Hypercalcemia (high calcium)

What is hypercalcemia?

Calcium in the blood is tightly regulated by parathyroid hormone (PTH), vitamin D, and calcitonin. Normal serum calcium ranges from 2.2 to 2.6 mmol/L. Hypercalcemia is defined as a corrected serum calcium above 2.6 mmol/L.

As with hypocalcemia, total calcium must always be interpreted alongside albumin. Elevated albumin from dehydration can cause apparent hypercalcemia. Corrected or ionised calcium provides the true picture.

Severity determines clinical urgency:

• Mild hypercalcemia (2.6 to 3.0 mmol/L) is often asymptomatic and commonly discovered incidentally.

• Moderate hypercalcemia (3.0 to 3.5 mmol/L) causes symptoms including fatigue, nausea, and cognitive changes requiring investigation and treatment.

• Severe hypercalcemia (above 3.5 mmol/L) is a medical emergency causing confusion, cardiac arrhythmias, and renal failure requiring immediate hospitalisation.

Symptoms of hypercalcemia

Hypercalcemia symptoms are often described as bones, groans, stones, and moans, reflecting the four main clinical domains affected. Common signs include:

• Excessive thirst and frequent urination as the kidneys work to excrete excess calcium

• Nausea, vomiting, constipation, and loss of appetite

• Fatigue, weakness, and lethargy

• Bone pain or tenderness from calcium being mobilised out of bones

• Kidney stones from calcium crystallising in the urinary tract

• Confusion, poor concentration, depression, or in severe cases altered consciousness

• Muscle weakness and reduced reflexes

• In severe cases: cardiac arrhythmias and renal failure requiring emergency treatment

Important: Calcium above 3.5 mmol/L with confusion, severe nausea, or cardiac symptoms requires immediate emergency medical care.

What causes hypercalcemia?

The vast majority of hypercalcemia cases are caused by one of two conditions. Identifying which one is the critical clinical question.

• Overactive parathyroid glands: the most common cause. A small, usually harmless growth on these glands causes them to release too much hormone, which pulls calcium out of your bones and into your blood.

• Malignancy: certain serious illnesses can cause calcium levels to rise quickly by affecting the bones or releasing specific proteins. This usually requires urgent medical attention.

• Vitamin D toxicity: taking too much Vitamin D can cause the body to absorb more calcium than it can actually manage.

• Specific inflammatory conditions: illnesses like sarcoidosis or tuberculosis can cause your body to produce extra active Vitamin D, which in turn raises calcium.

• Lack of movement: prolonged bed rest or lack of weight-bearing activity can cause bones to release calcium into the bloodstream.

• Medications: certain drugs, including lithium, some water tablets (diuretics), or overusing calcium-based antacids, can cause a spike.

• Genetics: some people are born with a harmless genetic trait that keeps their calcium levels slightly higher than average without causing any health problems.

How is hypercalcemia detected?

Hypercalcemia is detected through blood testing, with supporting markers identifying the underlying cause.

Blood tests Elfcare's panel includes calcium alongside the key related markers:

• Total calcium and albumin-corrected calcium: these are the primary markers. Corrected calcium provides the true calcium status independent of albumin levels.

• Albumin: essential for accurate calcium interpretation, as dehydration and other conditions affecting albumin alter total calcium readings.

• Phosphate: helps distinguish between gland issues (low levels) and other causes like vitamin D toxicity (high levels).

• ALP: a marker of bone activity; high levels can indicate bone turnover or damage.

• Magnesium: provides context on how your body is regulating minerals.

• Creatinine and eGFR: assess kidney function, as hypercalcemia causes nephrogenic diabetes insipidus and progressive renal damage if untreated.

• 25-OH Vitamin D: identifies vitamin D toxicity as a cause and assesses baseline vitamin D status.

• Total PSA: relevant when prostate cancer is a possible source of bone metastases causing hypercalcemia in men.

• CRP: reflects systemic inflammation relevant to granulomatous conditions and malignancy-associated hypercalcaemia.

Abdominal MRI Elfcare's full body MRI provides a visual check that blood tests cannot. It directly images the neck to look for parathyroid growths, the kidneys for stones caused by calcium buildup, and the abdomen for any masses that might be driving the elevation.

Why early detection matters

Mild chronic hypercalcemia from primary hyperparathyroidism can persist for years causing progressive but silent kidney damage, bone density loss, and cardiovascular risk. When identified early, a parathyroid adenoma can be removed surgically with excellent long-term outcomes. Malignancy-associated hypercalcemia identified early allows for treatment of the primary cancer before severe metabolic complications develop. Kidney stones, cognitive decline, and irreversible renal damage from undetected chronic hypercalcemia are all preventable with early identification and management.

How Elfcare can help

Elfcare's blood panel covers calcium, albumin-corrected calcium, phosphate, ALP, magnesium, kidney function, vitamin D, and CRP, providing the complete picture of calcium status and the most likely underlying cause. The pattern of calcium, phosphate, and ALP together is particularly informative in distinguishing primary hyperparathyroidism from malignancy-associated hypercalcemia.

Our full body MRI images the neck region and kidneys, identifying parathyroid adenomas and kidney stones as structural correlates of hypercalcemia.

If our blood tests or MRI identify hypercalcemia or a suspicious finding, we take care of further diagnostics or refer you to the appropriate specialist.