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Question 1
Correct
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Which of the following statements concerning hepatitis D is TRUE:
Your Answer: It can only be transmitted with, or to somebody who is infected with, Hepatitis B.
Explanation:Hepatitis D virus (HDV) is an RNA virus that was discovered in 1977 and is structurally unrelated to the hepatitis A (HAV), hepatitis B (HBV), and hepatitis C (HCV) viruses. HDV causes a unique infection that requires the assistance of HBV viral particles to replicate and infect hepatocytes. Its clinical course is varied and ranges from acute, self-limited infection to acute, fulminant liver failure. Chronic liver infection can lead to end-stage liver disease and associated complications (including accelerated fibrosis, liver decompensation, and hepatocellular carcinoma).
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 2
Incorrect
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A 22-year-old woman is brought in by ambulance from her GP surgery with suspected meningitis. She has been given a dose of benzylpenicillin already.What is the mechanism of action of benzylpenicillin? Select ONE answer only.
Your Answer:
Correct Answer: Inhibition of cell wall synthesis
Explanation:Penicillins and the other ß-lactam antibiotics are bactericidal. They produce their antimicrobial action by preventing cross-linkage between the linear peptidoglycan polymer chains that make up the bacterial cell wall. They, therefore, inhibit cell wall synthesis.An overview of the different mechanisms of action of the various types of antimicrobial agents is shown below:Mechanism of actionExamplesInhibition of cell wall synthesisPenicillinsCephalosporinsVancomycinDisruption of cell membrane functionPolymyxinsNystatinAmphotericin BInhibition of protein synthesisMacrolidesAminoglycosidesTetracyclinesChloramphenicolInhibition of nucleic acid synthesisQuinolonesTrimethoprim5-nitroimidazolesRifampicinAnti-metabolic activitySulfonamidesIsoniazid
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 3
Incorrect
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You examine a 48-year-old patient who has had proximal weakness, hypertension, and easy bruising in the past. She exhibits considerable face fullness and truncal obesity on examination. You diagnose her with Cushing's syndrome.When would her random cortisol level likely be abnormal?Â
Your Answer:
Correct Answer: 2400 hrs
Explanation:Cortisol levels fluctuate throughout the day, with the greatest levels occurring around 0900 hours and the lowest occurring at 2400 hrs during sleep.The diurnal swing of cortisol levels is lost in Cushing’s syndrome, and levels are greater throughout the 24-hour period. In the morning, levels may be normal, but they may be high at night-time, when they are generally repressed.
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 4
Incorrect
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Which of the following best describes a natural killer cell:
Your Answer:
Correct Answer: A large granular lymphocyte that kills by inducing target cell apoptosis.
Explanation:Natural killer (NK) cells are cytotoxic CD8 positive cells that lack the T-cell receptor. They are large cells with cytoplasmic granules. NK cells are designed to kill target cells that have a low level of expression of HLA class I molecules, such as may occur during viral infection or on a malignant cell. NK cells do this by displaying several receptors for HLA molecules on their surface. When HLA is expressed on the target cell these deliver an inhibitory signal into the NK cell. When HLA molecules are absent on the target cell this inhibitory signal is lost and the NK cell can then kill its target. In addition, NK cells display antibody-dependent cell-mediated cytotoxicity. In this, antibody binds to antigen on the surface of the target cell and then NK cells bind to the Fc portion of the bound antibody and kill the target cell.
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 5
Incorrect
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Which of the following medications may lessen warfarin's anticoagulant effect:
Your Answer:
Correct Answer: Phenytoin
Explanation:Phenytoin will decrease the level or effect of warfarin by affecting hepatic/intestinal enzyme CYP3A4 metabolism.Metronidazole will increase the level or effect of warfarin by affecting hepatic enzyme CYP2C9/10 metabolism.NSAIDs, when given with Warfarin, increase anticoagulation.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 6
Incorrect
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A known epileptic is transported in status epilepticus by ambulance. On the way to the hospital, she took some diazepam.Which of the following statements about diazepam is correct?
Your Answer:
Correct Answer: It crosses into breast milk
Explanation:Diazepam boosts GABA’s effects, giving it sedative, hypnotic, anxiolytic, anticonvulsant, and muscle-relaxing properties. It can be administered orally, rectally, or intravenously.With a half-life of 20-100 hours, it is a long-acting benzodiazepine. Midazolam, oxazepam, and alprazolam are examples of short-acting benzodiazepines with a half-life of less than 12 hours (Xanax).If used in the presence of hepatic impairment, benzodiazepines can cause coma. If treatment is necessary, benzodiazepines with shorter half-lives should be used in lower doses. Diazepam is a sedative that crosses into breast milk and should be avoided by breastfeeding mothers.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 7
Incorrect
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Which of the following microbes binds strongly to CD4 antigen:
Your Answer:
Correct Answer: HIV
Explanation:HIV mainly infects CD4+ T helper cells. Viral replication results in progressive T-cell depletion and impaired cell-mediated immunity with subsequent secondary opportunistic infections and increased risk of malignancy. B-cell function is also reduced as a result of lack of T-cell stimulation.HIV is not a notifiable disease.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 8
Incorrect
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C-reactive protein (CRP) synthesis is predominantly stimulated by which of the following cytokines:
Your Answer:
Correct Answer: IL-6
Explanation:Activated leukocytes, adipocytes, and endothelial cells all release interleukin 6 (IL-6), a significant proinflammatory cytokine. The main downstream mediator of the acute phase response is C-reactive protein, which is predominantly produced by IL-6–dependent hepatic biosynthesis.
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This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 9
Incorrect
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A 65-year-old man comes for a visit at the clinic with complaints of abdominal pain. On inquiring about drug history, you find out that he has been taking around 8-10 paracetamol to help relieve the pain. Out of the following, which one is believed to be the main mechanism of action for paracetamol?
Your Answer:
Correct Answer: Selective inhibition of COX-3 receptors
Explanation:The FDA categorizes Paracetamol as an NSAID (nonsteroidal anti-inflammatory drug) as it is believed to selectively inhibit cyclo-oxygenase 3 (COX-3) receptors in the brain and spinal cord. COX-3 is a unique variant of the more known COX-1 and COX-2. It is responsible for the production of prostaglandins in central areas, which sensitizes free nerve endings to the chemical mediators of pain. Therefore, by selectively inhibiting COX-3, paracetamol effectively reduces pain sensation by increasing the pain threshold.Acetaminophen does not inhibit cyclooxygenase in peripheral tissues and, therefore, has no peripheral anti-inflammatory effects.The antipyretic actions of acetaminophen are likely attributed to direct action on heat-regulating centres in the brain, resulting in peripheral vasodilation, sweating, and loss of body heat.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 10
Incorrect
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A 2nd-year medical student is solving an exam paper with questions about the immune system. She comes across a question regarding innate immunity. Innate immunity is the immunity naturally present within the body from birth. Which ONE of the following is not a part of this type of immunity?
Your Answer:
Correct Answer: Antibody production
Explanation:Innate immunity, also called non-specific immunity, refers to the components of the immune system naturally present in the body at birth. The components of innate immunity include: 1) Natural Killer Cells 2) Neutrophils 3) Macrophages 4) Mast Cells 5) Dendritic Cells 6) Basophils. Acquired or adaptive immunity is acquired in response to infection or vaccination. Although the response takes longer to develop, it is also a more long-lasting form of immunity. The components of this system include: 1) T lymphocytes 2) B lymphocytes 3) Antibodies
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 11
Incorrect
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Regarding hepatitis C, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Anti-HCV IgG antibodies are diagnostic of acute infection.
Explanation:Anti-HCV IgG antibodies indicate exposure to hepatitis C but this could be acute, chronic or resolved infection. If the antibody test is positive, HCV RNA should be tested for, which if positive indicates that a person has current infection with active hepatitis C.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 12
Incorrect
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What is the primary route of transmission of Norovirus?
Your Answer:
Correct Answer: Oral-faecal route
Explanation:Norovirus is spread primarily by faecal-oral contact, but it can also be spread through contact with an infected person, ingestion of contaminated food or water, or contact with contaminated surfaces or items.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 13
Incorrect
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A patient presents with epistaxis. She tells you that she has a rare platelet disorder and gives you her haematology outpatient letter that contains information about it. You learn that her disorder is caused by low levels of glycoprotein IIb/IIIa.What is the SINGLE most likely diagnosis?
Your Answer:
Correct Answer: Glanzamann’s thromboasthenia
Explanation:Glanzmann’s thromboasthenia is a rare platelet disorder in which platelets contain defective or low levels of glycoprotein IIb/IIIa.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 14
Incorrect
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What does the correlation coefficient r = 0 indicate with regards to linear relationships between two variables?
Your Answer:
Correct Answer: There is no correlation between two variables
Explanation:r = 0 if there is no correlation between two variables. The closer that r is to 0, the weaker the correlation.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 15
Incorrect
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The arterial blood gas (ABG) of a 56-year-old woman shows type A lactic acidosis.What is the most likely cause of her lactic acidosis?
Your Answer:
Correct Answer: Left ventricular failure
Explanation:Lactic acidosis is a common finding in critically ill patients and commonly associated with other serious underlying pathologies. It occurs when pH is 5 mmol/L. Anion gap is increased in lactic acidosis.Acquired lactic acidosis is classified into two subtypes:Type A: lactic acidosis due to tissue hypoxia andType B: due to non-hypoxic processes affecting the production and elimination of lactateSome causes of type A and type B lactic acidosis include:Type A lactic acidosisLeft ventricular failureSevere anaemiaShock (including septic shock)AsphyxiaCardiac arrestCO poisoningRespiratory failureSevere asthma and COPDType B lactic acidosis:Regional hypoperfusionRenal failureLiver failureSepsis (non-hypoxic sepsis)Thiamine deficiencyAlcoholic ketoacidosisDiabetic ketoacidosisCyanide poisoningMethanol poisoningBiguanide poisoning
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 16
Incorrect
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Adenosine is primarily indicated for which of the following:
Your Answer:
Correct Answer: Paroxysmal supraventricular tachycardia
Explanation:Adenosine is usually the treatment of choice for terminating paroxysmal supraventricular tachycardia including those associated with accessory conduction pathways e.g. Wolff-Parkinson-White syndrome.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 17
Incorrect
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When a child has mumps, how long should he or she be off from school?
Your Answer:
Correct Answer: 5 days from onset of swelling
Explanation:To avoid the spread of infection, infected patients should be isolated. Patients should avoid going to school, childcare, or job for five days after the swelling has occurred.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 18
Incorrect
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A 58-year-old man with a long history of poorly controlled hypertension complains of a headache and vision blurring today. In triage, his blood pressure is 210/192 mmHg. A CT head scan is scheduled to rule out the possibility of an intracranial haemorrhage. You make the diagnosis of hypertensive encephalopathy and rush the patient to reus to begin blood pressure-lowering treatment. He has a history of brittle asthma, for which he has been admitted to the hospital twice in the last year.Which of the following is the patient's preferred drug treatment?
Your Answer:
Correct Answer: Nicardipine
Explanation:End-organ damage (e.g. encephalopathy, intracranial haemorrhage, acute myocardial infarction or ischaemia, dissection, pulmonary oedema, nephropathy, eclampsia, papilledema, and/or angiopathic haemolytic anaemia) characterises a hypertensive emergency (also known as ‘accelerated hypertension’ or malignant hypertension’ It’s a life-threatening condition that necessitates rapid blood pressure reduction to avoid end-organ damage and a negative outcome.Hypertensive encephalopathy is a syndrome that includes headaches, seizures, visual changes, and other neurologic symptoms in people who have high blood pressure. It is reversible if treated quickly, but it can progress to coma and death if not treated properly.Any patient with suspected hypertensive encephalopathy should have an urgent CT scan to rule out an intracranial haemorrhage, as rapid blood pressure reduction could be dangerous in these circumstances.The drug of choice is labetalol, which reduces blood pressure steadily and consistently without compromising cerebral blood flow.An initial reduction of approximately 25% in mean arterial pressure (MAP) over an hour should be aimed for, followed by a further controlled MAP reduction over the next 24 hours. In patients who are unable to take beta-blockers, nicardipine can be used as a substitute.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 19
Incorrect
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All of the following statements are considered true regarding nominal variables, except:
Your Answer:
Correct Answer: The central tendency of a nominal variable is given by its median
Explanation:A nominal variable is a type of variable that is used to name, label or categorize particular attributes that are being measured. It takes qualitative values representing different categories, and there is no intrinsic ordering of these categories.A nominal variable is one of the 2 types of categorical variables and is the simplest among all the measurement variables. Some examples of nominal variables include gender, name, phone, etc.A nominal variable is qualitative, which means numbers are used here only to categorize or identify objects. They can also take quantitative values. However, these quantitative values do not have numeric properties. That is, arithmetic operations cannot be performed on them. If the variable is nominal, the mode is the only measure of central tendency to use.
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This question is part of the following fields:
- Evidence Based Medicine
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Question 20
Incorrect
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What is the effect of activated vitamin D on the renal handling of calcium:
Your Answer:
Correct Answer: Increases calcium reabsorption in the distal tubule
Explanation:Activated vitamin D acts to:GUT:increase calcium and phosphate absorption in the small intestine (the main action)KIDNEYS:increase renal calcium reabsorption (in the distal tubule via activation of a basolateral Ca2+ATPase pump), increase renal phosphate reabsorption, inhibit 1-alpha-hydroxylase activity in the kidneys (negative feedback)PARATHYROID GLANDS:inhibit PTH secretion from the parathyroid glands
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 21
Incorrect
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Dysuria and urinary frequency are symptoms of a 29-year-old woman. A urine dipstick is used to detect the presence of blood, protein, leucocytes, and nitrites in the urine. You diagnose a urinary tract infection and give antibiotics to the patient.In the United Kingdom, which of the following antibiotics has the highest percentage of E.coli resistance?
Your Answer:
Correct Answer: Trimethoprim
Explanation:In the United Kingdom, antibiotic resistance is becoming a significant factor in the treatment of urinary tract infections and pyelonephritis. E. coli (the main causative organism of both urinary tract infections and acute pyelonephritis) resistance to the following antibiotics in laboratory-processed urine specimens is:30.3 percent trimethoprim (varies by area from 27.1 to 33.4 percent )19.8 percent co-amoxiclav (varies by area from 10.8 to 30.7 percent )Ciprofloxacin (Cipro): 10.6% (varies by area from 7.8 to 13.7 percent )Cefalexin has a concentration of 9.9%. (varies by area from 8.1 to 11.4 percent )
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 22
Incorrect
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Regarding penicillin antibiotics, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Patients with a history of atopy are at higher risk of hypersensitivity reactions.
Explanation:Allergic reactions to penicillins occur in 1 – 10% of exposed individuals; anaphylactic reactions occur in fewer than 0.05% of treated patients. Patients with a history of atopic allergy are at higher risk of anaphylactic reactions to penicillins. Patients with a history of anaphylaxis, urticaria, or rash immediately after penicillin use should not receive a penicillin or other beta-lactam antibiotics; about 0.5 – 6.5 % of penicillin-sensitive patients will also be allergic to the cephalosporins. Patients with a history of a more minor rash (i.e. non-confluent, non-pruritic rash restricted to a small area of the body) or delayed reaction (rash occurring more than 72 hours after penicillin administration), may not be truly allergic and may be considered for penicillin or beta-lactam treatment in severe infection (although possibility of allergy should be borne in mind). Other beta-lactam antibiotics (including cephalosporins) can be used in these patients.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 23
Incorrect
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A 30-year old male is taken to the emergency room after suffering a blunt trauma to the abdomen. He is complaining of severe abdominal pain, however all his other vital signs remain stable. A FAST scan is performed to assess for hemoperitoneum.If hemoperitoneum is present, it is most likely to be observed in which of the following areas?
Your Answer:
Correct Answer: Liver
Explanation:The Focused Assessment with Sonography in Trauma (FAST) is an ultrasound protocol developed to assess for hemoperitoneum and hemopericardium. Numerous studies have demonstrated sensitivities between 85% to 96% and specificities exceeding 98%.The FAST exam evaluates four regions for pathologic fluid: (1) the right upper quadrant, (2) the subxiphoid (or subcostal) view, (3) the left upper quadrant, and (4) the suprapubic region.The right upper quadrant (RUQ) visualizes the hepatorenal recess, also known as Morrison’s pouch, the right paracolic gutter, the hepato-diaphragmatic area, and the caudal edge of the left liver lobe. The probe is positioned in the sagittal orientation along the patient’s flank at the level of the 8 to 11 rib spaces. The hand is placed against the bed to ensure visualization of the retroperitoneal kidney. The RUQ view is the most likely to detect free fluid with an overall sensitivity of 66%. Recent retrospective evidence suggests the area along the caudal edge of the left lobe of the liver has the highest sensitivity, exceeding 93%.
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 24
Incorrect
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The renal team is currently prescribing erythropoietin to a patient with chronic kidney disease.Which of the following statements about erythropoietin is correct?
Your Answer:
Correct Answer: It protects red blood cell progenitors from apoptosis
Explanation:Erythropoietin is a glycoprotein hormone that regulates the formation of red blood cells (red cell production). It is mostly produced by interstitial fibroblasts in the kidney, which are located near the PCT. It is also produced in the liver’s perisinusoidal cells, however this is more common during the foetal and perinatal periods.The kidneys produce and secrete erythropoietin in response to hypoxia. On red blood cells, erythropoietin has two main effects:- It encourages stem cells in the bone marrow to produce more red blood cells.- It protects red blood cell progenitors and precursors from apoptosis by targeting them in the bone marrow.As a result of the increased red cell mass, the oxygen-carrying capacity and oxygen delivery increase.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 25
Incorrect
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A critically ill 48-year-old individual appears with symptoms and signs of an anaphylactic reaction.In an allergic reaction, which of the following is an absolute contraindication to the injection of adrenaline?
Your Answer:
Correct Answer: None of the other options
Explanation:Even if the following relevant contraindications exist, adrenaline can be given in life-threatening anaphylactic reactions:Coronary artery disease (CAD) Coronary artery disease (CAD) Second stage of labourHypertension that is uncontrolledSevere Ventricular arrhythmias
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This question is part of the following fields:
- Pharmacology
- Respiratory Pharmacology
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Question 26
Incorrect
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A 30-year-old male with a known allergy to natural latex rubber presents with an allergic reaction to a food he has just eaten. Which ONE of these foods is most likely to cause an associated hypersensitivity in him?
Your Answer:
Correct Answer: Banana
Explanation:About one third of patients with allergy to natural latex rubber (NRL) have an associated allergy to some plant-derived foods. It is known as the latex-fruit syndrome and occurs commonly with consumption of fresh fruits. Banana and avocado are the most implicated fruits but it can also be seen with tomato, kiwi and chestnut.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 27
Incorrect
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Which of the following nerves is most likely associated with an anterior shoulder dislocation?
Your Answer:
Correct Answer: Axillary nerve
Explanation:In an anterior dislocation, the arm is an abducted and externally rotated position. In the externally rotated position, the posterosuperior aspect of the humeral head abuts and drives through the anteroinferior aspect of the glenoid rim. This can damage the humeral head, glenoid labrum, or both. An associated humeral head compression fracture is described as a Hill Sach’s lesion. If large enough, it can lead to locked dislocations that may require open reduction. The glenoid labrum is a fibrocartilaginous structure that rings the circumference of the glenoid fossa. Bankart lesions are injuries to the anteroinferior glenoid labrum complex and the most common capsulolabral injury. A bony Bankart lesion refers to an associated fracture of the glenoid rim. These capsulolabral lesions are risk factors for recurrent dislocation.Axillary nerve injury is identified in about 42% of acute anterior shoulder dislocations. Nerve transection is rare, and traction injuries are more common. Arterial injury has also been described. The subclavian artery becomes the axillary artery after passing the first rib. The distal portion of the axillary artery is anatomically fixed and, therefore, susceptible to injury in anterior dislocations. Ischemic injury, including pseudoaneurysm and arterial laceration, is rare but carries marked morbidity if not quickly identified.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 28
Incorrect
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Regarding Clostridium tetani, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Germination and outgrowth of clostridial spores depends on anaerobic conditions.
Explanation:Clostridium tetani is found in normal human intestinal flora, although infection is predominantly exogenous. Tetanospasmin, an exotoxin produced by C. tetani is responsible for the neurotoxic effects of tetanus, largely by preventing the release of the inhibitory neurotransmitter GABA, resulting in prolonged excitation. Clostridium tetani is an obligate anaerobe, with an incubation period of about 3 – 21 days (average 10 days).
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 29
Incorrect
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A 70-year-old woman presents with right-sided loss of pain and temperature sense on the body as well as left-sided loss of pain and temperature sense on the face. She also has complaints of vertigo, nausea, and tinnitus. Further examination of her cranial nerves suggest the presence of Horner's Syndrome. An MRI and CT scan was ordered and results showed that she is suffering from a left-sided stroke. Branches of which of the following arteries are most likely implicated in the case?
Your Answer:
Correct Answer: Posterior inferior cerebellar artery
Explanation:Wallenberg syndrome is also known as lateral medullary syndrome and posterior inferior cerebellar artery syndrome. It is the most common posterior circulation ischemic stroke syndrome. The primary pathology of Wallenberg syndrome is occlusion of the posterior inferior cerebellar artery (PICA) or one of its branches.It is characterized by vertigo with nystagmus, nausea and vomiting, and sometimes hiccups, dysphonia, dysarthria, and dysphagia often present with ipsilateral loss of gag reflex, ipsilateral ataxia with a tendency to fall to the ipsilateral side, pain and numbness with impaired facial sensation on the face, impaired taste sensation, and impaired pain and temperature sensation in the arms and legs.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 30
Incorrect
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The least likely feature expected to be seen in a lesion of the frontal lobe is which of the following?
Your Answer:
Correct Answer: Loss of two-point discrimination
Explanation:Lesions in different areas give rise to different symptoms. Lesions of the parietal lobe give rise to loss of two-point discrimination. Lesions to Broca’s area give rise to expressive dysphasia results from damage Lesions to the primary motor cortex give rise to contralateral weakness of the face and arm. Lesions to the prefrontal cortex give rise to personality change. Lesions to the frontal eye field give rise to conjugate eye deviation towards side of lesion.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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SESSION STATS - PERFORMANCE PER SPECIALTY
