Introduction. Orbital myositis (OM) is a rare ocular extra-intestinal manifestation (EIM) of inflammatory bowel disease (IBD). It can present with a myriad of ophthalmologic symptoms including pain and swelling due to acute or recurrent inflammation of one or more extraocular muscles. We present the case of a young female with Crohn’s disease (CD) who developed OM.
A 26-year-old female with a three year history of inflammatory, ileal, Crohn’s disease, currently controlled on vedolizumab, presented with two days of left eye pain, swelling, and difficulty with extraocular movements associated with nausea. She was initially seen by optometry who prescribed topical prednisolone drops for presumed anterior scleritis, but her symptoms continued to progress and she presented to the hospital. Labs including ESR and CRP were normal. MRI of orbits showed abnormal signal and enhancement of the left medial rectus muscle consistent with inflammatory myositis. She was started on pulse dose IV steroids with marked improvement by the next day. Workup for sarcoidosis, IgG4 disease, and Grave’s disease was negative. Oral steroids were continued on discharge with repeat MRI 4 months later showing near resolution of her orbital inflammation, but she still continued to endorse persistent pain in her left eye requiring steroid therapy. Throughout this, she had no additional gastrointestinal complaints, fecal calprotectin level was 30 mcg/g, MR Enterography performed was unremarkable, and Ileocolonoscopy performed with biopsies did not demonstrate any active disease, all consistent with remission of CD. Given her persistent ocular symptoms and inability to wean off steroid therapy, 6-mercaptopurine was added to the gut-specific agent vedolizumab as a steroid-sparing agent to control the EIM of her Crohn’s disease. Anti-TNF agents were not chosen since the patient had a history of primary non-response to infliximab.
Although ocular extra-intestinal manifestations including episcleritis and uveitis can present in up to 10% of patients with IBD, OM is very rare and has only been described in isolated case reports. Data shows a predominance in females and a higher incidence in CD than ulcerative colitis. Symptoms can vary, and include orbital pain, swelling, diplopia, and ophthalmoplegia. OM appears to be independent from bowel inflammation in the majority of cases, and can precede gastrointestinal symptoms or present during remission of CD. The pathophysiology is poorly understood, though proposed mechanisms describe immune complex formation due to cross-reactivity between colonic mucoproteins and extraocular muscles. Diagnosis is best established by MRI, which shows characteristic hypersignal and contrast enhancement of the involved muscle. The first line treatment is high-dose systemic steroids with prolonged taper, which leads to rapid resolution of symptoms. Due to the high incidence of recurrence, long-term therapy is essential though can be challenging given limited data for effective agents. Literature review shows antimetabolites can be a safe and effective steroid-sparing treatment. Although there is limited data for the newer biologic therapies, anti-TNF agents have been historically used with success. An individualized approach to treatment is necessary, with consideration of prior biologic exposure as well as adverse effects.