title: Differential diagnosis of scrub typhus meningitis from bacterial meningitis using clinical and laboratory features.
abstract: BACKGROUND
  Central nervous system (CNS) involvement in the form of meningitis or meningoencephalitis is common in scrub typhus. As specific laboratory methods remain inadequate or inaccessible in developing countries, prompt diagnosis is often difficult.
  
  
  OBJECTIVE
  To identify the clinical and laboratory parameters that may help in differentiating scrub typhus meningitis from bacterial meningitis.
  
  
  METHODS
  This is a cross-sectional analysis of adult patients admitted with scrub typhus and bacterial meningitis to a tertiary care teaching institute in South India.
  
  
  METHODS
  A comparison of clinical and laboratory features of 25 patients admitted with meningitis to a university teaching hospital during a 15-month period was made. These patients had meningitis diagnosed based on abnormal cerebrospinal fluid (CSF) analysis with either positive IgM scrub typhus ELISA serology (n =16) or with CSF culture isolating bacteria known to cause bacterial meningitis (n =9). The clinical and laboratory features of the patients with scrub typhus meningitis and bacterial meningitis were compared.
  
  
  RESULTS
  The mean age was similar in the scrub typhus and bacterial meningitis groups (44.0 ± 18.5 years vs. 46.3 ± 23.0 years). Features at admission predictive of a diagnosis of scrub typhus meningitis were duration of fever at presentation >5 days (8.4 ± 3.5 days vs. 3.3 ± 4.2 days, P < 0.001), CSF white cell count of a lesser magnitude (83.2 ± 83.0 cells/cumm vs. 690.2 + 753.8 cells/cumm, P < 0.001), CSF lymphocyte proportion >50% (83.9 ± 12.5% vs. 24.8 ± 17.5% P < 0.001), and alanine aminotransferase (ALT) elevation more than 60 IU (112.5 ± 80.6 IU vs. 35 ± 21.4 IU, P =0.02).
  
  
  CONCLUSIONS
  This study suggests that clinical features, including the duration of fever and laboratory parameters such as CSF pleocytosis, CSF lymphocyte proportion >50%, and ALT values are helpful in differentiating scrub typhus from bacterial meningitis.
authors: Department of Medicine and Infectious Diseases, Christian Medical College, Vellore, Tamil Nadu, India.
authors: George M
authors: GM
authors: Varghese
authors: Anoop
authors: A
authors: Mathew
authors: Sudhir
authors: S
authors: Kumar
authors: Oriapadickal Cherian
authors: OC
authors: Abraham
authors: Paul
authors: P
authors: Trowbridge
authors: Elizabeth
authors: E
authors: Mathai
mesh_terms: D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D006801:Humans; D016920:Meningitis, Bacterial; D012189:Retrospective Studies; D012612:Scrub Typhus / Q000175:diagnosis