Ustekinumab-Associated Posterior Reversible Encephalopathy Syndrome in a Patient With Crohn's Disease.

Ustekinumab is a common biologic therapy for the treatment of inflammatory bowel disease. Posterior reversible encephalopathy syndrome (PRES) is an uncommon condition consisting of a constellation of neurologic findings and characteristic findings on imaging. The association between ustekinumab and PRES is not well defined. We present a case of PRES in a patient with Crohn's disease on ustekinumab and a brief review of the literature. Clinicians should be aware of this rare complication with high morbidity in patients with inflammatory bowel disease on ustekinumab and be able to recognize clinical symptoms.