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U N I T 8
Gastrointestinal and Hepatobiliary Function
be confirmed by esophageal pH probe studies or barium
fluoroscopic esophagography. In severe cases, esopha-
goscopy may be used to demonstrate reflux and obtain
a biopsy.
Various treatment methods are available for infants
and children with gastroesophageal reflux. Small, fre-
quent feedings are recommended because of the asso-
ciation between gastric volume and transient relaxation
of the esophagus. Thickening an infant’s feedings with
cereal tends to decrease the volume of reflux, decrease
crying and energy expenditure, and increase the calo-
rie density of the formula.
13
In infants, positioning on
the left side seems to decrease reflux. In older infants
and children, raising the head of the bed and keeping
the child upright may help. Medications usually are not
added to the treatment regimen until pathologic reflux
has been documented by diagnostic testing. Antacids
are the most commonly used antireflux therapy and are
readily available over the counter. H
2
-receptor antago-
nists and proton pump inhibitors may be used in chil-
dren with persistent reflux. Prokinetic agents (e.g.,
metoclopramide, a dopamine-2 and 5-hydroxytrypta-
mine [5-HT
3
] receptor antagonist; bethanechol, a cho-
linergic agonist) may be used in selected cases.
Cancer of the Esophagus
Worldwide, the incidence of esophageal cancer var-
ies widely, undoubtedly reflecting environmental and
dietary influences. It is relatively uncommon in the
United States, accounting for about 2% of cancer
deaths.
7
There are two types of esophageal cancer: ade-
nocarcinoma and squamous cell carcinoma.
6,7,15
Adenocarcinomas typically arise in a background of
Barrett esophagus and long-standing GERD. They usu-
ally occur in the distal third of the esophagus and may
invade adjacent areas of the stomach. Risk of adenocar-
cinoma is greater in those with documented esophageal
dysplasia and is further increased by tobacco use, obe-
sity, and prior radiation therapy. Esophageal carcinomas
occur more frequently in Caucasians and are seven times
more common in men than women.
6
Molecular stud-
ies have suggested that the pathogenesis of adenocar-
cinoma from Barrett esophagus is a multistep process,
with the development of dysplasia being a critical step
in the process.
6
Thus, endoscopic surveillance of persons
with Barrett esophagus provides the means for detect-
ing adenocarcinoma at an earlier stage, when it is most
amenable to curative surgical resection.
15
In contrast to adenomas, squamous carcinomas tend to
occur in the middle of the esophagus. Risk factors include
alcohol and tobacco use, esophageal injury, achalasia, and
frequent consumption of very hot beverages.
6
The regions
with the highest incidences are Iran, central China, Hong
Kong, Brazil, and South Africa.
6
The majority of esopha-
geal squamous carcinomas in Europe and the United
States are at least partially attributable to alcohol and
tobacco use. However, this form of cancer is also common
in areas where alcohol and tobacco use are uncommon.
Thus, nutritional deficiencies, as well as polycyclic
hydrocarbons, nitrosamines, and other mutagenic com-
pounds such as those found in fungus-contaminated food
may be important contributing factors.
6
Dysphagia is by far the most frequent complaint of
persons with esophageal cancer. It is apparent first with
ingestion of bulky food, later with soft food, and finally
with liquids. Unfortunately, it is a late manifestation of
the disease. Unintentional weight loss, anorexia, fatigue,
and pain on swallowing also may occur.
Treatment of esophageal cancer depends on tumor
stage.
15
Surgical resection provides a means of cure
when done in early disease and palliation when done in
late disease. Radiation may be used as an alternative to
surgery. Chemotherapy may be used before surgery to
decrease the size of the tumor or it may be used along
with irradiation and surgery in an effort to increase
survival. The prognosis for persons with cancer of the
esophagus, although poor, has improved. Even with
modern forms of therapy, however, the long-term sur-
vival is limited because, in many cases, the disease has
already metastasized by the time the diagnosis is made.
SUMMARY CONCEPTS
■■
The esophagus is a fixed muscular tube through
which swallowed food and liquids move as they
pass from the pharynx to the stomach. Dysphagia
refers to difficulty in swallowing; it can result from
altered neuromuscular function or from disorders
that produce narrowing of the esophagus.
Achalasia is an incomplete relaxation of the lower
esophageal sphincter during swallowing.
■■
A diverticulum of the esophagus is an
outpouching of the esophageal wall caused by a
weakness of the muscularis layer.
■■
Hiatal hernia is characterized by a protrusion or
herniation of the stomach through the esophageal
hiatus of the diaphragm.There are two anatomic
patterns of herniation: the sliding or more
common type, in which there is a bell-shaped
protrusion of the stomach above the diaphragm,
and the paraesophageal hernia, in which a
portion of the stomach enters the thorax through
a widened opening.
■■
Gastroesophageal reflux refers to the backward
movement of gastric contents into the esophagus,
a condition that causes heartburn. Persistent
reflux of gastric contents into the esophagus can
result in a condition called gastroesophageal
reflux disease (GERD). Complications of GERD,
which result from erosion and/or irritation of
the mucosal surface of the esophagus, include
esophagitis, strictures of the esophagus, and
Barrett esophagus.
