A patient with neuronal intranuclear inclusion disease developed encephalitis‐like symptoms after cerebral angiography

Patients with neuronal intranuclear inclusion disease (NIID) can present with encephalitis‐like symptoms such as recurrent paroxysmal fever and unconsciousness. To date, no specific triggers for these symptoms have been reported. In our case, an 78‐year‐old woman became unconscious and developed fever after cerebral angiography. The patient had experienced four episodes of unconsciousness and fever in the past 7 years. Postangiography, she immediately became unconscious and developed fever. No vascular abnormalities were found and magnetic resonance imaging of the brain revealed expanding white matter lesions and hyperintense lesions along the corticomedullary junction. Genetic analysis revealed an abnormal GGC repeat expansion in NOTCH2NLC. Thus, we diagnosed the patient with NIID. We suggest that cerebral angiography is a possible trigger for encephalitis‐like symptoms in NIID.