Tools Developed for Early Meningitis Diagnosis

A predictive model based on two blood tests and a clinical sign will allow physicians assess whether or not a suspected case of meningitis is bacterial or viral in origin.

Bacterial meningitis is a serious infection of the fluid in the spinal cord and the fluid that surrounds the brain commonly caused by three types of bacteria: Haemophilus influenzae type b, Neisseria meningitidis, and Streptococcus pneumoniae bacteria. The diagnosis is usually made by growing the bacteria in culture from cerebral spinal fluid obtained from a lumbar puncture.

In a recent report from the UK Health Protection Agency's (HPA; London, UK) annual conference, analysis of data collected on 720 patients from all probable cases of bacterial and viral meningitis was presented. The patients had been admitted to participating hospitals in the South West, West Midlands and London regions of England. The date was collected from July 1, 2008 and June 30, 2009.

After examining the clinical symptoms, biochemistry and microbiology of 385 confirmed cases of meningitis over a 12 month period, the team identified three factors based on routine clinical assessment and early available laboratory test results that help differentiate between bacterial and viral meningitis. The results showed that the peripheral polymorphonuclear leukocyte (PMN) count, C-reactive protein level in the blood and rash are strongly associated with bacterial meningitis. Leukocyte PMN counts above 16 × 109/L, and a C-reactive protein level of more than 100 mg/L associated with a hemorrhagic rash, were most likely to be found in confirmed cases of bacterial meningitis. The normal PMN count varies with age, but the range is usually between 2.5 × 109/L to 7.5 × 109/L and a normal C-reactive protein is less than 10mg/L.

Oluwatoyin O. Ejidokun M.B. B.S., M.Sc., Ph.D.,, who led the study team, said, "While further testing needs to take place to test the accuracy of the model, this simple model offers the prospect of a rapid predictive tool to help clinical and public health management of suspected bacterial meningitis cases." Swift diagnosis of bacterial meningitis is crucial to protecting public health as it means potentially lifesaving interventions can be put in places, such as prescribing antibiotics to the patient and people they have been in contact with.
Related Links:
UK Health Protection Agency