Sporadic postinfectious neuromyasthenia.

Outbreaks of epidemic neuromyasthenia have occurred throughout the world for many years, but sporadic cases have only recently been recognized. Fifty consecutive previously well patients with prolonged and excessive fatigue after an apparent acute infection were investigated. Most were well educated, active, unmarried women aged 30 to 40 years. The precipitating infection had many clinical presentations. The chronic phase of the illness was characterized by a fairly common set of symptoms. Physical examination and laboratory testing generally gave normal results. Of the 50 patients 16 were found to be infected with Epstein-Barr virus, 7 with other viruses, 4 with parasites and 2 with Mycoplasma pneumoniae. The causative agent was not known in 22 cases. The mean duration of the illness was 27.6 months, and the mean proportion of time lost from work or school was 39%. Drug therapy was not beneficial; supportive therapy was useful. Further investigation is required to determine optimal management of sporadic neuromyasthenia.