Practice questions › Davidson's Principles of Medicine › Davidson's Medicine - Part 3: Clinical Medicine
19 Clinical biochemistry and metabolic medicine MCQs
Davidson's Medicine - Part 3: Clinical Medicine · Davidson's Principles of Medicine · 9 practice questions
- Hyponatraemia
- Lipids
- Magnesium
- Diuretics and tubular disorders
- Sodium and diuretics
- Hypokalaemia
- Inherited metabolic disease
- Acid-base
1. A patient with type 2 diabetes starts an SGLT2 inhibitor and albuminuria falls, and another with hypovolaemic hyponatraemia has urinary sodium of 45 mmol/L. Which statements are correct?
- AIncreased hyperfiltration, and extrarenal loss
- BReduced tubuloglomerular feedback lowers glomerular hyperfiltration, and renal sodium loss is likely because extrarenal loss gives urinary sodium below 30
- CNo effect on feedback, and water intoxication
- DReduced glomerular filtration by blockade, and SIADH
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B. Reduced tubuloglomerular feedback lowers glomerular hyperfiltration, and renal sodium loss is likely because extrarenal loss gives urinary sodium below 30 SGLT2 inhibitors reduce sodium reabsorption and glomerular hyperfiltration; hypovolaemic hyponatraemia with urinary sodium above 30 indicates renal loss.
2. A patient with oedema takes furosemide, another with hypertension takes a thiazide, and a third has hypokalaemia with low blood pressure and reduced urinary calcium. Which transporters and diagnosis fit?
- ANKCC2 in the thick ascending limb, NCCT in the early distal tubule, and Gitelman syndrome from NCCT loss of function
- BNCCT, NKCC2, and Bartter syndrome from NKCC2 loss
- CENaC, aquaporin, and Liddle syndrome
- DSGLT2, NKCC2, and Conn syndrome
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A. NKCC2 in the thick ascending limb, NCCT in the early distal tubule, and Gitelman syndrome from NCCT loss of function Loop diuretics block NKCC2, thiazides block NCCT; Gitelman has decreased urinary calcium while Bartter has increased.
3. A patient with hyponatraemia and polyuria has vasopressin measurement requested. Which statement is correct?
- AVasopressin is preferred and specific
- BVasopressin is suppressed in hypovolaemia
- CCopeptin is used instead because plasma vasopressin is unstable and levels are raised in hypovolaemic and most hypervolaemic states
- DCopeptin is a steroid
Show answer
C. Copeptin is used instead because plasma vasopressin is unstable and levels are raised in hypovolaemic and most hypervolaemic states Copeptin is a surrogate derived from the vasopressin precursor and may aid the differential of hyponatraemia with polyuria.
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