KS is a multi-focal neoplastic disease that originates from the lymphatic endothelium, most frequently involving the skin. Also commonly involved are the mucous membrane, lymph nodes, gastrointestinal system and lungs. Lesions have been reported in virtually every organ including the heart and central nervous system. Human herpes virus-8 has been strongly implicated as a co-factor in the pathogenesis of KS. In HIV-infected patients, KS is an AIDS-defining illness.
Gastrointestinal involvement in KS is frequent in patients with advanced HIV disease. In one series of KS, gastrointestinal lesions were found in up to 51% of the cases . Most clinical series have underestimated the overall incidence of luminal gastrointestinal involvement with KS because intestinal lesions rarely lead to symptoms. In a prospective endoscopic evaluation of 50 AIDS patients with KS, gastrointestinal tract involvement was present in almost all cases . In another series, gastrointestinal involvement was reported in 40% of cases at initial diagnosis and up to 80% at autopsy.
Gastrointestinal involvement commonly occurs in association with cutaneous lesions or lymph node involvement, with gastrointestinal tract involvement alone occurring in only 3.5% of cases . The absence of skin or lymph node KS, however, does not exclude the possibility of gastrointestinal involvement . Gastrointestinal KS is mostly found in the stomach and duodenum with jejunum, ileum or large bowel rarely being involved. The biliary tract is also commonly involved. Lesions appear either as macule, sub-mucosal growth or as nodules . Most of the lesions (80%) are clinically silent with bleeding, protein-losing enteropathy, mal-absorption and obstructive jaundice being the most common presentation. Gastrointestinal obstruction has also been rarely reported .
IRIS is an inflammatory reaction to an opportunistic pathogen and/or tumor antigen that occurs early after initiation of HAART in patients with AIDS and is temporally related to an increase in the host's CD4+ lymphocyte count . IRIS is most frequently observed in individuals with severe CD4+ T-cell depletion and is believed to be due to reconstitution of immune responses to a previously existing (but clinically occult or previously treated) pathogen or tumor antigen, rather than development of a new opportunistic infection or progression of opportunistic infection due to treatment failure. Our patient had AIDS and started on HAART therapy. He was admitted with severe pain abdomen after four weeks of HAART and diagnosed to be having intestinal obstruction. An emergency laparotomy was done which showed matted small bowel loops with purple colored patches and cysts with adhesions on the small bowel serosal surface and mesentery. Adhesiolysis and resection were done and the lesion sent for histopathological examination, which showed it to be a case of KS. Our patient had no features of KS during initiation of HAART. An ultrasound of his abdomen was also normal.
Initiation of HAART is usually associated with a regression of KS. However in this case there was probably a rapid increase in the size of the KS lesion, causing intestinal obstruction. Several features of this case suggest that the worsening symptoms and clinical finding represented IRIS rather than progressive KS. The rise in his CD4 count and the temporal relationship of bowel obstruction to HAART initiation also support the diagnosis of KS-IRIS.
Although KS is prevalent among HIV-1 infected persons, IRIS during anti-retroviral treatment of AIDS-associated KS has only been reported three times [5–7]. In one case, laryngeal obstruction occurred in a patient with known KS shortly after initiation of HAART . In the second case, parotid gland KS developed in an individual two years after initiation of HAART, despite there being good CD4+ lymphocyte reconstitution and virus suppression . In the third case, rapidly progressive KS lesions with lymphadenopathy and tissue swelling occurred in a patient during anti-retroviral treatment, despite an increased CD4+ lymphocyte count and decreased HIV-1 level and KS-associated herpes virus replication .
In a review of 5,832 patients with AIDS undergoing HAART, Bower et al. identified 150 therapy-naïve patients with a first presentation of KS and recorded their clinic-pathologic features prospectively. They identified ten patients with IRIS-KS in the patient cohort of HIV patients with KS who were started on HAART.
This is a rare case of IRIS associated with AIDS-related gastrointestinal limited KS, presenting as an acute intestinal obstruction. It is likely that KS-associated IRIS is more common than the literature reflects due to limited awareness of this condition. It is important for clinicians to realize that KS-associated IRIS does not indicate failure of HAART or a need for changes in the anti-retroviral regimen. Instead, chemotherapy in conjunction with HAART can effectively control the symptoms of IRIS as well as resolve KS, especially when KS-IRIS is severe or there is visceral involvement.