Mycoplasma pneumoniae-related hepatitis in children.

Mycoplasma pneumoniae (M. pneumoniae) is a small bacterium characterized by the absence of cell wall. It is a human pathogen causing upper and lower respiratory infections, both in adults and children. However, it is also considered to be implicated in the pathogenesis of several types of extra-respiratory diseases, including some gastrointestinal disorders. The liver involvement in children during or after M. pneumoniae infections is analyzed and discussed in this review. Through a systematic literature search, it is evidenced that M. pneumoniae is not infrequently associated with alteration of liver function, but rarely causes acute and severe hepatitis in children. M. pneumoniae should be considered as an unusual cause of acute hepatitis in children, whenever the most common hepatotropic viruses have been excluded. The pathogenesis of M. pneumoniae-related hepatitis is likely to be immune-mediated: both the innate and adaptive immune responses may play a fundamental role. However, the exact pathological mechanisms have to be elucidated yet. Further clinical studies are needed in order to understand the actual relevance of this microorganism in liver disease and its pathogenesis.