Central nervous system vasculitides

Central nervous system (CNS) vasculitides represent a heterogeneous group of inflammatory diseases affecting the walls of blood vessels in the brain, spinal cord, and the meninges.

Please refer to the article on vasculitis for a general discussion of that entity. 

The aim of this article will be to discuss the primary angiitis of the CNS (PACNS) since the other vasculitides are already discussed in specific articles. 

CNS vasculitides are classified as 1,2:

  • primary: confined to the CNS with no involvement of other systems - referred as PACNS
  • secondary: occurs in the context of a systemic inflammatory or infectious process

Please, note that this classification is different from that one used when discussing systemic vasculitides.

PACNS remains a rare disorder: an estimated average annual incidence rate of 2.4 cases per million. It affects patients of all ages, but peaks at around 50 years of age, with males affected more commonly than females 1.

Secondary causes of CNS vasculitis far exceed in number PACNS 2. Please refer to each specific vasculitis for further details.  

Clinical features of PACNS are non-specific. The diagnosis is made based on Calabrese’s criteria 4, including:

  • the presence of an acquired otherwise unexplained neurological or psychiatric deficit
  • the presence of either classic angiographic or histopathological features of angiitis within the CNS (biopsy remains the standard of reference for diagnosis 3)
  • no evidence of systemic vasculitis or any disorder that could cause or mimic the angiographic or pathological features of the disease

When part of a systemic disorder, the diagnosis may be easier, unless the cerebral symptoms are the first to manifest. Please refer to a specific vasculitis for further details on clinical manifestation. 

For almost all forms of vasculitis, including PACNS, the triggering factor is unknown 3

CNS secondary vasculitides:

Imaging findings for PACNS are usually variable and nonspecific, with ischemic infarctions the most common lesions, occurring in 53% of cases 5

May show areas of hypoattenuation.

Digital subtraction angiography shows focal or multifocal segmental narrowing of both small and medium-sized blood vessels, occlusions are also present. The same findings could be demonstrated in both CTA and MRA.

More specific to show multiple infarctions: usually bilateral, affecting different vascular territories of variable size, and in various stages of healing. 

T2 and FLAIR high-intensity lesions in the white matter are also very common in PACNS, but completely nonspecific. Meningeal enhancement and intracranial hemorrhage can also be seen.

Vessel wall MRI (VW-MRI) may be a useful adjunct to conventional MRI, allowing differentiation between vasculitis, where there is contrast enhancement of the affected arterial wall, and other causes of vascular narrowing, such as intracranial atherosclerotic plaque, reversible cerebral vasoconstriction syndrome, dissection, and moyamoya disease 7

PACNS is managed with high dose steroids and cytotoxic agents 3

PACNS was initially reported in 1959 by Humberto Cravioto and Irwin Feigin 6.

Remember that despite being composed by nonspecific findings, MRI is almost 100% sensitive for PACNS and a normal exam practically excludes this diagnosis 1

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Article information

rID: 33352
Tags: cases, cases
Synonyms or Alternate Spellings:
  • Cerebral vasculitis
  • CNS vasculitis
  • Primary angiitis of the CNS
  • Primary angiitis of the central nervous system
  • Central nervous system vasculitis
  • Primary angiitis of the central nervous system (PACNS)

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