Chronic kidney failure is the most common cause of<unk> . Failing kidneys do not convert enough vitamin D to its active form, and they do not adequately excrete phosphate. When this happens, insoluble calcium phosphate forms in the body and removes calcium from the circulation. Both processes lead to hypocalcemia and hence<unk> .<unk>  can also result from malabsorption (chronic pancreatitis, small bowel disease, malabsorption-dependent bariatric surgery) in that the fat-soluble vitamin D can not get reabsorbed. This leads to hypocalcemia and a subsequent increase in parathyroid hormone secretion in an attempt to increase the serum calcium levels. A few other causes can stem from inadequate dietary intake of calcium, a vitamin D deficiency, or steatorrhea.
Secondary hyperparathyroidism
Primary hyperparathyroidism
Tertiary hyperparathyroidism
Familial hypocalciuric hypercalcemia
Normophosphatemic familial tumoral calcinosis
Pseudohypoparathyroidism
Pseudopseudohypoparathyroidism
Parathyroid adenoma