The Presentation of Multiple Perforations in the Small Bowel as Cytomegalovirus Related Immune Reconstitution Inammatory Syndrome in an HIV-infected Patient: a Case Report

Background: Multiple perforations in the small bowel as cytomegalovirus (CMV) related immune reconstitution inammatory syndrome (IRIS) in an human immunodeciency virus (HIV)-infected patient is very rare. Up to now, only ve IRIS-associated cases including our case were reported. We performed pathological examination, metagenomic next-generation sequencing (mNGS), CMV and immune cells immunohistochemical staining for rapid diagnosis and differential diagnosis. Case presentation: We describe a case with multiple perforations in the small bowel as CMV related IRIS in an HIV-infected patient. The patient appeared multiple perforations in the small bowel after 26 days of antiretroviral therapy (ART). The patient underwent exploratory laparotomy. Partial resection and surgical repair of small intestine were performed. CMV enteritis was conrmed by immunohistochemistry staining and other opportunistic infections were excluded by mNGS. However, he died from intestinal obstruction and septic shock at 55 days after surgery. Conclusions: Perforations due to CMV related IRIS are very rare, and usually lack the prodromal period symptoms of abdominal pain and diarrhea. It is not easily foreseen and appears shortly after ART. The condition of intestinal perforations is lethal, and early identication and surgical treatment are lifesaving. Multiple perforations in the small bowel as CMV related IRIS in an HIV-infected patient is very rare. Up to now, only ve IRIS-associated cases including our case were reported. The patient in our case appeared multiple perforations in the small bowel after 26 days of ART. After partial enterectomy, we performed pathological examination, mNGS, CMV and immune cells immunohistochemical for rapid diagnosis and differential diagnosis. CMV enteritis was conrmed and other opportunistic infections were excluded.


Background
Multiple perforations in the small bowel as CMV related IRIS in an HIV-infected patient is very rare. Up to now, only ve IRIS-associated cases including our case were reported. The patient in our case appeared multiple perforations in the small bowel after 26 days of ART. After partial enterectomy, we performed pathological examination, mNGS, CMV and immune cells immunohistochemical staining for rapid diagnosis and differential diagnosis. CMV enteritis was con rmed and other opportunistic infections were excluded.
Toxoplasma antibodies of IgG and IgM were negative. Liver function and kidney function were normal. His CD4 + T cell count has already increased into 75cells/μL. CMV-DNA load was 1.3×10 4 copies/ml. He was treated with intravenous ganciclovir. Ten days later, his fever disappeared. However, the patient presented persistent left lower abdominal pain which was spastic and tolerable. He had no abdominal distension, nausea, vomiting. The patient was conscious and had normal blood pressure(BP) 115/65mmHg, respiratory rate (R) 16 times / min, pulse frequency (P) 88 times / min and body temperature(T) 36.8℃. Abdominal examination showed that the abdomen was soft and at, left upper abdominal tenderness, without rebound pain and muscle tension. Bowel sounds were 4 times / min. A standing x-ray of the abdomen in a tertiary level hospital revealed bilateral moderate intraperitoneal free air (Fig 1A). Intestinal perforation was considered. However, he and his family members declined surgical treatment and temporarily agreed with conservative treatment. Patients were given gastrointestinal decompression, proton pump inhibitors, ertapenem combined with levo oxacin, and nutritional support. Twenty four hours later, the vital signs were T 38.4℃, BP 110 / 70mmHg, P 130 times / min, R 18 times / min. The patient had tenderness pain in the left upper abdomen and right lower abdomen and whole abdominal rebound pain and muscle tension. We rechecked the standing x-ray of the abdomen found bilateral massive intraperitoneal free air (Fig 1B). Abdominal color ultrasound showed pneumoperitoneum and pelvic effusion. The images of abdomen computed tomography (CT) showed free gas with a low diaphragm ( Fig 1C).
Retested blood showed leukocyte 8.74×10 9 /L, lymphocyte 0.65×10 9 /L, granulocyte 7.96 ×10 9 /L, Hb 103 g/L, and PLT 338×10 9 /L. Alanine transaminase (ALT) was 102U/L (9-50 U/L) and creatinine (Cr) was 92 μmol/L (59-104 μmol/L). An exploratory laparotomy was performed. A total of 1000 ml of suppurative peritoneal uid was cleared. Multiple perforations (40,50,65,140,240 cm proximal to the terminal ileum) were found at the antimesenteric border of small bowel. The largest diameter of holes was 1cm. Furthermore, multiple localized discolorations on the serosal surface of small intestine were presented indicating multiple deep ulcers (20,80,100,220 cm proximal to the terminal ileum). Partial enterectomy(35cm) and surgical repair of small bowel were performed. Histopathological showed the mucosa, submucosa and muscular layer were destroyed, neutrophil in ltration and granulation tissue formation were observed (Fig 2A). The serosa and myometrium showed pyogenic necrosis and a large number of neutrophils in ltrated ( Fig 2B). There were intranuclear and intracytoplasmic inclusions typical of cytomegalovirus ( Fig 2C). CMV enteritis was con rmed by hematoxylin-eosin staining and immunohistochemistry staining ( Fig 2D). There were a variety of in ammatory cell in ltration, including MUM1 positive plasma cells (Fig 2E), CD68 positive tissue cells (Fig 2F), CD8 positive lymphocytes (Fig 2G), and a small amount of CD4 positive lymphocytes ( Fig 2H). Kaposi's sarcoma was rstly excluded. In order to identify other possible co-infectious pathogens, formalin-xation and para n-embedded (FFPE) samples from a section of the resected bowel were sent to BGI PathoGenesis Pharmaceutical Technology (BGI-Shenzhen) for metagenomic next-generation sequencing (mNGS), which indicated CMV mono-infection without co-infections such as salmonella, tuberculosis, histoplasmosis, nontuberculous mycobacteria, cryptococcosis, amebiasis, microsporidium, schistosomiasis. Intravenous ganciclovir at 5 mg/kg twice per day for another 2 weeks followed by 5 mg/kg/day for 1 month was applied.
His CMV-DNA load was already less than 500 copies/mL. The patient had no fever and abdominal pain. He discharged home at 17 days after surgery and continued to take oral medication of ART without taking oral ganciclovir for secondary prophylaxis. One month after discharge, the patient was admitted again for abdominal pain and vomiting. The patient was conscious. The vital signs were T 36.5℃, BP 110 / 76mmHg, P 103 times / min, R 16 times / min. A standing x-ray of the abdomen did not show free gas and liquid gas level ( Fig 1D). However, 24 hours later, the condition of this patient aggravated with a fever and decreased blood pressure. The vital signs were T 38.4℃, BP 90 / 48mmHg, P 140 times / min. Blood routine test showed leukocyte 5.52×10 9 /L, lymphocyte 0.38×10 9 /L, granulocyte 4.35 ×10 9 /L, Hb 88 g/L, PLT 158 ×10 9 /L. Amylase, lipase, myocardial enzyme, liver function and renal function were normal. We rechecked the standing x-ray of the abdomen showed visible dilated intestines and liquid gas level (Fig 1E). Adhesive intestinal obstruction and septic shock was diagnosed. The patient received meropenem, rehydration transfusion, dopamine, gastrointestinal decompression. Unfortunately, the patient's condition deteriorated and died at 55 days after surgery.

Discussion And Conclusions
The multiple small bowel perforations in this case were associated with CMV related immune reconstitution in ammatory syndrome (IRIS). Up to now, only ve IRIS-associated cases including our case were reported [1][2][3][4] (summarized in Table 1). Most cases lacked prodromal symptom of diarrhea. The durations from ART initiation to develop bowel perforation were totally within two months. It is noted that these cases were exclusively associated with men especially with homosexual contact history. Among IRIS-related cases, small bowel perforations were common involved. Differently, our patient demonstrated severe secondary purulent peritonitis pre-operation which was the cause of short-term death. Shortening interval to operation once perforation was essential for survival. Therefore, it is actually challenging for us to make an early diagnosis and an early treatment. Non-traumatic small bowel perforation is rare [5][6]. The common causes in the general population are tuberculosis, Crohn's disease, and malignancies [7]. The most common cause in HIV-infected population is CMV infection though there has been a dramatic decrease at ART era.
The most common presenting symptoms of CMV gastroenteritis are fever, abdominal pain and diarrhea, while disease limited to the small bowel could be asymptomatic. CMV enteritis presenting as perforation in HIVinfected population showed a high mortality due to high postoperative complications including reperforation, bowel obstruction and severe sepsis complicated by multi-organ failure [8]. CMV colitis could be a manifestation of unmasking or paradoxical IRIS [9][10][11]. The pathogenesis of gastrointestinal CMV disease is believed to be submucosal vasculitis with thrombosis resulting in ischemia, ulcers, thinning of the intestinal wall with subsequent perforation and gangrene [12]. Histologic examination showed multiple areas of mucosal ulceration with acute and chronic in ammation. Transmural in ammation and necrosis was found at the perforation sites. The gold standard for diagnosis is the discovery of cytomegalic cells with viral inclusions bodies in epithelial, endothelial, smooth muscle, and in ammatory cells [13,14]. Infection is con rmed by immunohistochemistry for immediate early antigen of CMV. Real-time PCR and CMV culture are alternative laboratory method. As an important diagnostic tool, the signi cance of mNGS using FFPE samples of lesions for this case could help us to make differential diagnosis among various co-infections such as tuberculosis, non-tuberculous mycobacteria, histoplasmosis, and salmonella, which all might be associated with bowel perforations in HIV-infected patients.
In conclusion, bowel perforations shortly post-ART could be considered as CMV related IRIS in HIV-infected individuals. Up to now, in HIV-infected patients with asymptomatic CMV viremia, preemptive anti-CMV therapy was not recommended in HIV-infected population. However, preemptive anti-CMV therapy in advanced HIVinfected patients in some studies proved to be effective [15][16]. Routine enteroscopy and capsule endoscopy screening were not recommended. In order to prevent life-threatening CMV colitis, taking ART early and maintaining high CD4 + T cell counts are feasible. Alerting atypical manifestations of the disease and rapid initiating individualized therapy are crucial. Last but not least, identifying high-risk individuals and the use of preemptive anti-CMV therapy may be lifesaving. Intensifying education in assessment and monitoring to patients should be achieved among HIV specialists. Among the sickest individuals, clari ng the high risk factors correlated with mortality may guide us to take up the optimal interventions as soon as possible.

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Not applicable (no datasets were generated or analyzed during the current study) Competing interests: The authors declared no potential con icts of interest with respect to the research, authorship, and/or publication of this article.