenesis of these syndromes involves the cross-reaction of antibodies with gangliosides in the peripheral nervous system. While Guillain-Barre syndrome is characterized by muscle weakness and paralysis, Miller Fisher syndrome is characterized by ophthalmoplegia, areflexia, and ataxia.
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This question is part of the following fields:
- Neurological System
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Question 38
Incorrect
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A teenage girl with suspected sensorineural hearing loss is being educated by her physician about the anatomy of the auditory system. The doctor informs her that there are three bones responsible for transmitting sound waves to the eardrum. Can you identify the correct sequence in which these bones are present?
Your Answer:
Correct Answer: Malleus, incus, stapes
Explanation:The order in which sound waves are transmitted to the oval window, the entrance to the inner ear, is through the bones known as malleus, incus, and stapes. The vestibulocochlear nerve plays a significant role in the process of sensorineural hearing.
Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.
In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.
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This question is part of the following fields:
- Neurological System
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Question 39
Incorrect
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A 50-year-old man comes to your clinic with complaints of chronic fatigue. He also reports experiencing decreased sensation and pins and needles in his arms and legs. During the physical examination, you notice that he appears very pale. The patient has difficulty sensing vibrations from a tuning fork and has reduced proprioception in his joints. Upon further inquiry, he reveals a history of coeliac disease but admits to poor adherence to the gluten-free diet.
What is the location of the spinal cord lesion?Your Answer:
Correct Answer: Dorsal cord lesion
Explanation:Lesions in the dorsal cord result in sensory deficits because the dorsal (posterior) horns contain the sensory input. The dorsal columns, responsible for fine touch sensation, proprioception, and vibration, are located in the dorsal/posterior horns. Therefore, a dorsal cord lesion would cause a pattern of sensory deficits. In this case, the patient’s B12 deficiency is due to malabsorption caused by poor adherence to a gluten-free diet. Long-term B12 deficiency leads to subacute combined degeneration of the spinal cord, which affects the dorsal columns and eventually the lateral columns, resulting in distal paraesthesia and upper motor neuron signs in the legs.
In contrast, an anterior cord lesion affects the anterolateral pathways (spinothalamic tract, spinoreticular tract, and spinomesencephalic tract), resulting in a loss of pain and temperature below the lesion, but vibration and proprioception are maintained. If the lesion is large, the corticospinal tracts are also affected, resulting in upper motor neuron signs below the lesion.
A central cord lesion involves damage to the spinothalamic tracts and the cervical cord, resulting in sensory and motor deficits that affect the upper limbs more than the lower limbs. A hemisection of the cord typically presents as Brown-Sequard syndrome.
A transverse cord lesion damages all motor and sensory pathways in the spinal cord, resulting in ipsilateral and contralateral sensory and motor deficits below the lesion.
The spinal cord is a central structure located within the vertebral column that provides it with structural support. It extends rostrally to the medulla oblongata of the brain and tapers caudally at the L1-2 level, where it is anchored to the first coccygeal vertebrae by the filum terminale. The cord is characterised by cervico-lumbar enlargements that correspond to the brachial and lumbar plexuses. It is incompletely divided into two symmetrical halves by a dorsal median sulcus and ventral median fissure, with grey matter surrounding a central canal that is continuous with the ventricular system of the CNS. Afferent fibres entering through the dorsal roots usually terminate near their point of entry but may travel for varying distances in Lissauer’s tract. The key point to remember is that the anatomy of the cord will dictate the clinical presentation in cases of injury, which can be caused by trauma, neoplasia, inflammatory diseases, vascular issues, or infection.
One important condition to remember is Brown-Sequard syndrome, which is caused by hemisection of the cord and produces ipsilateral loss of proprioception and upper motor neuron signs, as well as contralateral loss of pain and temperature sensation. Lesions below L1 tend to present with lower motor neuron signs. It is important to keep a clinical perspective in mind when revising CNS anatomy and to understand the ways in which the spinal cord can become injured, as this will help in diagnosing and treating patients with spinal cord injuries.
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This question is part of the following fields:
- Neurological System
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Question 40
Incorrect
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A 14-year-old boy is brought to the clinic by his mother due to concerns about his height compared to other boys his age. The boy also shares that he often receives comments about his appearance, with some likening him to a toy doll. What can be inferred about the pattern of hormone release that he may be lacking?
Your Answer:
Correct Answer: It is released in a pulsatile manner
Explanation:The doll-like appearance of the boy in his presentation suggests that he may be suffering from growth hormone deficiency, which can cause short stature, forehead prominence, and maxillary hypoplasia. The hypothalamus controls the release of growth hormone through the pulsatile release of growth hormone releasing hormone. Therefore, measuring GHRH levels is not a useful method for investigating growth hormone deficiency.
Understanding Growth Hormone and Its Functions
Growth hormone (GH) is a hormone produced by the somatotroph cells in the anterior pituitary gland. It plays a crucial role in postnatal growth and development, as well as in regulating protein, lipid, and carbohydrate metabolism. GH acts on a transmembrane receptor for growth factor, leading to receptor dimerization and direct or indirect effects on tissues via insulin-like growth factor 1 (IGF-1), which is primarily secreted by the liver.
GH secretion is regulated by various factors, including growth hormone releasing hormone (GHRH), fasting, exercise, and sleep. Conversely, glucose and somatostatin can decrease GH secretion. Disorders associated with GH include acromegaly, which results from excess GH, and GH deficiency, which can lead to short stature.
In summary, GH is a vital hormone that plays a significant role in growth and metabolism. Understanding its functions and regulation can help in the diagnosis and treatment of GH-related disorders.
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This question is part of the following fields:
- Endocrine System
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