Expansion
Primary hyperparathyroidism and malignancy account for 90 per cent
Expansion
Parathyroid hormone raised or inappropriately normal
- Primary hyperparathyroidism (commonest in the community, usually an adenoma)
- Tertiary hyperparathyroidism in chronic kidney disease
- Familial hypocalciuric hypercalcaemia, distinguished by a low urinary calcium
Parathyroid hormone suppressed
- Malignancy (commonest in hospital): PTHrP secretion (squamous carcinoma), bone metastases, myeloma
- Vitamin D excess, or granulomatous disease (sarcoidosis, tuberculosis) producing extrarenal 1-alpha hydroxylase
- Thyrotoxicosis, immobilisation, thiazides, lithium
- Milk-alkali syndrome, adrenal insufficiency
Symptoms follow the old rhyme of stones, bones, abdominal groans and psychic moans, with polyuria and polydipsia from nephrogenic diabetes insipidus.
Treatment of severe hypercalcaemia: aggressive rehydration with saline first, since patients are profoundly volume depleted, then bisphosphonates for malignancy. Loop diuretics are no longer routinely recommended and should follow rehydration if used at all.