skip to main content

Primary hyperparathyroidism — SCE Endocrinology MCQ

Instant feedback + full explanation. One question, done properly.

HardCalcium/BonePrimary hyperparathyroidismSCE Endocrinology

A woman has lifelong mild hypercalcaemia, non-suppressed PTH and no complications. Paired urine and serum results are: urine calcium 2.0 mmol/L, urine creatinine 8 mmol/L, serum calcium 2.70 mmol/L, serum creatinine 72 micromol/L. What is the calculated calcium:creatinine clearance ratio and interpretation?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — 0.0067, favouring familial hypocalciuric hypercalcaemia

Explanation lettering: C = shown as A · A = shown as B · D = shown as C · B = shown as D

E is correct. CCCR = (urine calcium × serum creatinine in mmol/L)/(serum calcium × urine creatinine): serum creatinine 72 micromol/L = 0.072 mmol/L, so (2.0×0.072)/(2.70×8)=0.0067. A value below 0.01 favours FHH, although overlap, vitamin-D deficiency, CKD, lithium and thiazides require consideration and genetic testing may be needed. Values above 0.02 more often favour PHPT; intermediate values are indeterminate.

Reference: https://www.endocrinology.org/media/boodt50x/bilezikian-et-al-guidelines.pdf