PSPal Surgery

Causes of hypercalcaemia

Calcium tells you there is a problem. PTH tells you where it is. Phosphate confirms it.

Written and clinically reviewed by , consultant minimally invasive and bariatric surgeon, Al-Makassed Hospital, Jerusalem, and Assistant Professor of Surgery, Al-Quds University. Last updated .

Almost every cause of a high calcium can be sorted with two numbers taken together. Plot the calcium against the PTH and you get four boxes — and only one of them is a surgical disease.

PTH HIGH or inappropriately normal PTH LOW / suppressed CALCIUM HIGH CALCIUM LOW PRIMARY HYPERPARATHYROIDISM the gland has stopped listening — an adenoma Phosphate LOW · urine calcium high Also here: tertiary HPT, lithium, thiazides, and FHH — which must be excluded first → This is the surgical quadrant NON-PARATHYROID HYPERCALCAEMIA the glands are behaving correctly, switching off · Malignancy — PTHrP, bone metastases, myeloma · Granulomatous disease, lymphoma (1,25-D) · Vitamin D or calcium excess, thyrotoxicosis → Find and treat the cause SECONDARY HYPERPARATHYROIDISM an appropriate response to a low calcium · Vitamin D deficiency — phosphate low · Chronic kidney disease — phosphate HIGH · Malabsorption, bypass surgery → Treat the cause, not the PTH HYPOPARATHYROIDISM no hormone is being made — phosphate HIGH · Post-surgical — thyroid or parathyroid surgery, neck dissection. By far the commonest cause. · Magnesium depletion · autoimmune · DiGeorge → The ward problem
Four quadrants, four diseases. Adding the phosphate separates the two causes inside each lower box, and separates PTH-driven hypercalcaemia (phosphate low) from all the rest.

The phrase that earns marks

“A PTH that is normal in the face of a high calcium is not a normal PTH — it is inappropriately normal, and it means the same thing as a raised one. A healthy gland faced with hypercalcaemia should be completely suppressed.”

Primary hyperparathyroidism or malignancy?

Between them these two account for the large majority of hypercalcaemia, and the history separates them before any test comes back.

Primary hyperparathyroidismMalignancy
OnsetMonths to yearsDays to weeks
CalciumUsually under 12 mg/dLOften above 13 mg/dL
PTHHigh or inappropriately normalSuppressed
SymptomsMild or absentMarked — drowsy, vomiting, dehydrated
MechanismAutonomous glandPTHrP, osteolytic metastases, myeloma, calcitriol from lymphoma
OutlookCured by an operationA marker of advanced disease

The order of investigation

Calcium and albumin → repeat to confirm → PTH, phosphate, magnesium, renal function and 25(OH) vitamin D → then a 24-hour urine calcium. Only when that panel says primary hyperparathyroidism do you ask for imaging.

Imaging does not make this diagnosis

A scan tells you where a gland is. It never tells you whether the patient has the disease, and a negative scan does not overturn the biochemistry or cancel the operation.

Asking about the history

Most primary hyperparathyroidism today is found on a routine biochemistry panel, so the textbook “stones, bones, abdominal groans and psychic moans” is a useful prompt and a misleading expectation. Ask about each explicitly — patients rarely volunteer fatigue or constipation as symptoms. Then ask the five that change management: how long the calcium has been abnormal, the drug history (thiazides, lithium, calcium and vitamin D supplements, antacids), red flags for cancer, stones and fractures, and the family history of hypercalcaemia, neck surgery or MEN syndromes.

Related pages

NextPrimary hyperparathyroidismWho gets an operation, and why.EmergencyHypercalcaemic crisisFluids first — and not furosemide.ToolCorrected calciumCheck the number before you diagnose.TopicCalcium and the parathyroidThe circuit all of this rests on.