Central nervous system (CNS) vasculitis is a rare but potentially serious disorder in which inflammation damages the blood vessels supplying the brain and spinal cord. When the inflammation occurs without an identifiable systemic disease or infection, it is generally called Primary Angiitis of the Central Nervous System (PACNS). The condition can affect small arteries, arterioles, veins, capillaries, and larger intracranial vessels, disrupting the normal delivery of oxygen and nutrients to nervous tissue.
Inflammation can cause blood-vessel walls to thicken, narrow, weaken, or become irregular. As a result, blood flow may be reduced, producing ischemia and small or large strokes. Damaged vessels can also leak blood, causing microhemorrhages or, less commonly, larger hemorrhages. Because different regions of the nervous system may be affected, symptoms vary considerably. Persistent or recurrent headaches, memory and concentration problems, confusion, seizures, personality or behavioral changes, vision disturbances, weakness, sensory loss, and stroke-like episodes are among the possible manifestations. The disease can develop gradually or, in some cases, produce sudden neurological deterioration.
CNS vasculitis is broadly divided into primary and secondary forms. Secondary CNS vasculitis occurs as part of another condition, such as systemic autoimmune disease, infection, malignancy, or exposure to certain drugs. PACNS, by contrast, is confined predominantly to the CNS and has no identifiable underlying systemic cause. Because many other disorders can produce similar symptoms and MRI abnormalities, diagnosis is challenging and usually requires a combination of clinical assessment, brain and spinal imaging, laboratory investigations, cerebrospinal-fluid analysis, and sometimes tissue biopsy.
Within PACNS, clinicians commonly recognize different patterns based on the size of the affected vessels and the findings on angiography. Small-vessel PACNS, sometimes called angiography-negative or non-angiographic PACNS, affects vessels below the resolution of conventional cerebral angiography. Patients may develop encephalopathy, cognitive impairment, seizures, persistent headaches, or inflammatory lesions that can resemble brain tumors. Magnetic resonance imaging often shows abnormalities, but these findings are not specific. Consequently, brain biopsy, when feasible, can be particularly important for establishing the diagnosis and distinguishing vasculitis from infection, malignancy, or other inflammatory diseases. Histological patterns may include granulomatous, lymphocytic, or necrotizing inflammation.
Medium- and large-vessel PACNS affects larger intracranial arteries and their major branches. Conventional catheter angiography may reveal abnormalities such as alternating areas of narrowing and dilation, although these findings are not unique to vasculitis. High-resolution vessel-wall MRI can provide additional information by demonstrating inflammatory changes in the vessel wall. Patients with this phenotype more often experience focal neurological symptoms, transient ischemic attacks, or ischemic strokes involving larger vascular territories.
Treatment generally aims to suppress abnormal immune activity and prevent further vascular injury. Depending on disease severity, physicians may use high-dose corticosteroids together with immunosuppressive medicines such as cyclophosphamide, followed by longer-term maintenance therapy in appropriate cases. Because treatment itself can carry significant risks, management requires specialist neurological and rheumatological supervision.
Although PACNS is uncommon, early recognition is important. Its symptoms can mimic infections, tumors, migraines, multiple sclerosis, or other vascular disorders. Advances in MRI, vessel-wall imaging, cerebrospinal-fluid testing, and biopsy techniques are improving clinicians' ability to identify this complex disease and tailor treatment to its underlying pattern.
Central Nervous System Vasculitis: A Rare Inflammatory Disorder of the Brain and Spinal Cord
