Triatominae bug (Chagas disease vector)
Symptoms may not occur after infection (acute phase) or they may be nonspecific as flu symptoms (in 30% of the cases). Two-thirds of the infected individuals never develop complications (undetermined form). One-third will experience damage to target organs [5–7]. The heart is the target organ most affected among patients with chronic disease (60%). Chagasic cardiomyopathy is characterized by cardiac dilatation and conduction system abnormalities (typically right bundle branch block) [1, 5, 8]. The gastrointestinal system is affected in 20% of the cases, especially the esophagus or colon, with a 60% concomitance of cardiac manifestation [7, 9, 10].
There is no vaccine for prevention of Chagas’ disease or specific treatment for the chronic stage [5].
Chagas’ Disease Esophagopathy
Pathophysiology
Chagas’ disease esophagopathy (CDE) is caused by immune destruction of the esophageal intramural ganglia. This process begins in anticipation of symptoms since the disease usually clinically manifests more than 15 years after contagion. Neural damage in idiopathic achalasia (IA) seems to be degenerative and leads to destruction of the Auerbach’s myenteric plexus affecting only inhibitory neurons [9–12]. On the other side, inhibitory and excitatory neurons seem to be affected in CDE. This aganglionosis affects esophageal body contraction and lower esophageal sphincter relaxation.
Clinical Presentation
Clinical presentation for CDE and IA is similar. Dysphagia is the main symptom in almost all cases. Regurgitation, weight loss, and thoracic pain are also very frequent. A remarkable difference in presentation is, however, the time of complaint. It is common to find patients with two decades of dysphagia in CDE. This is probably caused by access to treatment in underdeveloped countries where the disease is endemic. Moreover, the vector insect inhabits rural areas, distant from large urban centers [11, 13].
Esophageal Motility
Esophageal achalasia is defined manometrically by aperistalsis and inadequate relaxation of the lower esophageal sphincter [12, 14, 15]. High-resolution manometry provides a more detailed evaluation of the disease including a classification based on esophageal pressurization. The same classification may be applied to CDE [12, 15] although type III was not present in patients with CDE probably due to the loss of inhibitory and excitatory ganglia in CDE, different from IA [11, 12]. CDE and IA are comparable in regard to manometric findings although higher pressures of the esophageal body are noticed in patients with IA and basal and residual pressures of the LES are lower in patients with CDE. This may be attributed to a more pronounced esophageal dilatation in patients with CDE [15]. It is still unclear if the Chicago Classification may predict prognosis in patients with CDE similarly to IA [15–19]. The higher prevalence of lower esophageal sphincter basal pressure in patients with CDE [15, 20] does not seem to affect outcomes even though some authors propose that better results are found in patients with hypertonic lower esophageal sphincter [21].
Interestingly, some authors recently questioned the need for complete aperistalsis to define achalasia [12]. Chagas’ disease is a natural model for achalasia since patients without any clinical complain may be followed to evaluate deterioration or not of motility. Some studies did find some undetermined abnormalities in these patients, especially multipeaked waves, spontaneous activity, and repetitive waves [14, 15, 20].
Esophageal Dilatation
The degree of esophageal dilatation is an indicative of the disease severity and tailors therapy according to some authors. CDE is characteristically represented by esophageal dilatation, probably related to the delay in treatment as previously mentioned. Over 70% of the patients will present with >4 cm of esophageal caliber at first presentation in CDE series [22].
Esophageal dilatation may define end-stage disease. The threshold for advanced disease is variable. Some adopt the limit of 6 cm for maximum esophageal diameter [23], while others use 7 cm [24]. Most Brazilian surgeons adopt 10 cm as the upper limit [25]. Esophageal diameter > 10 cm can be found in up to 40% in CDE series [26].
Other Manifestations
Esophageal stasis is accentuated in dilated esophagi. This leads to secondary findings in the mucosa at the upper digestive endoscopy, especially esophagitis due to intrinsic production of acid during bacterial fermentation of retained food and leukoplakia, a premalignant finding [25, 26]. The risk for esophageal cancer is 10–50 times greater in patients with achalasia, and it is greater in patients with CDE probably due to the long-lasting time of symptoms [26, 27].
Epiphrenic diverticula are common in achalasia, but there is no evidence for a different incidence in patients with CDE as compared to IA [28, 29].
Evaluation
A complete work-up is necessary for the diagnosis and evaluation of patients with suspected CDE, not different from IA [30].
Upper digestive endoscopy is a mandatory test to exclude other diseases including pseudoachalasia due to an esophagogastric junction tumor, particularly because achalasia increases the risk for esophageal cancer.
Esophageal manometry is the gold standard test for the diagnosis of achalasia due to objective evaluation of peristalsis, detection of alterations even in incipient cases, and the possibility to define prognosis.
The heart and the colon may be other target organs of the Chagas’ disease. Thus, a cardiologic evaluation is necessary in all patients. A colonic evaluation is necessary if this organ may be used to replace the esophagus after and esophagectomy.
Patients with massive dilatation of the esophagus must be carefully prepared for therapy. The risk for aspiration is great due to food stasis in the esophagus. Prolonged fasting and attention during intubation are mandatory. Pulmonary evaluation is welcome since subclinical aspiration may affect the lungs.
Treatment (Table 3.2)
Pharmacological
Treatment options for Chagas’ disease esophagopathy
Treatment | Observations |
|---|---|
Pharmacological | Limited use |
Endoscopic – cardia dilatation | Frequent use in initial cases as primary therapy (dilatation <4 cm). Excellent/good results in over 80% |
Endoscopic – botulinum toxin injection | Low level of evidence for outcomes in patients with Chagas’ disease Different pathophysiology as compared to idiopathic disease may bring inferior outcomes |
Endoscopic – peroral myotomy | Few studies in Chagas’ disease Questionable value and feasibility in end-stage disease |
Surgical – Heller myotomy | Frequently used Excellent/good results in over 80% |
Surgical – esophagectomy | Frequently used for end-stage disease (dilatation >10 cm) |
Surgical – other | Low level of evidence for outcomes in patients with Chagas’ disease Laparoscopic Heller myotomy may be a better alternative in end-stage cases |
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