Hypercalcaemia
Hypercalcaemia is a raised albumin-adjusted serum calcium, most often caused by primary hyperparathyroidism or malignancy; PTH is the pivotal fork, while severe or rapidly symptomatic hypercalcaemia is an emergency requiring careful rehydration and specialist treatment.
Definition
Hypercalcaemia is an albumin-adjusted serum calcium above the laboratory reference range. It is classified by severity and speed of rise, and mechanistically as PTH-dependent or PTH-independent.
First principles
PTH is the diagnostic fork
A high calcium should suppress PTH. If PTH is raised or inappropriately within the reference range, think PTH-dependent disease: primary or tertiary hyperparathyroidism, or familial hypocalciuric hypercalcaemia (FHH). If PTH is suppressed, think PTH-independent disease, especially malignancy, vitamin-D-mediated disease, granulomatous disease or drugs.
This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.

