What might cause severe abdominal bloating & diarrhea 3 years after ileocolonic resection and adalimumab/methotrexate treatment?
Surgical success, new onset symptoms. Three years after successful ileocolonic resection and anastomosis, a 28-year-old man presents with a 3-month history of abdominal bloating and loose stools. Up until then he had done well on a post-surgical regimen of adalimumab SQ every other week and methotrexate PO weekly. Laboratory study results include normal hemoglobin, elevated serum folate, and low B12.
What would you do next? No active disease is seen in the colon, neoterminal ileum, or anastomosis; the anastomosis is widely patent. You initiate B12 supplementation. Which of the strategies above would you then pursue?
Answer: C. Initiate a course of antibiotics. Differentiating between a flare of Crohn disease and another cause of worsening symptoms is critical in long-term management. There is no evidence of active disease seen on imaging or in specific laboratory results. Taken together the patient’s new symptoms and lab results of concern are a classic presentation of small intestinal bacterial overgrowth (SIBO).
Significant risk for SIBO. Two significant risk factors for the development of SIBO in this patient are IBD and surgically-altered anatomy. In cases such as this one whre here is a high probability of SIBO, empiric therapy with antibiotics is the best choice. Adjustment of adalimumab would be appropriate only if there were evidence of a disease flare.
Suggested reading: Quigley EM, Abu-Shanab A. Small intestinal bacterial overgrowth. Infect Dis Clin North Am. 2010;24:943-59.
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