[Idiopathic brachial neuritis following general anesthesia].

A 25-year-old woman complained of intense pain in her left shoulder several hours after augmentation mammaplasty under general anesthetic; pain was followed by marked sensory and motor deficit in the same arm. A diagnosis of idiopathic brachial neuritis was made after the main causes of intraoperative nerve damage had been ruled out. The shoulder pain resolved after 3 weeks but the sensory and motor deficit remained unchanged. An electrophysiological study performed at 4 weeks revealed abnormalities suggestive of edema or inflammation and an absence of signs of denervation. These findings and the favorable clinical course confirmed the diagnosis of idiopathic brachial neuritis. After 3 months, only mild weakness and numbness in the deltoid region persisted. Although most postoperative neuropathies are iatrogenic, idiopathic brachial neuritis should be included in the differential diagnosis when no evident cause is found. This syndrome is rare but may appear spontaneously after any type of surgery or anesthetic technique; the prognosis is good. Diagnosis, which can be based on symptoms, imaging and electrophysiological studies, is important both for clinical management and for establishing medical and legal liability.