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Question 1
Incorrect
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A psychology student conducts a study examining the relationship between age and the level of anxiety in individuals. She found that there was not a significant difference in anxiety levels between age groups, however, there was a widespread away from the mean anxiety level in all age groups.
What term is used to define the measurement of this spread of results?Your Answer: Standard error
Correct Answer: Variance
Explanation:Understanding Variance as a Measure of Spread
Variance is a statistical measure that helps to determine how far apart a set of scores is from the mean. It is calculated by taking the square of the standard deviation. In other words, variance is a way to quantify the amount of variability or spread in a data set. It is a useful tool in many fields, including finance, engineering, and science, as it can help to identify patterns and trends in data. By understanding variance, researchers and analysts can gain insights into the distribution of data and make more informed decisions based on their findings. Overall, variance is an important concept to grasp for anyone working with data, as it provides a way to measure the degree of variability in a set of scores.
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This question is part of the following fields:
- General Principles
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Question 2
Correct
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A 43-year-old woman comes to your clinic complaining of unexplained weight gain, cold intolerance, and fatigue. You suspect hypothyroidism and decide to conduct a test on her serum levels of thyroid stimulating hormone (TSH) and free thyroxine (T4). The release of thyroid hormone is regulated through a negative feedback mechanism. Which of the following is not regulated through a negative feedback mechanism?
Your Answer: Clotting cascade
Explanation:The clotting cascade is an example of a positive feedback mechanism, where the presence of clotting factors attracts further clotting factors until a functioning clot is formed. On the other hand, blood sugar, blood pressure, and cortisol are controlled via negative feedback mechanisms. When blood sugar rises, insulin is released to transport glucose into cells, lowering blood sugar. When BP is low, the RAAS is activated to increase BP through vasoconstriction and retention of salt and water. Cortisol is released in response to ACTH, which is inhibited by high levels of cortisol through negative feedback on the hypothalamus and anterior pituitary.
The Coagulation Cascade: Two Pathways to Fibrin Formation
The coagulation cascade is a complex process that leads to the formation of a blood clot. There are two pathways that can lead to fibrin formation: the intrinsic pathway and the extrinsic pathway. The intrinsic pathway involves components that are already present in the blood and has a minor role in clotting. It is initiated by subendothelial damage, such as collagen, which leads to the formation of the primary complex on collagen by high-molecular-weight kininogen (HMWK), prekallikrein, and Factor 12. This complex activates Factor 11, which in turn activates Factor 9. Factor 9, along with its co-factor Factor 8a, forms the tenase complex, which activates Factor 10.
The extrinsic pathway, on the other hand, requires tissue factor released by damaged tissue. This pathway is initiated by tissue damage, which leads to the binding of Factor 7 to tissue factor. This complex activates Factor 9, which works with Factor 8 to activate Factor 10. Both pathways converge at the common pathway, where activated Factor 10 causes the conversion of prothrombin to thrombin. Thrombin hydrolyses fibrinogen peptide bonds to form fibrin and also activates factor 8 to form links between fibrin molecules.
Finally, fibrinolysis occurs, which is the process of clot resorption. Plasminogen is converted to plasmin to facilitate this process. It is important to note that certain factors are involved in both pathways, such as Factor 10, and that some factors are vitamin K dependent, such as Factors 2, 7, 9, and 10. The intrinsic pathway can be assessed by measuring the activated partial thromboplastin time (APTT), while the extrinsic pathway can be assessed by measuring the prothrombin time (PT).
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This question is part of the following fields:
- Haematology And Oncology
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Question 3
Incorrect
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A 6-year-old girl presents to the emergency department with her parents, who are concerned about her extremely swollen legs. The patient reports feeling fine and has no significant medical history.
Upon examination, there is pitting edema that extends to the lower abdominal wall. Laboratory tests confirm hypoalbuminemia.
A urine dipstick reveals ++++ proteinuria and no red blood cells.
What is the probable result of electron microscopy of a renal biopsy?Your Answer: Kimmelstiel-wilson lesions
Correct Answer: Effacement of podocyte foot processes
Explanation:Effacement of podocyte foot processes is observed in minimal change disease on electron microscopy, indicating fusion of podocytes. This condition is the most common cause of nephrotic syndrome in children, which is characterized by hypoalbuminemia, edema, and marked proteinuria. Although normal glomerular architecture may be observed in minimal change disease when viewed with a light microscope, electron microscopy is necessary to detect the effacement of podocyte foot processes. Kimmelstiel-Wilson lesions are not a feature of minimal change disease, as they are commonly observed in diabetic nephropathy. Similarly, mesangial cell proliferation is not a hallmark of minimal change disease, as it is typically observed in membranoproliferative glomerulonephritis, which presents as a nephritic syndrome and is not consistent with the patient’s symptoms. Overall, minimal change disease is typically responsive to steroid treatment and has a favorable prognosis.
Minimal change disease is a condition that typically presents as nephrotic syndrome, with children accounting for 75% of cases and adults accounting for 25%. While most cases are idiopathic, a cause can be found in around 10-20% of cases, such as drugs like NSAIDs and rifampicin, Hodgkin’s lymphoma, thymoma, or infectious mononucleosis. The pathophysiology of the disease involves T-cell and cytokine-mediated damage to the glomerular basement membrane, resulting in polyanion loss and a reduction of electrostatic charge, which increases glomerular permeability to serum albumin.
The features of minimal change disease include nephrotic syndrome, normotension (hypertension is rare), and highly selective proteinuria, where only intermediate-sized proteins like albumin and transferrin leak through the glomerulus. Renal biopsy shows normal glomeruli on light microscopy, while electron microscopy shows fusion of podocytes and effacement of foot processes.
Management of minimal change disease involves oral corticosteroids, which are effective in 80% of cases. For steroid-resistant cases, cyclophosphamide is the next step. The prognosis for the disease is generally good, although relapse is common. Roughly one-third of patients have just one episode, one-third have infrequent relapses, and one-third have frequent relapses that stop before adulthood.
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This question is part of the following fields:
- Renal System
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Question 4
Incorrect
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A father brings his 3-year-old child to the pediatrician with a 3-week history of perianal itching that is not improving. The father mentions that the itching seems to be more severe at night. He is worried because his older son, who shares a room with the affected child, has also started experiencing similar symptoms in the past few days.
What organism is most likely causing these symptoms?Your Answer: Taenia solium
Correct Answer: Enterobius vermicularis
Explanation:A 3-year-old child is experiencing perianal itching, especially at night, which may be caused by Enterobius vermicularis (pinworm). This condition is usually asymptomatic, but the itching can be bothersome. Diagnosis involves applying sticky tape to the perianal area and sending it to the lab for analysis.
Clonorchis sinensis infection is caused by eating undercooked fish and can lead to biliary tract obstruction, resulting in symptoms such as abdominal pain, nausea, and jaundice. It is also a risk factor for cholangiocarcinoma.
Echinococcus granulosus is a tapeworm that is commonly found in farmers who keep sheep. Dogs can become infected by ingesting hydatid cysts from sheep, and the eggs are then spread through their feces. Patients may not experience symptoms for a long time, but they may eventually develop abdominal discomfort and nausea. A liver ultrasound scan can reveal the presence of hepatic cysts.
Taenia solium is another type of tapeworm that is often transmitted through the consumption of undercooked pork. It can cause neurological symptoms and brain lesions that appear as a swiss cheese pattern on imaging.
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 5
Correct
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A 49-year-old man presents to a tertiary hospital with symptoms of fatigue, malaise, fever, and weight loss. He has a chronic cough with green sputum and reports emigrating from India to the UK 17 years ago. A Mantoux test is positive, and his two children are offered an interferon-gamma release assay to detect exposure. Which type of cell is responsible for releasing interferon-gamma as part of the immune response?
Your Answer: T Helper 1 cells (Th1 cells)
Explanation:Overview of Cytokines and Their Functions
Cytokines are signaling molecules that play a crucial role in the immune system. Interleukins are a type of cytokine that are produced by various immune cells and have specific functions. IL-1, produced by macrophages, induces acute inflammation and fever. IL-2, produced by Th1 cells, stimulates the growth and differentiation of T cell responses. IL-3, produced by activated T helper cells, stimulates the differentiation and proliferation of myeloid progenitor cells. IL-4, produced by Th2 cells, stimulates the proliferation and differentiation of B cells. IL-5, also produced by Th2 cells, stimulates the production of eosinophils. IL-6, produced by macrophages and Th2 cells, stimulates the differentiation of B cells and induces fever. IL-8, produced by macrophages, promotes neutrophil chemotaxis. IL-10, produced by Th2 cells, inhibits Th1 cytokine production and is known as an anti-inflammatory cytokine. IL-12, produced by dendritic cells, macrophages, and B cells, activates NK cells and stimulates the differentiation of naive T cells into Th1 cells.
In addition to interleukins, there are other cytokines with specific functions. Tumor necrosis factor-alpha, produced by macrophages, induces fever and promotes neutrophil chemotaxis. Interferon-gamma, produced by Th1 cells, activates macrophages. Understanding the functions of cytokines is important in developing treatments for various immune-related diseases.
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This question is part of the following fields:
- General Principles
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Question 6
Correct
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A patient visiting the neurology outpatient clinic presents with a motor deficit. The neurologist observes muscle fasciculations, flaccid weakness, and decreased reflexes.
What is the location of the lesion?Your Answer: Peripheral nerve
Explanation:A lower motor neuron lesion can be identified by a decrease in reflex response.
When a lower motor neuron lesion occurs, it can result in reduced tone, weakness, and muscle fasciculations. These neurons originate in the anterior horn of the spinal cord and connect with the neuromuscular junction.
On the other hand, if the corticospinal tract is affected in the motor cortex, internal capsule, midbrain, or medulla, it would cause an upper motor neuron pattern of weakness. This would be characterized by hypertonia, brisk reflexes, and an upgoing plantar reflex response.
Reflexes are automatic responses that our body makes in response to certain stimuli. These responses are controlled by the nervous system and do not require conscious thought. There are several common reflexes that are associated with specific roots in the spinal cord. For example, the ankle reflex is associated with the S1-S2 root, while the knee reflex is associated with the L3-L4 root. Similarly, the biceps reflex is associated with the C5-C6 root, and the triceps reflex is associated with the C7-C8 root. Understanding these reflexes can help healthcare professionals diagnose and treat certain conditions.
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This question is part of the following fields:
- Neurological System
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Question 7
Incorrect
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As part of your placement in a geriatric ward, you attend a pharmacology seminar on drug metabolism. During the presentation, your supervisor briefly mentions drugs that exhibit zero-order kinetics. Towards the end, he turns to you and asks you to name one such drug.
What is your response?Your Answer: Testosterone
Correct Answer: Heparin
Explanation:Heparin exhibits zero-order kinetics, which means that a constant amount of the drug is eliminated per unit time. This rate of elimination remains constant regardless of the total drug concentration in the plasma. Other drugs that commonly exhibit zero-order kinetics include phenytoin, ethanol, and salicylates.
Understanding Drug Metabolism: Phase I and Phase II Reactions
Drug metabolism involves two types of biochemical reactions, namely phase I and phase II reactions. Phase I reactions include oxidation, reduction, and hydrolysis, which are mainly performed by P450 enzymes. However, some drugs are metabolized by specific enzymes such as alcohol dehydrogenase and xanthine oxidase. The products of phase I reactions are typically more active and potentially toxic. On the other hand, phase II reactions involve conjugation, where glucuronyl, acetyl, methyl, sulphate, and other groups are typically involved. The products of phase II reactions are typically inactive and excreted in urine or bile. The majority of phase I and phase II reactions take place in the liver.
First-Pass Metabolism and Drugs Affected by Zero-Order Kinetics and Acetylator Status
First-pass metabolism is a phenomenon where the concentration of a drug is greatly reduced before it reaches the systemic circulation due to hepatic metabolism. This effect is seen in many drugs, including aspirin, isosorbide dinitrate, glyceryl trinitrate, lignocaine, propranolol, verapamil, isoprenaline, testosterone, and hydrocortisone.
Zero-order kinetics describe metabolism that is independent of the concentration of the reactant. This is due to metabolic pathways becoming saturated, resulting in a constant amount of drug being eliminated per unit time. Drugs exhibiting zero-order kinetics include phenytoin, salicylates (e.g. high-dose aspirin), heparin, and ethanol.
Acetylator status is also an important consideration in drug metabolism. Approximately 50% of the UK population are deficient in hepatic N-acetyltransferase. Drugs affected by acetylator status include isoniazid, procainamide, hydralazine, dapsone, and sulfasalazine. Understanding these concepts is important in predicting drug efficacy and toxicity, as well as in optimizing drug dosing.
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This question is part of the following fields:
- General Principles
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Question 8
Correct
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You are a final year medical student working in the emergency department. You have been asked to see a 25-year-old male presenting with a red, painful eye. He reports a gritty discomfort in his right eye which has been increasing in severity throughout the last day. He has no significant past medical history, although reports having a recent upper respiratory tract infection. He works as a plumber and has been on an active construction site for much of the day without eye protection.
On examination, the right eyelid appears swollen and mildly erythematous. There is a watery discharge from the eye. The conjunctiva is widely injected. The eye has a full range of movements and the pupil is equal and reactive to light. There is no reduction in visual acuity. There is a small dark corneal lesion with an orange halo at the 3-o'clock position with minor fluorescein uptake around its periphery.
What is the most likely cause for the presenting symptoms?Your Answer: Iron-containing corneal foreign body
Explanation:When someone presents with a red eye, it is often due to an ocular foreign body. If the foreign body contains iron, it may have a distinctive orange halo. Dendritic corneal ulcers, which have a characteristic shape visible with fluorescein staining, are caused by HSV-1 viruses from the herpesviridae family. It is important to avoid using topical steroids in these cases. Plant-based foreign bodies are more likely to cause infection than inert foreign bodies like plastic or glass, or oxidizing foreign bodies like iron. Viral conjunctivitis typically presents with bilateral, itchy, painful red eyes with watery discharge and small follicles on the tarsal conjunctiva. Acute angle closure crisis is a serious emergency that causes a painful, red eye with a poorly responsive pupil that is mid-dilated. Iron-containing foreign bodies begin to oxidize within six hours of contact with the corneal surface, leading to an orange ring of ferrous material that disperses into the superficial corneal layers and tear film surrounding the foreign body.
Corneal foreign body is a condition characterized by eye pain, foreign body sensation, photophobia, watering eye, and red eye. It is important to refer patients to ophthalmology if there is a suspected penetrating eye injury due to high-velocity injuries or sharp objects, significant orbital or peri-ocular trauma, or a chemical injury has occurred. Foreign bodies composed of organic material should also be referred to ophthalmology as they are associated with a higher risk of infection and complications. Additionally, foreign bodies in or near the centre of the cornea and any red flags such as severe pain, irregular pupils, or significant reduction in visual acuity should be referred to ophthalmology. For further information on management, please refer to Clinical Knowledge Summaries.
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This question is part of the following fields:
- Neurological System
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Question 9
Incorrect
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What is the primary location for haematopoiesis during the first and second trimesters of foetal development?
Your Answer: Yolk Sac
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 10
Correct
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At a routine appointment, a teenage girl is being educated by her GP about the ovarian cycle. The GP informs her that the theca of the pre-antral follicle has receptors for hormones that help in the production of significant amounts of hormones. What is the type of receptor present on the theca?
Your Answer: LH receptors
Explanation:LH binds to LH receptors on thecal cells, stimulating the production of androstenedione. This androgen is then converted into oestradiol by aromatase in the granulosa cells.
The process of follicle development can be divided into several stages. Primordial follicles contain an oocyte and granulosa cells. Primary follicles are characterized by the development of the zona pellucida and proliferation of granulosa cells. Pre-antral follicles develop a theca layer. Mature or Graafian follicles are marked by the presence of an antrum. Finally, the corpus luteum forms after the oocyte is released due to enzymatic breakdown of the follicular wall.
It is important to note that FSH, progesterone, testosterone, and oestrogen receptors are not involved in the production of oestradiol from androstenedione.
Anatomy of the Ovarian Follicle
The ovarian follicle is a complex structure that plays a crucial role in female reproductive function. It consists of several components, including granulosa cells, the zona pellucida, the theca, the antrum, and the cumulus oophorus.
Granulosa cells are responsible for producing oestradiol, which is essential for follicular development. Once the follicle becomes the corpus luteum, granulosa lutein cells produce progesterone, which is necessary for embryo implantation. The zona pellucida is a membrane that surrounds the oocyte and contains the protein ZP3, which is responsible for sperm binding.
The theca produces androstenedione, which is converted into oestradiol by granulosa cells. The antrum is a fluid-filled portion of the follicle that marks the transition of a primary oocyte into a secondary oocyte. Finally, the cumulus oophorus is a cluster of cells surrounding the oocyte that must be penetrated by spermatozoa for fertilisation to occur.
Understanding the anatomy of the ovarian follicle is essential for understanding female reproductive function and fertility. Each component plays a unique role in the development and maturation of the oocyte, as well as in the processes of fertilisation and implantation.
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This question is part of the following fields:
- Reproductive System
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Question 11
Correct
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Electrophysiology studies are being conducted in a young boy with suspected Wolff-Parkinson-White syndrome, who has experienced recurrent episodes of sudden palpitations. The procedure involves catheterization within the heart to evaluate the electrical activity and determine the conduction velocity of various parts of the conduction pathway.
Which segment of this pathway exhibits the highest conduction velocity?Your Answer: Purkinje fibres
Explanation:The Purkinje fibres have the fastest conduction velocities in the heart, at approximately 4m/sec, due to different connexins in their gap junctions. They allow depolarisation throughout the ventricular muscle. Atrial muscle conducts at around 0.5m/sec, the atrioventricular node conducts at a slow rate, and the Bundle of His conducts at 2m/sec, but not as rapidly as the 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 12
Correct
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A 65-year-old male with a diagnosis of lung cancer presents with fatigue and lightheadedness. Upon examination, the following results are obtained:
Plasma sodium concentration 115 mmol/L (137-144)
Potassium 3.5 mmol/L (3.5-4.9)
Urea 3.2 mmol/L (2.5-7.5)
Creatinine 67 µmol/L (60-110)
What is the probable reason for his symptoms based on these findings?Your Answer: Syndrome of inappropriate ADH secretion
Explanation:Syndrome of Inappropriate ADH Secretion
Syndrome of inappropriate ADH secretion (SIADH) is a condition characterized by low levels of sodium in the blood. This is caused by the overproduction of antidiuretic hormone (ADH) by the posterior pituitary gland. Tumors such as bronchial carcinoma can cause the ectopic elaboration of ADH, leading to dilutional hyponatremia. The diagnosis of SIADH is one of exclusion, but it can be supported by a high urine sodium concentration with high urine osmolality.
Hypoadrenalism is less likely to cause hyponatremia, as it is usually associated with hyperkalemia and mild hyperuricemia. On the other hand, diabetes insipidus is a condition where the kidneys are unable to reabsorb water, leading to excessive thirst and urination.
It is important to diagnose and treat SIADH promptly to prevent complications such as seizures, coma, and even death. Treatment options include fluid restriction, medications to block the effects of ADH, and addressing the underlying cause of the condition.
In conclusion, SIADH is a condition that can cause low levels of sodium in the blood due to the overproduction of ADH. It is important to differentiate it from other conditions that can cause hyponatremia and to treat it promptly to prevent complications.
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This question is part of the following fields:
- Respiratory System
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Question 13
Correct
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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: 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 14
Correct
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A woman in her 30s experiences sudden swelling in both legs during pregnancy. Her mother and aunt also had a history of this issue. What is the probable underlying abnormality?
Your Answer: Anti cardiolipin antibodies
Explanation:Antiphospholipid syndrome is a condition where the body’s immune system produces antibodies that cause blood clots and pregnancy-related complications. The diagnosis requires one clinical event and two positive blood tests spaced at least 3 months apart. The antibodies associated with this syndrome are lupus anticoagulant, anti-cardiolipin, and anti-β2-glycoprotein. Antiphospholipid syndrome can be primary or secondary, with the latter occurring in conjunction with other autoimmune diseases. In severe cases, the condition can lead to organ failure, known as catastrophic antiphospholipid syndrome. Treatment typically involves anticoagulant medication such as heparin, while warfarin is avoided during pregnancy due to its teratogenic effects.
Hypercoagulability is a condition where the blood has an increased tendency to clot. There are several types of thrombophilia, each with their own unique features. Antithrombin deficiency is a rare genetic defect that increases the risk of thrombotic events by 10 times. Heparin may not be effective in treating this condition as it works via antithrombin. Protein C and S deficiency, which accounts for up to 5% of thrombotic episodes, occurs when there is a lack of natural anticoagulants that are produced by the liver. Factor V Leiden is the most common genetic defect accounting for deep vein thrombosis (DVT) and may account for up to 20% or more of thrombotic episodes. Antiphospholipid syndrome is a multi-organ disease that can involve pregnancy and cause both arterial and venous thrombosis. It is characterized by either Lupus anticoagulant or Anti cardiolipin antibodies, and requires anticoagulation with an INR between 3 and 4.
In summary, hypercoagulability is a condition where the blood has an increased tendency to clot. There are several types of thrombophilia, each with their own unique features. Antithrombin deficiency, protein C and S deficiency, factor V Leiden, and antiphospholipid syndrome are some of the most common types of thrombophilia. It is important to identify and treat these conditions to prevent thrombotic events.
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This question is part of the following fields:
- Haematology And Oncology
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Question 15
Incorrect
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A 70-year-old-man arrives at the emergency department with dysphasia, right-sided neglect, and right-sided weakness. He has a medical history of hypertension, hypercholesterolemia, type two diabetes mellitus, and a 20-pack-year smoking history. His symptoms began 55 minutes ago.
Which part of the brain is likely affected by this stroke based on the presented symptoms?Your Answer: Smaller arteries of anterior circulation e.g. upper or lower division of middle cerebral artery
Correct Answer: Middle and anterior cerebral arteries
Explanation:A total anterior circulation infarct affects the middle and anterior cerebral arteries, which is the correct answer (option 1). Option 2 is only true for a partial anterior circulation infarct, while option 3 is true for a lacunar infarct. Option 4 is true for a posterior circulation infarct, and option 5 would result in quadriplegia and lock-in-syndrome.
Stroke: A Brief Overview
Stroke is a significant cause of morbidity and mortality, with over 150,000 strokes occurring annually in the UK alone. It is the fourth leading cause of death in the UK, killing twice as many women as breast cancer each year. However, the prevention and treatment of strokes have undergone significant changes over the past decade. What was once considered an untreatable condition is now viewed as a ‘brain attack’ that requires emergency assessment to determine if patients may benefit from new treatments such as thrombolysis.
A stroke, also known as a cerebrovascular accident (CVA), is a sudden interruption in the vascular supply of the brain. There are two main types of strokes: ischaemic and haemorrhagic. Ischaemic strokes occur when there is a blockage in the blood vessel that stops blood flow, while haemorrhagic strokes occur when a blood vessel bursts, leading to a reduction in blood flow. Symptoms of a stroke may include motor weakness, speech problems, swallowing problems, visual field defects, and balance problems.
Patients with suspected stroke need to have emergency neuroimaging to determine if they are suitable for thrombolytic therapy to treat early ischaemic strokes. The two types of neuroimaging used in this setting are CT and MRI. If the stroke is ischaemic, and certain criteria are met, the patient should be offered thrombolysis. Once haemorrhagic stroke has been excluded, patients should be given aspirin 300mg as soon as possible, and antiplatelet therapy should be continued. If imaging confirms a haemorrhagic stroke, neurosurgical consultation should be considered for advice on further management. The vast majority of patients, however, are not suitable for surgical intervention. Management is therefore supportive as per haemorrhagic stroke.
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This question is part of the following fields:
- Neurological System
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Question 16
Correct
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These thyroid function tests were obtained on a 55-year-old female who has recently been treated for hypertension:
Free T4 28.5 pmol/L (9.8-23.1)
TSH <0.02 mU/L (0.35-5.5)
Free T3 10.8 pmol/L (3.5-6.5)
She now presents with typical symptoms of hyperthyroidism.
Which medication is likely to have caused this?Your Answer: Amiodarone
Explanation:Amiodarone and its Effects on Thyroid Function
Amiodarone is a medication that can have an impact on thyroid function, resulting in both hypo- and hyperthyroidism. This is due to the high iodine content in the drug, which contributes to its antiarrhythmic effects. Atenolol, on the other hand, is a beta blocker that is commonly used to treat thyrotoxicosis. Warfarin is another medication that is used to treat atrial fibrillation.
There are two types of thyrotoxicosis that can be caused by amiodarone. Type 1 results in excess thyroxine synthesis, while type 2 leads to the release of excess thyroxine but normal levels of synthesis. It is important for healthcare professionals to monitor thyroid function in patients taking amiodarone and adjust treatment as necessary to prevent complications.
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This question is part of the following fields:
- Cardiovascular System
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Question 17
Correct
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A 20-year old woman arrives at the Emergency department after a night out with her friends. According to her friends, she has been talking to herself about nonsensical things and appears agitated and restless. During the examination, it is noted that her reflexes are heightened and an electrocardiogram (ECG) reveals ventricular ectopics. What type of substance abuse is suspected in this case?
Your Answer: Ecstasy
Explanation:Ecstasy Overdose
Ecstasy, also known as MDMA, is a drug that stimulates the central nervous system. It can cause increased alertness, euphoria, extroverted behavior, and rapid speech. People who take ecstasy may also experience a lack of desire to eat or sleep, tremors, dilated pupils, tachycardia, and hypertension. However, more severe intoxication can lead to excitability, agitation, paranoid delusions, hallucinations, hypertonia, and hyperreflexia. In some cases, convulsions, rhabdomyolysis, hyperthermia, and cardiac arrhythmias may also develop.
Severe cases of MDMA poisoning can result in hyperthermia, disseminated intravascular coagulation, rhabdomyolysis, acute renal failure, hyponatremia, and even hepatic damage. In rare cases, amphetamine poisoning may lead to intracerebral and subarachnoid hemorrhage and acute cardiomyopathy, which can be fatal. Chronic amphetamine users may also experience hyperthyroxinemia.
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This question is part of the following fields:
- Pharmacology
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Question 18
Correct
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What stage of cellular respiration is responsible for the production of pyruvic acid?
Your Answer: Glycolysis
Explanation:The Versatility of Pyruvic Acid in Cellular Metabolism
Pyruvic acid is a simple alpha-keto acid that plays a crucial role in several metabolic pathways within the cell. It serves as a central intersection where different pathways converge and diverge. One of the primary ways pyruvic acid is produced is through glycolysis, where glucose is broken down into pyruvic acid. Depending on the cell’s needs, pyruvic acid can be converted back into glucose through gluconeogenesis or used to synthesize fatty acids through the acetyl-CoA pathway. Additionally, pyruvic acid can be used to produce the amino acid alanine.
Pyruvic acid is also involved in respiration, where it enters the Krebs cycle under aerobic conditions. This cycle produces energy in the form of ATP, which is used by the cell for various functions. Under anaerobic conditions, pyruvic acid can ferment into lactic acid, which is used by some organisms as a source of energy.
In summary, pyruvic acid is a versatile molecule that plays a critical role in cellular metabolism. Its ability to be converted into different molecules depending on the cell’s needs makes it an essential component of many metabolic pathways.
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This question is part of the following fields:
- Basic Sciences
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Question 19
Correct
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A 35-year-old man is stabbed in the right chest and requires a thoracotomy. During the procedure, the right lung is mobilized and the pleural reflection at the lung hilum is opened. Which of the following structures is not located in this area?
Your Answer: Azygos vein
Explanation:The pulmonary ligament extends from the pleural reflections surrounding the hilum of the lung and covers the pulmonary vessels and bronchus. However, it does not contain the azygos vein.
Anatomy of the Lungs
The lungs are a pair of organs located in the chest cavity that play a vital role in respiration. The right lung is composed of three lobes, while the left lung has two lobes. The apex of both lungs is approximately 4 cm superior to the sternocostal joint of the first rib. The base of the lungs is in contact with the diaphragm, while the costal surface corresponds to the cavity of the chest. The mediastinal surface contacts the mediastinal pleura and has the cardiac impression. The hilum is a triangular depression above and behind the concavity, where the structures that form the root of the lung enter and leave the viscus. The right main bronchus is shorter, wider, and more vertical than the left main bronchus. The inferior borders of both lungs are at the 6th rib in the mid clavicular line, 8th rib in the mid axillary line, and 10th rib posteriorly. The pleura runs two ribs lower than the corresponding lung level. The bronchopulmonary segments of the lungs are divided into ten segments, each with a specific function.
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This question is part of the following fields:
- Respiratory System
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Question 20
Correct
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As a GP, you are approached by a 16-year-old girl named Lily who has a family history of breast cancer and is concerned about her own risk. Her mother carries the BRCA1 gene and has undergone a prophylactic mastectomy. Lily is requesting to be tested for the gene, but you have never encountered a case where a patient under 18 years has requested BRCA1 genetic testing before. You are unsure about the appropriateness of offering the test to someone so young, but Lily and her mother are insistent. What is the next best course of action?
Your Answer: Discuss the pros and cons of testing and implications for treatment with both Chloe and her mother. If you decide that she is competent to decide about testing then provide written information and additional materials to help them consider the matter further. Advise them that you would like further advice from the genetics and breast teams before you all make a final decision about whether to test.
Explanation:Balancing Autonomy and Medical Professionalism in Genetic Testing
In cases where a patient requests genetic testing, medical professionals must balance the patient’s autonomy with their own duty to act in the patient’s best interests. This is particularly important when dealing with minors, as they may not fully understand the implications of a positive test result. In such cases, it is important to consider the psychological impact of testing and whether it is appropriate to provide the test at this time.
As a medical professional, it is important to take the patient’s request seriously and not dismiss it or leave it to others to decide. However, it is also important to assess the patient’s capacity to make decisions and to consider whether testing is truly in their best interests. If necessary, seeking expert help in counseling the patient and their family can be beneficial.
Ultimately, medical professionals must balance the patient’s autonomy with their own duty to act in the patient’s best interests. This may mean declining to provide a test if it is not appropriate or if the patient lacks the capacity to fully understand the implications of a positive result. By carefully considering these factors, medical professionals can ensure that they are providing the best possible care to their patients.
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This question is part of the following fields:
- Ethics And Law
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Question 21
Correct
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A 55-year-old man is undergoing investigation for anemia. What is the typical pairing of globin chains that can be found in a healthy adult?
Your Answer: α2β2
Explanation:Oxygen Transport and Factors Affecting Haemoglobin Saturation
Oxygen transport in the body is mainly carried out by erythrocytes, with only 1% of oxygen being transported as a solution due to its limited solubility. The amount of oxygen transported depends on the concentration of haemoglobin and its degree of saturation. Haemoglobin is a globular protein composed of four subunits, with two alpha and two beta subunits forming globin. Haem, which surrounds an iron atom in its ferrous state, can form two additional bonds with oxygen and a polypeptide chain. The oxygenation of haemoglobin is a reversible reaction, and the molecular shape of haemoglobin facilitates the binding of subsequent oxygen molecules.
The oxygen dissociation curve describes the relationship between the percentage of saturated haemoglobin and partial pressure of oxygen in the blood, and it is not affected by haemoglobin concentration. The curve can be shifted to the right or left by various factors. Chronic anaemia, for example, causes an increase in 2,3 DPG levels, which shifts the curve to the right, resulting in lower oxygen delivery. The Haldane effect causes a shift to the left, resulting in decreased oxygen delivery to tissues, while the Bohr effect causes a shift to the right, resulting in enhanced oxygen delivery to tissues. Factors that shift the curve to the left include low levels of H+, pCO2, 2,3-DPG, and temperature, as well as the presence of HbF, methaemoglobin, and carboxyhaemoglobin. Factors that shift the curve to the right include raised levels of H+, pCO2, and 2,3-DPG, as well as increased temperature.
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This question is part of the following fields:
- Haematology And Oncology
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Question 22
Incorrect
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As a physician, assessing a 23-year-old male who arrived at the emergency department with a triceps muscle injury causing left elbow extension loss. Can you identify the origin of the long head of this muscle?
Your Answer: Coracoid process
Correct Answer: Infraglenoid tubercle of the scapula
Explanation:The triceps muscle, which gets its name from the Latin word for three-headed, is responsible for extending the elbow. It is made up of three heads: the long head, which originates from the infraglenoid tubercle of the scapula; the lateral head, which comes from the dorsal surface of the humerus; and the medial head, which originates from the posterior surface of the humerus. These three sets of fibers come together to form a single tendon that inserts onto the olecranon process of the ulna.
Anatomy of the Triceps Muscle
The triceps muscle is a large muscle located on the back of the upper arm. It is composed of three heads: the long head, lateral head, and medial head. The long head originates from the infraglenoid tubercle of the scapula, while the lateral head originates from the dorsal surface of the humerus, lateral and proximal to the groove of the radial nerve. The medial head originates from the posterior surface of the humerus on the inferomedial side of the radial groove and both of the intermuscular septae.
All three heads of the triceps muscle insert into the olecranon process of the ulna, with some fibers inserting into the deep fascia of the forearm and the posterior capsule of the elbow. The triceps muscle is innervated by the radial nerve and supplied with blood by the profunda brachii artery.
The primary action of the triceps muscle is elbow extension. The long head can also adduct the humerus and extend it from a flexed position. The radial nerve and profunda brachii vessels lie between the lateral and medial heads of the triceps muscle. Understanding the anatomy of the triceps muscle is important for proper diagnosis and treatment of injuries or conditions affecting this muscle.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 23
Correct
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A 15-year-old male patient comes to the clinic with a skin rash and tremors. Upon conducting a urine chromatography test, it is found that he has elevated levels of neutral amino acids. The diagnosis is Hartnup disease. Can you identify which of the following options is an essential neutral amino acid?
Your Answer: Tryptophan
Explanation:Essential Amino Acids
Essential amino acids are those that the body cannot produce in sufficient quantities to meet the needs of cells. Therefore, they must be obtained through the diet. The essential amino acids include isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. During childhood, arginine and histidine are also considered essential amino acids. Mnemonics can be used to help remember these essential amino acids. Aspartate and serine are not essential amino acids, while arginine and histidine are positively charged and therefore not essential. The only essential amino acid that is both neutral and essential is tryptophan.
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This question is part of the following fields:
- Clinical Sciences
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Question 24
Correct
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What is the name of the intercellular junctional mechanism that allows cells to be electrically connected?
Your Answer: Gap junction
Explanation:Cell Junctions: Types and Functions
Gap junctions are found where two adjacent cell membranes meet, allowing for electrical communication between cells. Desmosomes are specialized proteins that help cells stick together, particularly in epithelial tissue. Tight junctions prevent water and solutes from leaking out of cells. Zonula adherens junctions are cell junctions that connect to the actin cytoskeleton. These different types of cell junctions play important roles in maintaining the structure and function of tissues in the body.
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This question is part of the following fields:
- Clinical Sciences
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Question 25
Incorrect
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Sarah, a 25-year-old type 1 diabetic, is interested in joining a local running group. As her physician, it is important to inform her of the potential impact this increase in physical activity may have on her blood sugar levels. What advice do you give her?
Your Answer: He is at risk of an early drop due to glucose uptake and a late rise hours later due to adrenaline secretion
Correct Answer: He is at risk of an early and a late drop, hours later, in his blood glucose due muscle uptake and replacement of glycogen
Explanation:Glucose levels are impacted by exercise in various ways. Firstly, there is an initial decrease due to the increased uptake of glucose in the muscles through GLUT-2, which does not require insulin. Secondly, during high-intensity sports, the release of adrenaline and cortisol can cause a temporary increase in blood glucose levels, especially during competitive events. Finally, there is a delayed decrease as the muscles and liver glycogen are utilized during exercise and then replenished over the following hours.
Glycogenesis – the process of storing glucose as glycogen
Glycogenesis is the process of converting glucose into glycogen for storage in the liver and muscles. This process is important for maintaining blood glucose levels and providing energy during times of fasting or exercise. The key enzyme involved in glycogenesis is glycogen synthase, which catalyzes the formation of α-1,4-glycosidic bonds between glucose molecules to form glycogen. Branching enzyme then creates α-1,6-glycosidic bonds to form branches in the glycogen molecule. Glycogenin, a protein that acts as a primer for glycogen synthesis, is also involved in the process. Glycogenesis is regulated by hormones such as insulin and glucagon, which stimulate and inhibit glycogen synthesis, respectively. Understanding the process of glycogenesis is important for understanding how the body stores and utilizes glucose for energy.
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This question is part of the following fields:
- Endocrine System
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Question 26
Incorrect
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Where exactly can the vomiting center be found?
Your Answer: Midbrain
Correct Answer: Medulla oblongata
Explanation:Here are the non-GI causes of vomiting, listed alphabetically:
– Acute renal failure
– Brain conditions that increase intracranial pressure
– Cardiac events, particularly inferior myocardial infarction
– Diabetic ketoacidosis
– Ear infections that affect the inner ear (labyrinthitis)
– Ingestion of foreign substances, such as Tylenol or theophylline
– Glaucoma
– Hyperemesis gravidarum, a severe form of morning sickness in pregnancy
– Infections such as pyelonephritis (kidney infection) or meningitis.Vomiting is the involuntary act of expelling the contents of the stomach and sometimes the intestines. This is caused by a reverse peristalsis and abdominal contraction. The vomiting center is located in the medulla oblongata and is activated by receptors in various parts of the body. These include the labyrinthine receptors in the ear, which can cause motion sickness, the over distention receptors in the duodenum and stomach, the trigger zone in the central nervous system, which can be affected by drugs such as opiates, and the touch receptors in the throat. Overall, vomiting is a reflex action that is triggered by various stimuli and is controlled by the vomiting center in the brainstem.
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This question is part of the following fields:
- Neurological System
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Question 27
Incorrect
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A 24-year-old man has been admitted to the emergency department after falling off a roof and has been diagnosed with a Colles' fracture by the radiologist. The medical team plans to perform a closed reduction of the fracture, and they intend to use a haematoma block with lidocaine to facilitate a quick and painless reduction. What is a potential side effect that may occur after a haematoma block with lidocaine?
Your Answer: Ventricular arrhythmia
Correct Answer: Mental status change
Explanation:Lidocaine has been known to affect mental status by crossing the blood-brain barrier quickly and blocking inhibitory neurons in the brain. This can lead to a decrease in seizure threshold and a decline in mental function. While hypertension is a recognized side effect of lidocaine, it does not cause hypotension. While constipation can be a side effect of lidocaine, it is not known to cause diarrhea. While there is no evidence to suggest that lidocaine causes sexual dysfunction, it is used in the treatment of premature ejaculation. Lidocaine is a class 1b anti-arrhythmic drug used to treat ventricular arrhythmias and does not cause them.
Overview of Local Anaesthetic Agents
Local anaesthetic agents are drugs that block nerve impulses and provide pain relief in a specific area of the body. Lidocaine is a commonly used amide local anaesthetic that is also used as an antiarrhythmic drug. It is metabolized in the liver, protein-bound, and excreted in the urine. Toxicity can occur with excessive administration or in patients with liver dysfunction or low protein states. Acidosis can also cause lidocaine to detach from protein binding. Treatment for local anaesthetic toxicity involves the use of IV 20% lipid emulsion. Drug interactions with lidocaine include beta blockers, ciprofloxacin, and phenytoin. Cocaine is another local anaesthetic agent that is rarely used in mainstream surgical practice. Bupivacaine has a longer duration of action than lidocaine and is useful for topical wound infiltration. However, it is cardiotoxic and contraindicated in regional blockage. Levobupivacaine is a less cardiotoxic alternative. Prilocaine is less cardiotoxic than other local anaesthetic agents and is preferred for intravenous regional anaesthesia. Adrenaline can be added to local anaesthetic drugs to prolong their duration of action and permit higher doses, but it is contraindicated in patients taking MAOI’s or tricyclic antidepressants. The maximum total doses of local anaesthetic agents depend on the type of drug and are based on ideal body weight.
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This question is part of the following fields:
- General Principles
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Question 28
Incorrect
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A 7-year-old boy is brought to the doctor by his father with a complaint of frequent urination and excessive thirst. Upon conducting a fasting blood glucose test, the results are found to be abnormally high. The doctor suspects type 1 diabetes and initiates first-line injectable therapy.
What characteristic of this medication should be noted?Your Answer: Decreases cellular uptake of potassium
Correct Answer: Decreases serum potassium
Explanation:Insulin stimulates the Na+/K+ ATPase pump, which leads to a decrease in serum potassium levels. This is the primary treatment for type 1 diabetes, where the pancreas no longer produces insulin, causing high blood sugar levels. Injectable insulin allows glucose to enter cells, and insulin also increases cellular uptake of potassium while decreasing serum potassium levels. Insulin also stimulates muscle protein synthesis, reducing muscle protein loss. Insulin is secreted in response to hyperglycaemia, where high blood sugar levels trigger the beta cells of the pancreas to release insulin in healthy individuals.
Insulin is a hormone produced by the pancreas that plays a crucial role in regulating the metabolism of carbohydrates and fats in the body. It works by causing cells in the liver, muscles, and fat tissue to absorb glucose from the bloodstream, which is then stored as glycogen in the liver and muscles or as triglycerides in fat cells. The human insulin protein is made up of 51 amino acids and is a dimer of an A-chain and a B-chain linked together by disulfide bonds. Pro-insulin is first formed in the rough endoplasmic reticulum of pancreatic beta cells and then cleaved to form insulin and C-peptide. Insulin is stored in secretory granules and released in response to high levels of glucose in the blood. In addition to its role in glucose metabolism, insulin also inhibits lipolysis, reduces muscle protein loss, and increases cellular uptake of potassium through stimulation of the Na+/K+ ATPase pump.
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This question is part of the following fields:
- Endocrine System
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Question 29
Incorrect
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A 78-year-old man comes to the emergency department complaining of double vision. According to his wife, he fell in the garden earlier today and hit his head on a bench. During the examination, you notice that his left eye is fixed in a down and out position. After performing a CT scan, you discover that he has an extradural hematoma on the left side. These types of hematomas are often caused by the middle meningeal artery rupturing. Which foramina does this artery use to enter the cranium?
Your Answer: Foramen ovale
Correct Answer: Foramen spinosum
Explanation:The correct answer is the foramen spinosum, which is a small opening in the cranial cavity that allows the meningeal artery to pass through.
The foramen lacerum is covered with cartilage during life and is sometimes described as the passage for the nerve and artery of the pterygoid canal. However, it is more accurate to say that they pass into the cartilage that blocks the foramen before entering the pterygoid canal, which is located in the anterior wall of the foramen.
The foramen ovale is an oval-shaped opening that allows the mandibular nerve to pass through.
The foramen magnum is the largest of the foramen and is located in the posterior of the cranial cavity. It allows the brainstem and associated structures to pass through.
Foramina of the Base of the Skull
The base of the skull contains several openings called foramina, which allow for the passage of nerves, blood vessels, and other structures. The foramen ovale, located in the sphenoid bone, contains the mandibular nerve, otic ganglion, accessory meningeal artery, and emissary veins. The foramen spinosum, also in the sphenoid bone, contains the middle meningeal artery and meningeal branch of the mandibular nerve. The foramen rotundum, also in the sphenoid bone, contains the maxillary nerve.
The foramen lacerum, located in the sphenoid bone, is initially occluded by a cartilaginous plug and contains the internal carotid artery, nerve and artery of the pterygoid canal, and the base of the medial pterygoid plate. The jugular foramen, located in the temporal bone, contains the inferior petrosal sinus, glossopharyngeal, vagus, and accessory nerves, sigmoid sinus, and meningeal branches from the occipital and ascending pharyngeal arteries.
The foramen magnum, located in the occipital bone, contains the anterior and posterior spinal arteries, vertebral arteries, and medulla oblongata. The stylomastoid foramen, located in the temporal bone, contains the stylomastoid artery and facial nerve. Finally, the superior orbital fissure, located in the sphenoid bone, contains the oculomotor nerve, recurrent meningeal artery, trochlear nerve, lacrimal, frontal, and nasociliary branches of the ophthalmic nerve, and abducent nerve.
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This question is part of the following fields:
- Neurological System
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Question 30
Correct
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Sophie is a 20-year-old female who was involved in a road traffic accident and brought into the hospital by the air ambulance. She suffered multiple injuries, the most significant being a fractured pelvis that caused a large internal bleed. When she arrives, the team handover that she was started on noradrenaline after she dropped her blood pressure.
Which receptors were stimulated to increase her blood pressure?Your Answer: α1
Explanation:α1 adrenergic receptors cause smooth muscle contraction, mainly in response to noradrenaline, leading to increased systemic vascular resistance and blood pressure. α2 receptors inhibit the release of norepinephrine and mediate vasopressor effects. β2 receptors cause bronchodilation in the lungs, while β3 receptors promote adipolysis and thermoregulation in adipose tissue. α3 receptors are neuronal receptors often paired with β2 subunits for acetylcholine reuptake.
Adrenergic receptors are a type of G protein-coupled receptors that respond to the catecholamines epinephrine and norepinephrine. These receptors are primarily involved in the sympathetic nervous system. There are four types of adrenergic receptors: α1, α2, β1, and β2. Each receptor has a different potency order and primary action. The α1 receptor responds equally to norepinephrine and epinephrine, causing smooth muscle contraction. The α2 receptor has mixed effects and responds equally to both catecholamines. The β1 receptor responds equally to epinephrine and norepinephrine, causing cardiac muscle contraction. The β2 receptor responds much more strongly to epinephrine than norepinephrine, causing smooth muscle relaxation.
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This question is part of the following fields:
- General Principles
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