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Chagas digestivo
Dr. João Carlos Pinto Dias
Presidente
Chagas Digestivo. Contexto y Antecedentes
"Entre os enfermos que o vinham diariamente procurar, alguns acusavam moléstias cujas
qualificações eram complicadas e estrambóticas; assim declaravam -se salteados de engasgue ,
espinhela caída, mal de encalhe, tosse de cachorro, feridas brabas, almorreimas, erisipelas, ou até
asombração e mau-olhado. Quem se queixava de engasgue era o capataz de uma fazenda
chamado do Vau, distante umas boas cinquenta l éguas. Sr. doutor, disse o enfermo, a minha vida
é um contínuo lidar de sofrimentos. Estou com este mal vai fazer cinco anos no São João, por
sinal que me veio com uma grande dor na boca do estômbago. Vezes h á que eu não posso engolir
nada, sem beber muitos goulos de água, de maneira que me encharco todo e fico que mal me
mexo de um lugar para outro. Ë a dor, perguntou Cirino, ainda a sente? Toda a vida, respondeu o
capataz...O que me aflege mais é que há comidas então que não me passam a goela...É um fastio
dos meus pecados...Boto uns pedacinhos no bucho e parece-me que dentro tenho um bolo que
me está a subir e a descer pela garganta. (Taunay, 1862).
La enfermedad de Chagas en el tracto digestivo (ECD) es considerada hoy dia como muy importante en
grandes extensiones del área endémica de la enfermedad de Chagas. Desde antaño ya se conocian los
síntomas casi espec íficos del megaesófago, como en la descripci ón del Visconde de Taunay en su
romance "Inoc ência", transcripto arriba para Mato Grosso, Brasil. Tambien los científicos Spix & Martius
han referido el s íntoma en Minas Gerais y Piauí, por 1823, asi como Kidder & Fletcher lo mencionan en
São Paulo, Brasil, en 1857 (Rezende , 1998). En una detallada revisi ón histórica, Joffre Rezende
recuerda que 46 años pasaron desde las descripciones originales de Carlos Chagas y el reconocimiento
de la etiología chagásica del megaesófago (Rezende, 1998). De fundamental importancia fueron los
trabajos del patólogo Fritz Köberle, quien ha comprobado definitivamente la etiologia y la patogenia de la
ECD, en los años 50. En este sentido, el fenómeno básico de la ECD es la desnervación intramural de los
plexos del sistema nervioso autonómico mio -ent érico, especialmente los para-simpáticos. Esta
desnervación es mas intensa en la fase aguda, ocurriendo de manera sistemática y universal, en
conexión con lesiones inflamatorias en la proximidad con los plexos afectados, produciendo ganglionitis,
periganglionitis y miositis (Lopes & Chapadeiro 1997, Köberle 1968).. La dispersión de la ECD es grande,
principalmente abarcando las regiones central y austral de Sud America, en donde la prevalencia de
megaesófago puede variar de 3 hasta 10% entre poblaciones chagásicas no seleccionadas, debendo ser
relativamente m ás pequeña la prevalencia de la colopatía chagásica (Dias & Coura 1997, Rezende
2.000). Aunque todos los sectores del tracto digestivo puedan ser afectados por la ECD, las alteraciones
mas frecuentes y mas importantes se encuentran en el esófago y el colon terminal; las alteraciones
básicas de la ECD presentan naturaleza motora, pero tambien alteraciones de absorción y de secreción
pueden estar presentes (Rezende 2.000). La ECD puede presentarse precozmente yá en la fase aguda
de la E. de Chagas, especialmente el megaesófago; sin embargo, el megacolon es siempre la
manifestación más tardia, encontrandose la mayor proporción de los enfermos arriba de los 40 años de
edad (Dias & Coura 1997, Rezende 2.000). La ECD se ha detectado principalmente en Sud América,
siendo muy rara en Venezuela, México y América Central. Sin embargo, hay casos reportados en México,
Honduras y Guatemala; en Bolivia ocurre una situación especial, por la aparente predominancia del
megaesófago en los llanos y pre-cordillera, mientras el megacolon predomina en el altiplano y tierras altas
(Dias & Coura 1997, Mendoza 1998). De particular interés es el "megacolon de las alturas", detectado en
las tierras altas de Bolivia y Peru, en pacientes sin serologia positiva para Chagas. Es parecido al
megacolon chagásico y prevalece en alturas de 3.500 m o más, aparentemente vinculado con dietas muy
ricas en fibras. Esta afecci ón clinicamente se presenta como vólvulo y no como fecaloma, no recidivando
después de la intervención quir úrgica, como sucede con el mega chagásico (Mendoza 1998).. En estas
areas, la existencia de infección chagásica seguramente constituye factor adicional para una mayor
prevalencia de disfunci ón colónica en la población (Dias & Coura 1997, Rezende 2.000). La ECD, aunque
no sea tan impactante desde el punto de vista m édico-social, trae gran sufrimiento a los afectados,
resultando en desnutrición para los casos de megaesófago avanzado, así como muerte para los
pacientes con megacolon, por la ocurrencia no muy rara de vúlvulos. Hay variaciones regionales en
cuanto la asociación de ECD con la cardiopat ía chagásica crónica, en proporciones que van desde los 20
hasta los 60%. Por otro lado, la asociación de megacolon con megaesófago en el mismo paciente es muy
frecuente, en particular en los grupos de edad mas elevados (Mendoza 1998, Rezende 2000).
En los últimos años se observa un gran avance en el tratamiento de la ECD, especialmente en el terreno
de las intervenciones quirúrgicas. La inclusión del tema de la ECD en este simposio virtual es muy
oportuna, desde que la enfermedad existe y debe ser reconocida por todos los médicos de los paises
endémicos, incluso por los cardiólogos, quienes reciben un gran número de pacientes crónicos. En
particular, el reconocimiento de la ECD en sus etapas mas iniciales es de gran importancia para el
manejo adecuado del paciente, en cuando las intervenciones son mucho más fáciles y tienen carácter
preventivo de las formas m ás graves. Los Autores encargados de las ponencias en esta mesa son de
reconocida experiencia y capacidad didáctica. El Prof. Meneghelli viene de la importante escuela de
Ribeirão Preto, Brasl, en donde fué dicípulo de Köberle, de Büller Vieira, de Pedreira de Freitas y de otros
grandes pioneros. Por su turno, los Dres Mitelman y Gimenez traen su experiencia desde sus estudios
hospitalarios y laboratoriales, lo que nos irá a brindar múltiples posibilidades de aclarar el tema y
profundizar algunas cuestiones epidemiológicas y cl ínicas, de gran inter és para los pacientes afectados.
Terminando esta introdución, recuerdense el reporte de Lozano-Kasten (2.000), de Jalisco, México,
dando cuenta de la detección de varios casos de ECD en aquel País simplemente porque se decidió
realizar una búsqueda sistematizada de la afección entre individuos con sintomatología de colon o
esófago, en servicios de Gastroenterología, en determinada región endémica.
Referencias
Dias JCP & Coura JR 1997. Epidemiologia. In Dias JCP & Coura JR (organ.) Clínica e Terapêutica da Doença de Chagas.Uma abordagem
prática para o mclínico geral. Rio de Janeiro, Editora Fiocruz, p. 33-66.
Lopes ER & Chapadeiro E 1997. Anatomia Patol ógica da doença de Chagas humana. In Dias JCP & Coura JR (organ.) Clínica e
Terapêutica da Doença de Chagas.Uma abordagem prática para o mclínico geral. Rio de Janeiro, Editora Fiocruz, p. 67-84
Köberle F 1968. Chagas disease and Chagas syndromes.: the pathology of American trypanosomiasis. Advances in Parasitology 6 : 63-116.
Lozano-Kasten F 2000. Processo criativo e reconhecimento epidemiológico da doença de Chagas no M éxico. Revista da Sociedade
Brasileira de Medicina Tropical 33 : 231.
Mendoza EC 1998. Megacolon chagásico. Santa Cruz de la Sierra: Hospital Japonés/Cooperación Técnica Japonesa, 95 p.
Rezende JM, 1998. Megaes ôfago chag ásico (mal de engasgo). Dados históricos sobre o reconhecimento de sua etiologia.
Gastroenterologia Contemporânea 2: 6-15.
Rezende JM & Moreira H 2.000. Forma digestiva da doen ça de Chagas. In. Brener Z, Andrade ZA & Barral -Netto M (organ.) Trypanosoma
cruzi e doen ça de Chagas, 2a . edição. Rio de Janeiro, Guanabara Koogan Ed., p. 297-343.
Taunay V, 1862. Inoc ência . Porto Alegre, L&PM Edit. (1999), pág. 162
Relatos
Enteropatía chagásica
Dr. Ulysses Meneghelli
Chagas digestivo
Dr. Jorge Mitelman y Dra. Luisa Giménez
Tope
Chagasic enteropathy
Ulysses G. Meneghelli
Professor Titular do Departamento de Cl ínica Médica
da Faculdade de Medicina de Ribeirão Preto (USP)
Introduction
Chagas' disease is provoked by a protozoon, Trypanosoma cruzi, Chagas, 1909. The acute form of the
disease can be particularly severe or even lethal, but may also be non-apparent or may be confused with
other diseases, frequently going unperceived. In most cases the disease is diagnosed during the chronic
phase, when the major and most common expressions of the disease are manifestations of cardiac
involvement (arrhythmias, disorders of nerve impulse conduction, cardiomegaly, cardiac failure and
sudden death) and of the digestive tract (dysphagia, megaesophagus, intestinal constipation, megacolon).
The predominance of one or another of these manifestations is the basis for the recognition of the cardiac
(1) and digestive (2) forms of the disease, as opposed to the indeterminate form, which can only be
revealed by positivity of the serologic test.
The etiology of megaesophagus and megacolon, which are endemic in South America, especially in the
rural zones of Brazil, was linked to Chagas' disease only more than 40 years after the discovery of the
disease, based on serologic (3) and histopathological (4) studies, on experimental reproduction of the
disease in laboratory animals (5) and on patient follow-up during the acute phase of the disease (6).
Although megaesophagus and megacolon are the most common and most expressive digestive
manifestations of the chronic phase of Chagas' disease, others occur less frequently, such as
megaduodenum, megajejunum and megaileum. In addition, dysfunction of the small intestine of chagasic
patients can be demonstrated by functional tests even in the absence of symptomatic manifestations.
The pathogeny of dysfunction and dilation of segments of the digestive tract in Chagas' disease is based
on denervation of the complex network of intramural neurons, today known as enteric nervous system.
The destruction of intramural neurons in megaesophagus and megacolon was identified many years ago
(7,8) and was later confirmed by meticulous neuronal counts performed in megaesophagus and in nondilated esophagus, in the stomach , in different parts of the small intestine, in megacolon, and in nondilated colon of chagasic patients (9).
In this presentation, chagasic enteropathy will be approached from the viewpoint of involvement of the
duodenum, jejunum and ileum alone or in combination, due to Chagas' disease in the chronic phase.
Chagasic enteropathy is much less frequent and less studied than esophageal and colon disease of the
same etiology. However, studies on this type of disease are important to expand knowledge about the
digestive form of Chagas' disease, to include it among the causes of the intestinal pseudo-obstruction
syndrome and of bacterial overgrowth in the small intestine, and mainly for adequate diagnosis and
treatment.
II - Structural changes: intramural denervation and "megas"
Small bowel dysfunction and dilation are due to the lesions and destruction of neurons of the enteric
nervous system in the involved viscera. In experimentally infected animals, denervation of the submucosal
and myenteric plexuses of the small bowel has been confirmed (10,11,12). The same occurs in naturally
infected cats and dogs (13). The percentages of denervation shown in Table 1 were detected in humans
with the chronic phase of Chagas' disease and with no dilation of any segment of the small bowel. In
cases of enteric "megas", denervation is likely to reach much higher percentages, as also observed in
megaesophagus and megacolon. The complete disappearance of intramural neurons has been
documented in cases of megaduodenum (17).
Table 1 - Percent reduction in the number of neurons of the enteric nervous system of the small
bowel of patients with chronic Chagas' disease.
Duodenum (14)
Jejunum (15)
Ileum (16)
Submucosal plexus Myenteric plexus
50%
50%
33%
36%
42%
51%
As a consequence of denervation, the duodenum becomes hypersensitive to cholinergic agents and this
type of response to the application of an acetylcholine analogue can be a way to demonstrate intramural
denervation. The Mecholyl (metacholine) test performed with manometric monitoring of the duodenum
showed hyperactive reactions in 70% of chagasic patients with megaesophagus, as opposed to only 10 %
of chagasic patients without "megas", demonstrating that duodenopathy is more frequent in patients with
clear involvement of other segments of the digestive tube by the disease (18).
Electron microscopy reveled that the neuronal lesions of the jejunum are less intense than those of the
esophagus or colon and that the remaining cells show ultrastructural lesions. The least damaged cells
show an increase in the number and volume of osmophilic granules suggesting hypersecretion of
neurotransmitters, perhaps reflecting the complexity of the disorder of neuroregulation of the functions of
the organ. The presence of inflammatory foci and of interstitial fibrosis in smooth muscle has also been
recorded (19). Hypertrophy of the circular and longitudinal musculature was detected in the duodenum
(17).
The mechanisms determining the degenerative lesions of the neurons and even their complete destruction
in the viscera of the digestive tract of chagasic patients are still incompletely understood. They act starting
from the acute phase of the disease (20) but continue during the chronic phase. It was first proposed that
a neurotoxin released by the parasite near the focal points of infection during the acute phase of the
disease was a preponderant determinant of neural injury (20). The possibility has been raised that the
inflammatory process itself may be the cause of denervation or that denervation may result from the
participation of specific cellular and humoral responses to T. cruzi developed by the host, including
autoimmunity (21,22,23,24).
The final result of denervation of the enteric nervous system determined by Chagas' disease is dilation of
the involved organ, the most expressive manifestation of the digestive form of the disease. Koeberle (20)
proposed that, as a consequence of damage to intramural innervation, motor uncoordination of the
attacked visceral organ occurs, followed by delayed transit of its content, stagnation and retention,
continuous distention of muscle fibers which become hypertrophied, and finally dilation ("mega"). He
considered the functional status of the visceral organ to be an important factor in the determination of the
"mega". According to the cited author, the "mega" will develop only if the functional activity of the visceral
organ is continuously demanded. He proposed that dilation of the esophagus and colon occurs more
frequently than dilation of other viscera of the digestive tube because more demands are made on these
organs since, in contrast to other segments and especially the small bowel, they work with solid material.
He considered the presence of a defect in sphincter function to be an important factor in the development
of the "mega", as is the case for megaesophagus, but not an essential one, citing the megaduodenum and
megajejunum as a proof. He also stated that the degree of denervation and of the corresponding
functional disorder may affect the duration of the time needed for the development of the "mega".
However, other factors have been considered to participate in the pathogeny of the "megas" (23).
The detection of "megas" in the small bowel is not frequent, but the megaduodenum is considered to be
the segment of the digestive tube that is most often found to be dilated after the colon and esophagus. In a
series of 800 autopsies, 185 cases of megacolons, 158 of megaesophagus and only 20 of
megaduodenum and 4 of megajejunum were detected (9). Dilation of the ileum is exceptionally rare (25).
Dilation of the segments of the small bowel is frequently associated with megaesophagus and/or
megacolon (17,18). When a radiological method is used, however, the incidence of megaduodenum
increases. Fonseca (26) detected dilation of the first portion of the duodenum in 30% of cases of
megaesophagus.
III - Physiopathology
The function most consistently found to be altered in chagasic enteropathy is motor activity, which greatly
depends on the regulatory activity of the enteric nervous system. Although dilation of the duodenum,
jejunum and ileum is not frequent, the motor impairment of segments of the small bowel is high in the
digestive form of Chagas' disease. Radiological studies have revealed a high incidence of changes in
tonus and transit time in the duodenum, jejunum and ileum of patients with megaesophagus (26,27).
Manometry of the proximal small bowel has also revealed frequent abnormalities among patients with
megaesophagus and/or megacolon (28), as commented below.
Studies on small bowel motility both under fasting and postprandial conditions have demonstrated
perceptible alterations due to the intramural denervation caused by Chagas' disease. Normally, during
fasting the small intestine presents successive cycles of motor activity known as interdigestive migrant
motor complex (IMMC). In most persons, at intervals of 80 to 120 minutes a set of repeated contractions
of frequency identical to the basal local electric rhythm (12/min) arises in the duodenum. These
contractions cover a segment of about 25 cm and migrate in a caudal direction, and their frequency is
progressively reduced, reaching 7-8/min in the ileum. The velocity of migration of the set of contractions is
about 6 to 8 cm/min in the duodenum-proximal jejunum. The duration of the sequence of contractions at
the recording point is about 5 min in the proximal jejunum. This type of motor activity is phase III of the
IMMC and is followed by phase I, characterized by motor quiescence and refractoriness, which lasts 15 to
60 minutes. The motor activity then reappears gradually in the form of distinct manometric patterns until it
culminates in a new phase III. The motor activity of the interdigestive period has been proposed to be
important to lead to the colon non-absorbed food remains, secretions and cell detritus which, if retained,
would favor excessive bacterial proliferation. The pattern of contractions that characterizes the IMMC is
immediately interrupted by food ingestion, with the occurrence of a motor activity comparable to phase II
of the IMMC. The duration of IMMC interruption by a meal depends on the composition and the physical
properties of the food ingested (29).
The main manometric abnormality detected in the proximal small bowel of fasting chagasic patients was a
reduction in the velocity of propagation of phase III (Figure 1). The duration of phase III was also shown to
be longer in the jejunum but not in the duodenum, and the calculated length of the intestinal segment in
phase III was lower than normal. These alterations mainly occurred among patients with megaesophagus
and/or megacolon (28).
Figure 1 - Velocity of propagation of phase III of the IMMC in control individuals, in chagasic patients with no disease of the
digestive tract, in chagasic patients with megacolon (blank squares), with megaesophagus (blank circles), and with megacolon and
megaesophagus (squares with blank circles). The arrows indicate patients with megaduodenum (28).
Another remarkable change observed was the non-interruption of the IMMC by the ingestion of a meal of
approximately 530 kcal (Figure 2), which exclusively occurred in patients with megaduodenum and
megajejunum (30), or an attenuation of the responses to the meal revealed by prolonged manometry of
the small bowel (31). Considering that Chagas' disease may be seen as a natural human model of
denervated digestive viscera (32), these findings permit a suggestion of a physiological nature: the
integrity of the enteral nervous system in the small intestine is necessary for the normal migration of the
IMMC as well as for its interruption by food ingestion.
Figure 2 - Phase III of the IMMC, typical of fasting motility, arising 40 minutes after the end of a 530 kcal meal ingested by a patient
with megaduodenum and megajejunum demonstrates the faulty process that occurred in the transformation of the interdigestive
motor pattern to the digestive pattern. The reappearance of the interdigestive pattern should occur at least 90 to 120 minutes after
the end of the ingestion of a test meal. The patient also presented operated grade I megaesophagus (cardiomyotomy) and
megacolon (30).
Transit time studies using scintigraphy methods and the expired nitrogen test have shown a delayed
arrival of the test meal to the cecum associated with slow transit in the distal small bowel (33).
The changes in small bowel motility caused by intramural denervation may create conditions that favor
bacterial proliferation due to content stagnation. In fact, hyperproliferation of aerobic bacteria and the
presence of anaerobic bacteria in the small bowel have been documented in patients with chagasic
megaesophagus, with the number of colonies being as high in some cases as those occurring in patients
with the clinical syndrome of bacterial overgrowth in the small bowel. Since the participation of changes in
gastric secretion was excluded, the abnormality was attributed to disorders of local motility (34). In support
of this hypothesis, it was observed that two cases of chagasic megajejunum with clearly detectable
alterations upon manometry and with confirmed bacterial overgrowth in the small bowel developed the
typical clinical syndrome of bacterial overgrowth (chronic diarrhea, evidence of malabsorption and
improvement with antibacterial treatment) (35).
Intestinal absorption function has been little studied in Chagas' disease. It was first observed that chagasic
patients, especially those with clear involvement of the digestive tube as revealed by megaesophagus or
megacolon presented abnormal responses to an oral glucose (GTT) (36), galactose (37) and xylose (38)
overload test. The abnormal response to an oral overload with these monosaccharides was characterized
by a high peak of their concentration in blood 30 minutes after ingestion, followed by a rapid fall. Abnormal
GTT curves were detected in about 65% of patients with digestive tube "megas" (39). On the other hand,
the responses to an intravenous glucose overload did not differ between chagasic patients and controls
(40). These facts suggest that rapid monosaccharide absorption may occur in Chagas' disease, explaining
the abnormalities observed when an overload of these substances was administered orally. Another
possibility could be that the rapid gastric emptying of the test solution immediately after ingestion may
expose the proximal small bowel to an excessive amount of monosaccharide, forcing rapid absorption.
Favoring this hypothesis, it was demonstrated that an accelerated emptying of the liquid contained in the
gastric cavity occurs probably due to the loss of the ability of the chagasic stomach to accommodate to
distention (41).
In order to test directly the absorption ability of the proximal small bowel of chagasic patients, the method
of continuous intestinal perfusion with indicators of variation in dilution was used. Glucose solutions of four
different increasing concentrations (0.5, 1.0, 2.5, and 5.0%) were infused at a constant flow through a tube
placed in the distal duodenum or proximal jejunum over a standardized period of time, and samples were
collected 30 cm downstream from the point of infusion. This permitted an estimate of the amount of
glucose absorbed between the two points and the data obtained were used to construct a dose-response
type of curve. The intestinal segment under study in chagasic patients with an abnormal GTT was found to
show kinetic characteristics indicating a greater capacity for glucose transport (greater Vmax), but less
affinity (greater Km) than controls (39,42). Thus, an epithelium with a greater absorption capacity,
permitting monosaccharide hyperabsorption may explain, at least in part, the abnormal GTT of chagasic
patients. It has been proposed that this dysfunction in glucose absorption may be determined by the
intramural denervation of the small bowel demonstrated in Chagas' disease (39,42).
The 131I oleic acid test used at the time to study lipid absorption showed low radioactivity curves in blood
after ingestion in 30% of the chagasic patients studied. Considering that most of these patients showed
normal gastric emptying as evaluated by a radiological method, it was concluded that the disease may
cause a slow lipid absorption but without affecting the total amount absorbed since fecal radioactivity was
normal (43). Intestinal absorption was later studied in chagasic patients by the intrajejunal administration
of 131I oleic acid. Since no differences in results were observed between chagasic patients and controls, it
was concluded that the abnormalities observed in the oral test were probably due to delayed gastric
emptying of the test meal ingested (44).
The mucosa of the small bowel contains cells whose function is to secrete peptides having the most varied
regulatory actions both locally and at a distance. Intramural denervation would be expected to have some
effect on this secretion. However, it was observed that chagasic patient with clear impairment of the
digestive tract shown by megaesophagus, did not present any abnormality in motilin, enteroglucagon or
gastric inhibitor peptide levels either under basal conditions or after stimulation by and oral or intravenous
glucose overload or by insulin hypoglycemia (45). I another study on this same type of patients, no
changes in cholecystokinin, motilin or enteroglucagon levels were detected in the basal state or after
intravenous administration of secretin associated or not with duodenal instillation of phenylalanine (46).
IV - Clinical manifestations and diagnosis
The clinical manifestations of chagasic enteropathy occur after the development of dilatation of one or
more of the anatomical segments of the small bowel, They are almost always associated with concomitant
symptoms of megaesophagus and/or megacolon. The presence of only motor or absorptive dysfunction of
the small bowel, detectable by special tests, does not seem to be sufficient to provoke symptoms or signs
of significance to the patient. There is no systematic description of the manifestations of small bowel
"megas". Investigators of the digestive form of Chagas' disease have reported only few personally
observed cases (18,47,48); particularly outstanding in this respect is the report by Raia et al. (17) on 11
cases of megaduodenum.
There is a wide gamut of clinical expressions of ectasic chagasic enteropathy, ranging from the absence
of symptoms, with detection only by radiological examination indicated for other purposes, to signs and
symptoms belonging to at least three types of syndromes: dyspeptic syndrome, intestinal pseudoobstruction syndrome, and bacterial overgrowth syndrome of the small bowel. It may be stated that clinical
manifestations tend to be more expressive and severe the greater the extent of dilation of the small bowel.
Within the dyspeptic picture, patients with "megas" of the small bowel may present a sensation of
postprandial fullness and discomfort in the epigastrium (18,48). Pain, which is not always present, may
vary in intensity and type and may occur during the early or late postprandial period. Raia et al. (17,47)
pointed out that the clinical picture of megaduodenum can be that of gastric stasis of a progressive nature,
characterized by vomiting of food ingested many hours before, dehydration, epigastric pain and visible
gastric peristalsis, and lesions of the duodenal and gastric mucosa, and includes the possibility of bleeding
and even stomach rupture. Another important complication is represented by esophageal mucosa injuries
due to prolonged contact with material stagnating in the stomach, with reflux into the esophagus. In a case
observed by us, reflux disease was present in a particularly severe form since it was facilitated by a
previous surgical intervention in the cardia for the treatment of megaesophagus. It should be remembered
that gastric stasis in the absence of small bowel dilation in chagasic patients may be due to gastropathy of
the same etiology (47,49).
As previously mentioned, cases of megajejunum are rare. In the few cases we observed, the condition
was always associated with megaduodenum. Megajejunum has also been reported to occur separately or
associated with megaileum (18,47,48). Patients with megajejunum may be asymptomatic or may present
well defined clinical signs and symptoms such as intestinal pseudo-obstruction associated or not with
syndrome of bacterial overgrowth in the small bowel. Abdominal distention, the presence of continuous
pain or of cramps, the visible peristalsis, the intestinal constipation and the detection of fluid levels in small
bowel loops by simple abdominal radiography in the orthostatic position are the elements composing the
picture of pseudo-obstruction of the small bowel. The occurrence of continuous chronic diarrhea or of
diarrhea alternating with periods of intestinal constipation or other symptoms of pseudo-obstruction
suggests a diagnosis of bacterial overgrowth in the small bowel. This hypothesis is reinforced when there
is evidence of intestinal malabsorption such as weight loss and clinical and laboratory signs of steatorrhea,
anemia or hypocalcemia. The diagnosis of bacterial overgrowth may be confirmed by the demonstration of
strictly anaerobic bacteria in the upper portions of the small bowel, where they are not normally found, or
by the increased number of colonies in duodenal aspirates (35,48,50). The hydrogen test may also
indicate the presence of bacterial overgrowth by the early elevation of the content of this gas in expired air
collected at regular intervals after the ingestion of 180 ml of a 10% lactulose solution (35). The presence of
a high hydrogen rate in expired air when the patient is still fasting also indicates the syndrome of bacterial
overgrowth of the small bowel (35). Complete remission of diarrhea and general clinical improvement of
the patient with antibiotic treatment may be considered a positive diagnostic test for the syndrome (35).
The patient with megaileum described by Santos et al. (25) presented chronic diarrhea, abdominal
distention and signs and symptoms of intestinal subocclusion resolved by clinical treatment. In summary,
clinical manifestations similar to those of megajejunum.
The diagnosis of dilation of small bowel segments due to Chagas' disease is confirmed by standard
radiological examination of the stomach and duodenum or of the entire small bowel. This examination
permits the identification of the megabulb or of other segmental dilations of the duodenum, the
megajejunum, megaileum, and total dilation of the small bowel (Figure 3). These examinations are also
useful for the obligatory differential diagnosis with organic causes of intestinal obstruction. Endoscopic
examination is indicated for the diagnosis of changes in the mucosae of the esophagus, stomach and
duodenum consequent to stasis, which may range from inflammation to ulcer and bleeding, and may also
aid the differential diagnosis with organic causes of stomach and duodenum obstruction. It may also
indicate the diagnosis of megaduodenum.
Figure 3 - Contrast radiographs of the proximal small bowel of a patient with megacolon and chronic diarrhea. The megaduodenum
can be observed on the left, as well as the mark of compression exerted by the superior mesenteric artery on the third portion of
the organ. Dilation of jejunal loops and contrast retention can be seen on the right, since the radiograph was taken 90 minutes after
the ingestion of a barium suspension. The patient presented the bacterial overgrowth syndrome.
For an etiological diagnosis it is indispensable to confirm serologically the presence of Chagas' disease by
immunofluorescence or by any other tests with good performance. The epidemiological antecedents, the
concomitant presence of megaesophagus and/or megacolon or of electrocardiographic changes
compatible with Chagas' heart disease are other elements that should be considered in order to establish
an etiologic diagnosis.
V - Treatment
When the patient only shows dyspeptic signs and symptoms, treatment may be limited to dietary
adjustments, especially with the recommendation of bland meals free of substances that irritate the
mucosae, reduction of the amounts of fatty foods, meals of small volume, and good food mastication.
Although the efficacy of prokinetic medications in these pathological conditions is unknown, the use of
domperidone at habitual doses could be attempted. In the presence of reflux esophagitis, proton pump
inhibitors are indicated even for continuous use, the same applying to the presence of marked gastritis or
duodenitis.
Surgical treatment of megaduodenum is reserved for cases in which stasis is clinically important and
consists of duodenojejunal anastomosis close to the duodenojejunal angle, this being the type of
operation most frequently used by Raia (17). Rezende (18) pointed out that surgical treatment should be
indicated only in cases in which the symptoms are unequivocally due to the megaduodenum and not only
on the basis of radiological findings.
In cases of megajejunum or megaileum, partial enterectomy is indicated as long as the respective dilated
segments are not extensive (18). The operations, however, should be avoided when long segments of the
small bowel are dilated. In these cases, clinical treatment of the obstructive episodes should be instituted,
with interruption of oral feeding, continuous gastric aspiration, correction of dehydration and of electrolyte
disorders and, eventually, the use of total parenteral nutrition (18,48).
The bacterial overgrowth syndrome of the small bowel should be treated with antimicrobial drugs
(tetracycline, chloramphenicol, cephalosporine, metronidazole, etc.), usually at similar or even lower doses
than those used for the treatment of infectious processes, for 3 or 4 weeks. Bacterial sensitivity tests do
not always indicate the best antibiotic for each case. Since the motor abnormality is persistent, the
periodic use of antimicrobial agents may be necessary. If the picture is not resolved with a given antibiotic,
indicating bacterial resistance, it is necessary to switch to another one. Associated nutritional disorders
due to the malabsorption provoked by bacterial overgrowth should also be corrected.
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microscópio eletrônico. Rev. Inst. Med. Trop. São Paulo 1971; 13: 76-91.
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disease. Dig. Dis. Sci. 1983; 28: 294-299.
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megajejunum. XXIII Congresso Panamericano de Enfermedades Digestivas, Buenos Aires, Argentina, 1993.
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Gastroenterology 1995; 108: A592,
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35 - Aprile LRO, Troncon LEA, Meneghelli UG. Síndrome do supercrescimento bacteriano no intestino delgado no megajejunum chagásico.
Arq. Gastroenterol. S ão Paulo 1995; 32: 71-78.
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Rev. Goiana Med. 1960; 6: 155-165.
37 - Meneghelli UG, Reis LCF. Estudos sobre o metabolismo dos hidratos de carbono na mol éstia de Chagas. III. A prova de sobrecarga
oral de galactose. Rev. Assoc. Med. Brasil. 1967; 13: 3-10.
38 - Meneghelli UG, Vieira CB, Padovan W et al. O teste da d -xilose na moléstia de Chagas. Arq. Gastroenterol S ão Paulo 1971; 8: 191198.
39 - Meneghelli UG. Estudos sobre a absorção intestinal de glicose, xilose e ácido oléico 131I na forma crônica da moléstia de Chagas.
Tese. Faculdade de Medicina de Ribeir ão Preto (USP), Ribeirão Preto, 1969.
40 - Meneghelli UG, Reis LCF, Vichi FL, Lima Filho EC. Estudos sobre o metabolismo de hidratos de carbonio na mol éstia de Chagas. IV.
Provas intravenosas de tolerância à glicose e à tolbutamida. Rev. Paul. Med. 1969; 75: 281 - 288.
41 - Oliveira RB, Troncon LEA, Meneghelli UG et al. Impaired gastric accomodation to distension and rapid gastric emptying in patients with
Chagas' disease. Dig. Dis. Sci. 1080; 25: 790-794.
42 - Meneghellli UG, Padovan W, Lima Filho, EC et al. Intestinal absorption of glucose in chronic Chagas' disease studied by the continuous
perfusion technique. Arq. Gastroenterol. São Paulo 1971; 8: 109-118.
43 - Meneghelli UG, Iazigi N, Vieira CB, Padovan W, Godoy RA. O teste do ácido oléico 131I na forma crônica da moléstia de Chagas. Rev.
Goiana Méd. 1972; 18: 75-90.
44 - Oliveira RB, Meneghelli UG, Padovan W et al. A absorção intestinal do ácido olêico 131I administrado por via intrajejunal em
chagásicos cr ônicos. Rev. Goiana Med. 1978; 24: 1-16.
45 - Long RG, Albuquerque RH, Prata A et al. Response of plasma pancreatic and gastrointestinal hormones to oral and intravenous
glucose and insulin hypoglicemia in Chagas' disease. Gut 1980; 21: 772-777.
46 - Mott CB, Guarita DR, Sipahi AM et al. Horm ônios gastroenteropancre áticos em portadores da doença de Chagas crônica. Rev. Hosp.
Cli. Fac. Med. S. Paulo 1989; 44: 63-72.
47 - Raia AA, Gama-Rodrigues JJ. Megaduodenum. In Manifesta ções digestivas da mol éstia de Chagas. AA Raia, ed., Sarvier, São Paulo,
1983, pp 191-202.
48 - Troncon LEA. Doen ça de Chagas: enteropatia. In Tópicos em Gastroenterologia 2. LP Castro, PRS Rocha, AS Cunha, ed., Medsi, Rio
de Janeiro, 1991, pp. 229-244.
49 - Vieira CB, Godoy RA, Meneghelli UG. Gastropatia chagásica crônica: novas perspectivas de diagnóstico. Rev. Assoc. Méd. Brasil.
1969; 15: 383 -384.
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Ulysses G. Meneghelli
E. mail: [email protected]
Fax 55.16.633-6695
Postal: Avenida Sumaré 414
14025-450 - Ribeirão Preto (SP)
Brasil
Tope
Chagas Digestivo
Gimenez Luisa; Mitelman Jorge
Hospital de Agudos Dr.Teodoro Alvarez. Servicio de Cardiología. Sector Chagas
La enfermedad de Chagas, endemia que afecta, según estimaciones de la OMS, a 3 millones de
personas en Argentina, de las cuales 500 mil son enfermos y el resto son portadores sanos, aunque
potencialmente algunos de ellos puedan presentar alguna patología con los años, no hay elementos que
permitan definir quienes la desarrollarán.
Sabemos que existen factores que involucran a las caracteristícas concernientes al parásito, como es el
tropismo, polimorfismo, virulencia, número de inoculaciones, cepa, y otros referidos a la raza, constituci ón
genética del individuo, edad, reacción inmunológica y nutrición.
La distribución del Chagas ha cambiado en los últimos años por las permanentes migraciones, de forma
tal que también se han modificado las características del mismo. Lo que antes se consideraba no
caracteristico de la enfermedad de Chagas, como la hipertensi ón arterial y la coronariopat ía, -por
ejemplo- son hoy patologías que se asocian con cada vez más frecuencia con la tripanosomiasis, al
modificarse el estilo de vida de los pacientes que se trasladaron a las grandes ciudades en busca de
trabajo. Asimismo en estos últimos años se empezaron a detectar patologías no propias de la región
como son las megavisceras digestivas (megaes ófago, megacolon, megaves ícula), urinarias, como
megauréter y megavejiga, que no se observaban en la Argentina, donde el Tripanosoma cruzi presentaba
tropismo por el coraz ón lo que se traduce por cardiomegalia. Hoy se encuentran estas visceromegalias
solas o asociadas.
En un hospital (servicio de Cirugía) de la zona sur del país (Viedma, Pcia. de Río Negro) se internó en un
periodo de 10 años a 39 pacientes residentes durante toda su vida en este lugar, con diagn óstico de
megacolon, de los cuales 22, tenían serología positiva para Chagas y 7 tenían cardiomegalia.
A partir de estas y otras observaciones es que decidimos valorar la prevalencia de esta patología en área
no endémica, encontrando el el término de dos años (1997-1998) sobre un número de 194 pacientes con
edad promedio de 48 años, oriundos de provincias de alta endemicidad. como Jujuy, Santiago del Estero
y Chaco:
1 megacolon sin cardiopat ía y 1 con cardiopat ía asociada; 4 pacientes con colecistectomia
(megaves ícula) sin cardiopat ía;1 megaesófago único; 4 cardiopatas con disfunción en tránsito
esofagoduodenal tratados por gastroenterólogos.
Con respecto a la fisiopatogenia de esta nosología que lleva a la dilataci ón de los órganos del aparato
digestivo con compromiso del tránsito normal, se conoce que existe parasitación de las células de la
cápsula de los ganglios de Auerbach y Meissner, las células de Shwann y c élulas musculares lisas y
estriadas.Todo esto conduce a una denervaci ón neurovegetativa comprobada por Koberle en 1959. Las
condiciones de los "megas" digestivos resultan de la destrucci ón masiva de neuronas en el plexo
mienterico durante la infección aguda y la incapacidad de las neuronas de regenerarse. Los órganos
megas se observan durante la vida adulta, cuando se presume que la pérdida fisiológica de neuronas en
un plexo ya dañado, alcanza niveles críticos apareciendo severa disperistalsis y una mayor dilatación de
los órganos.
El megaesófago es la patolog ía más frecuente siguiendole el megacolon en orden de detección; sin
embargo existen formas leves de disfunción digestiva en gran porcentaje de los pacientes que no
muestran patología manifiesta en los estudios del aparato digestivo habituales.
Frente a un megaesófago o megacolon debemos descartar su probable etiología chagásica, teniendo
presente que se manifiesta después de los 30 años (el megacolon no chagásico, es de origen congénito,
enfermedad de Hirschprung), sin predominio del sexo masculino y procedencia de zona endémica, lo que
se debe confirmar con la detección de serolog ía positiva para Chagas (Hemaglutinacion, Test de
inmunofluorescencia y Elisa).
Puede además. el megacolon aparecer asociado a megaesofago.
Con respecto a la sintomatología, el individuo debuta a través de las complicaciones (v ólvulo del
sigmoides y el fecaloma) que son recibidos por los servicios de cirugía o guardia, como una urgencia, no
siendo registrado su origen etiológico una vez resuelta la situación quirúrgica.
Existen distintas etapas que conducen a la dilatación comenzando con un alargamiento de la viscera
(Dolico) y las complicaciones son como señalarámos, el fecaloma, la impactación fecal y el vólvulo del
sigmoides. Sin embargo existen formas leves de disfunci ón digestiva que son controladas por
especialistas de servicios de gastroenterología, caracterizadas por constipación lentamente progresiva
que conducen a la dilatación. Los estudios con sustancias radiopacas solo evidencian visceromegalias
importantes, sin tener presente que la denervación de los plexos del tubo digestivo ocacionaría trastornos
de la absorción, motilidad y secrec íón pudiendo alcanzar distintos grados, de acuerdo a la magnitud de la
misma.
Si bien la literatura muestra una baja prevalencia de megas, esto es dificil de conocer por la dificultad del
estudio radiológico a realizar y por la ausencia de pesquisa por parte de los profesionales de la salud que
involucran no sólo al cardiológo sino a otras especialidades .
El tratamiento puede ser cl ínico o quirúrgico: el primero consiste en medidas higiénico-dieteticas (dietalavajes) para los casos cuya única expresión clinica es una constipaci ón de mediana importancia y para
evitar el fecaloma; los casos más graves, especialmente si han presentado alguna de las complicaciones
señaladas, son pasibles de tratamiento quirurgico. Son conocidas innumerables técnicas quirúrgicas,
siendo la de mejores resultados la de Duhamel para megacolon. Sin embargo en etapas avanzadas no
existe tratamiento promisorio siendo la única perspectiva positiva la prevención.
Como toda la patología que envuelve esta dolorosa enfermedad, el profesional no puede aportar
tratamientos eficaces, lo que conduce irremediablemente a su desinterés y a que el paciente conviva con
su dolencia sin encontrar solución adecuada.
Otras imágenes
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