Makindo Medical Notes

Related Subjects: | Familial Hypocalciuric Hypercalcaemia (FHH) | Primary Hyperparathyroidism | Lung Cancer | Hypercalcaemia | Multiple Myeloma | Oncological Emergencies | Bisphosphonates

⚠️ Hypercalcaemia = Albumin-adjusted Ca²⁺ > 2.6 mmol/L (UK) / > 10.5 mg/dL (US). 👉 >90% of cases due to malignancy or primary hyperparathyroidism.

🚑 Initial Management

💧 Hydration • Oral fluids 3–4 L/day if mild (Ca²⁺ <3.0 mmol/L) • IV 0.9% Saline 4–6 L/24h if moderate–severe (monitor for overload) • Restrict to 2–3 L/day if 💔 heart failure risk • Add loop diuretic (furosemide) only if fluid overloaded 🔍 Investigations • Serum Ca²⁺ (corrected), phosphate, ALP, renal function, PTH, vitamin D • CXR (lung Ca / sarcoid), ESR/CRP • Serum & urine paraproteins (myeloma) 💊 Drugs • Bisphosphonates: Zoledronate 4 mg IV (15 min) OR Pamidronate 60–90 mg IV (2–5 h) ↳ Onset 24–48 h, peak effect at 4–7 days • Steroids (Prednisolone 40–60 mg OD) if sarcoidosis, lymphoma, granulomatous disease • Calcitonin (100 units SC/IM q6–8h) for rapid short-term Ca²⁺ reduction • Denosumab if bisphosphonate-refractory or renal impairment ⏱ Monitoring • Daily Ca²⁺, renal function, fluid balance • ECG for arrhythmias (short QT, block, VT) 🛑 Refractory / Severe • Dialysis if life-threatening hypercalcaemia with renal/cardiac failure 📌 Treat Underlying Cause • Malignancy (oncology input) • Primary hyperparathyroidism (surgery) • Vitamin D excess, immobilisation, granulomatous disease

📏 Calcium Conversion

State	US (mg/dL)	UK (mmol/L)
Normal	8.5–10.5	2.12–2.62
Hypocalcaemia	<8.5	<2.12
Hypercalcaemia	>10.5	>2.62

Conversion: mg/dL × 0.25 = mmol/L

🩸 Causes of Hypercalcaemia

Cause	Features / Management
🦴 Primary Hyperparathyroidism	Bone pain, stones, constipation, mood changes. Labs: ↑ Ca²⁺, ↑/normal PTH, ↓ phosphate. Tx: Parathyroidectomy, hydration, bisphosphonates.
🎗️ Malignancy	Advanced cancer, weight loss, confusion. Labs: ↑ Ca²⁺, ↓ PTH, ↑ PTHrP. Tx: IV fluids, bisphosphonates, denosumab, treat tumour.
🌞 Vitamin D Excess	GI upset, dehydration. Labs: ↑ Ca²⁺, ↑ Vit D, ↓ PTH. Tx: Stop Vit D, fluids, steroids, bisphosphonates.
🫁 Sarcoidosis	Fatigue, polyuria, respiratory disease. Labs: ↑ Ca²⁺, ↑ 1,25 Vit D. Tx: Steroids + hydration.
💊 Thiazides	Mild, asymptomatic. Labs: ↑ Ca²⁺, ↓ PTH. Tx: Stop drug, monitor.
👨‍👩‍👧 Familial Hypocalciuric Hypercalcaemia (FHH)	Mild, lifelong, benign. Labs: ↑ Ca²⁺, ↓ urine Ca²⁺. Tx: None required.
🛏️ Immobilisation	High bone turnover states (Paget’s). Tx: Mobilisation, bisphosphonates.
🔥 Hyperthyroidism	Mild hypercalcaemia with thyrotoxic features. Tx: Treat thyroid disease.

🧾 Clinical Features – “Bones, Stones, Groans, Moans”

• 🦴 Bones: pain, fractures, myeloma
• 💎 Stones: renal calculi, polyuria, polydipsia
• 🤢 Groans: constipation, abdominal pain, pancreatitis
• 😵 Moans: confusion, depression, psychosis, coma
• Other: hypotonia, hypertension, band keratopathy 👁️

🔍 Investigations

• 🧪 FBC (anaemia in myeloma/malignancy)
• U&E: dehydration, renal failure
• ESR ↑ (myeloma, cancer)
• 📉 ECG: Short QT
• 🫁 CXR: SCC lung, sarcoidosis
• PTH: ↑ in primary hyperparathyroidism, ↓ in malignancy
• Urinary Ca²⁺ low in FHH
• Special tests: PTHrP, bone scan, Vit D, ACE (sarcoid)

💊 Definitive Management

• 💧 IV fluids (mainstay)
• 💊 Loop diuretics (after rehydration)
• 💉 Bisphosphonates (Zoledronate, Pamidronate)
• 🌿 Steroids (sarcoid, lymphoma)
• 🧪 Calcitonin or dialysis if refractory

📚 Reference

• Hypercalcaemia Guideline for Primary Care

🧑‍⚕️ Case Examples — Hypercalcaemia

• Case 1 (Primary Hyperparathyroidism): 🦴 A 62-year-old woman presents with fatigue, constipation, bone pain, and recurrent renal stones. Bloods: calcium 3.0 mmol/L, PTH inappropriately elevated, low phosphate. Analysis: Classic “bones, stones, abdominal groans, psychiatric overtones.” Commonest outpatient cause of hypercalcaemia. Diagnosis: Primary hyperparathyroidism due to parathyroid adenoma. Management: Definitive = parathyroidectomy (if symptomatic or criteria met). Interim = hydration, avoid thiazides/lithium, monitor bone density and renal function.
• Case 2 (Malignancy-Associated Hypercalcaemia): 🎗️ A 70-year-old man with lung cancer presents with confusion, dehydration, and constipation. Calcium 3.5 mmol/L, suppressed PTH, raised PTHrP. Analysis: Malignancy is the most common inpatient cause of severe hypercalcaemia, due to humoral (PTHrP) or osteolytic metastases. Diagnosis: Hypercalcaemia of malignancy. Management: IV fluids (saline rehydration), IV bisphosphonate (zoledronic acid), oncology input. Prognosis usually poor.
• Case 3 (Vitamin D Intoxication): 💊 A 55-year-old man on over-the-counter supplements presents with nausea, abdominal pain, and muscle weakness. Calcium 3.2 mmol/L, suppressed PTH, high 25-hydroxyvitamin D. Analysis: Excessive vitamin D → ↑ intestinal calcium absorption and bone resorption. Diagnosis: Vitamin D toxicity–induced hypercalcaemia. Management: Stop vitamin D, IV fluids, bisphosphonates if needed, steroids in refractory cases.