[Confusional form of Chlamydia psittaci encephalitis. Diagnostic value of microimmunofluorescence. A case].

A rare case of Chlamydia psittaci encephalitis is reported. The disease started with anxiety, agitation and fever (38.5 degrees C) accompanied with hallucinations and regressed within 48 hours, but a confusional syndrome persisted for 9 days. Alterations in the blood-brain barrier with low CSF protein levels and signs of lateralization could be demonstrated. The inflammatory syndrome remained discrete. The cause of the disease was disclosed by serology and epidemiological investigations. The spontaneous outcome was favourable, thus confirming that neurological forms of psittacosis are benign. This case shows that microimmunofluorescence is more sensitive than the complement fixation test and that significant levels of antibodies directed against Chlamydia psittaci may persist for almost one year in the absence of treatment.