CNS manifestations associated with Mycoplasma pneumoniae infections: summary of cases at the University of Helsinki and review.

CNS manifestations appear in one of 1,000 patients with Mycoplasma pneumoniae-associated infections. Encephalitis is the most frequent manifestation, but cases of meningitis, myelitis, and polyradiculitis, as well as many other symptoms (e.g., coma, ataxia, psychosis, and stroke), have been reported. The onset of these manifestations is usually acute, with lowered consciousness, convulsions, pareses, and other neurological signs. Severe, even fatal, cases are known. The pathophysiology of CNS manifestations is unknown. To our knowledge, M. pneumoniae has never been isolated from brain tissue, but instead it has been recovered from CSF specimens in at least seven cases. Besides direct invasion of M. pneumoniae into the brain, neurotoxic or autoimmune reaction within the brain tissue is suspected. At neuropathological examination, edema, demyelination, and microthrombi have been described. Improved diagnostic methods may reveal the pathophysiology of CNS manifestations associated with M. pneumoniae infection.