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Question 1
Incorrect
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When treating diabetic ketoacidosis (DKA), glucose should be given together with insulin as soon as the blood glucose concentration falls below 14 mmol/L in the form of:
Your Answer: 20% glucose intravenous infusion at a rate of 125 mL/hour
Correct Answer: 10% glucose intravenous infusion at a rate of 125 mL/hour
Explanation:In addition to the sodium chloride 0.9 percent infusion, glucose 10% should be given intravenously (into a large vein with a large-gauge needle) at a rate of 125 mL/hour once blood glucose concentration falls below 14 mmol/litre.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 2
Incorrect
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All of the following statements are incorrect about insulin except:
Your Answer: Insulin is secreted from pancreatic alpha cells.
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.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 3
Incorrect
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Antidiuretic hormone (ADH) has which of the following effects:
Your Answer: Increases water retention by increasing sodium reabsorption in the distal convoluted tubule
Correct Answer: Increases urine osmolality
Explanation:ADH binds V2 receptors on renal principal cells in the late distal tubule and collecting ducts, raising cAMP levels and causing intracellular vesicles to fuse with the apical membrane. In their membrane these vesicles have water channels called aquaporins, which increase the water permeability allowing greater water reabsorption and concentration of urine. ADH also binds to V1 receptor receptors on vascular smooth muscle, causing vasoconstriction and enhancing the effect of aldosterone on sodium reabsorption in the distal tubule. ADH release is stimulated primarily by raised plasma osmolality detected by osmoreceptors in the anterior hypothalamus. Other factors that increase ADH release include: extracellular fluid volume depletion, angiotensin II, nausea, pain, stress, exercise, emotion, hypoglycaemia. ADH release is inhibited by low plasma osmolality, alcohol, caffeine, glucocorticoids and atrial natriuretic peptide (ANP). ADH deficiency (or an inadequate response to ADH) results in diabetes insipidus. Excess levels of ADH results in syndrome of inappropriate ADH secretion (SIADH).
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 4
Incorrect
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Which of the following is NOT a typical effect caused by adrenaline:
Your Answer: Vasoconstriction of vessels in skin, mucous membranes and splanchnic bed
Correct Answer: Bronchoconstriction
Explanation:Actions of adrenaline:Cardiovascular system- Increased rate and force of cardiac contraction- Vasoconstriction of vessels in skin, mucous membranes and splanchnic bed- Vasodilation of skeletal muscle vessels- Increased cardiac output and blood pressureRespiratory system- Bronchodilation- Increased ventilation rateGastrointestinal system- Smooth muscle relaxation- Contraction of sphincters- Metabolism- Decreased insulin release- Increased glucagon release- Increased thermogenesis- Increased glycolysis- Increased lipolysisEye- Pupillary dilation
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 5
Incorrect
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All of the following are physiological effects of thyroid hormones except:
Your Answer: Increased protein breakdown
Correct Answer: Increased glycogenesis
Explanation:Thyroid hormones have multiple physiological effects on the body. These include:1. Heat production (thermogenesis)2. Increased basal metabolic rate3. Metabolic effects: (a) Increase in protein turnover (both synthesis and degradation are increased, although overall effect is catabolic)(b) Increase in lipolysis(c)Increase in glycogenolysis and gluconeogenesis4. Enhanced catecholamine effect – Increase in heart rate, stroke volume and thus cardiac output5. Important role in growth and development
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 6
Incorrect
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A 75-year-old man with rheumatoid arthritis had gained weight, developed resistant hypertension, muscle weakness, and ankle oedema. This patient is most likely suffering from what condition?
Your Answer: Renal artery stenosis
Correct Answer: Cushing's syndrome
Explanation:Overuse of cortisol medication, as seen in the treatment of patients with chronic asthma or rheumatoid arthritis, can cause Cushing’s syndrome. Weight gain, thin arms and legs, a round face, increased fat around the base of the neck, a fatty hump between the shoulders, easy bruising, wide purple stretch marks primarily on the abdomen, breasts, hips, and under the arms, weak muscles, hirsutism, hypertension, erectile dysfunction, osteoporosis, frontal alopecia, acne, depression, poor wound healing, and polycythaemia are all clinical features of Cushing’s syndrome.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 7
Correct
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Beta cells of the endocrine pancreas produce which of the following hormones:
Your Answer: Insulin
Explanation:Insulin is produced by beta cells, located centrally within the islets of Langerhans, in the endocrine tissues of the pancreas. Insulin is a polypeptide hormone consisting of two short chains (A and B) linked by disulphide bonds. Proinsulin is synthesised as a single-chain peptide. Within storage granules, a connecting peptide (C peptide) is removed by proteases to yield insulin. Insulin release is stimulated initially during eating by the parasympathetic nervous system and gut hormones such as secretin, but most output is driven by the rise in plasma glucose concentration that occurs after a meal. The effects of insulin are mediated by the receptor tyrosine kinase.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 8
Correct
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Adrenocorticotropic hormone release from the anterior pituitary is stimulated by which of the following:
Your Answer: Corticotropin-releasing hormone
Explanation:ACTH secretion is stimulated by corticotropin-releasing hormone (CRH) from the hypothalamus.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 9
Incorrect
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Which of the following statements is correct with regards to insulin receptors?
Your Answer: Insulin receptors are G-protein coupled receptors.
Correct Answer: Insulin has its intracellular effects via activation of tyrosine kinase.
Explanation:Most cells have insulin receptors present on them which can be sequestered into the cell to inactivate them. These receptors consist of two extracellular alpha subunits which contain the insulin-binding site and two transmembrane beta subunits. Because insulin is a polypeptide hormone, it must act via cell surface receptors as it is unable to readily cross the cell membrane. On binding to the receptor, the beta subunit of insulin autophosphorylation, which activates tyrosine kinase. As a result, there is an intracellular cascade of phosphorylation, causing a translocation of the glucose transporter GLUT4 and GLUT-1 to the plasma membrane of the affected cell. This facilitates glucose entry.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 10
Incorrect
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A patient with Conn’s syndrome will experience which of the following clinical features?
Your Answer: Hypercalcaemia
Correct Answer: Hypernatraemia
Explanation:Conditions to consider in the differential diagnosis of primary aldosteronism or Conn’s syndrome include hypertension, metabolic alkalosis, hypokalaemia, hypernatremia, and low renin levels.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 11
Correct
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Question 12
Incorrect
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Monoamine oxidase is primarily involved in the degradation of which of the following:
Your Answer: Cortisol
Correct Answer: Noradrenaline
Explanation:Catecholamines are broken down extracellularly and in the liver by catechol-O-methyltransferase (COMT) and intracellularly by monoamine oxidase (MAO).
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 13
Correct
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Diabetic ketoacidosis is characterised by which of the following:
Your Answer: Hyperglycaemia, ketonaemia and acidosis
Explanation:DKA is characterised by the biochemical triad:1. Hyperglycaemia (> 11 mmol/L)2. Ketonaemia (> 3 mmol/L)3. Acidosis (pH < 7.3 +/- HCO3 < 15 mmol/L)
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 14
Incorrect
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Question 15
Incorrect
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What is the effect of activated vitamin D on the renal handling of calcium:
Your Answer: Increases calcium filtration at the glomerulus
Correct Answer: Increases calcium reabsorption in the distal tubule
Explanation:Activated vitamin D acts to:GUT:increase calcium and phosphate absorption in the small intestine (the main action)KIDNEYS:increase renal calcium reabsorption (in the distal tubule via activation of a basolateral Ca2+ATPase pump), increase renal phosphate reabsorption, inhibit 1-alpha-hydroxylase activity in the kidneys (negative feedback)PARATHYROID GLANDS:inhibit PTH secretion from the parathyroid glands
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 16
Incorrect
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Regarding hypernatraemia, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: In acute severe hypernatraemia, seizures and intracranial vascular haemorrhage can occur as a result of brain cell lysis.
Explanation:Acute severe hypernatraemia is a medical emergency and requires inpatient management in a high dependency setting. Seizures and intracranial vascular haemorrhage as a result of brain cell crenation can occur. The cause is most commonly excessive water loss and the key aspect of treatment is aggressive fluid replacement (typically with normal saline as this is relatively hypotonic). If urine osmolality is low, diabetes insipidus (DI )should be considered and a trial of synthetic ADH given. In patients with known DI, it is essential to ensure synthetic ADH is given parenterally and that close fluid balance is observed.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 17
Incorrect
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Which of the following hormones is dysfunctional in diabetes insipidus:
Your Answer:
Correct Answer: Antidiuretic hormone
Explanation:Diabetes insipidus (DI) may result from a deficiency of ADH secretion (cranial DI) or from an inappropriate renal response to ADH (nephrogenic DI). As a result, fluid reabsorption at the kidneys is impaired, resulting in large amounts of hypotonic, dilute urine being passed with a profound unquenchable polydipsia.The biochemical hallmarks of DI are:High plasma osmolality (> 295 mOsm/kg)Low urine osmolality (< 300 mOsm/kg)Hypernatraemia (> 145 mmol/L)High urine volume
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 18
Incorrect
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Which of the following is NOT a typical clinical feature of diabetic ketoacidosis:
Your Answer:
Correct Answer: Cheyne–Stokes respiration
Explanation:Clinical features of DKA: Symptoms: Polyuria, polydipsia, thirst, lethargy, weight loss, nausea, vomiting, anorexia, abdominal pain, dehydration, headache, altered mental stateSigns: Dry mucous membranes, ketotic breath, tachycardia, hypotension, Kussmaul breathing, focal signs of precipitant e.g. infection
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 19
Incorrect
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A 43 year old lady who has a previous medical history of hyperthyroidism presents to the emergency room with sweating, palpitations and agitation. On examination, she is tachycardic, hypertensive and hyperpyrexic. She recently had a stomach bug and has not been able to take her medication regularly. The best medication to immediately treat her symptoms is which of the following?
Your Answer:
Correct Answer: Propranolol
Explanation:There is a high suspicion of a thyroid crisis in this patient and emergent treatment should be initiated even before the results of TFT’s have returned. Antiadrenergic drugs like IV propranolol should be administered immediately to minimise sympathomimetic symptoms. Antithyroid medications like propylthiouracil or carbimazole should be administered to block further synthesis of thyroid hormones. After thionamide therapy has been started to prevent stimulation of new hormone synthesis, there should then be delayed administration of oral iodine solution. Hydrocortisone administration is also recommended as it treats possible relative adrenal insufficiency while also decreases peripheral conversion of T4 to T3.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 20
Incorrect
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Which of the following statements is correct regarding hyponatraemia?
Your Answer:
Correct Answer: Correction of serum sodium that is too rapid can precipitate central pontine myelinolysis.
Explanation:Hyponatraemia refers to a serum sodium concentration < 135 mmol/L. It is safer to quickly correct acute hyponatremia than chronic hyponatremia but correction should not be too fast, especially in chronic hyponatraemia, because of the risk of central pontine myelinolysis. Hyponatraemia is usually associated with a low plasma osmolality. Under normal circumstances, if serum osmolality is low, then urine osmolality should also be low because the kidneys should be trying to retain solute. In SIADH, excess ADH causes water retention, but not the retention of solute. Therefore, urine that is concentrated and relatively high in sodium is produced, even though the serum sodium is low (urine osmolality > 100 mosmol/kg).
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 21
Incorrect
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All of the following are actions of insulin except:
Your Answer:
Correct 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
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 22
Incorrect
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Dexamethasone would be most useful for which of the following conditions:
Your Answer:
Correct Answer: Raised intracranial pressure secondary to malignancy
Explanation:Dexamethasone has a very high glucocorticoid activity in conjunction with insignificant mineralocorticoid activity. This makes it particularly suitable for high-dose therapy in conditions where fluid retention would be a disadvantage such as in the management of raised intracranial pressure or cerebral oedema secondary to malignancy. Dexamethasone also has a long duration of action and this, coupled with its lack of mineralocorticoid action makes it particularly suitable for suppression of corticotropin secretion in congenital adrenal hyperplasia. In most individuals a single dose of dexamethasone at night, is sufficient to inhibit corticotropin secretion for 24 hours. This is the basis of the ‘overnight dexamethasone suppression test’ for diagnosing Cushing’s syndrome.
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This question is part of the following fields:
- Endocrine
- Pharmacology
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Question 23
Incorrect
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A 25 year old woman who is a known diabetic is brought to the ED with diabetic ketoacidosis. She promptly received an insulin infusion. Which of the following are expected to increase upon infusion of insulin?
Your Answer:
Correct Answer: Blood pH
Explanation:Ketoacidosis is characterized by hyperglycaemia, glycosuria, hyperkalaemia, and metabolic acidosis with respiratory compensation. An insulin infusion would be able to address these by lowering blood glucose through increased insulin-mediated cellular uptake, lowering urine glucose concentration as cellular glucose uptake is increased, decreasing K+ in her blood by shifting it into cells, and increasing blood ph by addressing the metabolic acidosis. The metabolic acidosis is addressed by the reduction of ketoacids production thereby returning her blood ph to normal and reducing the need for compensatory hyperventilation.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 24
Incorrect
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A 32 year old woman presents with episodes of flushing, headaches and palpitations. On examination her blood pressure is significantly elevated. Which of the following is the most likely diagnosis:
Your Answer:
Correct Answer: Pheochromocytoma
Explanation:Phaeochromocytomas are catecholamine-secreting tumours which occur in about 0.1% of patients with hypertension. In about 90% of cases they arise from the adrenal medulla. The remaining 10%, which arise from extra-adrenal chromaffin tissue, are termed paragangliomas. Common presenting symptoms include one or more of headache, sweating, pallor and palpitations. Less commonly, patients describe anxiety, panic attacks and pyrexia. Hypertension, whether sustained or episodic, is present in at least 90% of patients. Left untreated phaeochromocytoma can occasionally lead to hypertensive crisis, encephalopathy, hyperglycaemia, pulmonary oedema, cardiac arrhythmias, or even death.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 25
Incorrect
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Which of the following causes type 1 diabetes mellitus?
Your Answer:
Correct Answer: Autoimmune destruction of beta-cells results in insulin deficiency
Explanation:Type 1 diabetes mellitus results from autoimmune destruction of the insulin-producing beta cells in the islets of Langerhans. This process occurs in genetically susceptible subjects, is probably triggered by one or more environmental agents, and usually progresses over many months or years during which the subject is asymptomatic and euglycemic.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 26
Incorrect
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Which of the following is a primary action of aldosterone:
Your Answer:
Correct Answer: Renal sodium reabsorption
Explanation:Aldosterone acts mainly at the renal distal convoluted tubule (DCT) to cause sodium retention and potassium loss. It increases the synthesis of transport mechanisms in the distal nephron including the Na+pump, Na+/H+symporter, and Na+and K+channels in principal cells, and H+ATPase in intercalated cells. Na+(and thus water) reabsorption and K+and H+secretion are thereby enhanced.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 27
Incorrect
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A 70 year old man who has a previous history of small cell lung cancer was found to have severe hyponatraemia on a recent blood test and he is sent to the emergency room. In the nephron, where is the likely cause of this abnormality?
Your Answer:
Correct Answer: Distal nephron
Explanation:In the cancer patient, hyponatremia is usually caused by the syndrome of inappropriate antidiuretic hormone (SIADH). This develops more frequently with small cell lung cancer (SCLC) than with other malignancies. The pathogenesis of this is as a result of the process whereby ADH binds V2 receptors on renal principal cells in the late distal tubule and collecting ducts, resulting in elevation of cAMP levels. Increased cAMP levels cause fusion of intracellular vesicles with the apical membrane. There are water channels called aquaporins in their membranes of these vesicles, and these increase the water permeability, thus facilitating increased water reabsorption and urine concentration. Thus, by increasing water retention, ADH causes blood to be diluted, which then decreases the concentration of solutes like sodium.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 28
Incorrect
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What is the pathophysiology of Cushing's syndrome:
Your Answer:
Correct Answer: Glucocorticoid excess
Explanation:Cushing’s syndrome is the name given to the clinical symptoms and signs induced by chronic glucocorticoid excess.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 29
Incorrect
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What is the pathophysiology of a phaeochromocytoma:
Your Answer:
Correct Answer: Catecholamine-secreting tumour
Explanation:Phaeochromocytomas are catecholamine-secreting tumours which occur in about 0.1% of patients with hypertension. In about 90% of cases they arise from the adrenal medulla. The remaining 10%, which arise from extra-adrenal chromaffin tissue, are termed paragangliomas. Common presenting symptoms include one or more of headache, sweating, pallor and palpitations. Less commonly, patients describe anxiety, panic attacks and pyrexia. Hypertension, whether sustained or episodic, is present in at least 90% of patients. Left untreated phaeochromocytoma can occasionally lead to hypertensive crisis, encephalopathy, hyperglycaemia, pulmonary oedema, cardiac arrhythmias, or even death.
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This question is part of the following fields:
- Endocrine
- Physiology
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Question 30
Incorrect
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Which of the following is NOT a typical clinical feature of osteomalacia:
Your Answer:
Correct Answer: Hypercalcaemia
Explanation:Features of osteomalacia include: Bone pain (particularly bone, pelvis, ribs)Neuromuscular dysfunction (particularly in the gluteal muscles, leading to waddling gaitPseudofractures on x-ray (looser zones)Elevated alkaline phosphatase, hypocalcaemia and low phosphate due to secondary hyperparathyroidism
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This question is part of the following fields:
- Endocrine
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
