Hypercalcaemia

[Society for Endocrinology – 2013]

Clinical features:

–       Polyuria and thirst,

–       Anorexia, nausea and constipation

–       Mood disturbance, cognitive dysfunction, confusion and coma

–       Muscle weakness

–       Renal impairment, nephrolithiasis, nephrocalcinosis

–       Shortened QT interval and dysrhythmias, hypertension, cardiomyopathy

–       Peptic ulceration, pancreatitis

–       Band keratopathy

Causes:

90% of hypercalcaemia is due to primary hyperparathyroidism or malignancy

Less common: thiazide diuretics, rhabdomyolysis, tertiary hyperparathyroidism, thyrotoxicosis, hypervitaminosis D, lithium, immobilisation, granulomatous disease, adrenal insufficiency, milk-alkali syndrome, hypervitaminosis A, theophylline toxicity, FHH, phaeochromocytoma

Investigation

Hx – symptom duration, underlying causes (eg. Weight loss, night sweats, cough), FHx, Drugs

Ex – cognitive impairment, fluid balance status, exam neck, respiratory, abdomen, breasts and lymph nodes

ECG – short QT interval or other abnormality

Bloods – Calcium adjusted for albumin, phosphate, PTH, urea and electrolyes

High calcium and high PTH =  primary or tertiary hyperparathyroidism

High calcium and low PTH = malignancy or other rarer causes

Management:

1.     Rehydration (iv 0.9% saline 4-6L in 24hrs)

2.     After rehydration, iv bisphosphonates (zolendronic acid 4mg over 15mins)

a.     Or pamidronate 30-90mg at 20mg/hr (depending on severity)

b.     Or ibandronic acid 2-4mg

c.     Can cause hypocalcaemia if Vit D deficiency or suppressed PTH

3.     Second line treatments:

a.     Glucocorticoids (inhibit 1,25-OHD production) – Prednisolone 40mg OD

b.     Calcitonin

c.     Calcimimetics

d.     Parathyroidectomy