The predominant effects of hypocalcaemia are on the nerves and muscles. Typical features include:
- tetany, painful cramps, and tingling in the extremities
- latent tetany may be demonstrated by Trousseau's and Chvostek's signs
- severe tetany may result in spontaneous spasm of the hand - main d'accoucheur - largely precipitated by exercise
- laryngeal spasm may cause stridor, obstructed respiration
- convulsions may occur as hypocalcaemia lowers the seizure threshold
- chronic hypocalcaemia may cause psychiatric effects - from general malaise to overt psychosis
Other features depend on the underlying cause. They are more features of chronic disease and may include:
- candidosis, dystrophic nails, alopecia, intracranial calcification especially of basal ganglia, cataracts, Addison's disease, mental deficiency, papilloedema, prolonged QT on ECG - from hypoparathyroidism
- rickets / osteomalacia - from vitamin D deficiency