[Red Flag] New onset headache in a person with possible HIV or cancer [Possible causes] Meningitis (chronic or carcinomatous), brain abscess including toxoplasmosis, metastasis [Diagnostic tests] Neuroimaging, lumbar puncture if neuroimaging is negative
People with HIV or cancer are immunosuppressed so are likely to get infections of the meninges or infections in the brain causing abscesses. Cancer can metastasize, or travel through the blood or lymph to other sites in the body.