Cytomegalovirus Infection

Cough, fever, diarrhea, and weight loss had disturbed a 52-year-old woman for 1 month. AIDS had been diagnosed 5 years earlier, but she had declined medical treatment. The patient's vital signs were stable when she was admitted to the hospital. Physical examination results were unremarkable except for thrush and mild, diffuse abdominal tenderness.

Results of complete blood cell count, blood chemistry, and liver function tests were all normal. The patient's CD4 count was less than 10/µL. Chest film findings were consistent with Pneumocystis carinii pneumonia, and trimethoprim-sulfamethoxazole therapy was begun.

Stool specimens were negative for ova, parasites, and Clostridium difficile, and bacterial cultures were negative for Mycobacterium avium-intracellulare. Colonoscopy revealed lesions characteristic of cytomegalovirus (CMV) colitis, for which the patient was given intravenous ganciclovir.

Vomiting and severe periumbilical pain developed on the 5th day of therapy. No abdominal distention or peritoneal signs were present, and pelvic examination results were normal. After an abdominal roentgenogram showed a small-bowel obstruction (A), an exploratory laparotomy was carried out. This revealed a volvulus and 3 ft of ischemic bowel, which were removed. The patient's postoperative course was complicated by septic shock and disseminated intravascular coagulation, and she died 5 days after the surgery.

CMV infection occurs frequently in the advanced stages of AIDS and can affect any organ system. In the gastrointestinal (GI) system, it can infect the esophagus, stomach, appendix, small intestine, colon, pancreas, and biliary tree.¹ Both the endothelial and epithelial cells of the submucosal small vessels are infected by CMV. The ensuing vasculitis and thrombosis lead to mucosal ischemia, hemorrhage, and gangrene.

CMV bowel infection typically presents as enterocolitis with chronic diarrhea, fever, abdominal pain, weight loss, melena, and hematochezia.² Acute GI syndromes include toxic megacolon, peritonitis, intussusception, and obstruction.³

The differential diagnosis of GI obstruction in AIDS includes (in addition to the usual causes among the general population) Kaposi's sarcoma; lymphoma; and opportunistic infection, such as that caused by CMV.⁴ Small-bowel obstruction in patients with CMV infection has been reported secondary to pseudotumor and diffuse enteropathy.⁵

This is the first reported case in which volvulus caused small-bowel obstruction in the setting of CMV infection. Such a finding should be included in the broad differential diagnosis of abdominal pain in patients with AIDS.

Another patient, a 35-year-old HIV-seropositive man, underwent colonoscopy for acute bleeding of the lower GI tract that lasted for 1 day. As seen here, edematous mucosa covered with fresh heme was interspersed with multiple clean-based ulcers (B). The biopsy specimen showed inclusion bodies consistent with CMV infection. The patient was treated with foscarnet, the bleeding ceased, and he was discharged from the hospital in stable condition several weeks later.

The gold standard of diagnosis of CMV infection is detection of viral inclusion bodies. The typical CMV cell appears as an "owl eye," a large cell with intranuclear inclusions surrounded by a clear halo (C, arrow). The cytoplasm may be clumped, representing its viral component. Although CMV inclusion bodies can be seen in normal mucosa, they can also cause focal or diffuse colitis or ulceration.

Therapy for infected patients requires an agent that can inhibit CMV replication. The most widely used is intravenous ganciclovir. Among patients with AIDS who were given ganciclovir for CMV colitis, response rates have ranged from 70% to 90%. Prolonged maintenance regimens are often required. Foscarnet is also active against CMV and appears to be effective for ganciclovir-resistant isolates.

REFERENCES:1. Welch K, Finkbeiner W, Alpers CE, et al. Autopsy findings in the acquired immunodeficiency syndrome. JAMA. 1984;252:1152-1159.
2. Drew WL. Cytomegalovirus infection in patients with AIDS. J Infect Dis. 1988;158:449-456.
3. Welson SE, Williams RA, eds. Surgical Problems in AIDS. New York; Igaaku-Shoin Press; 1994:91-105.
4. Cappell MS, Hassan T, Rosenthall S, Mascarenhas M. Gastrointestinal obstruction due to Mycobacterium avium-intracellulare associated with the acquired immunodeficiency syndrome. Am J Gastroenterol. 1992;87:1823-1827.
5. Wisser J, Zingman B, Wasik M, et al. Cytomegalovirus psudetumor presenting as bowel obstruction in a patient with acquired immunodeficiency syndrome. Am J Gastroenterol. 1992;87:772-774.