The various causes are diet deficiency, drug overdose
; drug side effects like diuretics, steroids, exercise, benign twitches usually affect eyelids, calf or thumb, triggered by stress and usually last for few days. Nervous system conditions that cause twitching are amyotrophic lateral sclerosis, muscle dystrophy. Usually there is no treatment necessary for benign muscle wasting. Consult a neurologist for certain blood tests to look for electrolytes, thyroid gland function and blood chemistry.