====== Isolated CNS vasculitis ======

===== General information =====

AKA isolated angiitis of the CNS. Rare (≈ 20 cases reported32 as of 1983); limited to vessels of CNS. Small vessel vasculitis is ≈ always present → segmental inflammation and necrosis of small leptomeningeal and parenchymal blood vessels with surrounding tissue ischemia or hemorrhage.

===== Presentation =====

Combinations of H/A, confusion, dementia, and lethargy. Occasionally seizures. Focal and multifocal brain disturbance occurs in > 80%. Visual symptoms are frequent (secondary either to involvement of choroidal and retinal arteries, or to involvement of visual cortex → visual hallucinations).
Evaluation
ESR & WBC count are usually normal. CSF may be normal or have pleocytosis and/or elevated pro- tein. CT may show enhancing areas of low density.
Angiography (required for diagnosis): characteristically shows multiple areas of symmetrical nar- rowing (“string of pearls” configuration). If normal, it does not exclude diagnosis.
Histological diagnosis (recommended): all biopsy material should be cultured. Brain parenchyma biopsy infrequently shows vasculitis. Leptomeningeal biopsy invariably shows involvement.

===== Treatment and outcome =====

Reportedly fatal if untreated, but may smolder for years.
Rarity of this condition makes treatment uncertain. Recommended: cyclophosphamide
(Cytoxan®) 2 mg/kg/d and prednisone 1 mg/kg/d qod therapy.
NB: this condition is thought to be T-cell mediated, but prednisone causes more B-cell suppres-
sion, therefore breakthrough during prednisone therapy is not uncommon.