Chapter 13
THE GUT IN AIDS
1. OVERVIEW
AIDS, the Acquired Immuno Deficiency Syndrome is caused by a virus, a retrovirus of unknown biologic origin. This virus selectively attacks the T lymphocytes of the CD 4 type and any cell with the CD 4 cell surface marker. Until the development of quite effective antiviral therapy in the late 1990’s, the so called HAART (Highly Active Antiretroviral Treatment) drug regimens, the syndrome was regarded as uniformly fatal. This was most often because of the almost inevitable opportunistic infections, frequently affecting the gut and lungs with strange or unusual organisms, difficult or impossible to treat. Given the high cost of HAART therapy, its use is largely confined to the affluent west. In the undeveloped world the magnitude of the AIDS problem is horrifying in its effects, not only on individuals, but on the societies concerned. Appropriate retroviral therapy has largely prevented or aborted the infective complications previously seen and two aspects are worth brief review:
• The gut complications seen before this therapy was developed and in those areas where it is not readily available.
• The not insignificant liver complications of the syndrome and its therapy.
2. THE GUT COMPLICATIONS IN THE UNTREATED (1).
These are predominantly:
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• Cytomegalovirus infections of the mouth, oesophagus and colon. These produce stomatitis, odynophagia, dysphagia and a most disabling diarrhoea.
• Candida likewise can affect the mouth, oesophagus and rectum.
Ultimately nearly all terminal AIDS patients develop candida stomatitis.
• Cryptosporidia which can cause an intractable diarrhoea.
• Cyclospora which shows some similarity to cryptosporidia.
• Microspora species – very small organisms recognised as common pathogens in AIDS.
• It is evident that with difficulty in eating and swallowing and diarrhoea, the story of AIDS is so often a terminal wasting disorder. For obscure reasons G lamblia and E histolytica infections are not increased in prevalence in AIDS.
• Infection with the standard enteric pathogens is also common – salmonella, shigella, Campylobacter as is Cl difficile infection as a response to the high usage of oral antibiotics in AIDS. The raising of the CD4 lymphocyte count with appropriate therapy is often dramatically beneficial in these patients where drugs to inhibit the organisms are often lacking. Kaposi’s sarcoma and non hodgkin’s lymphoma can occur almost anywhere in AIDS including the gut.
3. LIVER DISEASE
Liver disease in treated AIDS patients may result either from the infection or from the therapy. Parenchymal liver disease attributable to drugs, either prescribed or not, is the commonest cause of abnormal liver function tests in AIDS. Mycobacterial infection with either M. tuberculosis or M. avium species may affect either the gut or the liver. Recurrence of Hepatitis B infection in those regarded as cured occurs and co-infection with Hepatitis B and Hepatitis C together with HIV are frequent. The coincidence of HIV and chronic Hepatitis B carrier state is not uncommon and with the initiation of HAART in such patients there may be a dramatic flare up in the hepatitis.
Viral and protozoal infections of the liver are common especially Histoplasma, Candida, Cryptococcus; Kaposi’s sarcoma and Non Hodgkins lymphoma are also frequently seen.
It is clear that HAART therapy has totally changed the picture of AIDS
and that the treatment has the capacity to raise the CD 4 cell count to levels
where the risk of these infective complications is minimal. As a result there
is clear evidence of a fall in the incidence of these infections during the late
1990’s following the widespread use of such therapy(2).
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References
1. Wilcox CM. Gastrointestinal consequences of infection with human immunodeficiency virus in : Feldman M, Friedman LS, Sleisinger MH, eds. Sleisinger and Fordtran’s Gastrointestinal and Liver Disease: Pathophysiology, diagnosis, management. 7th Ed.
(Saunders, Philadalphia, 2002), vol. 1, pp. 487-506.
2. Kaplan JE, Hanson D, Dworkin HS et al. Epidemiology of human immunodeficiency virus – associated opportunistic infections in the United States in the era of highly active retroviral therapy. Clin. Infect. Dis. 30 (Suppl 1),S5-14 (2002).
