Tetany Question? - hopkinsk

[ArchivalUser]

Why hypocalcemia causes tetany?

[ArchivalUser]

Decreased extracel- lular Ca2+ causes increased excitability of excitable cells including sensory and motor nerves and muscle. Decreased extracellular Ca2+ lowers (makes more negative) the threshold potential; by lowering thresh- old potential, less inward current is required to depolarize to threshold and to reaction potentials. Thus, hypocalcemia produces tingling and numbness aka tetany which has 2 very significant symptoms as Troussue and Chvostek sign (effects on sensory nerves) and spontaneous muscle twitches (effects on motoneurons and the muscle itself ).