Lesson of the week

# Acute meningoencephalitis and meningitis due to primary HIV infection {#article-title-2} A wide differential diagnosis exists for meningoencephalitis and meningitis: causes include tuberculosis and infections caused by viruses such as enteroviruses, human herpesviruses (types 1-4, 5 (cytomegalovirus), and 6), paramyxovirus (mumps), measles virus, and adenoviruses. In one cohort, viral genomes were detected in consecutive samples of cerebrospinal fluid from 5% of patients (22 of 410); enteroviruses and human herpesviruses types 1-5 accounted for over 95% of cases.1 HIV infection was not detected. It is often overlooked as a potential cause of meningoencephalitis and meningitis. The clinical manifestations of primary HIV infection are well characterised and include fever, lethargy, flu-like illness, headache, pharyngitis, generalised rash, lymphadenopathy, and gastrointestinal disturbances.2 Neurological features, including aseptic meningitis, meningoencephalitis, and encephalitis, occur in up to 17% of patients and may be associated with more rapid progression of HIV related disease.3–11 Neurological symptoms may occur or develop up to 3 months after the onset of symptoms of primary HIV infection, when the other symptoms have resolved. We discuss one patient with meningoencephalitis and two patients with meningitis associated with primary HIV infection. In each patient the underlying diagnosis of primary HIV infection was not suspected initially resulting in a delay to diagnosis. Over a 16 month period three men with viral symptoms had presented to their general practitioner (n=2) and local emergency department. One patient required immediate admission and the others were subsequently admitted through the emergency department and local genitourinary clinic. The patients failed to disclose any risk factor for acquiring HIV infection and none had clinical stigmata of immunosuppression. The table summarises the clinical details of these patients. Here we report on case 1. View this table: Clinical details of patients with primary HIV infection A 34 year old man presented with a one week history of fever, nausea, and confusion. The previous …