Tetany is a classic sign of hypocalcemia, which refers to the presence of low calcium levels in the blood. Maintaining stable calcium levels is important for the adequate functioning of many cellular processes, such as neuronal activity, muscular contraction, hormone secretion, and blood coagulation. Blood calcium levels are regulated by the parathyroid hormone (PTH), which is released into the circulation when calcium levels are too low.
Hypocalcemia can result from a decreased level of PTH or, more rarely, increased resistance to its activity. This condition is known as hypoparathyroidism and can occur as a result of surgical removal of the parathyroid gland, autoimmune disorders or genetic conditions involving the parathyroid gland (e.g., DiGeorge syndrome), or magnesium deficiency.
Moreover, low levels of vitamin D can also lead to hypocalcemia. Vitamin D deficiency can result from a deficient diet, intestinal malabsorption, lack of sunlight exposure, or chronic kidney failure, among other causes. Finally, hypocalcemia can occur as a result of too much calcium leaving the blood, which can be seen in individuals with kidney failure, extensive burns, acute pancreatitis, severe infections, and treatment with several medications.
Aside from hypocalcemia, there are other metabolic irregularities that can also lead to tetany, including other electrolyte imbalances and disorders affecting the acid-base balance. Often, the cause of tetany involves a combination of metabolic abnormalities rather than a single cause.
