Neutropenic enterocolitis is a well-documented complication of chemotherapy for hematologic malignancies; however, the association between NE and HIV is far less reported. The pathogenesis of NE is not completely understood, and it may differ in patients being treated with chemotherapy versus those with HIV. In cancer patients, it appears that cytotoxic drugs may cause intestinal mucosal injury and profound neutropenia, leading to impaired host defense from intestinal flora. This microbial infection leads to production of bacterial endotoxins, bowel wall necrosis, hemorrhage, and subsequent septicemia. NE most often affects the cecum, and this may be due to its limited blood supply . In patients who are not as profoundly neutropenic, such as those with HIV, a different pathogenesis may be at play. Patients infected with HIV have lost their cell-mediated immunity and thus may be more susceptible to opportunistic infections and malignancies of the intestinal mucosa. This mucosal injury also impairs the host defense against intestinal flora and pathogenic bacteria .
The incidence of NE among adults with hematologic malignancies varies greatly in the literature, ranging from 0.8 to 26%, but the incidence in patients with HIV is unexplored [8, 9]. Further, several authors report mortality rates of 50% or higher in patients with NE, and mortality rates are even greater when treatment is delayed . Thus, prompt recognition of NE and initiation of treatment is crucial in reducing mortality. Patients classically present with a triad of symptoms: fever, abdominal pain, and neutropenia . Localized pain to the right lower quadrant, abdominal distension, and diarrhea, sometimes with lower gastrointestinal (GI) bleeding, as was seen in this case, are likely to be present. A presentation with localized pain to the right lower quadrant can mimic acute appendicitis, while diarrhea and acute lower GI bleeding are more suggestive of NE . Abdominal CT scan with contrast is the preferred diagnostic tool to distinguish between the two pathologies and identify bowel wall thickening (most often of the ileocecal region), which is the most common radiographic finding in NE . Other CT findings in neutropenic patients may include pneumatosis intestinalis, mesenteric stranding, bowel dilation, and mucosal enhancement . Ultrasound and plain radiographs may also be used, but these may be more likely to produce false negative results (23% and 48%, respectively) . Ultimately, the gold standard for diagnosis of NE is histologic examination via colonoscopy . However, this procedure is often contraindicated due to the risk of bowel perforation, as in this case.
Conservative management is the preferred approach for patients with NE. Upon recognition of the clinical and diagnostic indications for NE in patients with HIV, even without neutropenia, broad spectrum antimicrobial therapy should be initiated immediately . Bowel rest, nasogastric suction, IV fluids, and nutritional support are also appropriate supportive treatments. Serial abdominal examinations should be conducted to monitor for deterioration of clinical condition, and clinicians should be aware of the potential for acute hemodynamic decompensation, especially if prompt management is not initiated . Colectomy should be considered in case of acute hemodynamic instability, bowel perforation, massive hemorrhage, abscess formation, or lack of response to medical therapy . Finally, with regard to the risk of recurrence, a study of eight patients with leukemia found the recurrence rate of NE after conservative management was 67% . However, there have been no studies regarding the recurrence rate of NE in patients with HIV, so it is difficult to quantify in this specific population.
Overall, neutropenic enterocolitis, which typically presents with fever, abdominal pain, and bloody diarrhea, can be difficult to identify, particularly in patients without a history of malignancy. However, it should be considered in patients with HIV who present with these symptoms, even with a normal ANC and CD4 count above 200 cells/mm3. Prompt diagnosis can be made with CT imaging of the abdomen, and early initiation of broad-spectrum antibiotic therapy can greatly reduce the risk of morbidity and mortality in these patients.