Typhus group Rickettsia community-acquired bacterial central nervous system infections: We must think outside the box!

Typhus group rickettsiosis (TGR), caused by Rickettsia typhi and Rickettsia prowazekii, are globally distributed vector-borne diseases with increasing cases. Diagnosis is usually clinical, confirmed by seroconversion of IgG antibodies. Human infection occurs in diverse geographic areas with some developing CNS infection characterized by fever, headache, meningismus, and/or focal signs - usually beyond the first week of initial symptomatology. Seizures and other CNS manifestations have been observed. When untreated, infection may result in neurologic sequelae and even death. This study presents a systematic review of all documented cases of Rickettsia typhi meningoencephalitis published since 2015 with the addition of five cases of TGR in South Coastal Texas, USA. This review followed the guidelines outlined in PRISMA. A schematic explanation of the pathophysiology is offered. CSF may present with high opening pressure, mild to moderate pleocytosis, mildly elevated protein levels, and low csf/serum glucose ratio, or normal findings. Meningeal enhancement, intracranial hypertension, and focal abnormalities have been described in imaging studies, but can be normal. Treatment with doxycycline leads to prompt resolution of symptoms. Failure to initiate early empiric treatment can lead to serious consequences. The study recommends routine testing for TGR in patients from endemic areas with classical symptoms when other diagnoses are inconclusive or in cases with atypical presentations. The authors advocate for incorporating empiric treatment for murine typhus into community-acquired bacterial meningitis guidelines in endemic areas; and stress the importance of enhancing laboratory diagnostic capabilities in public health entities world-wide. Further studies of community acquired mengingoencephalitis caused by TGR are highly encouraged.