Mycoplasma pneumoniae: a cause of coma in the absence of meningoencephalitis.

Mycoplasma pneumoniae encephalitis is a recognized cause of reversible coma in children. As an etiology of infectious encephalitis, it yields a relatively poorer prognosis than most other causes of infectious encephalopathies. Encephalitis is generally diagnosed by a constellation of clinical symptoms and confirmed by a cerebrospinal fluid (CSF) examination revealing cell pleocytosis and elevated protein. That Mycoplasma pneumoniae encephalopathy can occur in the presence of a normal CSF examination is less well appreciated. The authors report two children who presented with coma and normal CSF findings in whom a diagnosis of acute Mycoplasma pneumoniae infection was made. The two children both had rapid and complete recovery over several days. These cases exemplify that coma can result from acute infection with Mycoplasma pneumoniae in the absence of an inflammatory CSF response and that a normal CSF may herald a more favorable prognosis.