Endocrinology & Metabolic

Hyperparathyroidism

Hyperparathyroidism is excessive parathyroid hormone secretion: primary disease causes hypercalcaemia through autonomous gland activity, while secondary disease is an appropriate response to chronic kidney disease or vitamin-D deficiency and tertiary disease becomes autonomous after prolonged stimulation.

Definition

Hyperparathyroidism is a disorder of excessive parathyroid hormone secretion. Primary disease is autonomous and usually causes hypercalcaemia; secondary disease is a physiological response to chronic kidney disease, phosphate disturbance or vitamin-D deficiency; tertiary disease is autonomous secretion after prolonged secondary stimulation.

First principles

PTH raises calcium and lowers phosphate

PTH increases renal calcium reabsorption, promotes renal phosphate wasting and stimulates renal activation of vitamin D. Activated vitamin D then increases intestinal calcium absorption. A raised calcium should suppress PTH; a high or inappropriately normal PTH therefore identifies PTH-dependent hypercalcaemia.

You’ve reached the end of the preview

The rest of this extended textbook page is part of full access. Create a free account to read the sample topics in full and try sample questions, then upgrade to unlock every high-yield and extended page, plus the complete question bank.

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.