European guidelines for diagnosis and management of patients with suspected herpes simplex encephalitis

Abstract

The current European guidelines for diagnosis and management of patients with tuspected herpes simplex encephalitis (HSE) [l] suggest that polymerase chain reaction (PCR) for Herpes simplex virus (HSV) should be performed on CSF samples from all patients diagnosed to have HSE on clinical grounds alone. Many clinicians will include HSE in the differential diagnosis of a wide range of presenting complaints and request HSV P C R prior to the results of CSF analysis being available. Laboratory tests using P C R are relatively expensive and, given the financial constraints applied by healthcare purchasers, any guidelines must ensure that such tests are performed appropriately. Accordingly, we exaniined the relationship between the results of HSV P C R and CSF white cell count (WCC) and protein content in samples taken from inpatients at the Leeds General Infirmary since January 1997. There was 3 clear relationship between the CSF WCC, protein content and HSV P C R result as shown in the table. Only three (So/;,) of the 58 samples tested were positive by HSV PCR. All three had raised CSF W C C (> 5 per nini') but only two had raised CSF protein (>0.45 g/l). Thirtyfour (59%) had normal CSF W C C (<5 per m i d ) and protein content (<0.45 g/l) of which twenty-one (36%) had CSF W C C < 1 per mni'. Cases of HSE with CSF W C C of less than 5 have been reported [2] but unfortunately the results of CSF protein content were not stated. Declining to process saniples with CSF WCC < I per mm3 and normal CSF protein content could reduce workload and reduce costs by approximately one-third. We will continue to process all requests for HSV PCR on CSF samples and compare results with