Congenital malformations - Edocr

Chapter 33
Esophageal Atresia and
Tracheoesophageal Fistula
PRAVEEN KUMAR
INTRODUCTION
Esophageal atresia (EA) is defined as the absence
of an esophageal segment and is often associated
with tracheoesophageal fistula (TEF), which is an
abnormal communication between the lumen of
the trachea and the esophagus. The Gross classification
is commonly used anatomic classification
system for this malformation and describes
the following five major variations (Fig. 33-1). 1
1. Type A—lesions include isolated esophageal
atresia without TEF and are seen in nearly
8% of all infants with this malformation.
2. Type B—defects include EA with TEF between
proximal pouch of esophagus and trachea.
This defect accounts for less than 1% of lesions.
3. Type C—defects are most common and seen
in 85–90% of all infants with TEFs and include
EA with TEF between distal pouch of
esophagus and trachea.
4. Type D—defects are characterized by EA and
two TEF between trachea and both proximal
and distal esophageal pouches. These defects
account for nearly 1% of all cases.
5. Type E—defects are characterized by presence
of TEF without an EA and are also called
H-type fistula. These defects are seen in 2–5%
of all cases.
EPIDEMIOLOGY/ETIOLOGY
EA with or without TEF occurs in between
1:3000 and 1:4000 births with no reported secular
trends or seasonal variation. A higher incidence
of these malformations has been reported
in non-Hispanic whites and in pregnancies with
multiple births. A higher male to female ratio
(1.3:1), higher incidence of prematurity and
small for gestational age have also been reported.
2–4 It usually occurs sporadically with no
identifiable genetic predisposition. The reports
of familial occurrences and presence of coexistent
anomalies suggest the possibility of heritable
genetic factors, teratogens, and more widespread
defects of embryogenesis in some cases.
The etiology when not part of a multiple malformation
syndrome is thought to be multifactorial.
EMBRYOLOGY
The esophagus and trachea develop from the
foregut between third and fifth week of gestation.
It is widely believed that two lateral longitudinal
tracheoesophageal folds develop and
fuse to form tracheoesophageal septum, which
separates ventral trachea from dorsal esophagus.
Disruption of normal partitioning by the
217
Copyright © 2008 by The McGraw-Hill Companies, Inc. Click here for terms of use.