Empiric Acyclovir Use for Suspected Herpes Simplex Meningoencephalitis, How Are We Doing?

Background:

Empiric use of acyclovir (ACV) for presumed Herpes meningoencephalitis (HME) is a common practice. The diagnosis of the syndrome requires imaging of the CNS and CSF analysis.

Objective:

To analyze the empiric use of intravenous (I.V) ACV, to determine appropriateness of treatment based on findings of clinical presentation, radiological and CSF findings.

Methods:

A retrospective review in a 680 bed tertiary care hospital between June 2008 and December 2015. Adult patients (Pts) treated with I.V ACV for presumed HME were included. Data was collected on demographics, co-morbid conditions, clinical manifestations, EEG, CT, MRI findings, lumbar puncture (LP) results, duration of ACV, side effects of ACV, and discharge diagnosis.

Results:

One hundred pts were included. Mean age 53 years (Range 18-91). Males 45(45%). Most common presentation was altered mental status in 73 (73%) pts. LP was done on 74(74%) pts, CSF HSV PCR was sent on 54/74 (73%) of them 3 (4%) had a (+) HSV PCR. Of the 74 LP’s, 51/74 (69 %) were (-) for Herpes PCR .Of the pts who didn’t have an LP 21/26(80%) presented with altered mental status. Elevated CSF WBC was seen in 40/69 (58%), elevated CSF RBC in 40/69 (58%), high CSF protein in 43/71(61%). MRI was done in 51 (51%) pts, 24/51 had both (-) MRI and (-) CSF Herpes PCR. Seven (13%) Pts had an abnormal MRI, one patient with an abnormal MRI had CSF HSV PCR (+). CT scan was done in 85/100 (85%), 82/85 (96%) were without contrast, 9/85 (10.5%) were (+). EEG was performed in 44 pts, and was (+) in 13 (30%). ACV therapy was started in the ER in 31(31%), mean duration of ACV treatment was 5 days (Range 1-17).Overall, ACV was continued in 91/100 (91%) despite lack of findings on imaging or CSF. Nine pts had worsening renal function after starting ACV treatment. Final discharge diagnosis included 26 unspecified altered mental status, aseptic meningitis in 15 pts, seizure disorder in 10, encephalitis of unknown cause in 9, drug overdose in 5, CVA in 3. Seven Pts expired; all from non HME related causes.

Conclusion:

In our hospital continuation of ACV treatment for presumed HME was common, despite lack of objective support of HME diagnosis. Guidelines for the diagnosis and treatment of HME are needed to improve ACV utilization,to avoid unnecessary toxicity of ACV and to reduce the associated cost.