Gastrointestinal Chagas Disease

The chronic phase of Chagas diseaseis presented in three clinical forms: indeterminate (no clinical manifestations), cardiac disease, and megaviscera syndromes. The latter comprise up to 18% of the infected individuals and most often present a compromise of the esophagus and colon. The physiological function of these organs depends on a perfect coordination/synchronization of muscular constriction and relaxation waves, in order to push a rather hard material (alimentary bolus and feces) through their cavity, and a coordinated transposition of two sphincters. When this function is hampered, a progressive increase in the diameter of both organs is produced, termed megaesophagusand megacolon. A clue for the cause of this dysfunction is the selective destruction of parasympathetic plexus neurons by the etiological agent of the disease, Trypanosoma cruzi. Besides motor alterations, secretory and absorptive functions may be affected. Why these features are observed in only some of the infected is not clear. A markedly discrete geographical distribution of digestive Chagas diseasecases below the equatorial line suggests it may be due to the type of circulating T. cruzi lineages (TcII and TcV). Different incidences according to gender and age are also seen. A number of neurotransmitters and neuropeptides have been linked to Chagas disease-associated megaviscera syndromes. Dysphagia and obstipation are clinical hallmarks of this disease, but serological diagnosis is necessary to exclude other possible causes, like idiopathic megaviscera. Association with cardiac involvement is observed in 20–30% of the cases, and 40% of the cases exhibit both megaesophagusand megacolon. Progression from mild to severe disease is seen in some of the cases, in which surgery is ultimately required. Fecaloma and volvulusare common complications of megacolon. In recent years, new methods have significantly improved post-surgery prognosis. Alternative treatments with botulinum toxin and by mechanical dilatation are indicated for specific cases. Other hollow viscera may be involved, albeit at lower frequencies, such as the stomach, duodenum, gallbladder, ureter, bladder, and others. However, these are usually also associated with megacolonand/or megaesophagus.