Hypercalcaemia at the IMT (Internal Medicine Training) clinical station is answered in three moves: state the severity band from the adjusted calcium, rehydrate with intravenous saline before anything else, and use the parathyroid hormone result to split the cause. According to the Society for Endocrinology emergency guidance, an adjusted calcium above 3.5 mmol/L requires urgent correction because of the risk of dysrhythmia and coma.

Key takeaways

  • The Society for Endocrinology bands hypercalcaemia by adjusted calcium: below 3.0 mmol/L is often asymptomatic, 3.0 to 3.5 mmol/L usually warrants prompt treatment, above 3.5 mmol/L needs urgent correction.
  • Ninety per cent of hypercalcaemia is primary hyperparathyroidism or malignancy, and a paired PTH separates them: high calcium with high PTH is parathyroid, high calcium with low PTH is malignancy or a rarer cause.
  • Rehydration is intravenous 0.9% saline, 4 to 6 litres in 24 hours, with monitoring for fluid overload in older patients and renal impairment.
  • Bisphosphonates come after saline: zoledronic acid 4 mg over 15 minutes, or pamidronate 30 to 90 mg at 20 mg per hour, with the calcium nadir at 2 to 4 days.
  • Loop diuretics are rarely used, only if fluid overload develops, and are not effective at lowering serum calcium.

How do you recognise hypercalcaemia in the scenario?

Hypercalcaemia presents as polyuria and thirst, anorexia, nausea and constipation, and a change in mood or cognition that can progress to confusion and coma. The station usually gives you a confused, dehydrated patient with a known cancer or a raised calcium on routine bloods.

Say that serum calcium is bound to albumin and that you would work from the albumin-adjusted value. The Society for Endocrinology lists renal impairment, a shortened QT interval with dysrhythmia, pancreatitis, peptic ulceration and muscle weakness among the features to look for.

What does the A to E assessment and first hour look like?

The first hour of a hypercalcaemia scenario is an A to E assessment, an ECG, intravenous access with bloods, and 0.9% saline running before the cause is known. Say the order out loud, because the panel is listening for saline before bisphosphonate.

  • Airway and breathing: usually intact, but a comatose patient with a calcium above 3.5 mmol/L needs airway protection and an early anaesthetic call
  • Circulation: assess fluid status, which is almost always depleted from polyuria and vomiting, and start intravenous 0.9% saline
  • Disability: conscious level and a cognitive assessment, since confusion is both a feature and a marker of severity
  • Exposure: examine the neck, chest, abdomen, breasts and lymph nodes for the underlying cause
  • ECG: look for a shortened QT interval or other conduction abnormalities and put the patient on a monitor

Which investigations confirm hypercalcaemia and find its cause?

The investigations for hypercalcaemia are the adjusted calcium, phosphate, parathyroid hormone, urea and electrolytes, and an ECG, all listed by the Society for Endocrinology as the first-line set. The PTH is the single test that changes the pathway.

In the history, ask about duration, weight loss, night sweats and cough, family history, and every drug and supplement including thiazides, lithium, vitamin D and calcium preparations. Familial hypocalciuric hypercalcaemia can mimic primary hyperparathyroidism with an inappropriately normal PTH, but rarely presents as an emergency.

What are the severity thresholds you must say?

The threshold that matters in hypercalcaemia is an adjusted calcium above 3.5 mmol/L, which the Society for Endocrinology says requires urgent correction. Between 3.0 and 3.5 mmol/L the patient may tolerate a slow rise but prompt treatment is usually indicated, and below 3.0 mmol/L urgent correction is not usually needed.

Give the number, not the adjective. A candidate who says 'a very high calcium' has not shown the panel that they know where the emergency starts.

What is the definitive management of severe hypercalcaemia?

Definitive management of severe hypercalcaemia is intravenous 0.9% saline, 4 to 6 litres in 24 hours, followed by an intravenous bisphosphonate if further treatment is needed. That sequence is the whole mark scheme for the management question.

  • Saline first: 4 to 6 litres of 0.9% sodium chloride over 24 hours, monitoring for overload if the patient is elderly or has renal impairment
  • Then a bisphosphonate: zoledronic acid 4 mg over 15 minutes, or pamidronate 30 to 90 mg depending on severity at 20 mg per hour, or ibandronic acid 2 to 4 mg; slower and reduced in renal impairment
  • Expect the nadir at 2 to 4 days, and warn that hypocalcaemia can follow if the patient is vitamin D deficient or PTH is suppressed
  • Second line: prednisolone 40 mg daily in lymphoma, granulomatous disease or vitamin D poisoning, effective in 2 to 4 days
  • Under specialist supervision: calcimimetics, denosumab or calcitonin if the response is poor, and dialysis if there is severe renal failure

In practice, the trap is the loop diuretic. The Society for Endocrinology states that furosemide is rarely used, only if fluid overload develops, and is not effective for reducing serum calcium. Saying 'saline and furosemide' costs marks.

When and to whom do you escalate hypercalcaemia?

Escalate hypercalcaemia to the medical registrar at the outset, to endocrinology for any calcium above 3.5 mmol/L or a parathyroid picture, and to critical care if there is coma, dysrhythmia or renal failure that may need dialysis. Oncology and palliative care join early when malignancy is the driver.

Parathyroidectomy can be considered in an acute presentation of primary hyperparathyroidism, so an early surgical conversation belongs in the answer when PTH is high and the calcium is not settling.

How do you hand over hypercalcaemia in one minute?

The hypercalcaemia handover uses SBAR with the number in the first sentence. Situation: a 68 year old with known breast cancer, confused, adjusted calcium 3.7 mmol/L. Background: two weeks of thirst and constipation, on no thiazide. Assessment: severe hypercalcaemia, likely malignant, ECG without dysrhythmia, dehydrated. Recommendation: 0.9% saline running, zoledronic acid prescribed for after rehydration, PTH sent, please review the calcium at 12 hours and reassess fluid balance.

What does the panel listen for in a hypercalcaemia answer?

The panel listens for the severity band, saline before bisphosphonate, the PTH split, and the bisphosphonate delay of 2 to 4 days, because each is a fact a candidate either knows or improvises. The internalmedicineinterview bank of 361 questions with AI-marked spoken practice exists to make those sentences automatic under time pressure.

What are the common mistakes in a hypercalcaemia station?

  • Giving a bisphosphonate before rehydration, or expecting it to work the same day
  • Adding furosemide to a dehydrated patient
  • Skipping the ECG and the cardiac monitor
  • Treating the number without asking why: no PTH, no drug history, no examination for malignancy
  • Forgetting the fluid-overload caution in an elderly patient with renal impairment

How this comes up at the IMT interview

Hypercalcaemia maps onto all three parts of the IMT clinical station. Investigations and diagnosis is the adjusted calcium, PTH and ECG; management is saline, then bisphosphonate, then cause; and communication is explaining to the patient why the drug that fixes the calcium will not act until later in the week. The handover minute is where the 3.5 mmol/L threshold and the fluid plan get said aloud with a time to review.