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Primary hyperparathyroidism
A high calcium with a high or "inappropriately normal" PTH is primary hyperparathyroidism, usually from a single adenoma; the diagnosis is biochemical, imaging only localises before surgery, and surgery is the only curative treatment.
Why it matters in the exam
The exam usually presents a patient with a high calcium found incidentally, or with kidney stones, osteoporosis, constipation and confusion. The first question is the diagnosis: a high or normal PTH together with a high calcium points to the parathyroids, whereas a suppressed PTH points to malignancy or excess vitamin D. It is important to exclude familial hypocalciuric hypercalcaemia (FHH) using the urinary calcium-to-creatinine clearance ratio, because FHH is not treated surgically.
The second question is who needs surgery: every symptomatic patient, and an asymptomatic patient who meets any criterion — a calcium level exceeding the upper limit by more than 1 mg/dL, osteoporosis or a vertebral fracture, kidney involvement, stones or high urinary calcium, or age under 50. Candidates are also asked about localisation methods (neck ultrasound, sestamibi scan, four-dimensional CT), intra-operative PTH measurement, "hungry bone syndrome" after surgery and the treatment of a hypercalcaemic crisis. It is also worth separating primary, secondary (chronic kidney disease, vitamin D deficiency) and tertiary (after kidney transplantation) hyperparathyroidism.
Key points
- High calcium with a high or normal PTH — primary hyperparathyroidism; exclude FHH.
- The cause in about 85% is a single adenoma.
- Surgery: everyone with symptoms; without symptoms — one criterion is enough (calcium, bone, kidney, age under 50).
- Imaging localises and does not diagnose; intra-operative PTH confirms success (fall of more than 50%).
- After surgery — think of hungry bone syndrome.
Summary table
| Topic | Details | Meaning |
|---|---|---|
| Causes | Single adenoma in about 85%, multigland hyperplasia (MEN1, MEN2A), carcinoma rare | Hyperplasia — suspect a familial syndrome |
| Diagnosis | High calcium with a high or normal PTH; exclude FHH (calcium-to-creatinine clearance ratio below 0.01) | Suppressed PTH — look for malignancy or excess vitamin D |
| Surgical indications in an asymptomatic patient | Serum calcium over 1 mg/dL higher than the normal ceiling; osteoporosis (T-score −2.5 or worse) or a vertebral fracture; eGFR under 60, kidney stones, or 24-hour urine calcium over 250 mg in women (300 in men); younger than 50 | One criterion is enough |
| Pre-operative localisation | Neck ultrasound, sestamibi, four-dimensional CT | Only after surgery has been decided; does not make the diagnosis |
| Surgery | Focused excision of the adenoma with intra-operative PTH (fall of more than 50% after 10 minutes) | Hyperplasia — bilateral exploration |
| After surgery | Hungry bone syndrome: low calcium, phosphate and magnesium | Give calcium and active vitamin D |
A free exam question
במהלך ניתוח אקספלורציה צווארית דו"צ לחולה עם היפרפאראתירואידיזם ראשוני זוהתה בלוטת פאראתיראויד ימנית עליונה ותחתונה במראה ת .קין. משמאל בלוטת פאראתיראויד שמאלית עליונה גם תקינה בלוטת פאראתיראויד שמאלית תחתונה לא זוהתה במקום הרגיל, הועלה חשד לבלוטה אקטופית. מהו המיקום השכיח ביותר למצוא בלוטה זו? (the question as examined, in Hebrew)
- א. מרווח טרכאואזופגלי
- ב. רטרואזופגלי
- ג. מדיאסטינום קידמי
- ד. מדיאסטינום אחורי
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Sources
- Evaluation and management of primary hyperparathyroidism: summary statement and guidelines from the Fifth International Workshop, 2022 — Diagnosis, indications for surgery and non-surgical management
- AAES Guidelines for Definitive Management of Primary Hyperparathyroidism, 2016 — Localisation and operative strategy
- Sabiston Textbook of Surgery, 21st edition (2022) — The Parathyroid Glands
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.