When I was a student, one of my senior teachers in neurology recounted how he’d travelled by train to another city for a consultation about his fasciculations while he was a resident. He’d been convinced he was dying of ALS but was embarrassed to seek help in his own city. Needless to say, he was still a going concern decades later. We all get fasciculations from time to time. They’re particularly common in the eyelids and can be exacerbated by anxiety, fatigue and stimulants.
While fasciculations can be a sign of muscle denervation due to lower motor neuron involvement by anything from spinal nerve root compression to amyotrophic lateral sclerosis, there should be weakness and atrophy in truly denervated muscles. Patients with benign fasciculation syndrome present with localized or widespread fasciculations without weakness or atrophy. EMG may be useful in excluding more serious conditions. The causes of benign fasciculation syndrome are unknown.
Blexrud et al followed 121 patients with benign fasciculations for 2 to 32 years after diagnosis. None of them developed motor neuron disease. Fully one-third of these patients were healthcare workers. Presumably, the knowledge that fasciculations may be bad news prompts a person to seek an opinion, while ignorance is bliss. Andrew Kirk, MD
1. Blexrud et al. Ann Neurol 1993 Oct: 34(4):622-5.