Hypercalcemia - Differential Diagnosis Algorithm

Primary Hyperparathyroidism

 • Adenoma

 • Hyperplasia

 • MEN 1 and 2A

Tertiary Hyperparathyroidism

 • Hypercalcemia (in the setting of long-standing secondary hyperparathyroidism) (e.g. Renal Failure, Post-Renal Transplant)

Familial Hypocalciuria Hypercalcemia

 • Autosomal Dominant Calcium Receptor Mutation (CaSR)

 • Other Familial Hypercalcemias (e.g. MEN)

Drug Side Effects

 • Thiazide Diuretics

 • Lithium

 • Vitamin A/lsotretinoin

Malignancy

 • PTH-Related Peptide (e.g. Breast, Kidney, Lung)

 • Cytokine-Mediated Bone Resorption (e.g. Multiple Myeloma, Lymphomas) Metastatic Bone Disease

Vitamin D Related

 • Excess Vitamin D/Calcitriol Intake

 • Unregulated Conversion of 25-OH D3 to 1,25-(OH)2D3 (e.g. Granulomatous Disease, Lymphoma)

Other

 • Excess Calcium Intake (e.g. Milk Alkali)

 • Immobilization

 • Adrenal Insufficiency

 • Thyrotoxicosis

 • Paget's Disease



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