A case of probable primary angiitis of the central nervous system (PACNS) presented with acute ischaemic stroke, rapidly progressive encephalopathy, multiple bilateral infarcts, and intracranial haemorrhages, with gradual improvement following immunosuppressive therapy with high-dose corticosteroids and azathioprine.
Key Findings
Background
The patient presented with acute ischaemic stroke that progressed to rapidly progressive encephalopathy with multiple bilateral infarcts and intracranial haemorrhages.
The patient was a man in his late 50s admitted initially with acute ischaemic stroke
Clinical course involved subsequent development of rapidly progressive encephalopathy
Imaging demonstrated multiple bilateral infarcts and intracranial haemorrhages
The combination of ischaemic and haemorrhagic lesions represented a significant diagnostic challenge
Results
Initial differential diagnoses of reversible cerebral vasoconstriction syndrome (RCVS) and posterior reversible encephalopathy syndrome (PRES) were considered before PACNS was identified.
Initial suspicion included reversible cerebral vasoconstriction syndrome (RCVS) and posterior reversible encephalopathy syndrome (PRES)
Repeated neuroimaging was required to reach the correct diagnosis
High-resolution black-blood MRI demonstrated vessel wall enhancement consistent with vasculitis
Extensive work-up was necessary to exclude systemic vasculitis, infection, malignancy, and cardioembolic sources
Results
High-resolution black-blood MRI showing vessel wall enhancement was the key imaging modality supporting the diagnosis of PACNS.
Repeated neuroimaging including high-resolution black-blood MRI was performed
Vessel wall enhancement consistent with vasculitis was demonstrated on this modality
Conventional imaging was insufficient to reach the diagnosis without this advanced technique
The findings met diagnostic criteria for probable PACNS
Results
The clinical and radiological findings met diagnostic criteria for probable PACNS, though definite diagnosis was not established due to absence of histopathological confirmation.
Definite diagnosis of PACNS requires histopathological confirmation by biopsy
Brain biopsy was not performed in this case
The case was classified as 'probable' PACNS based on clinical and radiological criteria
Extensive work-up excluded systemic vasculitis, infection, malignancy, and cardioembolic sources as alternative diagnoses
Results
Immunosuppressive therapy with high-dose corticosteroids and azathioprine led to gradual improvement of the encephalopathic state, although severe neurological deficits persisted.
Treatment consisted of high-dose corticosteroids combined with azathioprine
Gradual improvement of the encephalopathic state was observed following initiation of therapy
Despite improvement in encephalopathy, severe neurological deficits persisted
The case underscores the importance of repeated reassessment in patients with unexplained altered consciousness
What This Means
This research describes a challenging case of a man in his late 50s who was initially admitted for a stroke but whose condition worsened significantly, developing confusion, multiple strokes on both sides of the brain, and brain bleeding simultaneously. These findings were unusual because strokes and brain bleeds typically have different causes, making it difficult for doctors to identify what was wrong. After ruling out many possible causes — including infections, cancer, heart-related clotting problems, and other types of blood vessel inflammation affecting the whole body — advanced MRI brain imaging that specifically examines blood vessel walls revealed inflammation consistent with a rare condition called primary angiitis of the central nervous system (PACNS), a disease where the immune system mistakenly attacks blood vessels in the brain.
PACNS is notoriously difficult to diagnose because its definitive confirmation requires a brain biopsy, which carries its own risks and was not performed in this case. Instead, the diagnosis was classified as 'probable' PACNS based on imaging and clinical findings after exhaustive exclusion of other conditions. Treatment with high-dose steroids and the immunosuppressant drug azathioprine was started, which gradually reduced the confusion and altered mental state, though the patient was left with significant lasting neurological problems.
This research suggests that PACNS should be considered in patients who develop unexplained progressive brain dysfunction with a combination of strokes and brain bleeds, and that repeated imaging using advanced MRI techniques is important when the initial diagnosis is unclear. The case highlights how early and repeated reassessment — rather than anchoring on an initial diagnosis — can be critical when patients with altered consciousness do not improve as expected, and that timely immunosuppressive treatment may help limit further brain injury even when a definitive biopsy-based diagnosis cannot be obtained.
Gusatovic J, Stavngaard T, Gharehbagh S, West A. (2026). Diagnostic challenge in primary angiitis of the central nervous system: altered consciousness with multifocal infarcts and haemorrhages.. BMJ case reports. https://doi.org/10.1136/bcr-2025-270685