Page 163 - The Vasculitides Volumes 2

Central Nervous System Vasculitis Due to Infection 139

larger ones that is more likely to occur in immunocompromised hosts [78]. Cerebral
infarction complicates about 40% of patients with coccidioides meningitis leading to
alteration of mental status and emergency of focal deficits [4]. Stroke can occur years later
following the initial infection [78]. In general, acute infectious related injury can predispose
to vasculitic changes that include transmural inflammation with thrombosis and fibrinoid
necrosis, while chronic injury leads to intimal thickening, proliferation, and narrowing of the
lumen with little or no inflammation.

CSF culture is positive in 33% of cases, often in association with eosinophilic
pleocytosis. Complement fixation is positive in about 40% of serum and CSF specimens, but
seroconversion can take up to 12 weeks. Treatment involves high-dose fluconazole followed
by maintenance therapy. Voriconazole is a second line agent. A self-limited course of
corticosteroids can be given in the setting of cerebral infarction to reduce inflammation.

Cryptococcus Neoformans
The yeast form, Cryptococcus neoformans is the commonest cause of fungal meningitis

[4]. Vessels of the circle of Willis are most affected by the resultant basilar exudate. Vascular
involvement occurs early or late in 4% to 32% of cases. Diagnosis is made by the presence of
CSF cryptococcal antigen, India ink stain, and culture. Treatment involves induction therapy
with intravenous amphotericin and flucytosine for 2 weeks followed by consolidation with
fluconazole once CSF cultures are negative. Corticosteroids may offer a benefit in the setting
of stroke [79].

Exserohilum Rostratum
Exserohilum rostratum is a dematiaceous fungus and black mold that does not typically

cause human disease. It is a major contaminant in iatrogenic infections due to mold
contamination of methylprednisolone acetate. There was one fatal case of meningitis and
CNS vasculitis in an immunocompetent host who received a cervical epidural steroid
injection for chronic neck pain [80]. The diagnosis is based on culture and PCR of CSF.
Recommended therapy is liposomal amphotericin B and voriconazole, with monitoring of
drug levels [81].

Histoplasma Capsulatum
Histoplasma capsulatum is a dimorphic fungus that is endemic in the Ohio and

Mississippi River Valley, as well as parts of Latin America, Asia, and Africa [4, 82].
Although infection in immunocompetent hosts may remain asymptomatic or lead to mild
lower respiratory tract illness, others can experience disseminated infection with CNS
involvement in up to 20% of cases. The latter most commonly manifests meningitis however
strokes may accompany associated infective histoplasma endocarditis or associated
meningovascular disease with ensuing mortality of 11% to 100%. CSF culture and antigen
studies which show evidence of CNS infection can be supported by anti-histoplasma
antibodies. Treatment includes liposomal amphotericin followed by itraconazole or
fluconazole for at least one year.

Complimentary Contributor Copy