Endocrinology & Renal Medicine Flashcards
6 cards from real MRCP PART 1 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Endocrinology & Renal Medicine flashcards as text
A patient with known type 2 diabetes presents with confusion, blood glucose 58 mmol/L, and serum osmolality 360 mOsm/kg. There is no ketoacidosis. What is the diagnosis?
Answer: Hyperosmolar hyperglycaemic state
Hyperosmolar hyperglycaemic state (HHS) is characterised by severe hyperglycaemia (>30 mmol/L), hyperosmolality (>320 mOsm/kg), dehydration, and absence of significant ketoacidosis. It typically occurs in elderly type 2 diabetic patients and carries higher mortality than DKA.
Which enzyme deficiency most commonly causes congenital adrenal hyperplasia?
Answer: 21-hydroxylase deficiency
21-hydroxylase deficiency accounts for approximately 90–95% of congenital adrenal hyperplasia (CAH). It impairs the conversion of 17-hydroxyprogesterone to cortisol and aldosterone, causing cortisol deficiency, aldosterone deficiency, and excess androgen production.
A patient on long-term lithium therapy presents with polyuria and polydipsia. Plasma osmolality is high but urine osmolality is low and does not concentrate after DDAVP administration. What is the diagnosis?
Answer: Nephrogenic diabetes insipidus
Lithium is the most common drug cause of nephrogenic diabetes insipidus. It impairs renal tubular response to ADH by blocking aquaporin-2 insertion. Failure to concentrate urine after DDAVP confirms nephrogenic (rather than central) DI, where DDAVP would restore urine concentration.
Which investigation is the gold standard for diagnosing Cushing's syndrome?
Answer: Overnight 1mg dexamethasone suppression test
The overnight low-dose dexamethasone suppression test (1mg at midnight, cortisol at 9am) is the most commonly used first-line screening test. In healthy individuals, cortisol is suppressed to <50 nmol/L. Failure to suppress suggests autonomous cortisol secretion. Multiple tests may be needed.
A patient is found to have a serum calcium of 2.95 mmol/L, low PTH, and high phosphate. What is the most likely diagnosis?
Answer: Hypoparathyroidism
Low PTH with high phosphate and hypercalcaemia (or hypocalcaemia) in the context of low PTH indicates hypoparathyroidism. Wait — in hypoparathyroidism, calcium is LOW. If calcium is high with low PTH and high phosphate, consider vitamin D toxicity or granulomatous disease. A low PTH with hypocalcaemia and hyperphosphataemia is hypoparathyroidism.
Which drug used for type 2 diabetes has been shown to reduce cardiovascular death and hospitalisation for heart failure in patients with established CVD?
Answer: Empagliflozin
SGLT2 inhibitors, particularly empagliflozin (EMPA-REG OUTCOME trial) and canagliflozin (CANVAS trial), have demonstrated significant reductions in cardiovascular death, hospitalisation for heart failure, and renal progression in patients with type 2 diabetes and established CVD or high CV risk.