**4.** *C. pneumoniae* **and other neurological complications**

*A number of reports have focused on the involvement of C. pneumoniae* in other CNS disorders, particularly encephalitis or meningoencephalitis. Reported cases have not been not very frequent [26]. Most patients were young patients presenting with different neurological symptoms and/or neuro-radiological changes on computed tomography or MRI. In most cases, there were also accompanying well-defined respiratory symptoms, although in some cases these occurred prior to the onset

of neurological records. Three patients had cerebellar ataxia, acute demyelinating encephalitis, and Guillain-Barrè syndrome. *Chlamydia* was almost always detected serologically using microimmunofluorescence test (four-fold increase in IgG titer) and ELISA techniques based on the detection of specific anti-*C. pneumoniae* antibodies. One study found the presence of IgA-type antibodies, suggesting re-infection [131]. One note reported the use of PCR in a tracheal swab and increased *Chlamydia* IgM antibody titers [132]. These cases and a review of the literature have shown that *C. pneumoniae* infection, in addition to other *Chlamydia* species, can present with significant neurological symptoms. Therefore, the differential diagnosis of respiratory tract infections with neurological presentation should include chlamydial infections as well as *Mycoplasma* and *Legionella* infections.
