Stroke after initiation of interferon‐beta treatment for relapsing–remitting disseminated white matter disease

Background –  Interferon‐beta (INF‐ β ) is effective and used in reducing exacerbation frequency and disease progression in multiple sclerosis. In certain circumstances, INF‐ β can lead to rare side effects. Aims of the study –  We report the case of a 34‐year‐old female patient satisfying the McDonald criteria of multiple sclerosis without showing typical pathologic changes in cerebrospinal fluid (CSF). After introduction of INF‐ β treatment, she quickly developed further progression of her disseminated neurological symptoms and finally an ischemic cerebral infarction. Methods –  Evaluation of the patient included arterial angiography, magnetic resonance and positron emission tomography, histopathological assessment as well as a broad spectrum of serum and CSF analysis. Results –  All diagnostic evaluations and the clinical course revealed evidences for a primary angiitis of the CNS. We discuss the possible worsening due to inappropriate INF‐ β treatment in cerebral angiitis promoting severe cerebrovascular insufficiency. Conclusion –  The authors suggest that all diagnostic multiple sclerosis criteria including typical CSF findings should be ascertained before INF‐ β treatment is initiated.