CALCIUM-HYPERCALCEMIA CAUSES

SUMMARY

1. Primary/secondary/tertiary hyperparathyroidism.

2. Drugs: Vit D excess, Vit A excess, thiazide diuretic (decreases calcium excretion), lithium (increases PTH threshold, requiring Ca²⁺ to be higher to shut off PTH secretion).

3. Malignancy
- Myeloma: produces osteoclast activating factors.
- Some solid tumors: secrete PTH-related protein (different from PTH, which is suppressed by raised serum calcium).
- Metastasis: produce local osteoclast activating factors.

4. Sarcoidosis, TB, histoplasmosis, leprosy: through Vit D production by macrophages.

5. Immobility in the setting of hyperthyroidism, Paget's disease, adolescence.

6. Multi-trauma.

7. Genetic: Familial hypocalciuric hypercalcemia (FHH).

Reference(s)

Wilkinson, I., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].