Hypercalcemia of malignancy is the most common paraneoplastic syndrome seen in hospital, and it usually appears in advanced cancer. Most cases come from tumors that release PTH-related protein (PTHrP), such as squamous cell lung cancer, while others come from bone metastases or myeloma.
Key symptoms
- Thirst, frequent urination and dehydration
- Nausea, vomiting, constipation and abdominal pain
- Confusion, drowsiness and weakness
- Bone pain
- Symptoms that build quickly, over days to weeks
What you find on exam
- Dehydration: dry mouth, low blood pressure, fast pulse
- Mental status and level of consciousness
- Signs of the underlying cancer: weight loss, lung findings, masses
- Bone tenderness
- Reduced reflexes
Tests
- High calcium, corrected for albumin, or high ionized calcium
- PTH low (suppressed) and PTHrP high
- Kidney function and electrolytes; ECG for a short QT
- Search for the cancer: chest imaging, protein electrophoresis for myeloma
Treatment basics
- IV normal saline to restore volume
- Zoledronic acid IV; denosumab if kidney function is poor
- Calcitonin for a fast but short drop in severe cases
- Stop calcium, vitamin D and thiazides; dialysis if the kidneys fail
- Treat the cancer and discuss goals of care
Red flags
- Calcium over 14 mg/dL
- Confusion, coma or arrhythmia
- Acute kidney injury or inability to drink
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.