Increased intake or absorption

Milk-alkali syndrome

Vitamin D or vitamin A excess

Endocrine disorders

Primary hyperparathyroidism

Secondary or tertiary hyperparathyroidism (usually associated with hypocalcemia)

Acromegaly

Adrenal insufficiency

Pheochromocytoma

Thyrotoxicosis

Neoplastic diseases

Tumors producing PTH-related proteins (ovary, kidney, lung)

Plasma cell myeloma (elaboration of osteoclast-activating factor)

Lymphoma (occasionally from production of calcitriol)

Miscellaneous causes

Thiazide diuretics

Granulomatous diseases (production of calcitriol)

Paget disease of bone

Hypophosphatasia

Immobilization

Familial hypocalciuric hypercalcemia

Complications of kidney transplantation

Lithium intake