Hypercalcemia: workup and management
Raised corrected or ionized calcium. Primary hyperparathyroidism and malignancy cause about 90%. Severity and symptoms drive treatment: volume repletion first, then calcitonin and bisphosphonate, while PTH separates the cause.
Working diagnosis
Adult · US guidelines
Draft · awaiting physician review
01Orient
What's new in the evidence
- Endocrine Society 2023 hypercalcemia of malignancy guideline: denosumab is conditionally favored over IV bisphosphonates and recommended for refractory or recurrent cases
- Calcitonin plus a bisphosphonate or denosumab for severe hypercalcemia (Ca >14 mg/dL)
- No routine loop diuretics unless volume overloaded
Differential diagnoses
- Primary hyperparathyroidism
- Malignancy: PTHrP (squamous, renal, breast), osteolytic metastases, myeloma
- Calcitriol-mediated: lymphoma, granulomatous disease (sarcoid, TB)
- Medications: thiazides, lithium, vitamin D, calcium, vitamin A
- Immobilization, thyrotoxicosis
- Familial hypocalciuric hypercalcemia
02Assess
Risk scores and decision tools
- Corrected calcium = Ca + 0.8 × (4.0 − albumin); ionized calcium when available
- PTH first: suppressed PTH points to malignancy or vitamin D causes
- Severity: mild <12, moderate 12–14, severe >14 mg/dL
Key history questions
- Polyuria, thirst, constipation, abdominal pain, confusion, bone pain
- Kidney stones, fractures
- Known cancer, weight loss, smoking
- Supplements and drug history
- Family history of hypercalcemia
Examination findings
- Volume depletion
- Mental status
- Lymphadenopathy, breast or other masses
- Bone tenderness
03Investigate
Initial investigations
- Repeat calcium with albumin, or ionized calcium
- PTH
- BMP, phosphate, magnesium
- ECG (short QT)
Advanced investigations
- If PTH suppressed: PTHrP, 25-OH and 1,25-(OH)2 vitamin D
- SPEP, free light chains
- Imaging for malignancy
- 24 h urine calcium if FHH suspected
04Treat
Immediate management
- Isotonic saline about 200-300 mL/h, titrated to urine output 100-150 mL/h; adjust in HF or CKD
- Stop thiazides, calcium and vitamin D supplements
- Calcitonin 4 IU/kg SC or IM every 12 h for up to 48 h for rapid but short effect
First-line treatment
- Denosumab 120 mg SC (conditionally preferred in malignancy; repeat days 8 and 15, then monthly) or zoledronic acid 4 mg IV over ≥15 min (dose-adjust for kidney function)
- Denosumab is not renally cleared but carries a higher hypocalcemia risk in advanced CKD; replete vitamin D first
- Loop diuretics only after volume repletion, for fluid overload
Second-line treatment
- Denosumab for renal impairment or bisphosphonate-refractory cases
- Glucocorticoids for calcitriol-mediated causes (lymphoma, granulomatous disease)
- Hemodialysis for severe hypercalcemia with renal failure or neurological compromise
Specialist referrals
- Oncology if malignancy related
- Endocrinology and endocrine surgery for hyperparathyroidism
05Disposition
Admission criteria
- Calcium over 14 mg/dL, or symptomatic at any level
- AKI or altered mental status
- New malignancy-related hypercalcemia
Safe discharge criteria
- Mild (under 12 mg/dL) asymptomatic hypercalcemia
- Stable renal function with outpatient work-up arranged
Follow-up timing
- Repeat calcium in 1 week after discharge
Patient instructions
- Keep well hydrated
- Return with confusion, vomiting or severe constipation
Monitoring
- Calcium every 12-24 h
- Fluid balance and renal function
Clinical pearls and pitfalls
- Corrected calcium = measured Ca + 0.8 × (4.0 − albumin g/dL)
- Check vitamin D and dental status before repeated bisphosphonate dosing
RefGuidelines and landmark evidence
For education only. Typical adult starting points; confirm doses against renal function, allergies, interactions and your institution's protocols. Not a substitute for clinical judgment or senior review.