Cryptosporidium are protozoan parasites of subphylum sporozoa. The organism is frequently isolated from patients with AIDS and has been associated with liver and biliary tract involvement, gastroenteritis, and intractable diarrhea and weight loss. Diagnosis is by detection of cryptosporidial oocysts in stool specimens or by detection of the parasite on biopsy specimens. A variety of antibiotics and antiparasitic drugs have been used in the treatment, although none has been clearly successful.

Empyema: is usually of insidious onset and tuberculous in origin. It is a common problem in HIV patients. Underwater seal drainage may not suffice in many cases; only thin pus may drain comfortably through this tube. Open drainage is usually an adequate treatment.

Necrotizing fasciitis: usually demands radical and repeated excision of all infected tissue with a good margin of normal tissue. If the facilities of a hyperbaric oxygen chamber are available, it acts as a useful adjunct to radical surgery.

Mycobacterium avium intracellulare (MAI): This is an ubiquitous organism that has been rarely associated with disease processes before AIDS. Infection with MAI has been associated with severe abdominal pain, fever, weight loss, hepatomegaly, enterocolitis and the formation of inflammatory intra abdominal masses. An infection of the terminal ileum simulating Crohn's disease has been described₆. Characteristic findings of MAI infection on CT scan include the presence of diffuse jejunal wall thickening and enlarged lymph nodes. Definitive diagnosis is made by demonstration of acid fast organisms in biopsy specimens. Disseminated infections are resistant to therapy.

Osteomyelitis: Most frequently distal femur and proximal tibia are common bits for hematogenous osteomyelitis in adult HIV patients. Usually the disease is bilateral. Radiographs show diffuse osteopenia and bone destruction with little periosteal reaction. This is a very difficult disease to treat. The bacteriology is often a mixture of staphylococci and bowel organisms and only amputation will remove the infection.

Bacteraemia: It is usually frequent in patients with HIV disease and can also lead to infection of implants. So it is wise to avoid the use of implants wherever possible and to remove metal fixations after fractures have healed.

Kaposi's Sarcoma (KS): It was originally described as an indolent multicentric neoplasm occurring in older Caucasian men characterized by pigmented skin nodules on the lower extremities. The form of KS that affects patients with AIDS is a much more aggressive neoplasm with prominent lesions in the upper extremities and is associated with early lymph node metastasis. Gastrointestinal KS is associated with hemorrhage, obstruction and intussusception₇. Radiographic findings are diagnostic in many cases and the diagnosis is confirmed by endoscopy and biopsy.

Lymphoma: AIDS associated lymphomas tend to be aggressive and generally respond poorly to treatment. The presence of a non-Hodgkin's lymphoma in a patient with HIV infection establishes the diagnosis of AIDS; AIDS associated lymphomas have characteristics which differentiate them from the typical lymphomas. There is a high incidence of extranodal involvement and gastrointestinal involvement with obstruction, hemorrhage or perforation being common complications. Surgery may be required in some cases to establish the diagnosis or to treat complications. However, it has been well demonstrated that surgical intervention to debulk tumor mass does not improve survival of these patients.

Since many of the manifestations of AIDS may mimic acute surgical problems, a thorough attempt should be made to establish that a surgical condition exists. If indicated, a thorough history and physical examination can be supplemented by abdominal sonography or computerized tomography. The presence of positive cultures or biopsies does not rule out the possibility of a co-existing lesion. A consideration of gastrointestinal organ systems will present specific conditions that are frequently encountered.

Patients may present initially with oral lesions or may develop lesions later in the course of the syndrome. Oral candidiasis is the most common lesion seen and suggests esophageal involvement if associated symptoms are present.

Hairy leukoplakia is another specific lesion, which on biopsy has fibrillar projections and no mononuclear response. Papilloma and Epstein – Barr viruses have been localized in these lesions with electron microscopy. The recommended treatment for these lesions is surgical excision₈.

Oral KS lesions have been reported to cause pharyngeal obstruction₉. Therapy for KS of AIDS has not been as effective as for classic KS. Biopsy or excision of the lesion may be required for obstruction or diagnosis. The lesion may be confused with inflammatory or vascular lesions.

Candida, herpes virus or cytomegalovirus 10 may cause esophagitis in the AIDS patient. Diagnosis is made by oesophagoscopy and biopsy. Esophageal ulcers secondary to HIV infection have also been found to contain virus in the base of the ulcer under electron microscopy. There is no treatment for these lesions.

Most of the lesions in stomach and duodenum are caused by KS, CMV or lymphoma. These lesions can be associated with hemorrhage or obstruction. These tumors are generally of high grade and surgical excisions are associated with early recurrences.

CMV is also associated with severe gastritis and duodenitis and has also been associated with chronic ulcerations of G.I. Tract.

The surgeons may be called to evaluate fever, right upper quadrant pain and cholestasis in a patient with AIDS. Diagnosis is made more difficult by associated type A or type B hepatitis. The symptoms may even mimic choleystitis. The diagnosis is established by liver biopsy with the finding of intranuclear inclusion cells. MAI can also cause hepatitis. This syndrome is associated with hepatomegaly and an increased level of alkaline phosphatase.

CMV is also associated with acalculous choleystitis, dilatation of intra & extrahepatic bile ducts and cholangitis₁₁. Cholecystitis and cholangitis may also occur secondary to obstruction of the cystic or common bile duct from lymph-adenopathy, KS and lymphoma.

Lymphomas of small bowel are usually symptomatic and are known to cause pain, weight loss, obstruction, hemorrhage and perforation. Lymphomas in patients with AIDS tend to be extranodal. CT scan is usually diagnostic in more than 90% of patients ₁₂.

Intussusceptions of small bowel can also be seen associated with KS lesions or lymphoid hyperplasia₁₃.

MAI has been associated with a syndrome resembling terminal ileitis of Crohn's disease₁₄. CMV involvement of small bowel may also suggest inflammatory bowel disease. It can also present with perforations but usually with a fatal outcome.

Appendix: Acute appendicitis usually can be very difficult to diagnose until the disease has advanced to perforation in patients with AIDS. The most common presentation reported usually is worsening abdominal pain and diarrhea. The presence of fever or leukocytosis has not been reliable. The morbidity of a negative appendectomy can be significant in these patients, therefore the use of USG to supplement the diagnosis is advised₁₆. The surgeon should not be misled by positive stool cultures for enteric pathogens in ruling out acute appendicitis because they will be positive in a majority of patients.

Colon: Homosexual men with AIDS are usually prone to develop “ Gay bowel syndrome” i.e., risk for unusual opportunistic infection like enterocolitis, salmonella, shigella, camphylobacter, entamoeba and giardia. There infections are often associated with abdominal pain and diarrhea and at times may be severely affected by CMV with ulceration and perforation₁₈.

Anorectal disorders represent the most common surgical problem in homosexual patients infected with HIV virus. Many of these problems may be related to or exacerbated by sexual practices.

Anorectal infection with the human Papilloma virus (HPV) can lead to the development of anal condylomata acuminata and squamous cell carcinoma of the anus. When condylomata are small and few in number, they can be treated successfully with repeated applications of podophyllin or with electrofulgration₁₉. Patients with extensive anal condylomata are at significant risk for development of squamous cell carcinoma of the anus.₂₀. Early carcinomas may respond well to local excision₂₁ but advanced lesions are difficult to manage.

Primary rectal lymphomas have been identified in AIDS patients₂₂. This lesion may present as a mass or with necrosis. The tumor necrosis may simulate an anorectal abscess. Whenever an atypical lesion is encountered in anorectal lymphomas, further evaluation usually reveals evidence of a disseminated lymphoma.

Anal ulcers can result in severe pain and are frequently refractory to therapy. Herpes simplex virus and CMV are common causes of these lesions. KS may appear in the rectum as a mass or with ulceration. Diagnosis is confirmed by biopsy ₂₃,₂₄.

Open surgical lymph node biopsy in the AIDS patients has now been largely replaced by fine needle aspiration biopsy (FNAB). This provides adequate tissue for diagnosis in over 95% of cases₂₅. Surgical lymph node biopsy may be required for evaluation of suspicious or enlarging lymph nodes in the setting of a negative FNA or in those rare cases when a larger tissue specimen is required to further classify a lymphoma.

ITP & AIDS: The surgeon may also be called to evaluate chronic problems in patients with AIDS. Thrombocytopenic purpura can develop in approximately 7% of patients with HIV infection₂₆. The cause of this condition is unknown but may be directly related to HIV virus. The clinical presentation bears a striking similarity to ITP. Treatment, however, includes therapy with antiretroviral agents such as zidovudine (AZT). Splenectomy is indicated in non-responders and 75% may show some degree of improvement following surgery.