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Question 1
Incorrect
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A 67-year-old man visits the Medical Assessment Unit with complaints of abdominal pain. He reports experiencing generalised, colicky abdominal pain for a few weeks. The patient has a medical history of angina, hypertension, and type 2 diabetes mellitus. His regular medications include atorvastatin, metformin, ramipril, sitagliptin, and verapamil. During abdominal examination, he displays tenderness in the left lower quadrant. An abdominal X-ray reveals faecal loading. Which medication is most likely responsible for his presentation?
Your Answer:
Correct Answer: Verapamil
Explanation:Verapamil is known to induce constipation, making it the correct answer. This is a common side effect of calcium channel blockers, including verapamil.
Ramipril and atorvastatin are not typically linked to changes in bowel movements, whereas sitagliptin and metformin are more commonly associated with diarrhea.
Calcium channel blockers are a class of drugs commonly used to treat cardiovascular disease. These drugs target voltage-gated calcium channels found in myocardial cells, cells of the conduction system, and vascular smooth muscle. The different types of calcium channel blockers have varying effects on these areas, making it important to differentiate their uses and actions.
Verapamil is used to treat angina, hypertension, and arrhythmias. It is highly negatively inotropic and should not be given with beta-blockers as it may cause heart block. Side effects include heart failure, constipation, hypotension, bradycardia, and flushing.
Diltiazem is used to treat angina and hypertension. It is less negatively inotropic than verapamil, but caution should still be exercised when patients have heart failure or are taking beta-blockers. Side effects include hypotension, bradycardia, heart failure, and ankle swelling.
Nifedipine, amlodipine, and felodipine are dihydropyridines used to treat hypertension, angina, and Raynaud’s. They affect peripheral vascular smooth muscle more than the myocardium, which means they do not worsen heart failure but may cause ankle swelling. Shorter acting dihydropyridines like nifedipine may cause peripheral vasodilation, resulting in reflex tachycardia. Side effects include flushing, headache, and ankle swelling.
According to current NICE guidelines, the management of hypertension involves a flow chart that takes into account various factors such as age, ethnicity, and comorbidities. Calcium channel blockers may be used as part of the treatment plan depending on the individual patient’s needs.
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This question is part of the following fields:
- General Principles
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Question 2
Incorrect
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A 23-year-old man presents to an after-hours medical clinic following his return from a backpacking trip in Southeast Asia. He complains of abdominal pain, diarrhoea, and healing sores on the soles of his feet. Additionally, he has developed a new and extremely itchy rash that began in the perianal area and has spread to his buttocks over the last two hours. His vital signs include a respiratory rate of 18 breaths per minute, a heart rate of 92 beats per minute, and a blood pressure of 124/86 mmHg. He is not running a fever. What is the probable pathogen responsible for this presentation?
Your Answer:
Correct Answer: Strongyloides stercoralis
Explanation: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 3
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 4
Incorrect
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A 56-year-old man with a history of alcohol excess and type 2 diabetes presents to the emergency department in an intoxicated state. He takes metformin and his recent HbA1c was 44 mmol/mol. On arrival, his blood sugar is 5.1 mmol/L and he frequently needs to urinate. The examination is unremarkable except for his intoxicated state. His blood test shows a creatinine level of 66 µmol/L (55 - 120). What is causing the patient's polyuria?
Your Answer:
Correct Answer: ADH suppression in the posterior pituitary gland
Explanation:Alcohol bingeing can result in the suppression of ADH in the posterior pituitary gland, leading to polyuria.
Polyuria, or excessive urination, can be caused by a variety of factors. A recent review in the BMJ categorizes these causes by their frequency of occurrence. The most common causes of polyuria include the use of diuretics, caffeine, and alcohol, as well as diabetes mellitus, lithium, and heart failure. Less common causes include hypercalcaemia and hyperthyroidism, while rare causes include chronic renal failure, primary polydipsia, and hypokalaemia. The least common cause of polyuria is diabetes insipidus, which occurs in less than 1 in 10,000 cases. It is important to note that while these frequencies may not align with exam questions, understanding the potential causes of polyuria can aid in diagnosis and treatment.
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This question is part of the following fields:
- Renal System
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Question 5
Incorrect
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A 55-year-old man is undergoing a series of tests, including an electrocardiogram (ECG). The results show an elevated QT interval. He has a history of well-managed type II diabetes and COPD, and is currently taking metformin and azithromycin. He smokes 10 cigarettes per day and consumes 15 units of alcohol per week. Based on his medical history, what is the probable cause of his abnormal ECG?
Your Answer:
Correct Answer: Taking azithromycin
Explanation:Azithromycin, a macrolide, is sometimes prescribed in low doses to reduce the frequency of infective exacerbation in COPD patients. However, it’s important to note that macrolides can cause QT prolongation, which is a known side effect. While chronic alcoholics may have a higher incidence of prolonged QT, this patient’s drinking habits do not suggest chronic alcohol abuse. COPD is not associated with QT prolongation, but it may cause signs of right ventricular or atrial hypertrophy due to increased pulmonary artery pressure (known as cor pulmonale). Smoking, on the other hand, does not cause QT prolongation, but it can increase heart rate and shorten the QT interval and ST segment. Finally, it’s worth noting that metformin is not associated with ECG changes, but it can cause lactic acidosis, which is a serious side effect.
Macrolides are a class of antibiotics that include erythromycin, clarithromycin, and azithromycin. They work by blocking translocation during bacterial protein synthesis, ultimately inhibiting bacterial growth. While they are generally considered bacteriostatic, their effectiveness can vary depending on the dose and type of organism being treated. Resistance to macrolides can occur through post-transcriptional methylation of the 23S bacterial ribosomal RNA.
However, macrolides can also have adverse effects. They may cause prolongation of the QT interval and gastrointestinal side-effects, such as nausea. Cholestatic jaundice is a potential risk, but using erythromycin stearate may reduce this risk. Additionally, macrolides are known to inhibit the cytochrome P450 isoenzyme CYP3A4, which metabolizes statins. Therefore, it is important to stop taking statins while on a course of macrolides to avoid the risk of myopathy and rhabdomyolysis. Azithromycin is also associated with hearing loss and tinnitus.
Overall, while macrolides can be effective antibiotics, they do come with potential risks and side-effects. It is important to weigh the benefits and risks before starting a course of treatment with these antibiotics.
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This question is part of the following fields:
- General Principles
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Question 6
Incorrect
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A 42-year-old male is currently undergoing investigation for thoracic outlet syndrome at the vascular clinic.
Can you identify the crucial structure that passes in front of the scalene tubercle on the first rib?Your Answer:
Correct Answer: Subclavian vein
Explanation:Anatomy of the Subclavian Vein, Artery, and Brachial Plexus
The subclavian vein, artery, and brachial plexus are important structures in the upper extremity. The subclavian vein passes over the first rib anterior to the scalene tubercle, while the subclavian artery and lowest trunk of the brachial plexus pass posteriorly. The middle scalene muscle, known as the scalenus medius, spreads toward the cervical vertebrae. The subclavian artery arises from the arch of the aorta laterally to the common carotids. The superior intercostal artery passes inferiorly and posteriorly between the first and second ribs. Finally, the sympathetic trunk is lateral to the vertebral bodies and runs the entire length of the vertebral column.
In summary, the subclavian vein, artery, and brachial plexus are located in close proximity to each other in the upper extremity. their anatomy is important for medical professionals who may need to access or treat these structures. The subclavian vein passes anteriorly over the first rib, while the subclavian artery and brachial plexus pass posteriorly. The scalenus medius muscle is located in the middle of the scalene muscles and spreads toward the cervical vertebrae. The subclavian artery arises from the arch of the aorta laterally to the common carotids, and the superior intercostal artery passes between the first and second ribs. Finally, the sympathetic trunk runs the entire length of the vertebral column and is located lateral to the vertebral bodies.
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This question is part of the following fields:
- Clinical Sciences
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Question 7
Incorrect
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A 45-year-old pig farmer presents to the GP with complaints of abdominal discomfort and diarrhoea. Upon initial investigations, the patient is diagnosed with a tapeworm infection. Which immunoglobulin plays a primary role in eliminating this organism?
Your Answer:
Correct Answer: IgE
Explanation:IgE provides protection against parasitic infections, particularly helminths, by providing immunity. It also triggers the release of histamine. IgA fights off various infections but not primarily parasites, and is found in saliva, tears, and breast milk. IgD plays a role in activating B cells. IgG protects against a range of pathogens and aids in the phagocytosis of viruses and bacteria. It is also involved in rhesus disease as it can cross the placenta.
Immunoglobulins, also known as antibodies, are proteins produced by the immune system to help fight off infections and diseases. There are five types of immunoglobulins found in the body, each with their own unique characteristics.
IgG is the most abundant type of immunoglobulin in blood serum and plays a crucial role in enhancing phagocytosis of bacteria and viruses. It also fixes complement and can be passed to the fetal circulation.
IgA is the most commonly produced immunoglobulin in the body and is found in the secretions of digestive, respiratory, and urogenital tracts and systems. It provides localized protection on mucous membranes and is transported across the interior of the cell via transcytosis.
IgM is the first immunoglobulin to be secreted in response to an infection and fixes complement, but does not pass to the fetal circulation. It is also responsible for producing anti-A, B blood antibodies.
IgD’s role in the immune system is largely unknown, but it is involved in the activation of B cells.
IgE is the least abundant type of immunoglobulin in blood serum and is responsible for mediating type 1 hypersensitivity reactions. It provides immunity to parasites such as helminths and binds to Fc receptors found on the surface of mast cells and basophils.
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This question is part of the following fields:
- General Principles
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Question 8
Incorrect
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A teenage boy starts preparing for the 400 m fun run in his neighborhood. At the beginning, he relies solely on anaerobic respiration. What is the drawback of using anaerobic respiration?
Your Answer:
Correct Answer: It is a low efficiency process for the production of energy
Explanation:Types of Energy Generation in Exercise
Energy generation during exercise can be categorized into four types. The first type is impulse energy, which is the energy already present in the cell as ATP. This energy is used quickly and anaerobically, and must be regenerated rapidly to allow for sustained exercise. The second type is immediate energy, which is an anaerobic process that allows for rapid regeneration of ATP by using the creatine phosphate buffer system. This system can supply 6-7 seconds of maximal activity and can be improved through training and creatine supplementation.
The third type of energy generation is short-term energy, which is ATP generated anaerobically through glycolysis. This process rapidly creates an ATP supply from existing fuel stores to produce pyruvate. However, if oxygen is unavailable, lactic acid is formed, and intracellular pH will fall, reducing enzyme function and interfering with muscle cell function. This process is also an inefficient way of producing energy from glucose, as much less ATP is generated compared to aerobic methods.
Finally, any form of physical activity that requires sustained exertion for minutes or hours requires oxygen for aerobic respiration, which is the fourth type of energy generation. ATP can be produced from glucose and free fatty acids through metabolism using oxygen via the Krebs’ cycle and electron transfer chain, which is a highly efficient means of producing ATP. Each molecule of glucose produces 38 molecules of ATP.
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This question is part of the following fields:
- Clinical Sciences
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Question 9
Incorrect
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A 43-year-old man presents to his doctor with complaints of struggling to use the twist throttle on his motorcycle with his right hand. He sustained a mid-shaft fracture of his right humerus in a car accident 10 weeks ago, which was successfully treated with surgery. What is the most frequent nerve injury resulting from this type of fracture?
Your Answer:
Correct Answer: Radial nerve injury
Explanation:The most common nerve injury that occurs with a mid-shaft fracture of the humerus is radial nerve injury. This type of injury can cause a dropped wrist presentation, which is characterized by weakness in wrist extension and difficulty making a fist. The patient in the scenario describes difficulty accelerating on their motorcycle, which requires normal wrist extension and the ability to make a fist.
Other nerve injuries that can occur include axillary nerve injury, which affects shoulder abduction and external rotation and is usually caused by anterior shoulder dislocation. Median nerve injury can result in weakness of forearm pronation, wrist flexion, and thumb flexion, and is associated with carpal tunnel syndrome. Musculocutaneous nerve injury, on the other hand, does not typically affect wrist movements and is responsible for elbow flexion and certain shoulder movements.
The humerus is a long bone that runs from the shoulder blade to the elbow joint. It is mostly covered by muscle but can be felt throughout its length. The head of the humerus is a smooth, rounded surface that connects to the body of the bone through the anatomical neck. The surgical neck, located below the head and tubercles, is the most common site of fracture. The greater and lesser tubercles are prominences on the upper end of the bone, with the supraspinatus and infraspinatus tendons inserted into the greater tubercle. The intertubercular groove runs between the two tubercles and holds the biceps tendon. The posterior surface of the body has a spiral groove for the radial nerve and brachial vessels. The lower end of the humerus is wide and flattened, with the trochlea, coronoid fossa, and olecranon fossa located on the distal edge. The medial epicondyle is prominent and has a sulcus for the ulnar nerve and collateral vessels.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 10
Incorrect
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An orthopaedic surgeon discusses the risk of a total hip replacement to Maria, an 80-year-old female with hip osteoarthritis, in order to gain consent. She is concerned about the risk of sciatic nerve damage.
What is a reliable landmark that can be used to identify the sciatic nerve and minimize the risk of damage during the surgery?Your Answer:
Correct Answer: Inferior to the piriformis muscle
Explanation:The sciatic nerve, which consists of nerve roots L4-S3, exits the body through the greater sciatic foramen located below the piriformis muscle. It does not provide any muscle innervation in the gluteal area, but instead travels to the back of the thigh where it branches out to supply the hamstring muscles (biceps femoris, semitendinosus, and semimembranosus) and adductor magnus. Thus, the key reference point is the lower edge of the piriformis muscle.
Understanding the Sciatic Nerve
The sciatic nerve is the largest nerve in the body, formed from the sacral plexus and arising from spinal nerves L4 to S3. It passes through the greater sciatic foramen and emerges beneath the piriformis muscle, running under the cover of the gluteus maximus muscle. The nerve provides cutaneous sensation to the skin of the foot and leg, as well as innervating the posterior thigh muscles and lower leg and foot muscles. Approximately halfway down the posterior thigh, the nerve splits into the tibial and common peroneal nerves. The tibial nerve supplies the flexor muscles, while the common peroneal nerve supplies the extensor and abductor muscles.
The sciatic nerve also has articular branches for the hip joint and muscular branches in the upper leg, including the semitendinosus, semimembranosus, biceps femoris, and part of the adductor magnus. Cutaneous sensation is provided to the posterior aspect of the thigh via cutaneous nerves, as well as the gluteal region and entire lower leg (except the medial aspect). The nerve terminates at the upper part of the popliteal fossa by dividing into the tibial and peroneal nerves. The nerve to the short head of the biceps femoris comes from the common peroneal part of the sciatic, while the other muscular branches arise from the tibial portion. The tibial nerve goes on to innervate all muscles of the foot except the extensor digitorum brevis, which is innervated by the common peroneal nerve.
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This question is part of the following fields:
- Neurological System
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Question 11
Incorrect
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A 32-year-old male visits the GP after a soccer injury. During the game, he received a blow to the lateral side of his left leg, causing valgus strain on the knee. The GP suspects an unhappy triad injury. What are the three injuries typically associated with this triad?
Your Answer:
Correct Answer: Damage to the medial collateral ligament, medial meniscus and anterior cruciate ligament
Explanation:The unhappy triad refers to a set of knee injuries that happen when the knee experiences a lateral impact causing Valgus stress. This stress leads to tears in the medial collateral ligament and the medial meniscus, which are closely connected. Additionally, the anterior cruciate ligament is also affected and traumatized. However, the lateral collateral ligament, lateral meniscus, and posterior cruciate ligament are not involved in this triad.
Knee Injuries and Common Causes
Knee injuries can be caused by a variety of factors, including twisting injuries, dashboard injuries, skiing accidents, and lateral blows to the knee. One common knee injury is the unhappy triad, which involves damage to the anterior cruciate ligament, medial collateral ligament, and meniscus. While the medial meniscus is classically associated with this injury, recent evidence suggests that the lateral meniscus is actually more commonly affected.
When the anterior cruciate ligament is damaged, it may be the result of twisting injuries. Tests such as the anterior drawer test and Lachman test may be positive if this ligament is damaged. On the other hand, dashboard injuries may cause damage to the posterior cruciate ligament. Damage to the medial collateral ligament is often caused by skiing accidents or valgus stress, and can result in abnormal passive abduction of the knee. Isolated injury to the lateral collateral ligament is uncommon.
Finally, damage to the menisci can also occur from twisting injuries. Common symptoms of meniscus damage include locking and giving way. Overall, understanding the common causes and symptoms of knee injuries can help individuals seek appropriate treatment and prevent further damage.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 12
Incorrect
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A 54-year-old man visits his GP with his son after experiencing a fall at home. He has a history of alcoholism and is currently being treated by the gastroenterology team.
In the past few days, he has been feeling increasingly unsteady on his feet and has fallen once, but denies any head injury. His son made the appointment as he has noticed his father becoming more forgetful over the past week.
During the examination, the patient exhibits reduced sensation in his lower legs and nystagmus when looking to the side.
What is the most probable underlying diagnosis responsible for his recent symptoms?Your Answer:
Correct Answer: Wernicke-Korsakoff syndrome
Explanation:The Importance of Vitamin B1 (Thiamine) in the Body
Vitamin B1, also known as thiamine, is a water-soluble vitamin that belongs to the B complex group. It plays a crucial role in the body as one of its phosphate derivatives, thiamine pyrophosphate (TPP), acts as a coenzyme in various enzymatic reactions. These reactions include the catabolism of sugars and amino acids, such as pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex, and branched-chain amino acid dehydrogenase complex.
Thiamine deficiency can lead to clinical consequences, particularly in highly aerobic tissues like the brain and heart. The brain can develop Wernicke-Korsakoff syndrome, which presents symptoms such as nystagmus, ophthalmoplegia, and ataxia. Meanwhile, the heart can develop wet beriberi, which causes dilated cardiomyopathy. Other conditions associated with thiamine deficiency include dry beriberi, which leads to peripheral neuropathy, and Korsakoff’s syndrome, which causes amnesia and confabulation.
The primary causes of thiamine deficiency are alcohol excess and malnutrition. Alcoholics are routinely recommended to take thiamine supplements to prevent deficiency. Overall, thiamine is an essential vitamin that plays a vital role in the body’s metabolic processes.
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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 premature baby is born and the anaesthetists are struggling to ventilate the lungs because of insufficient surfactant. How does Laplace's law explain the force pushing inwards on the walls of the alveolus caused by surface tension between two static fluids, such as air and water in the alveolus?
Your Answer:
Correct Answer: Inversely proportional to the radius of the alveolus
Explanation:The Relationship between Alveolar Size and Surface Tension in Respiratory Physiology
In respiratory physiology, the alveolus is often represented as a perfect sphere to apply Laplace’s law. According to this law, there is an inverse relationship between the size of the alveolus and the surface tension. This means that smaller alveoli experience greater force than larger alveoli for a given surface tension, and they will collapse first. This phenomenon explains why, when two balloons are attached together by their ends, the smaller balloon will empty into the bigger balloon.
In the lungs, this same principle applies to lung units, causing atelectasis and collapse when surfactant is not present. Surfactant is a substance that reduces surface tension, making it easier to expand the alveoli and preventing smaller alveoli from collapsing. Therefore, surfactant plays a crucial role in maintaining the proper functioning of the lungs and preventing respiratory distress. the relationship between alveolar size and surface tension is essential in respiratory physiology and can help in the development of treatments for lung diseases.
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This question is part of the following fields:
- Basic Sciences
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Question 14
Incorrect
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A 46-year-old homeless man is admitted to the emergency department due to intoxication. He reports experiencing progressive weakness in his lower limbs, as well as tingling and numbness in his hands. Additionally, he has been having issues with his memory and vision. Upon examination, there is generalised weakness and reduced proprioception and vibration sensation in the distal limbs, worse in the hands than the feet. Romberg's test is negative, but Babinski is positive. The patient's knee reflexes are brisk, and ankle jerks are absent. Based on this presentation, which spinal pathways are affected?
Your Answer:
Correct Answer: Dorsal column & lateral corticospinal tracts
Explanation:Subacute combined degeneration of the spinal cord (SACD) is characterized by the patchy loss of myelin, primarily affecting the ascending dorsal columns and descending lateral corticospinal tracts. This results in a range of symptoms, including progressive weakness, tingling, numbness, and upper motor neuron signs in the lower limbs. Vision changes and cognitive decline may also occur.
While the dorsal column is affected in SACD, the ascending anterior spinothalamic tract, which carries crude touch and pressure information, is typically not involved. Muscle weakness due to lateral corticospinal tract involvement is a hallmark of SACD.
The anterior spinocerebellar tract, which carries unconscious proprioceptive and cutaneous information from the lower body, is not typically affected in SACD. Similarly, the lateral spinothalamic tract, which carries pain and temperature information, is not commonly involved.
The reticulospinal and vestibulospinal tracts, which are primarily involved in locomotion, postural control, and changes in head orientation, are also not commonly affected in SACD.
Subacute Combined Degeneration of Spinal Cord
Subacute combined degeneration of spinal cord is a condition that occurs due to a deficiency of vitamin B12. The dorsal columns and lateral corticospinal tracts are affected, leading to the loss of joint position and vibration sense. The first symptoms are usually distal paraesthesia, followed by the development of upper motor neuron signs in the legs, such as extensor plantars, brisk knee reflexes, and absent ankle jerks. If left untreated, stiffness and weakness may persist.
This condition is a serious concern and requires prompt medical attention. It is important to maintain a healthy diet that includes sufficient amounts of vitamin B12 to prevent the development of subacute combined degeneration of spinal cord.
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This question is part of the following fields:
- Neurological System
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Question 15
Incorrect
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A pregnant woman in her late 20s has been admitted to the hospital with suspected pre-eclampsia.
Which electrolyte is effective in treating pre-eclampsia?Your Answer:
Correct Answer: Magnesium
Explanation:Hypermagnesaemia: Causes and Symptoms
Hypermagnesaemia is a condition that occurs when there is an excess of magnesium in the body. Although hypomagnesaemia is more common in hospital inpatients, certain situations can lead to hypermagnesaemia. These include renal impairment, rhabdomyolysis, excessive oral or intravenous magnesium intake, and excessive rectal magnesium intake.
One of the treatment options for pre-eclampsia is intravenous magnesium infusion, which can also lead to hypermagnesaemia if overdosed. The clinical features of hypermagnesaemia include neuromuscular depression, respiratory depression, nausea and vomiting, flushing, hypersomnia, hypotension, and cardiac arrest. It is important to monitor magnesium levels in patients who are at risk of hypermagnesaemia to prevent any adverse effects.
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This question is part of the following fields:
- Clinical Sciences
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Question 16
Incorrect
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A parent brings her 7-year-old child to the doctor with complaints of a stuffy nose and clear nasal discharge for the past 3 days. The doctor suspects acute coryza and recommends regular use of paracetamol. What is the viral agent most commonly associated with this condition?
Your Answer:
Correct Answer: Rhinovirus
Explanation:Rhinovirus is the cause of the common cold.
Respiratory Pathogens and Associated Conditions
Respiratory pathogens are microorganisms that cause infections in the respiratory system. The most common respiratory pathogens include respiratory syncytial virus, parainfluenza virus, rhinovirus, influenzae virus, Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus, Mycoplasma pneumoniae, Legionella pneumophilia, and Pneumocystis jiroveci. Each of these pathogens is associated with specific respiratory conditions, such as bronchiolitis, croup, common cold, flu, community-acquired pneumonia, acute epiglottitis, atypical pneumonia, and tuberculosis.
Flu-like symptoms are often the first sign of respiratory infections caused by these pathogens, followed by a dry cough. Complications may include haemolytic anaemia, erythema multiforme, lymphopenia, deranged liver function tests, and hyponatraemia. Patients with Pneumocystis jiroveci infections typically have few chest signs and develop exertional dyspnoea. Mycobacterium tuberculosis can cause a wide range of presentations, from asymptomatic to disseminated disease, and may be accompanied by cough, night sweats, and weight loss.
Overall, understanding the different respiratory pathogens and their associated conditions is crucial for proper diagnosis and treatment of respiratory infections.
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This question is part of the following fields:
- General Principles
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Question 17
Incorrect
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A 55-year-old man visits his GP complaining of excessive thirst and urination for the past two weeks. Upon conducting various tests, it was determined that he has diabetes insipidus due to a hormone deficiency. Which gland is responsible for producing and releasing this hormone into the bloodstream?
Your Answer:
Correct Answer: Posterior pituitary
Explanation:ADH and oxytocin are secreted by the posterior pituitary.
When a person has diabetes insipidus, their kidneys are unable to concentrate urine due to a deficiency of antidiuretic hormone (ADH) or resistance to its action. This results in the production and excretion of a large volume of diluted urine.
The posterior pituitary, also known as the neurohypophysis, is the back part of the pituitary gland and is involved in the endocrine system. Unlike the anterior pituitary, it is not glandular and has a direct neural connection to the hypothalamus. It releases oxytocin and vasopressin/ADH directly into the bloodstream.
The pituitary gland is a small gland located within the sella turcica in the sphenoid bone of the middle cranial fossa. It weighs approximately 0.5g and is covered by a dural fold. The gland is attached to the hypothalamus by the infundibulum and receives hormonal stimuli from the hypothalamus through the hypothalamo-pituitary portal system. The anterior pituitary, which develops from a depression in the wall of the pharynx known as Rathkes pouch, secretes hormones such as ACTH, TSH, FSH, LH, GH, and prolactin. GH and prolactin are secreted by acidophilic cells, while ACTH, TSH, FSH, and LH are secreted by basophilic cells. On the other hand, the posterior pituitary, which is derived from neuroectoderm, secretes ADH and oxytocin. Both hormones are produced in the hypothalamus before being transported by the hypothalamo-hypophyseal portal system.
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This question is part of the following fields:
- Neurological System
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Question 18
Incorrect
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A 35-year-old male patient arrives at the emergency department following a bicycle accident. He reports experiencing pain and swelling in his right hand and has difficulty moving his thumb. Upon examination, there is reduced range of motion of the thumb and palpable tenderness over the anatomical snuffbox. However, his hand is neurovascularly intact. Can you identify the structures that form the lateral border of this anatomical landmark?
Your Answer:
Correct Answer: Extensor pollicis brevis and abductor pollicis longus tendon
Explanation:The tendons of the extensor pollicis brevis and abductor pollicis longus form the lateral border of the anatomical snuffbox, not the muscles themselves. This patient’s pain and tenderness over the anatomical snuffbox suggest a likely scaphoid fracture, which is a common injury resulting from a fall on an outstretched hand. It is important to keep in mind the boundaries of the anatomical snuffbox, which include the tendons of the extensor pollicis longus, brevis, and abductor pollicis muscles. The proximal border is the styloid process of the radius, the distal border is the apex of the snuffbox triangle, and the floor is made up of the trapezium and scaphoid bones.
The Anatomical Snuffbox: A Triangle on the Wrist
The anatomical snuffbox is a triangular depression located on the lateral aspect of the wrist. It is bordered by tendons of the extensor pollicis longus, extensor pollicis brevis, and abductor pollicis longus muscles, as well as the styloid process of the radius. The floor of the snuffbox is formed by the trapezium and scaphoid bones. The apex of the triangle is located distally, while the posterior border is formed by the tendon of the extensor pollicis longus. The radial artery runs through the snuffbox, making it an important landmark for medical professionals.
In summary, the anatomical snuffbox is a small triangular area on the wrist that is bordered by tendons and bones. It is an important landmark for medical professionals due to the presence of the radial artery.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 19
Incorrect
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A 50-year-old man presents to the emergency department with a 24-hour history of left knee pain and swelling. He has difficulty bearing weight on the left leg and reports no recent trauma, fevers, or chills. The patient has also been experiencing constipation, excessive urination, and fatigue for several months. He has a history of passing a kidney stone with hydration. He does not take prescription medications or use tobacco, alcohol, or illicit drugs.
During examination, the patient's temperature is 37.2 ºC (98.9ºF) and blood pressure is 130/76 mmHg. The right knee is tender, erythematous, and swollen. Arthrocentesis reveals a white blood cell count of 30,000/mm3, with a predominance of neutrophils and numerous rhomboid-shaped crystals.
What substance is most likely the composition of the crystals?Your Answer:
Correct Answer: Calcium pyrophosphate
Explanation:The patient is experiencing acute inflammatory arthritis, which is likely caused by pseudogout. This condition occurs when calcium pyrophosphate dihydrate crystals are deposited in the synovial fluid, and it is often associated with chronic hypercalcemia resulting from primary hyperparathyroidism. Pseudogout typically affects the knee joint, and the presence of rhomboid-shaped calcium pyrophosphate crystals in the synovial fluid is diagnostic. Calcium hydroxyapatite crystals are typically found in tendons, while calcium oxalate is the most common component of renal calculi. Xanthomas refer to the deposition of cholesterol and other lipids in soft tissues, while gout is characterized by the deposition of monosodium urate in joints and soft tissues.
Understanding Pseudogout
Pseudogout, also known as acute calcium pyrophosphate crystal deposition disease, is a type of microcrystal synovitis that occurs when calcium pyrophosphate dihydrate crystals are deposited in the synovium. This condition is commonly associated with increasing age, but younger patients who develop pseudogout usually have an underlying risk factor such as haemochromatosis, hyperparathyroidism, low magnesium or phosphate levels, acromegaly, or Wilson’s disease.
The knee, wrist, and shoulders are the most commonly affected joints in pseudogout. Diagnosis is made through joint aspiration, which reveals weakly-positively birefringent rhomboid-shaped crystals, and x-rays, which show chondrocalcinosis. In the knee, linear calcifications of the meniscus and articular cartilage can be seen.
Management of pseudogout involves joint fluid aspiration to rule out septic arthritis, followed by treatment with NSAIDs or intra-articular, intra-muscular, or oral steroids, similar to the treatment for gout. Understanding the risk factors and symptoms of pseudogout can help with early diagnosis and effective management of this condition.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 20
Incorrect
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A 70-year-old man is undergoing investigation for small intestine cancer due to his history of Crohn's disease. An adenocarcinoma of his duodenum is detected through endoscopy and histology. The oncologist is now examining his previous abdominal CT scan to determine if there is any nodal involvement.
Which group of lymph nodes could potentially be affected in this scenario?Your Answer:
Correct Answer: Superior mesenteric lymph nodes
Explanation:The superior mesenteric lymph nodes are responsible for draining the duodenum, which is the second section of the gastrointestinal system. This lymphatic drainage is important for staging gastrointestinal cancers, and is similar to the blood supply of the gut. While the coeliac lymph nodes drain the first part of the gastrointestinal system, the inferior mesenteric lymph nodes drain the third part, and the internal iliac lymph nodes drain the lower part of the rectum and some of the anal canal. The para-aortic lymph nodes are not involved in the drainage of the gastrointestinal system, but instead drain the genito-urinary system. It is important to understand the correct lymphatic drainage patterns for accurate cancer staging.
Lymphatic drainage is the process by which lymphatic vessels carry lymph, a clear fluid containing white blood cells, away from tissues and organs and towards lymph nodes. The lymphatic vessels that drain the skin and follow venous drainage are called superficial lymphatic vessels, while those that drain internal organs and structures follow the arteries and are called deep lymphatic vessels. These vessels eventually lead to lymph nodes, which filter and remove harmful substances from the lymph before it is returned to the bloodstream.
The lymphatic system is divided into two main ducts: the right lymphatic duct and the thoracic duct. The right lymphatic duct drains the right side of the head and right arm, while the thoracic duct drains everything else. Both ducts eventually drain into the venous system.
Different areas of the body have specific primary lymph node drainage sites. For example, the superficial inguinal lymph nodes drain the anal canal below the pectinate line, perineum, skin of the thigh, penis, scrotum, and vagina. The deep inguinal lymph nodes drain the glans penis, while the para-aortic lymph nodes drain the testes, ovaries, kidney, and adrenal gland. The axillary lymph nodes drain the lateral breast and upper limb, while the internal iliac lymph nodes drain the anal canal above the pectinate line, lower part of the rectum, and pelvic structures including the cervix and inferior part of the uterus. The superior mesenteric lymph nodes drain the duodenum and jejunum, while the inferior mesenteric lymph nodes drain the descending colon, sigmoid colon, and upper part of the rectum. Finally, the coeliac lymph nodes drain the stomach.
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This question is part of the following fields:
- Haematology And Oncology
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Question 21
Incorrect
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A 6-year-old boy is referred to the child assessment unit for recurrent urinary tract infections. He is started on antibiotics and sent home with advice on supportive care.
Upon his return a week later, his renal function tests have worsened and an ultrasound scan reveals hydronephrosis in his kidneys, ureters, and bladder. The diagnosis is acute pyelonephritis and further investigations are ordered to determine the underlying cause. A voiding cystourethrogram (VCUG) confirms the diagnosis of posterior urethral valves (PUV).
The child and parents are informed of the diagnosis and inquire about treatment options. What is the definitive treatment for PUV?Your Answer:
Correct Answer: Endoscopic valvotomy
Explanation:The preferred and most effective treatment for a child with posterior urethral valves (PUV) is endoscopic valvotomy. While bilateral cutaneous ureterostomies can be used for urinary drainage, they are not considered the definitive treatment for PUV. Bladder augmentation may be necessary if the bladder cannot hold enough urine or if bladder pressures remain high despite medication and catheterization. However, permanent antibiotic prophylaxis and catheterization are not recommended.
Posterior urethral valves are a frequent cause of blockage in the lower urinary tract in males. They can be detected during prenatal ultrasound screenings. Due to the high pressure required for bladder emptying during fetal development, the child may experience damage to the renal parenchyma, resulting in renal impairment in 70% of boys upon diagnosis. Treatment involves the use of a bladder catheter, and endoscopic valvotomy is the preferred definitive treatment. Cystoscopic and renal follow-up is necessary.
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This question is part of the following fields:
- Renal System
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Question 22
Incorrect
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A 48-year-old female patient complains of pain in the right hypochondrium. Upon palpation of the abdomen, she experiences tenderness in the right upper quadrant and reports that the pain worsens during inspiration. Based on the history and examination, the probable diagnosis is cholecystitis caused by a gallstone. If the gallstone were to move out of the gallbladder, which of the ducts would it enter first?
Your Answer:
Correct Answer: Cystic duct
Explanation:The biliary tree is composed of various ducts, including the cystic duct that transports bile from the gallbladder. The right and left hepatic ducts in the liver merge to form the common hepatic duct, which then combines with the cystic duct to create the common bile duct. The pancreatic duct from the pancreas also connects to the common bile duct, and they both empty into the duodenum through the hepatopancreatic ampulla (of Vater). The accessory duct, which may or may not exist, is a small supplementary duct(s) to the biliary tree.
The gallbladder is a sac made of fibromuscular tissue that can hold up to 50 ml of fluid. Its lining is made up of columnar epithelium. The gallbladder is located in close proximity to various organs, including the liver, transverse colon, and the first part of the duodenum. It is covered by peritoneum and is situated between the right lobe and quadrate lobe of the liver. The gallbladder receives its arterial supply from the cystic artery, which is a branch of the right hepatic artery. Its venous drainage is directly to the liver, and its lymphatic drainage is through Lund’s node. The gallbladder is innervated by both sympathetic and parasympathetic nerves. The common bile duct originates from the confluence of the cystic and common hepatic ducts and is located in the hepatobiliary triangle, which is bordered by the common hepatic duct, cystic duct, and the inferior edge of the liver. The cystic artery is also found within this triangle.
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This question is part of the following fields:
- Gastrointestinal System
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Question 23
Incorrect
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A woman who is 16 weeks pregnant has visited her general practitioner complaining of pain during urination. She has no other symptoms and no significant medical or drug history. Upon conducting a urine dipstick test, the results show positive for nitrites and leukocytes. The general practitioner suspects a potential urinary tract infection and wants to prescribe antibiotics. What is the most suitable antibiotic to prescribe in this situation?
Your Answer:
Correct Answer: Nitrofurantoin
Explanation:Urinary tract infections (UTIs) are common in adults and can affect different parts of the urinary tract. Lower UTIs are more common and can be managed with antibiotics. For non-pregnant women, local antibiotic guidelines should be followed, and a urine culture should be sent if they are aged over 65 years or have visible or non-visible haematuria. Trimethoprim or nitrofurantoin for three days are recommended by NICE Clinical Knowledge Summaries. Pregnant women with symptoms should have a urine culture sent, and first-line treatment is nitrofurantoin, while amoxicillin or cefalexin can be used as second-line treatment. Asymptomatic bacteriuria in pregnant women should also be treated with antibiotics. Men with UTIs should be offered antibiotics for seven days, and a urine culture should be sent before starting treatment. Catheterised patients should not be treated for asymptomatic bacteria, but if they are symptomatic, a seven-day course of antibiotics should be given, and the catheter should be removed or changed if it has been in place for more than seven days. For patients with signs of acute pyelonephritis, hospital admission should be considered, and local antibiotic guidelines should be followed. The BNF recommends a broad-spectrum cephalosporin or a quinolone for 10-14 days for non-pregnant women.
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This question is part of the following fields:
- General Principles
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Question 24
Incorrect
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A 43-year-old woman visits the GP with her spouse. She reports experiencing dryness in her eyes for the past four months. You suspect that the gland responsible for tear production may be impaired.
What is the venous drainage of this gland?Your Answer:
Correct Answer: Superior ophthalmic vein
Explanation:The superior ophthalmic vein is where the lacrimal gland drains its venous blood. The lacrimal gland is a gland that produces tears in response to emotional events or conjunctival irritation. The submandibular gland drains its venous blood into the anterior facial vein, which is located deep to the marginal mandibular nerve. The basilic vein is one of the main pathways for venous drainage in the arm and hand, connecting to the palmar venous arch distally and the axillary vein proximally. The retromandibular vein is formed by the union of the maxillary vein and the superficial temporal vein, and it is the venous drainage of the parotid gland. The inferior mesenteric vein, along with the superior mesenteric vein, is responsible for draining the colon.
The Lacrimation Reflex
The lacrimation reflex is a response to conjunctival irritation or emotional events. When the conjunctiva is irritated, it sends signals via the ophthalmic nerve to the superior salivary center. From there, efferent signals pass via the greater petrosal nerve (parasympathetic preganglionic fibers) and the deep petrosal nerve (postganglionic sympathetic fibers) to the lacrimal apparatus. The parasympathetic fibers relay in the pterygopalatine ganglion, while the sympathetic fibers do not synapse.
This reflex is important for maintaining the health of the eye by keeping it moist and protecting it from foreign particles. It is also responsible for the tears that are shed during emotional events, such as crying. The lacrimal gland, which produces tears, is innervated by the secretomotor parasympathetic fibers from the pterygopalatine ganglion. The nasolacrimal duct, which carries tears from the eye to the nose, opens anteriorly in the inferior meatus of the nose. Overall, the lacrimal system plays a crucial role in maintaining the health and function of the eye.
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This question is part of the following fields:
- Neurological System
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Question 25
Incorrect
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A 2-year-old toddler presents to the emergency department with a low-grade fever and difficulty breathing. The mother reports that the toddler has had some nasal discharge for the past two days and started coughing a few hours ago. The toddler has no significant medical history, being born full term at 39 weeks via normal vaginal delivery. The toddler is developmentally normal and received all vaccinations according to the immunisation schedule. During examination, the toddler appears lethargic and has a barking cough. Auscultation reveals an inspiratory stridor bilaterally, with no crepitations or wheezes heard. Air entry is equal bilaterally. The toddler's temperature is 38.3ºC, oxygen saturation is 93% based on pulse oximetry, blood pressure is 98/55 mmHg (normal range: SBP 72-140 mmHg; DBP 37-56 mmHg), and the heart rate is 120 beats per minute (normal range: 100-190 beats per minute).
What is the most likely association with this toddler's condition?Your Answer:
Correct Answer: Steeple sign
Explanation:The infant is displaying symptoms of croup, including a barking cough and inspiratory stridor, which is typical for their age. While chest radiographs are not typically used to diagnose croup, if a neck radiograph is taken, the steeple sign may be present, indicating subglottic narrowing due to inflammation of the larynx and trachea.
The thumb sign, which is indicative of an oedematous epiglottis, is not present in this case, and the infant does not display symptoms of epiglottitis, such as drooling or dysphagia. Additionally, the infant is not in the typical age range for epiglottitis.
The sail sign, which suggests left lower lobe collapse, is not present as the infant has equal bilateral air entry. The coffee bean sign, which is suggestive of sigmoid volvulus, is also not relevant as it typically presents with abdominal pain and distension, rather than respiratory symptoms, and is uncommon in children.
Croup is a respiratory infection that affects young children, typically those between 6 months and 3 years old. It is most common in the autumn and is caused by parainfluenza viruses. The main symptom is stridor, which is caused by swelling and secretions in the larynx. Other symptoms include a barking cough, fever, and cold-like symptoms. The severity of croup can be graded based on the child’s symptoms, with mild cases having occasional coughing and no audible stridor at rest, and severe cases having frequent coughing, prominent stridor, and significant distress or lethargy. Children with moderate or severe croup should be admitted to the hospital, especially if they are under 6 months old or have other airway abnormalities. Diagnosis is usually made based on clinical symptoms, but a chest x-ray can show subglottic narrowing. Treatment typically involves a single dose of oral dexamethasone or prednisolone, and emergency treatment may include high-flow oxygen or nebulized adrenaline.
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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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What is the primary location for haematopoiesis during the first and second trimesters of foetal development?
Your Answer:
Correct Answer: Liver
Explanation:The Development of Haematopoiesis in the Foetus
The development of haematopoiesis in the foetus is a complex process that involves several organs. Initially, the yolk sac is the primary site of haematopoiesis until around two months gestation when the liver takes over. The liver remains the most important site of haematopoiesis until about month seven when the bone marrow becomes the predominant site throughout life.
After the age of 20, haematopoiesis occurs mainly in the proximal bones, with production in the distal lone bones decreasing. However, in certain disease states such as β-thalassaemia, haematopoiesis can occur outside of the bone marrow, known as extra-medullary haematopoiesis. the development of haematopoiesis in the foetus is important for identifying potential abnormalities and diseases that may arise during this process.
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This question is part of the following fields:
- Haematology And Oncology
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Question 27
Incorrect
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A 32-year-old female patient complains of a disrupted menstrual cycle, decreased libido, and lactation despite never being pregnant. Upon blood testing, she is found to have elevated serum prolactin levels. Which medication is associated with causing hyperprolactinemia?
Your Answer:
Correct Answer: Cimetidine
Explanation:Hyperprolactinaemia in Women
Hyperprolactinaemia is a condition that affects women and is characterized by an excess of prolactin hormone in the body. This condition can present with various symptoms, including anovulatory infertility, reduced menstruation, production of breast milk, reduced libido, and vaginal dryness. The condition is caused by either disinhibition of the anterior pituitary or excess production due to a pituitary tumor. A serum prolactin concentration greater than 5000 mIU/L suggests a pituitary adenoma.
Moreover, hyperprolactinaemia can also be caused by certain prescription medications, including antihistamines, butyrophenones, cimetidine, methyldopa, metoclopramide, and phenothiazines. These medications are strongly associated with the condition and can lead to an increase in prolactin levels in the body.
It is important to understand the symptoms and causes of hyperprolactinaemia in women to seek appropriate medical attention and treatment. With proper diagnosis and management, women can effectively manage this condition and improve their quality of life.
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This question is part of the following fields:
- Pharmacology
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Question 28
Incorrect
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A 28-year-old presents to the hospital with severe wrist pain. He was playing basketball with his friends when he fell with his hand outstretched. On examination, there is significant tenderness at the anatomical snuffbox. Pain is elicited as the thumb is longitudinally compressed. His grip strength is also diminished.
A posteroanterior and lateral x-ray of the wrist joint is performed which gives inconclusive results. The patient's wrist is immobilized with a splint and he is advised an MRI in a week’s time for further evaluation.
The patient inquires about possible complications and the doctor expresses concern that if the blood supply is interrupted, the bone tissue may be compromised.
Which of the following structures is most likely to be responsible for this complication?Your Answer:
Correct Answer: Dorsal carpal branch of radial artery
Explanation:The primary neurovascular structure that can be affected by a scaphoid fracture is the dorsal carpal branch of the radial artery. This artery is responsible for supplying blood to the scaphoid bone, and a fracture can lead to a high risk of avascular necrosis in the proximal pole of the bone. Symptoms of a scaphoid fracture include tenderness in the anatomical snuffbox, pain when compressing the thumb longitudinally, and a loss of grip strength. While an X-ray may not provide a conclusive diagnosis, further imaging studies can confirm the presence of an occult fracture.
The other answer choices are incorrect. The common digital arteries originate from the superficial palmar arch and supply the fingers. The deep palmar arch primarily supplies the thumb and index finger. The proper digital arteries arise from the common digital arteries and supply the fingers.
A scaphoid fracture is a type of wrist fracture that usually occurs when a person falls onto an outstretched hand or during contact sports. It is important to identify scaphoid fractures as they can lead to avascular necrosis due to the unusual blood supply of the scaphoid bone. Patients with scaphoid fractures typically experience pain along the radial aspect of the wrist and loss of grip or pinch strength. Clinical examination involves checking for tenderness over the anatomical snuffbox, wrist joint effusion, pain on telescoping of the thumb, tenderness of the scaphoid tubercle, and pain on ulnar deviation of the wrist. Plain film radiographs and scaphoid views are used to diagnose scaphoid fractures, but MRI is considered the definitive investigation. Initial management involves immobilization with a splint or backslab and referral to orthopaedics. Orthopaedic management depends on the type of fracture, with undisplaced fractures typically treated with a cast and displaced fractures requiring surgical fixation. Complications of scaphoid fractures include non-union and avascular necrosis.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 29
Incorrect
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A 48-year-old patient attends the diabetic clinic with an HbA1c of 58mmol/mol. Despite his efforts to lose weight, his blood sugar levels remain high. You adjust his metformin dosage and schedule a follow-up appointment in 4 months. During the consultation, he confides in you about his difficulty in achieving and maintaining an erection, which has caused strain in his relationship. To address this issue, you prescribe a course of sildenafil. How does sildenafil improve erectile function?
Your Answer:
Correct Answer: Increased penile blood due to vasodilation through an increase in cGMP
Explanation:PDE 5 inhibitors, such as sildenafil, promote vasodilation by elevating the levels of cGMP. Sildenafil works by inhibiting the cGMP-specific phosphodiesterase type 5 (PDE5) enzyme, which is responsible for breaking down cGMP in the corpus cavernosum surrounding the penis. Sexual stimulation triggers the release of nitric oxide (NO) from nerve terminals and endothelial cells, leading to the synthesis of cGMP in smooth muscle cells. This results in the relaxation of penile arteries and corpus cavernosal smooth muscle, leading to increased blood flow and penile erection. By enhancing the amount of cGMP, sildenafil improves erectile function. This is achieved by reducing intracellular calcium concentration, which causes smooth muscle relaxation. The other options are incorrect because vasoconstriction, corpus cavernosal smooth muscle contraction, and increased intracellular calcium concentration would worsen erectile dysfunction.
Phosphodiesterase type V inhibitors are medications used to treat erectile dysfunction and pulmonary hypertension. They work by increasing cGMP, which leads to relaxation of smooth muscles in blood vessels supplying the corpus cavernosum. The most well-known PDE5 inhibitor is sildenafil, also known as Viagra, which is taken about an hour before sexual activity. Other examples include tadalafil (Cialis) and vardenafil (Levitra), which have longer-lasting effects and can be taken regularly. However, these medications have contraindications, such as not being safe for patients taking nitrates or those with hypotension. They can also cause side effects such as visual disturbances, blue discolouration, and headaches. It is important to consult with a healthcare provider before taking PDE5 inhibitors.
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This question is part of the following fields:
- General Principles
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Question 30
Incorrect
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A 72-year-old woman visits her doctor complaining of painful legs, particularly in her thighs, which occur after walking and subside on rest. She occasionally takes paracetamol to alleviate the pain. Her medical history includes hyperlipidaemia, type II diabetes mellitus, hypertension, and depression. The physician suspects that her pain may be due to claudication of the femoral artery, which is a continuation of the external iliac artery. Can you correctly identify the anatomical landmark where the external iliac artery becomes the femoral artery?
Your Answer:
Correct Answer: Inguinal ligament
Explanation:After passing the inguinal ligament, the external iliac artery transforms into the femoral artery. This means that the other options provided are not accurate. Here is a brief explanation of their anatomical importance:
– The medial edge of the sartorius muscle creates the lateral wall of the femoral triangle.
– The medial edge of the adductor longus muscle creates the medial wall of the femoral triangle.
– The femoral vein creates the lateral border of the femoral canal.
– The pectineus muscle creates the posterior border of the femoral canal.The inguinal canal is located above the inguinal ligament and measures 4 cm in length. Its superficial ring is situated in front of the pubic tubercle, while the deep ring is found about 1.5-2 cm above the halfway point between the anterior superior iliac spine and the pubic tubercle. The canal is bounded by the external oblique aponeurosis, inguinal ligament, lacunar ligament, internal oblique, transversus abdominis, external ring, and conjoint tendon. In males, the canal contains the spermatic cord and ilioinguinal nerve, while in females, it houses the round ligament of the uterus and ilioinguinal nerve.
The boundaries of Hesselbach’s triangle, which are frequently tested, are located in the inguinal region. Additionally, the inguinal canal is closely related to the vessels of the lower limb, which should be taken into account when repairing hernial defects in this area.
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This question is part of the following fields:
- Gastrointestinal System
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