[2][4] Otherwise symptoms may include numbness, muscle spasms, seizures, confusion, or in extreme cases cardiac arrest.

[2] Other causes include other forms of hypoparathyroidism, vitamin D deficiency, kidney failure, pancreatitis, calcium channel blocker overdose, rhabdomyolysis, tumor lysis syndrome, and medications such as bisphosphonates or denosumab.

[4] The neuromuscular symptoms of hypocalcemia are caused by a positive bathmotropic effect (i.e. increased responsiveness) due to the decreased interaction of calcium with sodium channels.

[10] However, in the setting of absent, decreased, or ineffective PTH hormone, the body loses this regulatory function, and hypocalcemia ensues.

[11][12] Some causes of hypocalcaemia are as follows:[citation needed] Physiologically, blood calcium is tightly regulated within a narrow range for proper cellular processes.