Long-term cognitive sequelae of acyclovir-treated herpes simplex encephalitis.

Area of Science:

• Neuroscience
• Infectious Diseases
• Neurology

Background:

• Herpes simplex type 1 encephalitis (HSVE) untreated leads to severe cognitive impairment.
• Acyclovir is the current gold standard treatment for HSVE, expected to reduce disease severity.
• Early intervention is crucial for managing HSVE outcomes.

Purpose of the Study:

• To assess the long-term neuropsychological outcomes in patients treated early with acyclovir for biopsy-proven HSVE.
• To determine if early acyclovir administration prevents residual cognitive deficits.
• To evaluate the efficacy of standard clinical screening in detecting subtle cognitive impairments post-HSVE.

Main Methods:

• Detailed clinical and formal neuropsychological assessments were conducted.
• Four consecutive patients with biopsy-proven HSVE treated early with acyclovir were followed for 1.5 to 4 years.
• Standard clinical mental status tests were used alongside specialized cognitive evaluations.

Main Results:

• All four patients exhibited significant residual cognitive deficits.
• Common impairments included dysnomia (word-finding difficulties) and impaired new learning (verbal and visual).
• Three patients had normal results on standard clinical mental status tests, yet showed deficits in formal testing.

Conclusions:

• Early acyclovir treatment for HSVE does not guarantee complete recovery and long-lasting neuropsychological deficits are probable.
• Subtle yet prognostically important cognitive deficits may be missed by standard clinical screening.
• Patients often cannot return to their previous functional level despite early antiviral therapy.