Prognostic values of a combination of intervals between respiratory illness and onset of neurological symptoms and elevated serum IgM titers in Mycoplasma pneumoniae encephalopathy

Background/Purpose To retrospectively analyze the clinical manifestations of Mycoplasma pneumoniae ( M. pneumoniae )-associated encephalopathy in pediatric patients. Methods Pediatric patients with positive serum anti- M. pneumoniae immunoglobulin M (IgM) were enrolled in this study. Clinical signs and symptoms, laboratory data, neuroimaging findings, and electrophysiological data were reviewed. Results Of 1000 patients identified, 11 (1.1%; male:female ratio = 7:4) had encephalopathy and were admitted to the pediatric intensive care unit. Clinical presentation included fever, symptoms of respiratory illness, and gastrointestinal upset. Neurological symptoms included altered consciousness, seizures, coma, focal neurological signs, and personality change. Neuroimaging and electroencephalographic findings were non-specific. Specimens of cerebrospinal fluid (CSF) for M. pneumoniae polymerase chain reaction (PCR) were negative. Higher M. pneumoniae IgM titers and longer intervals between respiratory and CNS manifestations were associated with worse outcomes. Conclusion Clinical manifestations of M. pneumoniae -associated encephalopathy were variable. Diagnosis of M. pneumoniae encephalopathy should not rely on CSF detection of M. pneumoniae by PCR. M. pneumoniae IgM titers and intervals between respiratory and CNS manifestations might be possibly related to the prognosis of patients with M. pneumoniae -associated encephalopathy.