Aetiology
- Increased osteoclastic activity (Malignancy, hyperparathyroidism)
- Decreased renal calcium excretion (hyperparathyroidism, renal failure Drugs (Thiazides, vitamin D, Lithium)
- Other (Sarcoidosis, TB, over ingestion of calcium / vit D, hyperthyroidism)
Classification
- Normal serum corrected calcium = 2.1 – 2.6 mmol/L
- Mild hypercalcaemia = 2.7 – 2.9 mmol/L
- Moderate hypercalcaemia = 3.0 – 3.4 mmol/L
- Severe hypercalcaemia = greater than 3.4 mmol/L
Clinical
- GI upset (anorexia, N&V, constipation)
- CVS effects (hypertension , short QT)
- Renal (polydipsia, polyuria)
- CNS (depression, psychoses, fitting, coma)
Algorithm
Management
- Hydration (N. saline)
- Enhance renal excretion ( add 40mg Frusemide once patient adequately rehydrated)
- Inhibit bone re-absorption (bisphosphonates, particularly in malignancy)
- Treat underlying problem and (consider steroids in sarcoidosis, vit D toxicity, haematological malignancies)
References
Re Zoledronic acid
- Green J et al. (1994) Preclinical pharmacology of CGP 42'446 a new, potent, heterocyclic bisphosphonate compound. Journal of Bone and Mineral Research. 9: 745-751
- Body J (1997) Clinical research update: zoledronate. Cancer. 80: 1699-1701
- Major P et al. (2001) Zoledronic acid is superior to pamidronate in the treatment of hypercalcaemia of malignancy. a pooled analysis of two randomized, controlled clinical trials. Journal of Clinical Oncology. 19: 558-567
- Cheer S and Noble S (2001) Zoledronic acid. Drugs. 61: 799-805
- Lee M et al. (2001) Bisphosphonate treatment inhibits the growth of prostate cancer cells. Cancer Researchp. 61: 2602-2608
- Berenson J et al. (2001) Zoledronic acid reduces skeletal-related events in patients with osteolytic metastases. Cancer. 91: 1191-1200
- Fleisch H (1998) Bisphosphonates: mechanisms of action. Endocrine Reviews. 19: 80-100