Scrub typhus meningitis: An emerging infectious threat

Background: Scrub typhus is prevalent in India although definite statistics are not available. Recent reports from several parts of India indicate that there is a resurgence of scrub typhus. There have been only few studies on scrub meningitis, most are case report. Methods: A prospective study done in Sir Padampat Mother and Child Health Institute, SMS Medical College, Jaipur to find cases of scrub typhus from August 2014 to December 2014. Diagnosis was made by a combination of an acute febrile illness with a positive scrub IgM ELISA. Lumbar puncture performed in patients with headache, vomiting, meningeal signs, seizures, or altered sensorium. Results: Forty nine cases of scrub typhus were found, and 7 (~15%) had meningitis. There were 25 males and 24 females. Only one patient had an eschar. Mean CSF cell count, lymphocyte percentage, CSF protein, CSF glucose/blood glucose, CSF ADA were 42 cells/μL, 97%, 81 mg/dL, 0.7 and 5.2 U/mL. Complications including thrombocytopenia, severe anemia, acute kidney injury and respiratory failure are more common in scrub typhus meningitis. There were no mortality from meningitis, all made uneventful recovery. Conclusion: Our finding is contrary to current perception that scrub typhus rarely causes meningitis. Meningitis in scrub typhus is mild with quick and complete recovery. Clinical features and CSF findings can mimic tuberculous meningitis, except for ADA levels. Both are endemic in india, so scrub IgM and CSF ADA levels may be helpful in differentiating these two and in avoiding prolonged empirical ATT in cases of lymphocytic meningitis.