Evidence of Axonal Reinnervation in Two Arthropod-Borne Viral Encephalomyelitis Patients

Flaviviruses are the main cause of epidemic encephalitis, yet the ratio of inapparent to apparent infections is high, ranging from 20:1 to 1,000:1 [1,2]. When symptomatic, some viruses may cause severe encephalomyelitis that may lead to lasting disability with lower motor neuron paralysis masquerading as poliomyelitis [review in 1, 3]. This syndrome is known as ‘Amyotrophy in Russian spring-summer encephalitis’ (A83) in the classification of neuromuscular disorders of the World Federation of Neurology [4]. We here report 2 patients with such a syndrome, also the subject of another, but clinicoepidemiological, report [5]. The features of our patients are summarized in table 1. Both had neck stiffness with headache, fever greater than 39 ° C, and their cerebrospinal fluid (CSF) showed a lymphocytic pleocytosis with an elevated protein content. Ceftriazone (2 g/day) was started intravenously and the patients improved within 2 days. Both gave a history of insect bite 3 weeks prior to admission. The 3rd day after admission, the patients developed, within hours, bilateral neck, periscapu-lar and brachial muscle weakness and respiratory failure. Both patients required intubation at the end of the 1st week. At the nadir of the disease, examination revealed ventilatory failure, bilateral are-flexic asymmetrical upper limb and neck flexor muscle weakness with amyotrophy, fasciculations, and absence of abdominal cuta-