[Neurological complications of Mycoplasma pneumoniae infections]

Mycoplasma pneumoniae (Mp) infections are well known for the classical clinical picture of primary atypical pneumonia. The infection shows a predilection for young age groups. Every fourth-fifth year Mp epidemics are seen, lasting several months particularly in autumn/wintertime. The last Mp epidemic in Denmark was seen autumn/winter 1991-1992. The central nervous system (CNS) is involved in less than 0.1% of all Mp infections, but among patients treated in hospital, CNS involvement occurs in up to 7%. Among patients with acute, febrile, nonbacterial CNS affection the incidence of Mp infections is shown to be 5%, with a maximum of 10% during Mp epidemics. In up to 20% the CNS complications are seen without preceding pulmonary symptoms. The pathogenesis is unknown, but probably involves several mechanisms. The spectrum of clinical findings is wide, ranging from mild meningeal signs to severe neurological symptoms and a poor outcome. Mp encephalitis has a particularly high morbidity and mortality. The effect of antibiotic treatment is doubtful, but the treatment is often instituted late. It may be debated, whether early antibiotic treatment can reduce the frequency of the CNS complications and their sequelae. Mp infection should be remembered as a differential diagnosis in any patient with fever and neurological symptoms. It can be recommended to add Mp diagnostic measures to the screening investigations, especially in patients with recent respiratory symptoms and during Mp epidemics. It is important to attempt to detect Mp by culture or polymerase chain reaction (PCR) from throat, respiratory tract and cerebrospinal fluid (CSF). Mp serology from blood and CSF should be performed early in cases where Mp infection is suspected.