Muscle atrophy and weight loss almost always are recognized by the time the patient seeks medical treatment. Fasciculations may be quite widespread and active. Surprisingly, the patient often ignores this symptom. Patients may have inappropriately active tendon reflexes and weak, wasted, twitching muscles. Muscle cramps are common.
Decubitus ulcers are rare.
The primary cause of death among patients electing to use ventilatory support is pulmonary infection. Cause is unknown. Often, neurologists need several weeks to rule out all other possible diagnoses in a patient presenting with upper and lower motor neuron signs. Clinically, the diagnosis is made with the support of electromyography and by exclusion of other neurologic diseases. Electromyography shows fibrillation and fasciculations.