Re: Encephalitis

Posted By CCF Neuro MD on June 21, 1997 at 15:06:39:

In Reply to: Encephalitis posted by Dr V A Wanigasekera MRCP on June 14, 1997 at 09:56:57:







: This is regarding a pt in the ICU.
32 yr old male presented with a history of 5 days fever and flue like symptoms and grand mal seizures of several hours duration.
On admisssion he showed behavioral abnormalities and was semi con.. CT-normal,LP - leucocytosis,
Was started on acyclovir 750mg,500mg,750mg daily. IgM antibodies for HSV type 1&2 were positive.
He showed rapid improvement and became rational within 24 hours and was fit free for about a day.
However the fits returned and increased in frequency despite being on several antiseizure medication. On the 6th day of acyclovir treatment he was ventilated due to the increasing frequency of seizures and a diazepam infusion was started. Acyclovir was with held for 24 hours to see whether the fits were due to Acyclo. Fits continued and he also developed a hemiparesis. Acyclovir was restarted. Any views on the above patient would be most welcome. If possible could you pl E mail direct.Thankyou.






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Dear Dr. Wanigasekara:
Your case brings up the issues of HSV encephalitis relapse, Acyclovir resistance, Acyclovir neurotoxicity, and appropriate management.
I would like to refer you to a recent consensus statement on the subject, which you may alredy be aware of : J Neurol Neurosurg Psych 61:339-345, 1996.
My understanding is as under.
1. Worsening seizures are unlikely to have been from acyclovir.
2. Acyclovir resistance is very rare in immunocompetent individuals. It is incresingly recognised in immunocompromised individuals in whom it can cause protracted severe disease. Resistance is usually due to viral thymidne kinase gene mutation, and may be treated with foscarnet.
3. There are several reports of HSVE relapse during or after a standard 10-14 day course of acyclovir (30mg/kg/d). A significant number of these, however, may be "post-infectious" in the sense that no evidence of active viral proliferation is found intrathecally.
4. PCR for HSV I and II are highly sensitive and specific tests that are now widely available, and (along with antibody tests) may help settle the question of continued disease activity.
5. Repeated imaging, and possibly a brain biopsy may help exclude another diagnosis, if at all a consideration.
This information is provided for general medical education purposes only.