From the Guidelines
Central nervous system (CNS) vasculitis is diagnosed through a combination of clinical evaluation, laboratory tests, imaging, and often brain biopsy, with the most recent and highest quality study suggesting that MRI head with IV contrast is a useful examination in the evaluation of CNS vasculitis 1. The diagnosis requires evidence of CNS inflammation, exclusion of other conditions, and confirmation of blood vessel inflammation. Key features include new-onset headaches, altered mental status, seizures, focal neurological deficits, and stroke-like episodes, particularly in younger patients without traditional vascular risk factors.
- Laboratory findings may show elevated inflammatory markers (ESR, CRP), abnormal cerebrospinal fluid with elevated protein and pleocytosis, and sometimes autoantibodies depending on the underlying cause.
- MRI typically reveals multifocal infarcts of varying ages in different vascular territories, while cerebral angiography may show vessel narrowing, dilation, or beading.
- Brain biopsy remains the gold standard for definitive diagnosis, showing inflammatory cell infiltration in vessel walls, as supported by a study from 2009 1.
- Treatment involves high-dose corticosteroids (methylprednisolone 1g IV daily for 3-5 days followed by oral prednisone 1mg/kg/day) combined with immunosuppressants like cyclophosphamide (1-2mg/kg/day orally or 750-1000mg/m² IV monthly), rituximab, azathioprine, or mycophenolate mofetil, with a study from 2021 suggesting that pulse cyclophosphamide has been used successfully to treat isolated angiitis of the CNS in children 1. Prompt diagnosis and treatment are essential as CNS vasculitis can cause permanent neurological damage or death if left untreated, with treatment typically continuing for at least 1-2 years with gradual tapering based on clinical response 1.
From the Research
CNS Vasculitis Diagnosis
- The diagnosis of CNS vasculitis is challenging due to its broad differential diagnosis and nonspecific initial clinical manifestations 2, 3.
- There are no specific clinical features or a classical clinical course, and no blood or imaging investigations that can confirm the diagnosis 3.
- Contrast catheter cerebral angiography is neither specific nor sensitive, yet still underpins the diagnosis in many published studies 3.
Diagnostic Approaches
- A careful, team-based approach with emphasis on ruling out possible mimics is paramount in the management of patients with CNS vasculitis 2.
- Obtaining tissue is important for diagnosis, and a new, binary set of diagnostic criteria has been proposed, dividing cases into 'definite' and 'possible' primary CNS vasculitis 3.
- Brain biopsy can be diagnostic of PCNSV in 71% of cases and demonstrates an alternative diagnosis in 37% of cases 4.
Clinical Characteristics
- Primary CNS vasculitis (PCNSV) remains a diagnostic challenge due to its variable and non-specific clinical manifestations 4.
- Clinical characteristics associated with abnormal biopsy and angiography include cognitive impairment, seizures, subacute or progressive onset, and abnormal CSF profile 4.
- Angiography-defined PCNSV are more likely to have an acute onset, focal weakness, and visual impairment on initial presentation 4.
Treatment
- Induction therapy for primary angiitis of the central nervous system (PACNS) often consists of steroids and cyclophosphamide 5.
- Maintenance therapy includes a prednisone taper and may be combined with medications such as azathioprine or mycophenolate mofetil 5.
- Relapse is common in PACNS, and medications such as rituximab and mycophenolate mofetil may be good alternatives in those who do not respond to initial treatment or who have relapse of disease 5.