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Question 1
Correct
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A 23-year-old has a known diagnosis of HIV. Blood is sent to the laboratory for tests.AIDS be diagnosed at a CD4 counts below?
Your Answer: 200 cells/mm 3
Explanation:A normal CD4 count ranges from 500-1000 cells/mm3.At CD4 count of less than 350 cells/mm3 treatment with anti-retroviral therapy should be considered.At a CD4 count of >200 cells/mm3 AIDS is diagnosed.
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This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 2
Correct
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Regarding non-Hodgkin lymphoma (NHL), which of the following statements is CORRECT:
Your Answer: There is a much greater predilection to disseminate to extranodal sites than in Hodgkin lymphoma.
Explanation:Non-Hodgkin’s lymphoma (NHL) refers to a group of lymphoproliferative malignancies (about 85% of B-cell and 15% of T or NK (natural killer) cell origin) with different behavioural patterns and treatment responses. This group of malignancies encompasses all types of lymphoma without Reed-Sternberg cells being present. The Reed-Sternberg cell is classically seen in Hodgkin’s lymphoma.NHL is five times as common as Hodgkin’s lymphoma. The peak incidence of NHL is in the 50-70 years age group, it affects men and women equally, but affects the Caucasian population more commonly than black and Asian ethnic groups.The following are recognised risk factors for NHL:Chromosomal translocations and molecular rearrangementsEpstein-Barr virus infectionHuman T-cell leukaemia virus type-1 (HTLV-1)Hepatitis CCongenital and acquired immunodeficiency statesAutoimmune disorders, e.g. Sjogren’s syndrome and Hashimoto’s thyroiditisThe most common clinical features at presentation are:Lymphadenopathy (typically asymmetrical and painless)Weight lossFatigueNight sweatsHepatosplenomegalyFor clinical purposes, NHL is divided into three groups: indolent, high-grade, and lymphoblastic.Indolent (low-grade) NHL:The cells are relatively matureDisease follows an indolent course without treatmentOften acceptable to follow a ‘watch and wait’ strategyLocal radiotherapy often effectiveRelatively good prognosis with median survival of 10 yearsHigh-grade NHL:Cells are immatureDisease progresses rapidly without treatmentSignificant number of patients can be cured with intensive combination chemotherapy regimensApproximately 40% cure rateLymphoblastic NHL:Cells are very immature and have a propensity to involve the CNSTreatment and progression are similar to that of acute lymphoblastic leukaemia (ALL)
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This question is part of the following fields:
- Haematology
- Pathology
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Question 3
Correct
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The patient is a 78-year-old woman who has recently developed left-sided hemiplegia. A CT head scan is performed, and the diagnosis of an ischaemic stroke is confirmed. Her blood pressure is currently very high, with the most recent measurement being 196/124 mmHg, according to the nurse in charge. While you wait for the stroke team to review her, she asks you to prescribe something to help lower the patient's blood pressure.Which of the following is the best drug treatment for this patient's BP reduction?
Your Answer: Labetalol
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.In the setting of a stroke syndrome (i.e., in the presence of focal neurological deficits), hypertensive emergencies usually necessitate a slower and more controlled blood pressure reduction than in other situations. Rapid reduction of MAP in the presence of an ischaemic stroke can compromise blood flow, leading to further ischaemia and worsening of the neurological deficit. In this situation, intravenous labetalol is the drug of choice for lowering blood pressure.Significantly elevated blood pressure (>185/110 mmHg) is a contraindication to thrombolysis, but there is some evidence for controlling blood pressure before thrombolysis in exceptional circumstances, when it is only slightly above this threshold.
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 4
Correct
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A 28-year-old woman in her second trimester is diagnosed with a psychiatric illness. She is started on treatment with a drug. The treatment results in her baby being born with poor tone, feeding problems, hypothyroidism, and a goitreOut of the following, which drug is most likely responsible for the baby's condition?
Your Answer: Lithium
Explanation:In pregnancy and postpartum, lithium is an effective treatment for relapse prevention in bipolar disorder. However, lithium has also been associated with risks during pregnancy for both the mother and the unborn child. Recent large studies have confirmed the association between first-trimester lithium exposure and an increased risk of congenital malformations.Lithium levels need to be monitored more frequently throughout pregnancy and the postnatal period. If given in the 1st-trimester, lithium is associated with a risk of fetal cardiac malformations, such as Ebstein’s anomaly. If given in the 2nd and 3rd-trimesters, there is a risk of the following:1. hypotonia2. lethargy3. feeding problems4. hypothyroidism5. goitre6. nephrogenic diabetes insipidus in the neonate
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 5
Correct
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Regarding cellular respiration, which of the following statements is CORRECT:
Your Answer: When fats are used as the primary energy source, an excess of acetyl-CoA is produced.
Explanation:Cellular respiration is the process by which cells obtain energy in the form of adenosine triphosphate (ATP). ATP transfers chemical energy from the energy rich substances in the cell to the cell’s energy requiring reactions e.g. active transport, DNA replication and muscle contraction.Cellular respiration is essentially a three step process: 1) Glycolysis, 2)The Krebs cycle, 3)The electron transfer system.The main respiratory substrate used by cells is 6-carbon glucose. Fats and proteins can also be used as respiratory substrates. When fats are being used as the primary energy source, in the absence of glucose, an excess amount of acetyl-CoA is produced, and is converted into acetone and ketone bodies. This can occur in starvation, fasting or in diabetic ketoacidosis. Proteins are used as an energy source only if protein intake is very high, or if glucose and fat sources are depleted.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 6
Correct
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After collapsing in his nursing home, a 70-year-old man is brought into the ER. He has diabetes mellitus and is on medication for it. An RBS of 2.0 mmol/L (3.9-5.5 mmol/L) is recorded in the ER. Out of the following, which medication for diabetes mellitus is LEAST likely responsible for his hypoglycaemic episode?
Your Answer: Metformin
Explanation:Metformin is a biguanide used as the first-line to treat type 2 diabetes mellitus. It has a good reputation as it has an extremely low risk of causing hypoglycaemia compared to the other agents for diabetes. It does not affect the insulin secreted by the pancreas or increase insulin levels. Toxicity with metformin can, however, cause lactic acidosis with associated hypoglycaemia.
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This question is part of the following fields:
- Endocrine Pharmacology
- Pharmacology
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Question 7
Correct
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Which of the following muscles is most responsible for thigh extension at the hip joint?
Your Answer: Hamstrings and gluteus maximus
Explanation:For hip extension, the gluteus maximus and hamstring muscles work together. To compensate for gluteus maximus weakness, the hamstring frequently acts as the primary hip extensor.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 8
Incorrect
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Which of the following is NOT a common side effect of diazepam:
Your Answer: Muscle weakness
Correct Answer: Bradycardia
Explanation:Adverse effects include:Drowsiness and lightheadednessConfusion and ataxia (especially in the elderly), amnesia, muscle weaknessHeadache, vertigo, tremor, dysarthria, hypotension, decreased libido, erectile dysfunction, gynaecomastia, urinary retentionParadoxical effects such as talkativeness, excitement, irritability, aggression, anti-social behaviour, and suicidal ideationWithdrawal symptoms, for example anxiety, depression, anorexia, impaired concentration, insomnia, abdominal cramps, palpitations, tremor, tinnitus and perceptual disturbancesTolerance and dependence (people who use benzodiazepines longer term can develop tolerance and eventual dependence)
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 9
Incorrect
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The causative organism for an infection in a patient you are reviewing is a facultative anaerobe.Which of these is a facultative anaerobic organism?
Your Answer: Campylobacter jejuni
Correct Answer: Staphylococcus aureus
Explanation:Facultative anaerobic bacteria make energy in the form of ATP by aerobic respiration in an oxygen rich environment and can switch to fermentation in an oxygen poor environment.Examples of facultative anaerobes are:Staphylococcus spp.Listeria spp.Streptococcus spp.Escherichia coliMycobacterium tuberculosis, and Pseudomonas aeruginosa are obligate aerobe. They require oxygen to growCampylobacter jejuni and Clostridium spp are obligate anaerobes.They live and grow in the absence of oxygen.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 10
Incorrect
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Regarding haemoglobin, which of the following statements is INCORRECT:
Your Answer: Haem synthesis occurs largely in the mitochondria.
Correct Answer: Haemoglobin synthesis occurs in mature erythrocytes.
Explanation:Haemoglobin is composed of four polypeptide globin chains each with its own iron containing haem molecule. Haem synthesis occurs largely in the mitochondria by a series of biochemical reactions commencing with the condensation of glycine and succinyl coenzyme A under the action of the key rate-limiting enzyme delta-aminolevulinic acid (ALA) synthase. The globin chains are synthesised by ribosomes in the cytosol. Haemoglobin synthesis only occurs in immature red blood cells.There are three types of haemoglobin in normal adult blood: haemoglobin A, A2 and F:- Normal adult haemoglobin (HbA) makes up about 96 – 98 % of total adult haemoglobin, and consists of two alpha (α) and two beta (β) globin chains. – Haemoglobin A2 (HbA2), a normal variant of adult haemoglobin, makes up about 1.5 – 3.5 % of total adult haemoglobin and consists of two α and two delta (δ) globin chains.- Foetal haemoglobin is the main Hb in the later two-thirds of foetal life and in the newborn until approximately 12 weeks of age. Foetal haemoglobin has a higher affinity for oxygen than adult haemoglobin. Red cells are destroyed by macrophages in the liver and spleen after , 120 days. The haem group is split from the haemoglobin and converted to biliverdin and then bilirubin. The iron is conserved and recycled to plasma via transferrin or stored in macrophages as ferritin and haemosiderin. An increased rate of haemoglobin breakdown results in excess bilirubin and jaundice.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 11
Correct
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The cutaneous circulation's principal role is thermoregulation. This process is aided by the existence of arteriovenous anastomoses.Which of the following anatomical areas has the greatest number of arteriovenous anastomoses?
Your Answer: Pinna of the ear
Explanation:Short vessels called arteriovenous anastomoses (AVAs) link tiny arteries and veins. They have a large lumen diameter. The strong and muscular walls allow AVAs to completely clog the vascular lumen, preventing blood flow from artery to vein (acting like a sphincter). When the AVAs open, they create a low-resistance connection between arteries and veins, allowing blood to flow into the limbs’ superficial venous plexuses. There is no diffusion of solutes or fluid into the interstitium due to their strong muscle walls.AVAs are densely innervated by adrenergic fibres from the hypothalamic temperature-regulation centre. High sympathetic output occurs at normal core temperatures, inducing vasoconstriction of the AVAs and blood flow through the capillary networks and deep plexuses. When the temperature rises, sympathetic output decreases, producing AVA vasodilation and blood shunting from the artery to the superficial venous plexus. Heat is lost to the environment as hot blood rushes near to the skin’s surface.AVAs are a specialized anatomical adaptation that can only be found in large quantities in the fingers, palms, soles, lips, and pinna of the ear.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 12
Correct
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A 69-year-old woman with new-onset back pain was diagnosed with osteopenia, osteolytic lesions, and vertebral collapse after undergoing a radiographic examination. Her laboratory results revealed anaemia and hypercalcemia. These findings most likely indicate what condition?
Your Answer: Myeloma
Explanation:Bone pain, pathologic fractures, weakness, anaemia, infection, hypercalcemia, spinal cord compression, and renal failure are all signs and symptoms of multiple myeloma (MM). The patient’s condition matched the signs and symptoms of myeloma.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 13
Incorrect
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On which of the following types of receptors does loperamide act?
Your Answer: Muscarinic receptors
Correct Answer: Opioid receptors
Explanation:Loperamide inhibits acetylcholine release from the myenteric plexus acts by action on opioid mu-receptors, and this then reduces bowel motility. The intestinal transit time is increased, thereby facilitating water reabsorption.
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This question is part of the following fields:
- Gastrointestinal
- Pharmacology
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Question 14
Incorrect
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Regarding pressures and airflow during the normal breathing cycle, which of the following statements is INCORRECT:
Your Answer: At rest, before inspiration begins, alveolar pressure equals atmospheric pressure.
Correct Answer: Negative intrapleural pressure causes dynamic compression of the airways.
Explanation:Dynamic compression occurs during forced expiration, when as the expiratory muscles contract, all the structures within the lungs, including the airways, are compressed by the positive intrapleural pressure. Consequently the smaller airways collapse before the alveoli empty completely and some air remains within the lungs (the residual volume).
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This question is part of the following fields:
- Physiology
- Respiratory
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Question 15
Incorrect
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Which coronary artery is mostly likely affected if an ECG shows a tombstone pattern in leads V2, V3 and V4?
Your Answer: Right coronary artery
Correct Answer: Left anterior descending artery
Explanation:Tombstoning ST elevation myocardial infarction can be described as a STEMI characterized by tombstoning ST-segment elevation. This myocardial infarction is associated with extensive myocardial damage, reduced left ventricle function, serious hospital complications and poor prognosis. Tombstoning ECG pattern is a notion beyond morphological difference and is associated with more serious clinical results.Studies have shown that tombstoning is more commonly found in anterior than non-anterior STEMI, thus, higher rates of left anterior descending artery disease are observed in patients with tombstoning pattern.The following ECG leads determine the location and vessels involved in myocardial infarction:ECG Leads Location Vessel involvedV1-V2 Septal wall Left anterior descendingV3-V4 Anterior wall Left anterior descendingV5-V6 Lateral wall Left circumflex arteryII, III, aVF Inferior wall Right coronary artery (80%) or Left circumflex artery (20%)I, aVL High lateral wall Left circumflex arteryV1, V4R Right ventricle Right coronary arteryV7-V9 Posterior wall Right coronary artery
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 16
Incorrect
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Regarding bile, which of the following statements is INCORRECT:
Your Answer: The gallbladder concentrates bile mainly by active transport of Na+ into the intercellular spaces of the lining cells.
Correct Answer: The sphincter of Oddi contracts to force bile from the gallbladder into the duodenum.
Explanation:Bile is secreted by hepatocytes. It is isotonic and resembles plasma ionically. This fraction of bile is called the bile acid-dependent fraction. As it passes along the bile duct, the bile is modified by epithelial cells lining the duct by the addition of water and bicarbonate ions; this fraction is called the bile acid-independent fraction. Overall, the liver can produce 500 – 1000 mL of bile per day. The bile is either discharged directly into the duodenum or stored in the gallbladder. The bile acid-independent fraction is made at the time it is required i.e. during digestion of chyme. The bile acid-dependent fraction is made when the bile salts are returned from the GI tract to the liver, and is then stored in the gallbladder until needed. The gallbladder not only stores bile but concentrates it by removing non-essential solutes and water, leaving bile acids and pigments, mainly by active transport of Na+into the intercellular spaces of the lining cells which, in turn, draws in water, HCO3-and Cl-from the bile and into the extracellular fluid. Within a few minutes of a meal, particularly when fatty foods have been consumed, the gallbladder contracts and releases bile into the bile duct. The sphincter of Oddi is relaxed, allowing the bile to pass into the duodenum through the ampulla of Vater.
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 17
Incorrect
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The qSOFA score is a bedside prompt designed to identify patients with suspected infection who are at greater risk for a poor outcome outside of the intensive care unit.Which of the following is one of the criteria used in the qSOFA score? Select ONE answer only.
Your Answer: Abbreviated mental test score <8
Correct Answer: Respiratory rate >22
Explanation:In February 2016 the Society of Critical Care Medicine published a JAMA article reformatting the definitions of sepsis in an attempt to overcome the shortcomings of the old definitions.The main changes are a new definition of sepsis, the replacement of the SIRS criteria with the quick Sepsis-related Organ Failure Assessment (qSOFA), and the complete removal of “severe sepsis” as an entity.The new definition of sepsis is that it is “life-threatening organ dysfunction caused by a dysregulated host response to infection.”Septic shock is “a subset of sepsis in which underlying circulatory and cellular metabolism abnormalities are profound enough to increase mortality.”In essence this means that septic shock is sepsis plus the following, despite adequate fluid resuscitation:Vasopressors required to maintain a MAP > 65 mmHgSerum lactate > 2 mmol/lThe qSOFA score is a bedside prompt designed to identify patients with suspected infection who are at greater risk for a poor outcome outside of the intensive care unit. It uses the following three criteria:Hypotension (SBP < 100 mmHg)Tachypnoea (RR > 22)Altered mental status (GCS < 15)The presence of 2 or more of the qSOFA criteria near the onset of infection is associated with greater risk of death or a prolonged intensive care unit stay.
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This question is part of the following fields:
- Pathology
- Pathology Of Infections
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Question 18
Correct
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Regarding Campylobacter gastroenteritis, which of the following statements is INCORRECT:
Your Answer: Infection usually requires antibiotic treatment.
Explanation:Campylobacter jejuni is the primary human pathogen, typically causing dysentery (bloody diarrhoea illness) following ingestion of contaminated meat, especially poultry. Infection is typically self-limiting and does not require antibiotic therapy. Campylobacter gastroenteritis is associated with the immune-mediated complications of Guillain-Barre syndrome, reactive arthritis and Reiter’s syndrome.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 19
Correct
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Bendoflumethiazide may cause all of the following electrolyte imbalances EXCEPT for:
Your Answer: Hypocalcaemia
Explanation:Common side effects of thiazide diuretics include:Excessive diuresis, postural hypotension, dehydration, renal impairmentAcid-base and electrolyte imbalanceHypokalaemia, hyponatraemia, hypomagnesaemia, hypercalcaemia, hypochloraemic alkalosisMetabolic imbalanceHyperuricaemia and goutImpaired glucose tolerance and hyperglycaemiaAltered plasma-lipid concentrationsMild gastrointestinal disturbances
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 20
Incorrect
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Which of the following data types does a pain-scoring system represent?
Your Answer: Discrete
Correct Answer: Ordinal
Explanation:Pain scoring systems are processes for assessing pain and the severity of illnesses that have been scientifically designed and tested. An example of ordinal categorical data is a pain scoring system.
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This question is part of the following fields:
- Evidence Based Medicine
- Statistics
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Question 21
Incorrect
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Which of the following organisms can penetrate intact skin:
Your Answer: Streptococcus pyogenes
Correct Answer: Leptospira spp.
Explanation:Leptospirosis is a bacterial disease caused byLeptospira spp. It is the most common zoonotic infection worldwide.It is usually contracted by exposure to water contaminated with the urine of infected animals (such as rodents, cattle, and dogs). The most important reservoirs are rodents, and rats are the most common source worldwide.The bacteria enter the body through the skin or mucous membranes. This is more likely if the skin is broken by leptospirosis is somewhat unusual in that it can enter the body through intact skin.
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This question is part of the following fields:
- Microbiology
- Principles
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Question 22
Incorrect
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ACE inhibitors are indicated for all of the following EXCEPT for:
Your Answer: Diabetic nephropathy
Correct Answer: Angina
Explanation:ACE inhibitors have many uses and are generally well tolerated. They are indicated for:Heart failureHypertensionDiabetic nephropathySecondary prevention of cardiovascular events
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 23
Correct
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Which of the following is NOT typically associated with eosinophilia:
Your Answer: Whooping cough
Explanation:An eosinophil leucocytosis is defined as an increase in blood eosinophils above 0.4 x 109/L.It is most frequently due to:Allergic diseases (e.g. bronchial asthma, hay fever, atopic dermatitis, urticaria)Parasites (e.g. hookworm, ascariasis, tapeworm, schistosomiasis)Skin diseases (e.g. psoriasis, pemphigus, urticaria, angioedema)Drug sensitivity
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This question is part of the following fields:
- Immune Responses
- Pathology
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Question 24
Correct
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Which of the following is NOT an advantage of a cohort study used to investigate the relationship between exposure to a risk factor and a future outcome:
Your Answer: Particularly suitable for rare diseases
Explanation:Advantages: ideal for studying associations between an exposure and an outcome when the exposure is uncommon, the time sequence of events can be assessed, they can provide information on a wide range of disease outcomes, the absolute and relative risk of disease can be measured directly, they can give a direct estimation of disease incidence ratesDisadvantages: costly and can take long periods of time if the outcome is delayed, subject to subject-selection and loss to follow-up bias, large sample size required for rare outcome of interest so it is not useful for rare diseases, prone to confounding
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This question is part of the following fields:
- Evidence Based Medicine
- Study Methodology
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Question 25
Incorrect
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A foot drop is a sign of damage to which of the following nerves?
Your Answer: Common fibular nerve
Correct Answer: Deep fibular nerve
Explanation:The deep fibular nerve was previously referred to as the anterior tibial nerve. It starts at the common fibular nerve bifurcation, between the fibula and the proximal part of the fibularis longus. Damage to this nerve can cause foot drop or loss of dorsiflexion since this nerve controls the anterior leg muscles.
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This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 26
Correct
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Antidiuretic hormone (ADH) levels are found to be increased in a young lady with unexplained hyponatraemia.Which of the following is a result of the release of ADH?
Your Answer: Small volumes of concentrated urine
Explanation:ADH, or antidiuretic hormone, is a hormone that regulates water and electrolyte balance. It is released in response to a variety of events, the most important of which are higher plasma osmolality or lower blood pressure. ADH increases plasma volume and blood pressure via acting on the kidneys and peripheral vasculature.ADH causes extensive vasoconstriction by acting on peripheral V1 Receptors.ADH binds to B2 Receptors in the terminal distal convoluted tubule and collecting duct of the kidney, increasing transcription and aquaporin insertion in the cells that line the lumen. Aquaporins are water channels that allow water to pass through the tubule and into the interstitial fluid via osmosis, lowering urine losses.The permeability of the distal collecting duct (the section within the inner medulla) to urea is likewise increased by ADH. More urea travels out of the tubule and into the peritubular fluid, contributing to the counter current multiplier, which improves the Loop of Henle’s concentrating power.Overall, there is enhanced urea and water reabsorption in the presence of ADH, resulting in modest amounts of concentrated urine. There is minimal urea and water reabsorption in the absence of ADH, resulting in huge amounts of dilute urine.
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This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 27
Correct
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A 65-year-old man complains of severe vertigo, nausea, and tinnitus. Upon presenting himself to the emergency room, it was observed that he is exhibiting ataxia, right-sided loss of pain and temperature sense on the face, and left-sided sensory loss to the body. An MRI and CT scan was ordered and the results showed that he is suffering from a right-sided stroke. Branches of which of the following arteries are most likely implicated in the case?
Your Answer: Basilar artery
Explanation:The lateral pontine syndrome occurs due to occlusion of perforating branches of the basilar and anterior inferior cerebellar (AICA) arteries. It is also known as Marie-Foix syndrome or Marie-Foix-Alajouanine syndrome. It is considered one of the brainstem stroke syndromes of the lateral aspect of the pons.It is characterized by ipsilateral limb ataxia, loss of pain and temperature sensation of the face, facial weakness, hearing loss, vertigo and nystagmus, hemiplegia/hemiparesis, and loss of pain and temperature sensation.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 28
Correct
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Among the following microorganisms, which is considered to be transmitted by invasion of intact skin?
Your Answer: Leptospira spp.
Explanation:Rodents and domestic animals are the primary reservoirs for the Leptospira spp, although other animals, including cows, horses, mongooses, and frogs, can also harbour the leptospires. Humans may be directly infected from animal urine or indirectly by contact with soil or water that is contaminated with urine from infected animals. Infected humans can shed leptospires in urine for up to 11 months, infected cows for 3.5 months, infected dogs for 4 years, and infected rodents possibly for their entire lifetime.The organisms enter the host through mucous membranes or abraded skin. The incubation period ranges from 5 to 14 days.
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This question is part of the following fields:
- Microbiology
- Principles Of Microbiology
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Question 29
Incorrect
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For an action potential to occur, which of the following must be true:
Your Answer: All of the above
Correct Answer: Depolarisation of the membrane must reach threshold potential
Explanation:For an action potential to occur, the membrane must become more permeable to Na+and the Na+influx must be greater than the K+efflux. An action potential occurs when depolarisation of the membrane reaches threshold potential. The membrane must be out of the absolute refractory period, however an action potential can still occur in a relative refractory period but only in response to a larger than normal stimulus.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 30
Correct
SESSION STATS - PERFORMANCE PER SPECIALTY
