Send to

Choose Destination
Clin Infect Dis. 2015 May 1;60(9):1377-83. doi: 10.1093/cid/civ051. Epub 2015 Jan 30.

Use of clinical and neuroimaging characteristics to distinguish temporal lobe herpes simplex encephalitis from its mimics.

Author information

Department of Neurology.
Department of Pediatrics, University of California, San Francisco Department of Kaiser Permanente, Oakland, California.
Department of Communicable Disease Emergency Response Branch.
Department of Viral and Rickettsial Disease Laboratory, California Department of Public Health, Richmond.
Department of Pediatrics, University of Alabama at Birmingham.
Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland.



We describe the spectrum of etiologies associated with temporal lobe (TL) encephalitis and identify clinical and radiologic features that distinguish herpes simplex encephalitis (HSE) from its mimics.


We reviewed all adult cases of encephalitis with TL abnormalities on magnetic resonance imaging (MRI) from the California Encephalitis Project. We evaluated the association between specific clinical and MRI characteristics and HSE compared with other causes of TL encephalitis and used multivariate logistic modeling to identify radiologic predictors of HSE.


Of 251 cases of TL encephalitis, 43% had an infectious etiology compared with 16% with a noninfectious etiology. Of infectious etiologies, herpes simplex virus was the most commonly identified agent (n = 60), followed by tuberculosis (n = 8) and varicella zoster virus (n = 7). Of noninfectious etiologies, more than half (n = 21) were due to autoimmune disease. Patients with HSE were older (56.8 vs 50.2 years; P = .012), more likely to be white (53% vs 35%; P = .013), more likely to present acutely (88% vs 64%; P = .001) and with a fever (80% vs 49%; P < .001), and less likely to present with a rash (2% vs 15%; P = .010). In a multivariate model, bilateral TL involvement (odds ratio [OR], 0.38; 95% confidence interval [CI], .18-.79; P = .010) and lesions outside the TL, insula, or cingulate (OR, 0.37; 95% CI, .18-.74; P = .005) were associated with lower odds of HSE.


In addition to HSE, other infectious and noninfectious etiologies should be considered in the differential diagnosis for TL encephalitis, depending on the presentation. Specific clinical and imaging features may aid in distinguishing HSE from non-HSE causes of TL encephalitis.


brain infection; encephalitis; herpes simplex; magnetic resonance imaging; temporal lobe

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center