Myositis of pterygoid muscles and superior ophthalmic vein and cavernous sinus thrombosis in active Crohn's disease undergoing ustekinumab treatment: a case report and literature review.

Introduction: Myositis is a rare extra-intestinal presentation in patients with inflammatory bowel diseases (IBD), and its occurrence has only been described in a few case reports. However, it is essential to consider other potential causes as patients with IBD are more susceptible to infections due to their immunocompromised status, which may also be exacerbated by immunosuppressive drugs contributing to myositis. Our case highlights the complexity and challenges in diagnosing and managing myositis in patients with IBD as well as a review of the literature. Case report: We report the case of a 17-year-old girl with active Crohn's disease (CD) undergoing ustekinumab (UST) treatment. She presented with sudden onset of pain and rapid progressive swelling of both jaws, along with eyelid swelling, blurred vision, and diplopia. Radiologic imaging revealed myositis affecting the pterygoid muscles, combined with thrombosis of the left superior ophthalmic vein and (partially) of the left cavernous sinus. Symptoms resolved completely after stopping UST treatment and initiating corticosteroids and enoxaparine. Discussion: Our report accounts for the second patient described in literature with myositis associated with CD while being treated with UST. The causal factor remains speculative, as both active CD and UST treatment may contribute to this complication. Sharing clinical experiences and reporting possible adverse events to regulatory agencies can enhance our understanding of rare complications and improve patient outcomes by providing therapeutic strategies.