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Question 1
Correct
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Aplastic crises in sickle cell anaemia is classically precipitated by which of the following infections:
Your Answer: Parvovirus B19
Explanation:A serious complication in sickle cell disease (SCD) is the aplastic crisis. This may be caused by infection with Parvovirus B-19 (B19V). This virus causes fifth disease, a normally benign childhood disorder associated with fever, malaise, and a mild rash. This virus infects RBC progenitors in bone marrow, resulting in impaired cell division for a few days.
Healthy people experience, at most, a slight drop in hematocrit, since the half-life of normal erythrocytes in the circulation is 40-60 days. In people with SCD, however, the RBC lifespan is greatly shortened (usually 10-20 days), and a very rapid drop in Hb occurs. The condition is self-limited, with bone marrow recovery occurring in 7-10 days, followed by brisk reticulocytosis. -
This question is part of the following fields:
- Haematology
- Pathology
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Question 2
Incorrect
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You've been requested to give a discussion to a group of medical students about cardiovascular physiology. One of them inquires about cardiac output and asks if you can explain it.
Which of the following statements is correct?
Your Answer: An average resting cardiac output in a man is 6 L/min
Correct Answer: An average resting cardiac output in a woman is 5 L/min
Explanation:The terminology cardiac output refers to the amount of blood pumped by the heart in one minute. Women’s rates are around 5 L/min, whereas men’s rates are somewhat higher, around 5.5 L/min.
Cardiac output (CO) is calculated by multiplying stroke volume (SV) by heart rate (HR):
CO = HR x SVAs a result, both stroke volume and heart rate are exactly proportional to cardiac output. There will be an increase in cardiac output if the stroke volume or heart rate increases, and a reduction in cardiac output if the stroke volume or heart rate lowers.
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This question is part of the following fields:
- Cardiovascular Physiology
- Physiology
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Question 3
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 4
Incorrect
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A 21 year old student presents to the emergency room with severe acute asthma. Salbutamol and ipratropium bromide nebuliser are prescribed. The most appropriate dose of salbutamol that should be prescribed initially for this patient is which of the following?
Your Answer: 0.5 mcg every 10 - 20 minutes
Correct Answer: 5 mg every 15 - 30 minutes
Explanation:The first line treatment for acute asthma is high-dose inhaled short-acting beta2-agonists like salbutamol or terbutaline. Oxygen use should be reserved for hypoxemic patients in order to maintain oxygen saturations of 94 – 98%. In patients with moderate to severe asthma, a pressurised metered dose inhaler with spacer device is preferred (4 puffs initially, followed by 2 puffs every 2 minutes according to response, up to 10 puffs, whole process repeated every 10 – 20 minutes if necessary). For patients with life-threatening features or poorly responsive severe asthma, the oxygen-driven nebuliser route is recommended (salbutamol 5 mg at 15 – 30 minute intervals). In patients with severe acute asthma that is poorly responsive to initial bolus dose, continuous nebulisation should be considered (salbutamol at 5 – 10 mg/hour). For those in whom inhaled therapy cannot be used reliably, the intravenous route is usually reserved.
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This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 5
Correct
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A young pregnant woman is in the late stages of her pregnancy. She is administered a drug that results in her newborn being born with respiratory depression. The baby also suffers from neonatal withdrawal syndrome.
Out of the following, which drug is most likely responsible for the baby's condition?Your Answer: Diazepam
Explanation:Benzodiazepines are used as a first-line treatment in breaking seizures and in status epilepticus as they are rapid-acting.
Use of benzodiazepines in the late third-trimester or exposure during labour is associated with great risks to the foetus/neonate. Babies can exhibit either floppy infant syndrome, or marked neonatal withdrawal symptoms. Symptoms vary from mild sedation, hypotonia, and reluctance to suck, to apnoeic spells, cyanosis, and impaired metabolic responses to cold stress. These symptoms have been reported to persist for periods from hours to months after birth.
They also cross into breast milk and should be used with caution in breastfeeding mothers
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This question is part of the following fields:
- CNS Pharmacology
- Pharmacology
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Question 6
Correct
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A patient suffers a lower limb fracture that causes damage to the nerve that innervates peroneus longus.
Peroneus longus receives its innervation from which of the following nerves? Select ONE answer only.Your Answer: Superficial peroneal nerve
Explanation:Peroneus brevis is innervated by the superficial peroneal nerve.
Peroneus longus is innervated by the superficial peroneal nerve.
Peroneus tertius is innervated by the deep peroneal nerve. -
This question is part of the following fields:
- Anatomy
- Lower Limb
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Question 7
Correct
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Regarding the glomerular filtration barrier, which of the following statements is CORRECT:
Your Answer: The main factor determining whether a substance is filtered or not is molecular weight.
Explanation:Molecular weight is the main factor in determining whether a substance is filtered or not – molecules < 7 kDa in molecular weight are filtered freely e.g. glucose, amino acids, urea, ions but larger molecules are increasingly restricted up to 70 kDa, above which filtration is insignificant. Negatively charged molecules are further restricted, as they are repelled by negative charges, particularly in the basement membrane. Albumin has a molecular weight of 69 kDa and is negatively charged, thus only very small amounts are filtered (and all of the filtered albumin is reabsorbed in the proximal tubule), whereas small molecules such as ions, glucose, amino acids and urea pass the filter without hindrance. This means that ultrafiltrate is virtually protein free, but otherwise has an identical composition of that of plasma. The epithelial lining of the Bowman's capsule consists of a single layer of cells called podocytes. The glomerular capillary endothelium is perforated by pores (fenestrations) which allow plasma components with a molecular weight of < 70 kDa to pass freely.
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This question is part of the following fields:
- Physiology
- Renal
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Question 8
Correct
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Which of the following clinical features would you least expect to see in a lesion of the frontal lobe:
Your Answer: Contralateral homonymous hemianopia with macular sparing
Explanation:Contralateral homonymous hemianopia with macular sparing results from damage to the primary visual cortex of the occipital lobe. Incontinence may occur due to damage of the cortical micturition centre in the prefrontal cortex. Primitive reflexes and inability to problem solve may occur due to damage to the prefrontal cortex. Motor weakness of the contralateral limb with UMN signs may occur due to damage of the primary motor cortex.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 9
Correct
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Clostridium difficile primarily causes which of the following infectious diseases:
Your Answer: Pseudomembranous colitis
Explanation:Clostridium difficile causes pseudomembranous colitis, an acute inflammatory diarrhoeal disease and an important cause of morbidity and mortality in hospitals. Gas gangrene is primarily caused by Clostridium perfringens. Tetanus is caused by Clostridium tetani. Toxic shock syndrome may be caused by Staphylococcus aureus or Streptococcus pyogenes. Necrotising fasciitis is most commonly caused by Streptococcus pyogenes but has a multitude of causes.
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This question is part of the following fields:
- Microbiology
- Pathogens
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Question 10
Incorrect
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If a patient dislocated his right shoulder and has been referred to the orthopaedic outpatient department for a follow-up after a successful reduction, which of the following is the most important position for him to avoid holding his arm in until he is seen in the clinic?
Your Answer: Arm held flexed across abdomen palm down
Correct Answer: Arm at 90 degrees to side with palm up
Explanation:The arm should be placed in a poly-sling that should be worn for about two weeks. A physiotherapist may give gentle movements for the arm to help in reducing stiffness and in relieving the pain. It is important that the patient must avoid positions that could cause re-dislocation.
The most important position to avoid is the arm being held out at 90 degrees to the side with the palm facing upwards, especially if a force is being applied. -
This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 11
Correct
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A 57-year-old woman has presented with cough and shortness of breath. Her GP had done some blood tests recently and told her that she had a positive ANA result.
Which of these statements is true about anti-nuclear antibodies (ANAs)? Select only ONE answer.
Your Answer: The presence of ANAs in rheumatoid arthritis is suggestive of Felty’s syndrome
Explanation:Anti-nuclear antibodies are auto-antibodies directed against a variety of nuclear antigens. There are different staining patterns and each pattern is suggestive of a different disorder.
Speckled staining is suggestive of mixed connective tissue disease.
Nucleolar staining is suggestive of scleroderma, while homogenous staining is suggestive of lupus.
Anti-double stranded DNA is suggestive of SLE while anti-histone antibodies are suggestive of drug-induced lupus.
ELISA testing is cheaper but not the most accurate means of testing for ANAs. Indirect immunofluorescence testing is the most accurate.
The presence of ANAs in rheumatoid arthritis is suggestive of Felty’s syndrome. Felty’s syndrome is characterized by a combination of rheumatoid arthritis, splenomegaly and neutropenia.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 12
Correct
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The big toe of a 59-year-old female is red, hot, and swollen. The patient is diagnosed with acute gout. You intend to start her on a nonsteroidal anti-inflammatory medicine (NSAID). Her husband was diagnosed with a peptic ulcer, and she is apprehensive about the potential adverse effects of NSAIDs.
Which of the following NSAIDs has the lowest chance of causing side effects?Your Answer: Ibuprofen
Explanation:Non-steroidal anti-inflammatory medications (NSAIDs) have slight differences in anti-inflammatory activity, but there is a lot of diversity in individual response and tolerance to these treatments. Approximately 60% of patients will respond to any NSAID; those who do not respond to one may well respond to another. Pain relief begins soon after the first dose, and a full analgesic effect should be achieved within a week, whereas an anti-inflammatory effect may take up to three weeks to achieve (or to be clinically assessable). If the desired results are not reached within these time frames, another NSAID should be attempted.
By inhibiting the enzyme cyclo-oxygenase, NSAIDs limit the generation of prostaglandins. They differ in their selectivity for inhibiting various types of cyclo-oxygenase; selective inhibition of cyclo-oxygenase-2 is linked to reduced gastrointestinal discomfort. Susceptibility to gastrointestinal effects is influenced by a number of different parameters, and an NSAID should be chosen based on the frequency of side effects.
Ibuprofen is an anti-inflammatory, analgesic, and antipyretic propionic acid derivative. Although it has fewer side effects than other non-selective NSAIDs, its anti-inflammatory properties are less effective. For rheumatoid arthritis, daily doses of 1.6 to 2.4 g are required, and it is contraindicated for illnesses characterized by inflammation, such as acute gout.Because it combines strong efficacy with a low incidence of adverse effects, Naproxen is one of the top choices. It is more likely to cause negative effects than ibuprofen.
Similar to ibuprofen, ketoprofen and diclofenac have anti-inflammatory characteristics, however they have additional negative effects.Indomethacin has a similar or better effect to naproxen, however it comes with a lot of side effects, such as headaches, dizziness, and gastrointestinal problems.
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This question is part of the following fields:
- Musculoskeletal Pharmacology
- Pharmacology
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Question 13
Correct
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Which of the following is NOT a benefit of low molecular weight heparin (LMWH) over unfractionated heparin therapy:
Your Answer: Its effects can be rapidly and completely reversed with protamine sulfate.
Explanation:Advantages of LMWHGreater ability to inhibit factor Xa directly, interacting less with platelets and so may have a lesser tendency to cause bleedingGreater bioavailability and longer half-life in plasma making once daily subcutaneous administration possibleMore predictable dose response avoiding the need for routine anticoagulant monitoringLower associated risk of heparin-induced thrombocytopenia or of osteoporosis
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 14
Incorrect
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Pancreatic ductal alkaline fluid secretion is mainly stimulated by which of the following hormones:
Your Answer: Cholecystokinin
Correct Answer: Secretin
Explanation:Pancreatic exocrine secretion is controlled by:
Parasympathetic stimulation which enhances secretion of both the enzyme and aqueous components
Sympathetic stimulation which inhibits pancreatic secretion
Secretin which stimulates secretion of the alkaline-rich fluid from ductal cells
Cholecystokinin which stimulates secretion of the enzyme-rich fluid from acinar cellsSomatostatin which inhibits secretion from both acinar and ductal cells
Gastrin which stimulates pancreatic acinar cells to secrete digestive enzymes -
This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 15
Correct
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Which of the following nerves supply the superficial head of the flexor pollicis brevis muscle?
Your Answer: The recurrent branch of the median nerve
Explanation:The two heads of the flexor pollicis brevis usually differ in their innervation. The superficial head of flexor pollicis muscle receives nervous supply from the recurrent branch of the median nerve, whereas the deep head receives innervation from the deep branch of the ulnar nerve, derived from spinal roots C8 and T1.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 16
Correct
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A 30-year old male is brought to the emergency room after a terrible fall during a photoshoot. The patient reported falling on his right forearm. There is evident swelling and tenderness on the affected area, with notable weakness of the flexor pollicis longus muscle. Radiographic imaging showed a fracture on the midshaft of the right radius.
Which of the following nerves is most likely injured in the case above?Your Answer: The anterior interosseous nerve
Explanation:Flexor pollicis longus receives nervous supply from the anterior interosseous branch of median nerve, derived from spinal roots C7 and C8.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 17
Incorrect
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The following are all examples of type IV hypersensitivity EXCEPT for:
Your Answer: Chronic transplant rejection
Correct Answer: Extrinsic allergic alveolitis
Explanation:Examples of type IV reactions includes:
Contact dermatitis
Hashimoto’s thyroiditis
Primary biliary cholangitis
Tuberculin skin test (Mantoux test)
Chronic transplant rejection
Granulomatous inflammation (e.g. sarcoidosis, Crohn’s disease) -
This question is part of the following fields:
- Immune Responses
- Pathology
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Question 18
Correct
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Which of the following statements is true about anterior cord syndrome?
Your Answer: There is preservation of proprioception
Explanation:Anterior cord syndrome is an incomplete cord syndrome that predominantly affects the anterior 2/3 of the spinal cord, characteristically resulting in motor paralysis below the level of the lesion as well as the loss of pain and temperature at and below the level of the lesion. The patient presentation typically includes these two findings; however, there is variability depending on the portion of the spinal cord affected. Other findings include back pain, or autonomic dysfunction such as hypotension, neurogenic bowel or bladder, and sexual dysfunction. The severity of motor dysfunction can vary, typically resulting in paraplegia or quadriplegia.
Proprioception, vibratory sense, two-point discrimination, and fine touch are not affected in anterior cord syndrome. These sensations are under the control of the dorsal column of the spinal cord, which is supplied by two posterior spinal arteries running in the posterior lateral sulci.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 19
Correct
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What kind of function loss do you anticipate in a 22-year-old guy who had a laceration to his arm, resulting in nerve damage in the antecubital fossa?
Your Answer: Opposition of thumb
Explanation:The symptoms of median nerve injury include tingling or numbness in the forearm, thumb, and three adjacent fingers, as well as gripping weakness and the inability to move the thumb across the palm.
Because the thenar muscles and the flexor pollicis longus are paralyzed, flexion, abduction, and opposition of the thumb at the MCPJ and IPJ are gone.
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This question is part of the following fields:
- Anatomy
- Upper Limb
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Question 20
Incorrect
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Which of these structures is the smallest and deepest component of muscle connective tissue?
Your Answer: Fascicle
Correct Answer: Endomysium
Explanation:There are three types of muscle:
Skeletal muscle
Cardiac muscle
Smooth muscleIndividual muscle is enveloped in a layer of dense irregular connective tissue called the epimysium. The epimysium protects the muscles from friction against bones and other muscles.
Skeletal muscle is composed of muscle fibres, referred to as myofibers which is ensheathed by a wispy layer of areolar connective tissue called the endomysium. The endomysium is the smallest and deepest component of muscle connective tissue.
Myofibers grouped together in bundles form fascicles, or fasciculi. These are surrounded by a type of connective tissue called the perimysium.
Beneath the endomysium lies the sarcolemma, an elastic sheath with infoldings that invaginate the interior of the myofibers, particularly at the motor endplate of the neuromuscular junction.
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This question is part of the following fields:
- Basic Cellular Physiology
- Physiology
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Question 21
Correct
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A 7-year-old boy is brought to the emergency room with complaints of a red and painful left eye. Upon physical examination, it was noted that there is the presence of conjunctival erythema. A mucopurulent discharge and crusting of the lid was also evident. A diagnosis of bacterial conjunctivitis was made.
According to the latest NICE guidelines, which of the following should NOT be a part of the management of this patient?Your Answer: Topical antibiotics should be prescribed routinely
Explanation:The following are the NICE guidelines on the management of bacterial conjunctivitis:
– Infective conjunctivitis is a self-limiting illness that usually settles without treatment within 1-2 weeks. If symptoms persist for longer than two weeks they should return for review.
– Seek medical attention urgently if marked eye pain or photophobia, loss of visual acuity, or marked redness of the eye develop.
– Remove contact lenses, if worn, until all symptoms and signs of infection have completely resolved and any treatment has been completed for 24 hours.
– Lubricant eye drops may reduce eye discomfort; these are available over the counter, as well as on prescription.
– Clean away infected secretions from eyelids and lashes with cotton wool soaked in water.
– Wash hands regularly, particularly after touching the eyes.
– Avoid sharing pillows and towels.
– It is not necessary to exclude a child from school or childcare if they have infective conjunctivitis, as mild infectious illnesses should not interrupt school attendance. An exception would be if there is an outbreak of infective conjunctivitis, when advice should be sought from the Health Protection Agency by the school.
– Adults who work in close contact with others, or with vulnerable patients, should avoid such contact until the discharge has settled. -
This question is part of the following fields:
- Microbiology
- Specific Pathogen Groups
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Question 22
Incorrect
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You review a patient with urinary sepsis and decide to start her on gentamicin.
Which statement about gentamicin is true?
Your Answer: It acts by binding to the 50S subunit
Correct Answer: Ototoxicity is a dose-related effect
Explanation:Gentamicin, an aminoglycoside antibiotic, acts by binding to the 30S subunit of the bacterial ribosome inhibiting the binding of aminoacyl-tRNA, and thus prevents initiation of protein synthesis.
Gentamicin is given by injection because it is NOT absorbed orally.
It is excreted in the kidneys by glomerular filtration
Gentamicin is not to be used for the treatment of Neisseria meningitidis, Neisseria gonorrhoea, or Legionella pneumophila.There is a risk of patient going into shock from lipid A endotoxin release.
Two of its most notable side effects are hearing loss reversible nephrotoxicity and which are both dose-related and levels should be monitored in patients.
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 23
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 24
Correct
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A 4-year-old girl is rushed to the Emergency Department by her grandparents after swallowing some of her grandfather's Warfarin tablets. On further questioning, it turns out that she took 5 of his 3 mg tablets which he needs to take due to a history of atrial fibrillation. The child appears healthy well-oriented in time, place and person, and has normal vitals.
What is the threshold dose of Warfarin that needs to be ingested for there to be a risk of anticoagulation?Your Answer: 0.5 mg/kg
Explanation:The clinical effects of Warfarin occur after a dose of greater than 0.5 mg/kg, and they will be observable 8-10 hours after consumption of the drug. The antidote used for Warfarin is Vitamin K.
1. In low-risk cases with no apparent bleeding:
an oral dose of 10 mg vitamin K2. If there is clinically significant bleeding
an intravenous dose of 250-300 mcg/kgActivated charcoal:
in cases of warfarin ingestion
binds to it and reduces the absorption of warfarin
the ingestion must have occurred within the last hour
There is, however, rarely a need for the use of activated charcoal because vitamin K is such as safe and effective antidote.Clotting studies, including an INR, can be performed, but small children who have ingested warfarin do not require INRs or follow up if they have been treated with 10 mg vitamin K. This dose of vitamin will completely reverse the anticoagulative effects of warfarin.
Perform INR if any of the following are present:
1. Delayed presentation (>6 hours)
2. Patients with symptoms or signs of anticoagulation
3. Possible massive ingestion -
This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 25
Incorrect
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Which of the following is NOT a typical feature of lithium toxicity:
Your Answer: Hyperreflexia
Correct Answer: Miosis
Explanation:Features of toxicity include:
Increasing gastrointestinal disturbances (vomiting, diarrhoea, anorexia)
Visual disturbances
Polyuria and incontinence
Muscle weakness and tremor
Tinnitus
CNS disturbances (dizziness, confusion and drowsiness increasing to lack of coordination, restlessness, stupor)
Abnormal reflexes and myoclonus
Hypernatraemia
With severe overdosage (serum-lithium concentration > 2 mmol/L) seizures, cardiac arrhythmias (including sinoatrial block, bradycardia and first-degree heart block), blood pressure changes, electrolyte imbalance, circulatory failure, renal failure, coma and sudden death may occur. -
This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 26
Incorrect
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How does an action potential in the motor end plate rapidly spread to the central portions of the muscle cells?
Your Answer: Z-lines
Correct Answer: Transverse tubules
Explanation:When the concentration of intracellular Ca2+rises, muscle contraction occurs. The pathway of an action potential is down tube-shaped invaginations of the sarcolemma called T-tubules (transverse tubules). These penetrate throughout the muscle fibre and lie adjacent to the terminal cisternae of the sarcoplasmic reticulum. The voltage changes in the T-tubules result in the opening of sarcoplasmic reticulum Ca2+channels and there is there is release of stored Ca2+into the sarcoplasm. Thus muscle contraction occurs via excitation-contraction coupling (ECC) mechanism.
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 27
Incorrect
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Regarding the accessory nerve, which of the following statements is INCORRECT:
Your Answer: The nerve originates from cervical segments C1 - C5.
Correct Answer: Accessory nerve palsy results in the inability to nod the head
Explanation:Accessory nerve palsy results in inability to shrug the shoulders and to rotate the head to look at the opposite side to the lesion.
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This question is part of the following fields:
- Anatomy
- Cranial Nerve Lesions
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Question 28
Correct
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You are prescribing ipratropium bromide for a patient who has presented with an exacerbation of her COPD. What is the mechanism of action of ipratropium bromide:
Your Answer: Muscarinic antagonist
Explanation:Ipratropium bromide is an antimuscarinic drug used in the management of acute asthma and COPD. It can provide short-term relief in chronic asthma, but short-acting β2agonists act more quickly and are preferred.
The BTS guidelines recommend that nebulised ipratropium bromide (0.5 mg 4-6 hourly) can be added to β2agonist treatment for patients with acute severe or life-threatening asthma or those with a poor initial response to β2 agonist therapy.
The aerosol inhalation of ipratropium can be used for short-term relief in mild chronic obstructive pulmonary disease in patients who are not already using a long-acting antimuscarinic drug (e.g. tiotropium).Its maximum effect occurs 30-60 minutes after use; its duration of action is 3-6 hours, and bronchodilation can usually be maintained with treatment three times per day.
The commonest side effect of ipratropium bromide is dry mouth. It can also trigger acute closed-angle glaucoma in susceptible patients. Tremor is commonly seen with β2agonists but not with antimuscarinics. Ipratropium bromide should be used with caution in: Men with prostatic hyperplasia and bladder-outflow obstruction (worsened urinary retention has been reported in elderly men), People with chronic kidney disease (CKD) stages 3 and above (because of the risk of drug toxicity), People with angle-closure glaucoma (nebulised mist of antimuscarinic drugs can precipitate or worsen acute angle-closure glaucoma) -
This question is part of the following fields:
- Pharmacology
- Respiratory
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Question 29
Correct
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A 22 year old student has recently returned from travelling around Kenya and presents to ED with a headache and persistent fever. Malaria is being considered as a potential diagnosis. Which of the following strains of malaria is most likely:
Your Answer: Plasmodium falciparum
Explanation:Malaria is an infectious disease transmitted by female of theAnophelesgenus of mosquito. It is a parasitic infection caused by the genusPlasmodium. Five species are recognized as causing disease in humans;Plasmodium falciparum,Plasmodium ovale,Plasmodium vivax,Plasmodium malariaeandPlasmodium knowlesi.
The classic symptom of malaria is the malarial paroxysm, a cyclical occurrence of a cold phase, where the patient experiences intense chills, a hot stage, where the patient feels extremely hot and finally a sweating stage, where the fever declines and the patient sweats profusely. On examination the patient may show signs of anaemia, jaundice and have hepatosplenomegaly without evidence of lymphadenopathy.Plasmodium falciparum is the most serious form and is responsible for most deaths. Severe or complicated malaria is suggested by the presence of impaired consciousness, seizures, hypoglycaemia, anaemia, renal impairment, respiratory distress and spontaneous bleeding.
Plasmodium falciparum is the most likely type in this case in view of the presentation.
Haemoglobinuria and renal failure following treatment is suggestive of blackwater fever, which is caused byPlasmodium falciparum. An autoimmune reaction between the parasite and quinine causes haemolysis, haemoglobinuria, jaundice and renal failure. This can be fatal.
The benign malarias: P.vivax, P. malariae and P.ovale are usually treated with chloroquine. A course of primaquine is also required in P.vivax and P.ovale infection. Artesunate is the drug treatment of choice for Plasmodium falciparum malaria. Quinine can still be used where artesunate is not available. Often combination therapy with drugs such as doxycycline or fansidar is also required. -
This question is part of the following fields:
- Microbiology
- Pathogens
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Question 30
Incorrect
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For an action potential to occur, which of the following must be true:
Your Answer: The membrane must be out of the relative refractory period
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 31
Correct
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A patient diagnosed with cranial nerve palsy exhibits asymmetrical movement of the palate, nasal regurgitation of food, and nasal quality to the voice.
Which of the following cranial nerves is most likely responsible for the aforementioned features?Your Answer: Vagus nerve
Explanation:The vagus nerve, ‘the wanderer’, contains motor fibres (to the palate and vocal cords), sensory components (posterior and floor of external acoustic meatus) and visceral afferent and efferent fibres.
Palatal weakness can cause nasal speech and nasal regurgitation of food. The palate moves asymmetrically when the patient says ‘ahh’. Recurrent nerve palsy results in hoarseness, loss of volume and ‘bovine cough’.
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This question is part of the following fields:
- Anatomy
- Central Nervous System
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Question 32
Correct
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Question 33
Incorrect
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Which of the following is NOT one of the cardinal features of acute inflammation:
Your Answer: Loss of function
Correct Answer: Discharge
Explanation:Classic signs:
Rubor (redness)
Calor (heat)
Dolour (pain)
Tumour (swelling)
Functio laesa (loss of function)
These classic signs are produced by a rapid vascular response and cellular events. The main function of these events is to bring elements of the immune system to the site of injury and prevent further tissue damage. -
This question is part of the following fields:
- Inflammatory Responses
- Pathology
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Question 34
Correct
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A 10-year-old girl presents with polyuria, polydipsia, and stomach pain. She has a history of type I diabetes mellitus. On blood gas analysis, she has metabolic acidosis. Diabetic ketoacidosis (DKA) is diagnosed, and therapy is initiated. She becomes increasingly confused when intravenous fluids and insulin are administered.
Which electrolyte imbalance is the MOSTÂ likely reason of the increased confusion
Your Answer: Hyponatraemia
Explanation:Because of the shift of water from the intracellular to the extracellular compartment as a result of hyperglycaemia and increased plasma osmolality, dilutional hyponatraemia is common in diabetic ketoacidosis (DKA).
If intravenous fluids are not delivered with caution, hyponatraemia might worsen, which can lead to increased degrees of disorientation. Hyponatraemia has also been linked to an increased risk of cerebral oedema, especially if blood glucose levels drop too quickly following treatment.
Headache, recurrence of vomiting, irritability, Glasgow Coma Scale score, inappropriate heart rate slowing, and rising blood pressure are the most common causes of death in paediatric DKA, and children should be monitored for the symptoms mentioned above. To prevent this from developing,  s low osmolarity normalization, attention to glucose and salt levels, as well as hydration over 48 hours, is necessary.Â
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This question is part of the following fields:
- Musculoskeletal Pharmacology
- Pharmacology
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Question 35
Correct
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The patient is a 61-year-old man with severe central chest pain. An acute myocardial infarction is revealed by his ECG. Clopidogrel is one of the medications he takes as part of his treatment.
Clopidogrel's direct mechanism of action is which of the following?Your Answer: Inhibition of platelet ADP receptors
Explanation:Clopidogrel, a thienopyridine derivative, prevents platelet aggregation and cross-linking by the protein fibrin by inhibiting the ADP receptor on platelet cell membranes (inhibits binding of ADP to its platelet receptor (P2Y12 ADP-receptor).
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This question is part of the following fields:
- Cardiovascular Pharmacology
- Pharmacology
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Question 36
Incorrect
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Polyuria and polydipsia develop in a patient with a history of affective disorder, who has been on long-term lithium treatment. She has a fluid deprivation test done because she is suspected of having nephrogenic diabetic insipidus. Which of the following urine osmolality findings would be the most reliable in confirming the diagnosis?
Your Answer: After fluid deprivation >300 mosmol/kg, after IM desmopressin <300 mosmol/kg
Correct Answer: After fluid deprivation <300 mosmol/kg, after IM desmopressin >800 mosmol/kg
Explanation:The inability to produce concentrated urine is a symptom of diabetes insipidus. Excessive thirst, polyuria, and polydipsia are all symptoms of this condition. There are two forms of diabetes insipidus: Nephrogenic diabetes insipidus and cranial (central) diabetes insipidus.
A lack of ADH causes cranial diabetic insipidus. Patients with cranial diabetes insipidus can have a urine output of up to 10-15 litres per 24 hours, however most patients can maintain normonatraemia with proper fluid consumption. Thirty percent of cases are idiopathic, while another thirty percent are caused by head injuries. Neurosurgery, brain tumours, meningitis, granulomatous disease (e.g. sarcoidosis), and medicines like naloxone and phenytoin are among the other reasons. There is also a very rare hereditary type that is linked to diabetes, optic atrophy, nerve deafness, and bladder atonia.
Renal resistance to the action of ADH causes nephrogenic diabetes insipidus. Urine output is significantly increased, as it is in cranial diabetes insipidus. Secondary polydipsia can keep serum sodium levels stable or raise them. Chronic renal dysfunction, metabolic diseases (e.g., hypercalcaemia and hypokalaemia), and medications, such as long-term lithium use and demeclocycline, are all causes of nephrogenic diabetes insipidus.
The best test to establish if a patient has diabetes insipidus vs another cause of polydipsia is the water deprivation test, commonly known as the fluid deprivation test. It also aids in the distinction between cranial and nephrogenic diabetes insipidus. Weight, urine volume, urine osmolality, and serum osmolality are all measured after patients are denied water for up to 8 hours. At the end of the 8-hour period, 2 micrograms of IM desmopressin is given, and measures are taken again at 16 hours.
The following are the way results are interpreted:
Urine osmolality after fluid deprivation : Urine osmolality after IM desmopressin
Cranial diabetes insipidus: <300 mosmol/kg : >800 mosmol/kg
Nephrogenic diabetes insipidus: <300 mosmol/kg : <300 mosmol/kg
Primary polydipsia: >800 mosmol/kg : >800 mosmol/kg -
This question is part of the following fields:
- Physiology
- Renal Physiology
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Question 37
Correct
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Which of the following ions is more abundant in extracellular fluid than in intracellular fluid:
Your Answer: Cl -
Explanation:Protein and phosphate are the primary intracellular anions, while chloride (Cl-) and bicarbonate are the predominant extracellular anions (HCO3-).
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This question is part of the following fields:
- Basic Cellular
- Physiology
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Question 38
Incorrect
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All of the following statements are incorrect about insulin except:
Your Answer: The effects of insulin are mediated by a G-protein coupled receptor.
Correct Answer: Proinsulin is cleaved into insulin and C peptide.
Explanation:Proinsulin is synthesised as a single-chain peptide. A connecting peptide (C peptide) within storage granules is removed by proteases to yield insulin.
Insulin:
1. is a polypeptide hormone consisting of two short chains (A and B) linked by disulphide bonds.
2. is produced by beta cells, located centrally within the islets of Langerhans, in the endocrine tissues of the pancreas.
3. release is stimulated initially during eating by the parasympathetic nervous system and gut hormones such as secretin. However, most output is driven by the rise in plasma glucose concentration that occurs after a meal.
4. effects are mediated by the receptor tyrosine kinase. -
This question is part of the following fields:
- Endocrine
- Physiology
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Question 39
Correct
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Which of the following is NOT a function of the commensal intestinal bacterial flora:
Your Answer: Breakdown of haem into bilirubin
Explanation:Commensal intestinal bacterial flora have a role in:Keeping pathogenic bacteria at bay by competing for space and nutrientConverting conjugated bilirubin to urobilinogen (some of which is reabsorbed and excreted in urine) and stercobilinogen which is excreted in the faecesThe synthesis of vitamins K, B12, thiamine and riboflavinThe breakdown of primary bile acids to secondary bile acidsThe breakdown of cholesterol, some food additives and drugs
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This question is part of the following fields:
- Gastrointestinal
- Physiology
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Question 40
Correct
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All of the following are actions of insulin except:
Your Answer: Increased gluconeogenesis
Explanation:Major Actions of Insulin:
↑ Glucose uptake into cells
↑ Glycogenesis
↓ Glycogenolysis
↓ Gluconeogenesis
↑ Protein synthesis
↓ Protein degradation
↑ Fat deposition
↓ Lipolysis
↓ Ketoacid production
↑ K+ uptake into cellsMajor Actions of Glucagon:
↓ Glycogenesis
↑ Glycogenolysis
↑ Gluconeogenesis
↓ Fatty acid synthesis
↑ Lipolysis
↑ Ketoacid production -
This question is part of the following fields:
- Endocrine
- Physiology
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Question 41
Correct
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Which of the following side effects has limited the use of etomidate as an intravenous induction agent:
Your Answer: Adrenocortical suppression
Explanation:Etomidate causes the least cardiovascular depression of the intravenous induction agents, with only a small reduction in the cardiac output and blood pressure. In the past, etomidate was widely used to induce anaesthesia in the shocked, elderly or cardiovascularly unstable patient. However, more recently it has become less popular as a single induction dose blocks the normal stress-induced increase in adrenal cortisol production for 4 – 8 hours, and up to 24 hours in elderly and debilitated patients. Although no increase in mortality has been identified following a single dose during induction of anaesthesia, the use of etomidate has declined due to a perceived potential morbidity.
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This question is part of the following fields:
- Anaesthesia
- Pharmacology
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Question 42
Correct
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A 54-year-old man who is acutely unwell has his blood sent for test and the results come back with a CRP of 115.
Which of these statements about C-reactive protein is FALSE?
Your Answer: It is produced in the bone marrow
Explanation:C-reactive protein(CRP) is synthesized in the liver in response to increased interleukin-6 (IL-6) secretion by macrophages and T-cells.
Some conditions that cause CRP levels to a rise include: bacterial infection, fungal infection, severe trauma, autoimmune disease, Organ tissue necrosis, malignancy and surgery.It is useful in the clinical setting as a marker of inflammatory activity and can be used to monitor infections.
CRP levels start to rise 4-6 hours after an inflammatory trigger and reaches peak levels at 36-50 hours.
In the absence of a disease process, the normal plasma concentration is less than 5 mg/l.
CRP is useful for monitoring inflammatory conditions (e.g. rheumatoid arthritis and malignancy), can be used as a prognostic marker in acute pancreatitis, and serial measurement can be used to recognize the onset of nosocomial infections in the intensive care settling.
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This question is part of the following fields:
- General Pathology
- Pathology
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Question 43
Incorrect
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Doxycycline is indicated first line for treatment of which of the following infections:
Your Answer: Gonorrhoea
Correct Answer: Chlamydia
Explanation:Doxycycline may be used first line for chlamydia, pelvic inflammatory disease (with metronidazole and ceftriaxone), acute bacterial sinusitis, exacerbation of chronic bronchitis, moderate-severity community acquired pneumonia and high-severity community acquired pneumonia (with benzylpenicillin).
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This question is part of the following fields:
- Infections
- Pharmacology
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Question 44
Incorrect
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You are reviewing a patient with hypocalcaemia secondary to hypoparathyroidism. Parathyroid hormone (PTH) acts to increased calcium reabsorption at which of the following sites in the nephron:
Your Answer: Descending loop of Henle
Correct Answer: Distal convoluted tubule
Explanation:Parathyroid hormone (PTH) is a peptide hormone synthesised by the chief cells of the parathyroid glands, located immediately behind the thyroid gland. PTH is primarily released in response to decreasing plasma [Ca2+] concentration. PTH acts to increase plasma calcium levels and decrease plasma phosphate levels.
Parathyroid hormone (PTH) acts to increase calcium reabsorption in the distal tubule of the nephron (by activating Ca2+entry channels in the apical membrane and the Ca2+ATPase pump in the basolateral membrane) and increase phosphate excretion by inhibiting reabsorption in the proximal tubule of the nephron. -
This question is part of the following fields:
- Endocrine
- Physiology
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Question 45
Correct
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Question 46
Correct
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Question 47
Correct
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Regarding aspirin at analgesic doses, which of the following statements is CORRECT:
Your Answer: It is contraindicated in patients with severe heart failure.
Explanation:Aspirin (at analgesic doses) is contraindicated in severe heart failure. Aspirin irreversibly inhibits cyclooxygenase (COX) enzymes resulting in decreased production of prostaglandins (which can lead to irritation of the gastric mucosa). The analgesic dose is greater than the antiplatelet dose, and taken orally it has a duration of action of about 4 hours. Clinical features of salicylate toxicity in overdose include hyperventilation, tinnitus, deafness, vasodilatation, and sweating.
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This question is part of the following fields:
- Central Nervous System
- Pharmacology
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Question 48
Incorrect
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Which of the following best describes the main sites of constriction of the ureters:
Your Answer: Where the ureter is crossed by the bifurcation of the abdominal aorta, at the pelvic brim and where the ureters enter the bladder
Correct Answer: At the ureteropelvic junction, at the pelvic brim and where the ureters enter the bladder
Explanation:At three points along their course, the ureters are constricted denoting the most likely areas for renal calculi to lodge:the first point is at the ureteropelvic junction (where the renal pelvis becomes continuous with the ureter)the second point is where the ureter crosses the common iliac vessels at the pelvic brimthe third point is at the vesicoureteric junction (where the ureter enters the wall of the bladder)
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This question is part of the following fields:
- Abdomen
- Anatomy
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Question 49
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 50
Incorrect
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A 70-year-old patient is diagnosed with Cushing's disease. She has a history of weight gain, hypertension, and easy bruising.
In this patient, which of the following is the MOST LIKELY UNDERLYING CAUSE?Your Answer: Iatrogenic administration of corticosteroids
Correct Answer: Pituitary adenoma
Explanation:Cushing’s syndrome is a collection of symptoms and signs caused by prolonged exposure to elevated levels of either endogenous or exogenous glucocorticoids.
The most common cause of Cushing’s syndrome is the iatrogenic administration of corticosteroids. The second most common cause of Cushing’s syndrome is Cushing’s disease.
Cushing’s disease should be distinguished from Cushing’s syndrome and refers to one specific cause of the syndrome, an adenoma of the pituitary gland that secretes large amounts of ACTH and, in turn, elevates cortisol levels. This patient has a diagnosis of Cushing’s disease, and this is, therefore, the underlying cause in this case.
The endogenous causes of Cushing’s syndrome include:
Pituitary adenoma (Cushing’s disease)
Ectopic corticotropin syndrome, e.g. small cell carcinoma of the lung
Adrenal hyperplasia
Adrenal adenoma
Adrenal carcinoma -
This question is part of the following fields:
- Endocrine Physiology
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
