A 37-year-old man presents with low back pain. He also endorses morning stiffness of his lower back. Both the pain and the stiffness improve with exercise. The patient has also noted bloody diarrhea over the past 2 weeks, but his friend told him that since he often weight-lifts, it is most likely secondary to hemorrhoids. Physical examination reveals pain on palpation over the sacroiliac joints. Dermatologic examination confirms several discrete violaceous nodules that are painful to palpation over the bilateral shins. Fecal occult blood test is positive and laboratory values reveal a hemoglobin level of 10.1 g/dL and high p-ANCA titers.
Which of the following is the most likely underlying disease contributing to this patient’s symptoms?
A. Celiac diseaseUlcerative colitis. This patient is presenting with signs and symptoms consistent with an underlying inflammatory bowel disease (IBD), most likely ulcerative colitis. The acute onset of bloody diarrhea in combination with anemia and positive fecal occult blood testing in the setting of his relatively young age lend credence to the diagnosis. This patient is also demonstrating extraintestinal manifestations of ulcerative colitis, including erythema nodosum and arthritis (similar in presentation to ankylosis spondylitis). p-ANCA is positive in high titers in ulcerative colitis, as seen with this patient. (A) Celiac disease is an autoimmune disease typified by malabsorption. Testing reveals anti-endomysial antibodies and anti-transglutaminase antibodies. Skin findings include dermatitis herpetiformis. (B) Reactive arthritis is characterized by nongonococcal urethritis, conjunctivitis, and arthritis. (D) Giardia lamblia infection causes a foul-smelling steatorrhea secondary to malabsorption. Bloody diarrhea is not present.