1420. CT of the head before Lumbar Puncture in adults with Community Acquired Meningitis: clinical utility and adherence to the Infectious Diseases Society of America guidelines
Session: Poster Abstract Session: CNS Infections
Saturday, October 5, 2013
Room: The Moscone Center: Poster Hall C
Background: The Infectious Diseases Society of America (IDSA) guidelines have recommendations for computed tomography (CT) scans of the head before lumbar puncture (LP) in adults with suspected community acquired meningitis (CAM). Adherence to these guidelines in clinical practice is unknown. The aim of this study was to identify if clinicians adhere to IDSA guidelines for the use of head CT before LP in patients with CAM and to assess the utility of the imaging studies. 

Methods: We performed a retrospective analysis of 638 adults with CAM admitted to 8 Memorial Hermann hospitals in Houston, Texas between January, 2005 and January, 2010. We collected data regarding demographics, medical history, clinical parameters and head CT findings. Indications for head CT were defined as: immunocompromised state, history of CNS disease, new onset seizures, papilledema, abnormal consciousness or focal neurologic deficits.

Results: Among 638 adults with CAM (median age: 37 years; range: 18-92), a head CT scan was done before the lumbar puncture in 570 (89%) subjects. Of these 570 CT scans, only 212 (37%) were indicated. Overall, clinicians did not adhere to clinical guidelines in 374/638 (59%) subjects. A CT of the head was not ordered when indicated in 16/228 (7%) individuals and performed when not indicated in 358/410 (87%). CT revealed intracranial abnormalities in 38/212 (18%) of subjects with an indication for brain imaging compared to 3/358 (1%) with no indication (p <0.05).   Of the 41 patients with abnormal imaging, 36% had chronic ischemic changes, 26% white matter abnormalities, 12% mass effect, 12% bleeding, 12% hypodensity, 7% hydrocephalus, 7% pneumocephalus, 7% cerebral edema, 7% infarct, and 10% other nonfocal abnormalities without mass effect. Abnormal imaging findings among the 3 patients with no indication for CT included chronic ischemic changes, lacunar infarct and subarachnoid hemorrhage in a patient subsequently diagnosed with herpes simplex encephalitis.

Conclusion: Most clinicians do not adhere to guidelines for head imaging in suspected CAM, thus delaying diagnostic LP and increasing costs. Usefulness of head CT in patients with CAM without an indication for imaging is limited and does not change the management of these patients.

Jorge D Machicado, MD1, Yuan Wang, MPH1, Nabil Khoury, MD1, Susan Wootton, MD2, Lucrecia Salazar, MD1 and Rodrigo Hasbun, MD1, (1)Internal Medicine, University of Texas Health Science Center, Houston, TX, (2)Pediatrics, University of Texas Health Science Center, Houston, TX


J. D. Machicado, None

Y. Wang, None

N. Khoury, None

S. Wootton, None

L. Salazar, None

R. Hasbun, None

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