Fasciculations

Spontaneous, involuntary, localized muscle contractions and relaxations, caused by spontaneous discharge of a lower motor neuron or its axon. Possible causes are stress, fatigue, sleep deprivation, caffeine, amphetamine, nicotine, intense exercise, electrolyte deficiency (magnesium, calcium, potassium), benign fasciculation syndrome, amyotrophic lateral sclerosis, spinal muscular atrophy, peripheral neuropathy, hyperthyroidism, kidney disease, and medications (anticholinergics, steroids, diuretics).