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Question 1
Correct
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Which of the following is most likely to cause a bitemporal hemianopia:
Your Answer: Pituitary adenoma
Explanation:A bitemporal hemianopia is most likely due to compression at the optic chiasm. This may be caused by pituitary tumour, craniopharyngioma, meningioma, optic glioma or aneurysm of the internal carotid artery. A posterior cerebral stroke will most likely result in a contralateral homonymous hemianopia with macular sparing.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 2
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: Co-amoxiclav
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 3
Correct
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What is the main mechanism of action of flecainide:
Your Answer: Blocks Na+ channels
Explanation:Flecainide inhibits the transmembrane influx of extracellular Na+ ions via fast channels on cardiac tissues resulting in a decrease in rate of depolarisation of the action potential, prolonging the PR and QRS intervals. At high concentrations, it exerts inhibitory effects on slow Ca2+ channels, accompanied by moderate negative inotropic effect.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 4
Correct
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A 45-year old man presented to the emergency room with complains of chest pain and breathlessness. Upon history taking and examination, it was discovered that he had a right-sided spontaneous pneumothorax and had a failed attempt at pleural aspiration. The pneumothorax is still considerable in size, but he remains breathless. A Seldinger chest drain was inserted but it started to drain frank blood shortly after. Which of the following complications is most likely to have occurred?
Your Answer: Intercostal artery laceration
Explanation:Injury to the intercostal artery (ICA) is an infrequent but potentially life-threatening complication of all pleural interventions. Traditional anatomy teaching describes the ICA as lying in the intercostal groove, protected by the flange of the rib. This is the rationale behind the recommendation to insert needles just above the superior border of the rib. Current recommendations for chest drain insertion suggest that drains should be inserted in the ‘safe triangle’ in order to avoid the heart and the mediastinum and be above the level of the diaphragm. The safe triangle is formed anteriorly by the lateral border of the pectoralis major, laterally by the lateral border of the latissimus dorsi, inferiorly by the line of the fifth intercostal space and superiorly by the base of the axilla. Imaging guidance also aids in the safety of the procedure.
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This question is part of the following fields:
- Anatomy
- Thorax
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Question 5
Correct
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Regarding the flexor digitorum profundus muscle, which of the following is true?
Your Answer: The medial aspect of the muscle is innervated by the ulnar nerve
Explanation:Flexor digitorum profundus is a fusiform muscle located deep within the anterior (flexor) compartment of the forearm. Along with the flexor pollicis longus and pronator quadratus muscles, it comprises the deep flexor compartment of the forearm.Flexor digitorum profundus has a dual innervation:(1) The medial part of the muscle, that inserts to the fourth and fifth digits, is innervated by the ulnar nerve (C8-T1);(2) The lateral part, that inserts to the second and third digits, is innervated by the median nerve, via anterior interosseous branch (C8-T1).
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 6
Correct
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Cardiac myocytes are connected to each other by which of the following:
Your Answer: Intercalated discs
Explanation:Adjacent cardiac myocytes are connected to each other by intercalated discs. The intercalated discs provide both a structural attachment by ‘glueing’ cells together at desmosomes and an electrical contact made up of proteins called connexons, called a gap junction, which essentially creates a low-resistance pathway between cells.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 7
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 8
Correct
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A 40-year-old man who has a history of asthma arrives at the emergency department complaining of palpitations that have been going on for 5 days. Which of the following beta-blockers is the safest for an asthmatic patient?
Your Answer: Atenolol
Explanation:Atenolol is a beta blocker, which is a type of medication that works by preventing certain natural substances in the body, such as epinephrine, from acting on the heart and blood vessels. This effect reduces heart rate, blood pressure, and cardiac strain. Atenolol, bisoprolol fumarate, metoprolol tartrate, nebivolol, and (to a lesser extent) acebutolol have a lower action on beta2 (bronchial) receptors and are thus cardio selective but not cardiac specific. They have a lower effect on airway resistance, although they are not without this adverse effect.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 9
Correct
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A 43-year old male is taken to the Emergency Room for a lacerated wound on the abdomen, situated above the umbilicus. A short segment of the small bowel has herniated through the wound.Which of these anatomic structures is the deepest structure injured in the case above?
Your Answer: Transversalis fascia
Explanation:The following structures are the layers of the anterior abdominal wall from the most superficial to the deepest layer:SkinFatty layer of the superficial fascia (Camper’s fascia)Membranous layer of the superficial fascia (Scarpa’s fascia)Aponeurosis of the external and internal oblique musclesRectus abdominis muscleAponeurosis of the internal oblique and transversus abdominisFascia transversalisExtraperitoneal fatParietal peritoneum
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This question is part of the following fields:
- Abdomen And Pelvis
- Anatomy
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Question 10
Incorrect
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Regarding a cohort study, which of the following statements is INCORRECT:
Your Answer: It is prospective.
Correct Answer: It is useful for rare diseases.
Explanation:A cohort study is a longitudinal, prospective, observational study that follows a defined group (cohort) matched to unexposed controls for a set period of time and investigates the effect of exposure to a risk factor on a particular future outcome. The usual outcome measure is the relative risk (risk ratio). A large sample size is required for a rare outcome of interest so it is not useful for rare diseases.
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This question is part of the following fields:
- Evidence Based Medicine
- Study Methodology
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Question 11
Incorrect
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A 71-year-old patient has been diagnosed with a dopamine-secreting neuroendocrine tumour.Which of the following statements about dopamine is correct?
Your Answer: It is released from the paraventricular nucleus of the hypothalamus
Correct Answer: It inhibits prolactin release from the anterior pituitary
Explanation:Dopamine is a neurotransmitter and amine hormone that is derived from the amino acid tyrosine. It is made in a number of places throughout the human body, both inside and outside the central nervous system. The adrenal medulla, dopamine neurons in the arcuate nucleus of the hypothalamus, the substantia nigra, and other areas of the brain produce dopamine.The tuberoinfundibular pathway refers to the dopamine neurons in the arcuate nucleus of the hypothalamus’ tubeal region. Dopamine is discharged into the hypothalamo-hypophyseal portal system from these neurons’ neurosecretory terminals at the median eminence.The major function of dopamine produced from the hypothalamus is to suppress prolactin production from the anterior pituitary, and it is released in reaction to excessive levels of prolactin secretion. Modulation of motor-control centres and activation of reward centres are two more crucial activities of the brain.Dopamine-secreting cells can also be found in other areas of the body, where they perform mostly paracrine functions (acting on nearby cells).
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This question is part of the following fields:
- Endocrine Physiology
- Physiology
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Question 12
Correct
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A 23-year-old male presents to his family physician with the complaint of repeated episodes of abdominal pain and the passage of dark coloured urine every morning. He also reports increasing fatigue over the past several months. On examination, there are raised, painful red nodules over the skin of the back. Laboratory workup shows haemolytic anaemia, leukopenia and thrombocytopenia. Which one of the following disorders is this patient most likely to have?
Your Answer: Paroxysmal nocturnal haemoglobinuria
Explanation:Paroxysmal nocturnal haemoglobinuria is an acquired genetic disorder that causes a decrease in red blood cells due to a membrane defect that allows increased complement binding to RBCs, causing haemolysis. Patients complain of dark-coloured urine first in the morning due to haemoglobinuria secondary to lysis of red blood cells overnight. Thrombosis occurs, which affects hepatic, abdominal, cerebral and subdermal veins. Thrombosis of hepatic veins can lead to Budd-Chiari syndrome, thrombosis of subdermal veins can lead to painful nodules on the skin, and thrombosis of cerebral vessels can lead to stroke. The presence of dark urine in the morning only and at no other time differentiates this condition from other conditions.Multiple myeloma would present with bone pain, signs of radiculopathy if there were nerve root compression and a history of repeated infections. Patients with Non-Hodgkin Lymphoma would complain of enlarged lymph nodes, fatigue, fever, weight loss and a history of repeated infections. Acute lymphoblastic leukaemia presents more commonly in children than in adults. The patient would complain of bone pain, and on examination, there would be hepatosplenomegaly.
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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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In adults, the conus medullaris of the spinal cord lies at which of the following vertebral levels:
Your Answer: T12/L1
Correct Answer: L1/L2
Explanation:At birth, the conus medullaris lies at L3. By the age of 21, it sits at L1/L2.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 14
Correct
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Question 15
Correct
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What is the primary function of collagen in wound healing?
Your Answer: Strength and support
Explanation:Key elements of the maturation stage include collagen cross-linking, collagen remodelling, wound contraction, and repigmentation. The tensile strength of the wound is directly proportional to the amount of collagen present. Numerous types of collagen have been identified; types I and III predominate in the skin and aponeurotic layers. Initially, a triple helix (tropocollagen) is formed by three protein chains; two are identical alpha-1 protein chains, and the third is an alpha-2 protein.
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This question is part of the following fields:
- Pathology
- Wound Healing
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Question 16
Correct
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Which of the following organisms can penetrate intact skin:
Your 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 17
Correct
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A 13-year-old male presents to the Emergency Department with a heavy nosebleed. His medical record shows that he was diagnosed with Haemophilia B as a child. What is the mode of inheritance of this disease?
Your Answer: X-linked recessive
Explanation:Deficiency of Factor IX causes Haemophilia B, and like the other Haemophilia’s, it has an X-linked recessive pattern of inheritance, affecting males born to carrier mothers.Haemophilia B is the second commonest form of haemophilia and is rarer than haemophilia A. Haemophilia B is similar to haemophilia A but is less severe. You can distinguish the two disorders by specific coagulation factor assays. The incidence of Haemophilia B is one-fifth of that of haemophilia A. In laboratory findings, you get prolonged APTT, normal PT and low factor IX for Haemophilia B. There is also a variation called Leyden, in which factor IX levels are below 1% until puberty, when they rise, potentially reaching as high as 40-60% of normal. This is thought to be due to the effects of testosterone at puberty.
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This question is part of the following fields:
- Haematology
- Pathology
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Question 18
Incorrect
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Innate, or non-specific, immunity is the immune system we are born with.Which of the following is NOT an example of innate immunity? Select ONE answer only.
Your Answer: Stomach acid
Correct Answer: T-lymphocytes
Explanation:Innate, or non-specific, immunity is the immune system we are born with.There are three aspects of innate immunity:1. Anatomical barriers, such as:The cough reflexEnzymes in tears and skin oilsMucus – which traps bacteria and small particlesSkinStomach acid2. Humoral barriers, such as:The complement systemInterleukin-13. Cellular barriers, such as:NeutrophilsMacrophagesDendritic cellsNatural killer cellsAntibody production is part of the specific, or inducible immune response. T-lymphocytesare responsible for the cell mediated immune response which is part of specific, or inducible immunity.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 19
Correct
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Which of the following is a contraindication for aspirin?
Your Answer: Children under 16 years
Explanation:Aspirin contraindications include: hypersensitivity to NSAIDs; asthma, rhinitis, and nasal polyps; and usage in children or teens.There is little evidence of allergic cross-reactivity for salicylates. However, due to similarities in chemical structure and/or pharmacologic activities, the possibility of cross-sensitivity cannot be completely ruled out.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 20
Correct
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All of the muscles of the tongue (other than the palatoglossus) are innervated by which of the following nerves:
Your Answer: Hypoglossal nerve
Explanation:All of the muscles of the tongue are innervated by the hypoglossal nerve, except for the palatoglossus, which is innervated by the vagus nerve.
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This question is part of the following fields:
- Anatomy
- Head And Neck
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Question 21
Correct
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You are treating a patient with a Clostridium difficile infection. His condition was found to be antibiotic-associated. Which of the following pieces of advice on preventing the spread of this disease should you give this patient?
Your Answer: Washing hands with soap and water
Explanation:Clostridium difficile (C. diff) can cause colitis, or inflammation of the colon. To prevent its spread, one should practice good hand hygiene, regularly clean areas of the home that may become contaminated with C. difficile, practice good hand hygiene, and clean surfaces, spills, and accidents.
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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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A 20-year-old boy took almost 25 tablets of paracetamol almost 4 hours ago. The boy is healthy and has no known comorbid or drug history. Out of the following metabolic pathways, which one is primarily responsible for the toxic effects of paracetamol?
Your Answer: Co-oxidation by peroxidases
Correct Answer: N-hydroxylation
Explanation:Paracetamol is predominantly metabolized in the liver by three main metabolic pathways:1. Glucuronidation (45-55%)2. Sulphate conjugation (30-35%)3. N-hydroxylation via the hepatic cytochrome P450 enzyme system (10-15%)Cytochrome P450 enzymes catalyse the oxidation of acetaminophen to the reactive metabolite N-acetyl-p-benzoquinoneimine (NAPQI). NAPQI primarily contributes to the toxic effects of acetaminophen. NAPQI is an intermediate metabolite that is further metabolized by fast conjugation with glutathione. The conjugated metabolite is then excreted in the urine as mercapturic acid. High doses of acetaminophen (overdoses) can lead to hepatic necrosis due to depleting glutathione and high binding levels of reactive metabolite (NAPQI) to important parts of liver cells.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 23
Incorrect
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Cryptococcus neoformans is primarily transmitted by which of the following routes:
Your Answer: Respiratory droplet spread
Correct Answer: Inhalation of spores
Explanation:Cryptococcus neoformans is found in bird droppings and transmission is by inhalation of spores, thus the lung is the primary site of infection.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 24
Incorrect
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In the Emergency Department, a 35-year-old woman actively seizing is brought in. She is quickly shifted into the resuscitation room and is administered a dose of benzodiazepine. The seizure is quickly terminated. Once the patient is stable, she tells you she is a known case of epilepsy and takes phenytoin to control it. Which of the following is the primary mechanism of action of phenytoin?
Your Answer: GABA receptor agonist
Correct Answer: Sodium channel blocker
Explanation:Phenytoin is in the anticonvulsants class of drugs and is used in the management and treatment of the following:1. epilepsy2. generalized tonic-clonic seizures3. complex partial seizures4. status epilepticus. It works by inactivating the voltage-gated sodium channels responsible for increasing the action potential. It is non-specific and targets almost all voltage-gated sodium channel subtypes. More specifically, phenytoin prevents seizures by inhibiting the positive feedback loop that results in neuronal propagation of high-frequency action potentials.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 25
Correct
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Which of the following is NOT a typical side effect of thiopental sodium:
Your Answer: Seizures
Explanation:Extravasation of thiopental during injection can lead to tissue damage. Accidental intra-arterial injection causes vasospasm and may lead to thrombosis and tissue necrosis. Other side effects include involuntary muscle movements on induction, cough and laryngospasm, arrhythmias, hypotension, headache and hypersensitivity reactions. Thiopental sodium has anticonvulsant properties and does not cause seizures.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 26
Incorrect
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Severe vomiting and diarrhoea were reported by a 25-year-old man. He's dehydrated and needs intravenous fluids to rehydrate. You give him cyclizine as part of his treatment.What is cyclizine's main mechanism of action?
Your Answer: 5-HT 3 receptor antagonism
Correct Answer: Antihistamine action
Explanation:Cyclizine is a piperazine derivative that functions as an antihistamine (H1-receptor antagonist). To prevent nausea and vomiting, it is thought to act on the chemoreceptor trigger zone (CTZ) and the labyrinthine apparatus. It has a lower antimuscarinic effect as well.
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 27
Incorrect
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Which of the following is most likely affected in De Quervain's tenosynovitis?
Your Answer: Extensor pollicis longus
Correct Answer: Extensor pollicis brevis
Explanation:De Quervain tenosynovitis is named after the Swiss surgeon, Fritz de Quervain, who first described it in 1895. It is a condition which involves tendon entrapment affecting the first dorsal compartment of the wrist. With this condition thickening of the tendon sheaths around the abductor pollicis longus and extensor pollicis brevis develops where the tendons pass in through the fibro-osseous tunnel located along the radial styloid at the distal wrist. Pain is exacerbated by thumb movement and radial and ulnar deviation of the wrist.The estimated prevalence of de Quervain tenosynovitis is about 0.5% in men and 1.3% in women with peak prevalence among those in their forties and fifties. It may be seen more commonly in individuals with a history of medial or lateral epicondylitis. Bilateral involvement is often reported in new mothers or child care providers in whom spontaneous resolution typically occurs once lifting of the child is less frequent.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 28
Correct
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Most of the lymph from vessels that drain the breast is collected in which of the following lymph nodes?
Your Answer: Axillary nodes
Explanation:Lymph is the fluid that flows through the lymphatic system. Axillary lymph nodes are near the breasts. They are often the first location to which breast cancer spreads if it moves beyond the breast tissue. They receive approximately 75% of lymph drainage from the breast via lymphatic vessels, laterally and superiorly. The lymph usually first drains to the anterior axillary nodes, and from here, through the central axillary, apical, and supraclavicular nodes in sequence.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 29
Correct
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Following the administration of a drug that was started a few months earlier, a patient presents with features of peripheral neuropathy.Which of the following drugs is most likely to cause peripheral neuropathy?
Your Answer: Isoniazid
Explanation:Isoniazid, a first-line agent for the treatment of tuberculosis, has the commonest side effect of peripheral neuropathy. It occurs in up to 20% of patients taking the drug at a dose > 6 mg/kg daily. Isoniazid combines with pyridoxine (vitamin B6) to form hydrazone, which is excreted in the urine. This causes a deficiency of biologically active pyridoxine leading to peripheral neuropathy.Peripheral neuropathy of isoniazid is prevented by the co-administration of pyridoxine at a dose of 10 mg for each 100 mg of isoniazid given.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 30
Incorrect
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Regarding chemical control of respiration, which of the following statements is INCORRECT:
Your Answer: There is a synergistic relationship between PO2 and PCO2 in stimulating ventilatory response.
Correct Answer: The blood-brain barrier is freely permeable to HCO3 - ions.
Explanation:CSF is separated from the blood by the blood-brain barrier. This barrier is impermeable to polar molecules such as H+and HCO3-but CO2can diffuse across it easily. The pH of CSF is therefore determined by the arterial PCO2and the CSF HCO3-and is not affected by blood pH.
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This question is part of the following fields:
- Physiology
- Respiratory
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SESSION STATS - PERFORMANCE PER SPECIALTY
