The authors present the case of an otherwise healthy 42-year-old man who was diagnosed with Crohn disease (CD) after presenting with acute vision loss from optic perineuritis (OPN). They say that the patient's optic nerve involvement with CD seems unique.
While extraintestinal inflammatory manifestations are common in inflammatory bowel disease (IBD), including CD, and the eye is often a site of extraintestinal involvement in CD, ocular manifestations are generally localized to the anterior chamber and ocular surface. Rarely, they involve the posterior pole, orbit, and optic nerve.
The patient presented to the emergency room following acute, painless loss of the entire visual field in the left eye that morning. He had experienced 10 days of abdominal cramping, low-grade fever and diarrhea. Visual acuity was 20/20 in the right eye and hand motions in the left eye. Visual fields showed a large central scotoma in the left eye. Pupils demonstrated a left relative afferent pupillary defect. Applanation tonometry indicated IOP of 6 mmHg in both eyes. Slit-lamp examination was significant for mild conjunctival injection with 1+ anterior chamber cells in both eyes.
He had an elevated white blood cell count of 19.5 cells per microliter and platelet count of 516 platelets per microliter. Magnetic resonance imaging of the brain and orbits revealed thickening of the orbital portion of the left optic nerve with enhancement of the optic nerve sheath, findings consistent with OPN, which is characterized by inflammation of the meninges surrounding the optic nerve.
Computed tomography of the abdomen showed wall thickening of the ascending, transverse, and descending colon indicative of colitis. A flexible sigmoidoscopy showed subtle patches of granular mucosa in the rectum and sigmoid colon along with discrete ulcerations of the colonic mucosa. Biopsies from the rectum demonstrated acute inflammation and noncaseating granulomas confirming the diagnosis of CD.
The patient was treated with intravenous methylprednisolone (1 g daily for one week) followed by an oral prednisone taper, as well as oral mesalamine and corticosteroid eye drops. Two weeks after presentation, funduscopy revealed multifocal choroidal infiltrates in the left eye and mild left optic disc swelling. Eight weeks after steroid therapy, these fundus findings resolved, and three months later, vision was 20/25 in the left eye, with mild dyschromatopsia, a central scotoma, and mild optic disc pallor. He was maintained on 5 mg of prednisone daily and mesalamine to treat CD.
The authors say the development of steroid-responsive choroidal lesions and anterior chamber cell in the patient supports the diagnosis of an inflammatory process involving the uveal tract. OPN is usually idiopathic and considered within the spectrum of nonspecific orbital inflammation (pseudotumor).
They say it is unknown whether systemic treatment with anti-inflammatory medications, such as 5-aminosalicylic acid and corticosteroids, to reduce IBD flares also prevents optic nerve inflammation. Many cases of IBD-associated optic nerve inflammation, including this one, are concurrent with gastrointestinal (GI) exacerbations. They say that GI disease control may help prevent extraintestinal inflammatory manifestations of IBD.