A 28-year-old man presents to the endocrine surgery clinic. He has a history of recurrent renal calculi and a recent fracture after minor trauma. Investigations reveal: serum calcium 3.1 mmol/L, phosphate 0.6 mmol/L, albumin 40 g/L, and serum intact PTH 145 pg/mL (reference 10–65 pg/mL). A Tc-99m sestamibi scan shows a focus of increased uptake inferior to the right lower thyroid pole. What is the diagnosis and appropriate treatment?
- A Secondary hyperparathyroidism; cinacalcet therapy
- B Primary hyperparathyroidism due to a parathyroid adenoma; focused parathyroidectomy ✓
- C Tertiary hyperparathyroidism; subtotal parathyroidectomy
- D Familial hypocalciuric hypercalcaemia; no surgery required
Explanation
Primary hyperparathyroidism — elevated serum calcium with inappropriately high (non-suppressed) PTH, low phosphate, and symptomatic end-organ damage (renal calculi, osteoporosis with fragility fracture) — is most commonly caused by a solitary parathyroid adenoma. A positive sestamibi scan localising the adenoma makes the patient suitable for minimally invasive (focused) parathyroidectomy guided by intraoperative PTH monitoring. Secondary hyperparathyroidism occurs in the context of renal failure or vitamin D deficiency with low/normal calcium. Tertiary hyperparathyroidism arises from autonomous hypersecretion after prolonged secondary hyperparathyroidism. Familial hypocalciuric hypercalcaemia shows very low urinary calcium excretion (calcium-creatinine clearance ratio < 0.01) and PTH is typically normal or mildly elevated.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
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