Chlamydia pneumoniae infection-related hemophagocytic lymphohistiocytosis and acute encephalitis and poliomyelitis-like flaccid paralysis.

A 3-year-old male presented with Chlamydia pneumoniae infection-related hemophagocytic lymphohistiocytosis (HLH). The patient developed an episode of HLH with severe skin eruption following C. pneumoniae pneumonia. Symptoms responded to steroid/cyclosporine A therapy, but the patient slowly lost consciousness and developed systemic flaccid paralysis. He was diagnosed with encephalitis/myelitis by brain and spinal MRI. Neurological symptoms and signs gradually resolved. We thought that the immune response to C. pneumoniae infection triggered the development of HLH, associated with unusual neurological complications. This report describes a novel case of C. pneumoniae-associated HLH and with poliomyelitis like flaccid paralysis.