# Hyperparathyroidism and Parathyroid Surgery

> Primary hyperparathyroidism and parathyroid surgery for NEET-PG Surgery: adenoma, sestamibi localisation, focused parathyroidectomy, Miami criterion and hungry bone syndrome.

- Canonical URL: https://prepelephant.com/topics/neet-pg/surgery/parathyroid-surgery
- Exam / course: NEET-PG · Subject: Surgery
- Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team
- First published: 2026-10-02
- Last updated: 2026-10-02
- How to cite: "Hyperparathyroidism and Parathyroid Surgery", PrepElephant, https://prepelephant.com/topics/neet-pg/surgery/parathyroid-surgery

## Direct answer

Primary hyperparathyroidism is the biochemical triad of raised serum calcium with raised (or inappropriately normal) parathyroid hormone and low or low-normal phosphate, caused in about 80–85 per cent by a single parathyroid adenoma, 10–15 per cent by four-gland hyperplasia (often MEN syndromes) and under 1–2 per cent by carcinoma. While Western series detect it as asymptomatic hypercalcaemia, Indian patients still commonly present with symptomatic bone or renal disease — 'stones, bones, abdominal groans and psychic moans'. Localisation by neck ultrasound and technetium-99m sestamibi scintigraphy allows a focused minimally invasive parathyroidectomy for solitary adenomas, with intraoperative PTH falling by more than half within 10 minutes (the Miami criterion) confirming cure; postoperative hypocalcaemia with hypophosphataemia signals the hungry bone syndrome.

## What you must remember

- Causes: single adenoma 80–85 per cent, multiglandular hyperplasia 10–15 per cent (think MEN1 and MEN2a), double adenoma a few per cent, carcinoma under about 1–2 per cent with palpable mass, hoarseness and very high calcium and PTH.
- Skeletal signs: osteitis fibrosa cystica with brown tumours, subperiosteal resorption of the phalanges, salt-and-pepper skull; renal: stones and nephrocalcinosis; others: constipation, peptic ulcer, pancreatitis, depression and fatigue.
- Hypercalcaemic crisis (calcium often above 14 mg/dL with dehydration and altered mentation) is treated with saline rehydration, then bisphosphonates or calcitonin before definitive surgery.
- Localisation: high-resolution ultrasound plus Tc-99m sestamibi (with SPECT if needed); 4D-CT is a problem-solver for negative or reoperative cases; localisation is not a diagnosis — biochemistry comes first.
- Focused parathyroidectomy suits a single localised adenoma, with cure predicted by the Miami criterion — over 50 per cent fall in intraoperative PTH 10 minutes after excision; four-gland subtotal (3.5 gland) exploration is for hyperplasia and MEN.
- Specific risks are recurrent laryngeal nerve injury and permanent hypoparathyroidism; postoperative hypocalcaemia with hypophosphataemia (hungry bone syndrome, as bone avidly takes up calcium) is treated with calcium and active vitamin D.
- MEN1 pairs parathyroid hyperplasia with pancreatic neuroendocrine tumours and pituitary adenoma; MEN2a adds phaeochromocytoma and medullary thyroid carcinoma — screen before operating.

## Common confusion

The exam contrasts primary, secondary and tertiary hyperparathyroidism. Secondary (vitamin D deficiency or chronic kidney disease driving PTH high with low or normal calcium) needs medical correction of the drive, not gland excision; tertiary hyperparathyroidism is autonomous PTH after long-standing secondary disease, classically in renal failure, and is the setting for subtotal parathyroidectomy. A second trap is treating hypercalcaemia of malignancy (PTH suppressed, PTHrP raised) as primary hyperparathyroidism — the PTH level separates them.

## Exam-focused takeaway

Learn the percentage breakdown of causes, the localisation pair (ultrasound and sestamibi), the Miami criterion, and the clinical eponyms (brown tumours, salt-and-pepper skull). Stems show a woman with renal stones, bone pain and corrected calcium of 11.8 with PTH of 120 asking the next investigation (localisation before focused surgery) or a postoperative day-1 calcium crash (hungry bone syndrome). MEN associations and the 50 per cent PTH drop are near-certain one-mark questions.

## Frequently asked questions

### What biochemical pattern defines primary hyperparathyroidism?
Hypercalcaemia with elevated or inappropriately normal parathyroid hormone and low or low-normal phosphate, ideally confirmed on repeated samples with albumin-corrected calcium.

### How is a single adenoma localised?
Neck ultrasound and technetium-99m sestamibi scintigraphy together, with SPECT or 4D-CT reserved for negative or reoperative cases, enabling focused exploration.

### What is the Miami criterion?
A fall of more than 50 per cent in intraoperative parathyroid hormone measured 10 minutes after excision, predicting removal of all hyperfunctioning tissue.

### What is hungry bone syndrome?
Severe postoperative hypocalcaemia with hypophosphataemia after parathyroidectomy as demineralised bone avidly absorbs calcium and phosphate, managed with calcium and calcitriol.