29th December 2024

Investigations in malignant hypercalcaemia

A number of investigations should be carried out when investigating malignant hypercalcaemia:

• Routine blood tests for serum calcium, albumin, adjusted calcium, renal function
• Bone profile including PO4, PTH, 25-hydroxyvitamin D, calcitriol
  • If PTH is normal or low in case of known malignancy, PTHrP. In PTHrP-producing tumours, PTHrP will be high, PTH suppressed, and PO4 low due to hyperphosphaturia
  • In calcitriol-mediated hypercalcaemia, calcitriol will be elevated
  • In cases of ectopic PTH production, PTH will be high
• ECG – may show shortened QT interval, J waves, or other abnormalities
• Bone scan or skeletal survey in patients with known or suspected osteolytic metastases, e.g. myeloma, known bone metastases, leukaemia
• Chest X-ray to look for lung cancer or other causes of hypercalcaemia including sarcoidosis or TB