Today, we discussed a young HIV-positive patient in Botswana who ultimately was diagnosed with tuberculous meningitis with immune reconstitution syndrome (IRIS). Some learning points:
1) HIV patients with headache are at significant risk for intracranial disease, including
- primary HIV related HA: aseptic meningitis, acute or chronic
- opportunistic infections: toxoplasmosis, cryptococcal meningitis, TB/ bacterial/viral meningitis, meningovascular syphilis, brain abscess, progressive multifocal leukoencephalopathy (JC virus), HSV or CMV encephalitis
- malignancy: CNS lymphoma, lymphomatous meningitis
- stroke or intracranial hemorrhage
2) HIV patients often will present without meningeal signs despite underlying meningitis.
3) To CT or not to CT: In this article in Academic Emergency Medicine, the following clinical findings would have identified 95% of new focal intracranial lesions on CT (and reduced CT use by 53%) were:
- new seizure, RR= 73
- depressed or altered orientation, RR = 39
- headache, different in quality, RR = 27
In this study, the most common intracranial lesion among patients with CD4 counts less than 200 was toxoplasmosis, while cerebrovascular accidents (ischemic or hemorrhagic) were most common in those with CD4 counts greater than 200.
4) Lumbar puncture also should be considered in cases such as these--and if there are any contraindications such as cerebral mass lesion/risk of herniation, papilledema, uncorrected bleeding disorder, or local infection at punter site.
Empiric antituberculous therapy should be started immediately in any patient with other TB history/exposure and a meningitis syndrome with CSF findings of low glucose concentration, elevated protein, and lymphocytic pleocytosis. CSF adenosine deaminase (ADA) level may be a useful adjunctive test for diagnosis of tuberculous meningitis but, elevated CSF ADA level may also be observed in the setting of bacterial infections. A minimum of three serial lumbar punctures should be performed at daily intervals for culture.