Introduction

Gastrointestinal (GI) dysfunction, a common occurrence in children with HIV disease, can be related to infectious agents, malnutrition, immunodeficiency, or HIV infection itself, and can result in retardation of growth, increased caloric requirements, and/or diarrhea/malabsorption. The absorption and utilization of nutrients is a primary function of the GI tract, but the immune system of the gut has been shown to be the major site of CD4+ lymphocyte depletion and viral replication [1]. The mucosal immune and enteric nervous systems interact with the epithelium to regulate intestinal function. Lymphocytes and macrophages produce cytokines and vasoactive peptides that can alter brush border epithelial cell enzyme expression, secretion, motility, or mucosal blood flow. These factors ultimately affect nutrient absorption. As immune function deteriorates in the HIV-infected child, intestinal function declines to a degree greater than might be expected due to opportunistic infections alone. The goal of this chapter is to present the GI aspects of HIV disease so that clinicians will begin intervention in the early stages of the disease, thereby minimizing the impact on growth and development.

The role of the GI tract in pathogenesis of HIV

HIV is acquired via the mucosa of the genital tract in most cases of heterosexual transmission and via the GI tract in most cases of mother-to-child transmission (MTCT). HIV infection of a child can occur through swallowing infected amniotic fluid in utero, or infected blood or cervical secretions during delivery and/or through ingesting infected breast milk in the postnatal period [2].