Overview
Look For
- Total calcium >2.60 mmol/L
- Ionised calcium >1.35 mmol/L
Aetiology
Causes of Hypercalcaemia
- Malignancy - local osteolysis, humoral hypercalcaemia of malignancy, multiple myeloma
- Hyperparathyroidism (primary / secondary / tertiary)
- Endocrine - thyrotoxicosis, Addison's disease
- Granulomatous disease - sarcoidosis, tuberculosis
- Prolonged immobilisation
- Drugs - calcium supplements, vitamin D, vitamin A, thiazides, lithium, oestrogens, anti-oestrogens, progestins
- Total parenteral nutrition (TPN)
- Familial hypercalcaemia-hypercalciuria (FHH)
Clinical Features
Signs and Symptoms
- Renal ('stones') - nephrolithiasis, nephrocalcinosis, nephrogenic diabetes insipidus
- GI ('groans') - nausea, reflux, peptic ulcers, pancreatitis, constipation
- CNS ('moans') - lethargy, depression, confusion, memory loss, coma
- MSK ('bones') - osteopaenia, bone pain, pathologic fractures
- Cardiovascular - hypertension, shortened QT
Approach
Further Investigations
- Check the patient's PTH
- If not elevated - check the PTH-related peptide (PTHrp), 25-hydroxy-vitamin D and 1,25-dihydroxy-vitamin D levels
- Elevated alkaline phosphatase (ALP) is suggestive of local osteolysis
- Specific tests such as TFTs, cortisol and myeloma screen may be useful
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