Immune Reconstitution Inflammatory Syndrome (IRIS) Causing Large Bowel Obstruction

Excerpt

A 41-year-old man presented with a 2-month history of progressive lower abdominal pain and distension accompanied with increased constipation. In the several days prior to admission, he had worsening pain and no bowel movements. He denied any fevers or chills but did relate a 25-pound weight loss over the previous 3 months. Of note, he had been diagnosed with HIV over 10 years ago but had been erratic with antiretroviral therapy (ART) compliance for many years. However, he reported that he had started dual ART with dolutegravir plus cobicistat-boosted darunavir approximately 2 months prior to this admission. On examination, he was hemodynamically normal and normothermic. The abdomen was soft and nontender but there was fullness in the lower abdomen though no definite masses. Rectal exam found an empty rectal ampulla with no masses. Laboratory values showed a WBC of 7.2, with normal electrolytes and serum lactate. Of note, his CD4 count was 178/mm³ with 30 copies/ml HIV-1 by PCR. A CT scan of the abdomen showed evidence of large bowel obstruction with a 6 cm sigmoid colon stricture (Fig. 1). The patient subsequently underwent a flexible sigmoidoscopy which confirmed a severe sigmoid stricture unable to be traversed (Fig. 2). Biopsies revealed benign colonic mucosa with focal ulceration, granulation tissue but no evidence of neoplasm. The next day, the patient was taken to the operating room for an exploratory laparotomy. Two areas of narrowing were found involving the left colon, in the proximal sigmoid colon and splenic flexure with moderate proximal dilatation. A left colectomy was undertaken in an oncologic fashion and intestinal continuity restored from the transverse colon to the rectum using a circular stapler in a side-to-end fashion. The postoperative course was uneventful with the patient discharged home on postoperative day 4 continuing his dual ART. Pathology on the colectomy specimen showed colonic strictures associated with marked lymphoplasmacytic inflammation, ulceration, and active inflammation with Epstein–Barr virus (EBV) positive cells consistent with EBV-associated colitis (Fig. 3). Stains for cytomegalovirus (CMV), acid-fast bacilli (AFB), and fungi were negative. Thirty lymph nodes were negative for malignancy.

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