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Q1: Definition and classification (2 min)
Examiner: Define hypercalcaemia. How do you classify the causes, and why does that classification matter?[1]
Expected answer:
- Hypercalcaemia = corrected serum calcium over 2.6 mmol/L (10.4 mg/dL); severe/hypercalcaemic crisis over 3.5 mmol/L (14 mg/dL).[1][4]
- Always correct for albumin: corrected Ca = measured Ca + 0.02 × (40 − albumin g/L).[1][4]
- Severity bands: mild (2.6 to 3.0), moderate (3.0 to 3.5), severe (over 3.5).[1][4]
- The pivotal classification is by PTH: PTH-dependent (primary or tertiary hyperparathyroidism, lithium, FHH, ectopic PTH) versus PTH-independent (malignancy via PTHrP or osteolysis, granulomatous disease, vitamin D intoxication, milk-alkali, thiazides, immobilisation, thyrotoxicosis, adrenal insufficiency).[1][4]
- The classification matters because the PTH level splits the differential at the first laboratory step and dictates the rest of the work-up.[1][4]
Q2: Acute severe hypercalcaemia — management (3 min)
Examiner: A 70-year-old man is brought in confused with a corrected calcium of 3.9 mmol/L. Take me through your management.[1][4]
Expected answer:
- ABCDE + cardiac monitoring (shortened QT, arrhythmia risk).[1][4]
- Aggressive isotonic saline 3 to 6 L over 24 h (200 to 500 mL/h titrated to euvolaemia and urine output) — the cornerstone; the patient is volume-depleted from polyuria (nephrogenic DI) and vomiting. Caution in cardiac/renal failure.[1][4]
- Stop thiazides, lithium, vitamin D, calcium, antacids.[1][4]
- Calcitonin 4 to 8 IU/kg SC q12h — fastest onset (4 to 6 h) as a bridge; tachyphylaxis at 48 h.[3]
- IV bisphosphonate: zoledronate 4 mg over 15 min or pamidronate 60 to 90 mg over 2 to 4 h — onset 24 to 48 h, nadir 4 to 7 days, lasts weeks. Avoid zoledronate if eGFR under 35 mL/min.[1][4]
- Denosumab 120 mg SC for refractory/malignancy (no renal adjustment; monitor for hypocalcaemia).[1][4]
- Glucocorticoids only for 1,25-OH-D-mediated disease (granulomatous, lymphoma, vitamin D intoxication).[1][4]
- Dialysis (low-calcium bath) for severe renal failure or refractory.[1][4]
- Measure PTH before treatment to confirm the cause; treat the underlying cause in parallel.[1][4]
Q3: Primary hyperparathyroidism — surgical indications and pitfalls (3 min)
Examiner: Which patients with primary hyperparathyroidism should have surgery, and what must you exclude before operating?[1][4]
Expected answer:
- Fifth International Workshop 2022 surgical criteria (any one): symptomatic (stones, fracture, osteitis fibrosa); Ca over 0.25 mmol/L (1.0 mg/dL) above ULN; T-score under −2.5 or vertebral fracture at any site including distal forearm; eGFR under 60 mL/min; nephrolithiasis or nephrocalcinosis; age under 50. AAES 2016 adds neuropsychiatric and cardiovascular.[1][4]
- Patients not meeting criteria can be monitored (annual Ca/creatinine; DEXA every 1 to 3 years).[1][4]
- Must exclude FHH before surgery: 24-h urinary calcium under 200 mg/day and Ca/Cr clearance ratio under 0.01; FHH is benign autosomal dominant — surgery does NOT cure it.[1][4]
- Must exclude MEN1 and MEN2A in young/multigland disease: phaeochromocytoma must be excluded before neck surgery in MEN2A.[1][4]
- Localisation: sestamibi SPECT/CT + neck ultrasound; 4D-CT as second-line; intraoperative PTH (Miami criterion) confirms cure.[1][4]
Q4: Complications and prognosis (2 min)
Examiner: What are the complications of parathyroidectomy, and what is the prognosis of treated versus untreated disease?[1][4]
Expected answer:
- Complications of parathyroidectomy: recurrent laryngeal nerve injury (hoarseness/stridor), postoperative hypocalcaemia (transient in up to 25 percent), hungry bone syndrome (severe prolonged hypocalcaemia, hypophosphataemia, hypokalaemia, hypomagnesaemia), neck haematoma (airway emergency), persistent/recurrent disease (missed adenoma, supernumerary gland).[1][4]
- Prognosis of treated PHPT: curative with parathyroidectomy (success over 95 percent with ioPTH); bone density improves over 1 to several years; stone risk falls.[1][4]
- Untreated asymptomatic PHPT: stable course in most, but 25 percent develop progressive bone loss, stones, or worsening hypercalcaemia over 15 years.[1][4]
- Malignancy hypercalcaemia: median survival 30 to 60 days untreated.[1][4]
- Parathyroid carcinoma: 5-year survival 85 percent; recurrence in 50 percent.[1][4]
References4ShowHide
- [1]Turner JJO. Hypercalcaemia - presentation and management Clin Med (Lond), 2017.PMID 28572230
- [2]Major PP, Coleman RE. Zoledronic acid in the treatment of hypercalcemia of malignancy: results of the international clinical development program Semin Oncol, 2001.PMID 11346861
- [3]Nussbaum SR. Pathophysiology and management of severe hypercalcemia Endocrinol Metab Clin North Am, 1993.PMID 8325291
- [4]Davidson TG. Conventional treatment of hypercalcemia of malignancy Am J Health Syst Pharm, 2001.PMID 11757206