What are the signs and symptoms of herpes simplex encephalitis (HSE)?

Updated: Jul 17, 2018
  • Author: Wayne E Anderson, DO, FAHS, FAAN; Chief Editor: Niranjan N Singh, MBBS, MD, DM, FAHS, FAANEM  more...
  • Print

Herpes simplex encephalitis (HSE) is an acute or subacute illness that causes both general and focal signs of cerebral dysfunction. It is sporadic and occurs without a seasonal pattern. Although the presence of fever, headache, behavioral changes, confusion, focal neurologic findings, and abnormal cerebrospinal fluid (CSF) findings are suggestive of HSE, no pathognomonic clinical findings reliably distinguish HSE from other neurologic disorders with similar presentations (see Workup). [4]

Patients may have a prodrome of malaise, fever, headache, and nausea, followed by acute or subacute onset of an encephalopathy whose symptoms include lethargy, confusion, and delirium. The following are typically the most common symptoms of HSE [5] :

  • Fever (90%)

  • Headache (81%)

  • Psychiatric symptoms (71%)

  • Seizures (67%)

  • Vomiting (46%)

  • Focal weakness (33%)

  • Memory loss (24%)

Signs and symptoms of neonatal HSE develop about 6-12 days after delivery, at which time lethargy, poor feeding, irritability, tremors, or seizures may be noted. Those with disseminated disease also have abnormal liver function test results and thrombocytopenia. In contrast to older patients, neonates often have herpetic skin lesions.

The initial presentation may be mild or atypical in immunocompromised patients (eg, those with HIV infection or those receiving steroid therapy).

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!