Ulcerative colitis (UC) is a chronic and debilitating disorder, characterized by inflammation of the colonic mucosa. UC can be considered a systemic disorder but UC-related manifestations in the central nervous system (CNS) are quite rare.

A 29-year-old man was admitted to the emergency department with repeated generalized tonic-clonic (GTC) type seizures. Based on brain CT, brain metastasis or hemorrhagic infarct was suspected. Diffusion-weighted image of brain MRI showed high signal in the left thalamus and heterogenous enhancement in the right parietal and left frontal lobes. This image indicated a cerebral infarct, but could not completely rule out cerebral metastasis and vasculitis, or any other pathology. However, the brain biopsy revealed multiple thromboemboli with acute inflammation and necrosis. Thus, the patient was diagnosed with multiple cerebral infarcts with cerebral vasculitis, occurring as a complication of UC.

In conclusion, CNS manifestations of UC are rare. However, clinicians should consider uncommon diagnoses like vasculitis and thromboembolism in patients with UC presenting with seizures.