Case of the Month

Fig 9, 10, 11

MRI TOF Angio of the brain after 12 weeks: There is diffuse narrowing of the A1 segment of the left ACA and the M1 and M2 segments of the left MCA.

Discussion:

Central nervous system (CNS) vasculitis is a heterogeneous group of inflammatory disorders that affects the blood vessels of the brain and spinal cord. The pathophysiology of CNS vasculitis involves inflammation and damage to the vessel walls, which can result in thrombosis, hemorrhage, and ischemia. CNS vasculitides are classified as [1, 2]. 

1. Primary: confined to the CNS with no involvement of other systems -

referred to as primary angiitis of the CNS               

2. Secondary: occurs in the context of a systemic inflammatory or infectious

process.

Classification of secondary vasculitides based on the type of vessels affected:

1. Small blood vessels: IgA arteritis, microscopic polyangiitis (also called microscopic polyarteritis), and granulomatosis with polyangiitis.

2. Large blood vessels: Takayasu arteritis (though CNS involvement is uncommon) and giant cell arteritis.

3. Medium-sized blood vessels: polyarteritis nodosa, Kawasaki disease,

systemic lupus erythematosus, rheumatoid arthritis, Sjogren syndrome,

antiphospholipid syndrome, systemic sclerosis, and eosinophilic granulomatosis with polyangiitis.

4. Vessels of variable sizes: Cogan syndrome and Behçet disease. The clinical presentation of CNS vasculitis is often nonspecific and can vary greatly depending on the involved vessels, the severity of inflammation, and the affected region of the CNS. Common symptoms include headache, focal neurological deficits, cognitive dysfunction, seizures, and encephalopathy. In some cases, psychiatric symptoms such as mood changes, personality shifts, or psychosis may predominate. [3]

The diagnosis of CNS vasculitis is primarily clinical, supported by radiological      findings and, in some cases, biopsy. In secondary vasculitis, systemic signs ofthe underlying disease (e.g., fever, weight loss, skin lesions) may provide clues.

However, primary CNS vasculitis (also referred to as primary angiitis of the CNS or PACNS) often occurs in the absence of systemic disease and can present as a purely neurological condition, further complicating diagnosis.

A definitive diagnosis of CNS vasculitis often requires a biopsy of the brain or meninges, although this is an invasive procedure that carries potential risks. In       some cases, the diagnosis can be established through the combination of clinical features, imaging findings, and the exclusion of other causes of neurological symptoms. High ESR, C-reactive protein (CRP) and increased cell count and protein in CSF may raise the suspicion of cerebral vasculitis [4, 5]. However, normal CSF findings do not definitively rule out CNS vasculitis [6].MRI is the gold standard [7] for evaluating CNS vasculitis, and the findings may include:

1. White Matter Abnormalities: areas of T2 hyperintensity and FLAIR (Fluid-Attenuated Inversion Recovery) abnormalities, which may reflect edema, ischemia, or gliosis. These lesions typically occur in a patchy, multifocal distribution and are most often located in the subcortical and periventricular regions [8].

2. Cortical and Subcortical Infarcts: Ischemic lesions are frequently seen on MRI, often in a non-arterial distribution, which can suggest vascular inflammation. Involvement of small vessels leading to infarctions is common and can manifest as a combination of diffuse and localized lesions (2). The ischemic areas may show enhancement after contrast administration, indicating active inflammation [9].

3. Vascular Abnormalities: MRA (Magnetic Resonance Angiography) is useful in detecting large-vessel narrowing or stenosis, but in cases of primary CNS vasculitis, these changes may be absent. In such cases, MRI findings of vessel wall enhancement (i.e., when there is thickening and contrast uptake) may suggest inflammation of the vascular wall [10].

4. Cerebral Hemorrhages: Intracranial hemorrhage can occur as a result of vascular rupture due to the inflammatory process, and this is particularly seen in cases with severe vasculitis. MRI will typically show areas of hyperintensity on T2-weighted sequences, and the hemorrhagic lesions may be associated with surrounding edema [11].

5. Digital subtraction angiography (DSA): Vascular changes typically seen in CNS vasculitis include narrowing, irregularities, or occlusion of small and medium-sized vessels, particularly in the posterior circulation. However, it is important to note that angiographic findings may be normal in primary CNS vasculitis, which is why imaging findings must be correlated with clinical symptoms and other diagnostic tests [12].

The treatment of CNS vasculitis typically involves immunosuppressive therapy to control the inflammatory process. Corticosteroids are the cornerstone of therapy, often combined with other immunosuppressive agents such ascyclophosphamide, methotrexate, or azathioprine. Early initiation of treatment is critical to prevent irreversible neurological damage and improve long-term outcomes [9].

Conclusion: The differential diagnoses mentioned above -specially RCVS should be considered and follow-up angiogram especially MR TOF angiogram (as it is non-invasive and does not require any radiation exposure) must be performed after a period of 12 weeks.