What are the clinical types of Primary Angiitis of the Central Nervous System/PCNSV?
• Granulomatous angiitis of CNS (GACNS) (50%–60% of patients): typically present with chronic insidious headaches along with focal or diffuse deficits involving brain, meninges, or spinal cord. Symptoms are usually present or recurring for >3 months before diagnosis is made. Abnormal brain MRI showing bilateral infarcts in subcortical white and deep gray matter and CSF showing aseptic meningitis. Angiogram may be normal. Biopsy demonstrates granulomatous vasculitis. Treatment with corticosteroids and CTX. Poor prognosis.
• Atypical PACNS: multiple presentations distinct from GACNS either clinically or pathologically, but treatments are the same.
• Mass-like presentation (5% of patients): present with solitary cerebral mass. Diagnosed by biopsy. Must rule out infectious or malignant process.
• Amyloid beta-related angiitis (ABRA; 20%–25% patients): amyloid β peptide deposition in arteries is seen in sporadic cerebral amyloid angiopathy (CAA). Patients with sporadic CAA are older (>65 years) than patients with typical PACNS/PCNSV. The most common manifestation is intracerebral hemorrhage. In a subset of patients with CAA, vascular inflammation is also present. This inflammation can be a transmural granulomatous vasculitis (40%), nongranulomatous vasculitis (20%), or perivascular nondestructive inflammation (30%–40%). Patients with vascular inflammation are diagnosed as having ABRA. Patients with ABRA are more prone to present with subacute cognitive decline, hallucinations, mental status changes, seizures, and cerebral hemorrhage than patients with typical GACNS. Patients with ABRA frequently have increased gadolinium leptomeningeal enhancement and can respond to immunosuppressive therapy, whereas patients with CAA without inflammation do not.
• Spinal cord presentations (rare): lesion limited to spinal cord. Diagnosed by biopsy.
• Nongranulomatous PACNS (20% patients): pathology shows lymphocytic infiltration or fibrinoid necrosis and not granulomatous findings on biopsy. Clinical presentation, treatment, and prognosis similar to GACNS. Must rule out infection and lymphoproliferative diseases presenting this way.
