6.3.4.2 Serology. Commercial tests that use complement fixation are not type-specific. Seroconversion from a zero baseline is usually diagnostic of a primary infection. In the case of recurrent infection, an immune response from a non-zero baseline may be detected. However, these tests cannot distinguish between initial and recurrent infections and have been replaced by sensitive tests such as ELISAs and RIAs. Type-specific serology tests (TSSTs) that detect HSV-specific glycoprotein G2, which is specific to HSV-2, and glycoprotein G1, which is specific to ABT 888 HSV-1 infection, are the only commercially available diagnostic tools to identify individuals with asymptomatic HSV infection, and can effectively
distinguish HSV-1 and HSV-2 with high sensitivities (80–98%) and specificities (≥96%) [58]. Case-controlled studies have shown that there are certain clinical situations where these tests may provide an aid to the diagnosis of HSV infection [59,60]. The clinical diagnosis of genital HSV infection has a low sensitivity and specificity; laboratory confirmation of infection and typing of HSV is essential as it influences
the management, prognosis and counselling of patients. 6.3.4.3 CNS disease. In patients with HSV encephalitis or meningitis, typical CSF findings include a lymphocytosis and mildly find more elevated protein [61,62]. Low CSF glucose levels may also occur. Abnormal findings on magnetic resonance imaging and electroencephalogram are supportive of a diagnosis of HSV encephalitis but not diagnostic. For both HSV meningitis and encephalitis, PCR detection of HSV DNA in the CSF is the diagnostic method of choice and has a high specificity and sensitivity [62,63]. For HSV encephalitis, false-negative results for PCR may occur within the first 72 h of the illness and then
10–14 days after the onset of symptoms. Incidence of false-positive PCR is extremely low. Culture of the CSF for HSV is of little value in HSV encephalitis and not recommended. PCR for HSV DNA in the CSF is the diagnostic method of choice for diagnosis of HSV encephalitis or meningitis (category III recommendation). First episode or severe recurrent orolabial herpes infection should be treated with antiviral therapy. Aciclovir 200–400 mg orally five times a day for 7–10 days is recommended (category many II recommendation), Alternative treatments are valaciclovir or famciclovir. For severe oral mucocutaneous disease treatment should be initiated with aciclovir intravenously 5–10 mg/kg every 8 h (category III recommendation). Most episodes of recurrent orolabial herpes are mild and self limiting. Episodic or suppressive antiviral therapy may be considered for those with severe or frequent recurrences. A study has shown equivalent efficacy of famciclovir 500 mg orally bd in comparison to aciclovir 400 mg orally five times a day in a mixed group of HIV-seropositive individuals with either orolabial (38%) or genital HSV [64].