Encyclopedia of Health and Medicine

C
cecum The first segment of the COLON (large
intestine) into which the ILEUM, the final segment
of the SMALL INTESTINE, empties digestive matter.
The cecum is a pouchlike structure located in the
lower right abdomen that absorbs water from the
waste, returning fluid to the body and consolidating
the waste for its journey through the end stage
of digestion. The rhythmic contractions of PERI-
STALSIS move the remaining solid waste into the
remainder of the colon. The APPENDIX extends from
the bottom of the cecum.
For further discussion of the cecum and the
colon within the context of gastrointestinal structure
and function, please see the overview section
“The Gastrointestinal System.”
See also ANUS; RECTUM.
celiac disease A condition affecting the SMALL
INTESTINE in which consuming foods that contain
gluten, a plant protein prominent in wheat, triggers
an inflammatory response that prevents the
intestinal mucosa (lining) from absorbing NUTRI-
ENTS. Gluten, and more specifically proteins it contains
called gliadins, acts as an ANTIGEN to initiate a
localized IMMUNE RESPONSE. Researchers believe
celiac disease has a genetic foundation, though the
specific GENE or genes responsible remain undetermined.
Though severe celiac disease can cause significant
NUTRITIONAL DEFICIENCIES that affect growth,
FERTILITY, and overall health, most people who
adopt a gluten-free diet are able to avert the
inflammatory episodes and minimize damage to
the intestinal mucosa. About 1 in 5,000 Americans
has celiac disease.
Symptoms and Diagnostic Path
Symptoms appear in celiac disease with exposure
to gluten, so usually do not become apparent until
21
after the age of two years when children begin
eating solid foods. People who have celiac disease
experience a broad range of symptoms, with some
people having virtually no indications they have
celiac disease until nutritional deficiencies become
problematic and other people suffering chronic
DIARRHEA, cramping, ABDOMINAL
DISTENTION, and
other gastrointestinal disruptions. Some people
have outbreaks of DERMATITIS herpetiformis, an
itchy SKIN RASH. An early indication of celiac disease,
especially in children, is the passing of large,
loose, light-colored, foul-smelling stools, which
suggests high fat excretion (STEATORRHEA) characteristic
of MALABSORPTION.
Celiac disease may affect any or all of the segments
of the small intestine, and the degree to
which it affects them determines the symptoms.
Many of the symptoms and signs of celiac disease
arise from health problems due to nutritional deficiencies
that correlate to the segment of small intestine
affected, manifesting in conditions such as
ANEMIA (deficiency of iron, suggesting involvement
of the DUODENUM and upper JEJUNUM) and frequent
nosebleeds (deficiency of VITAMIN K, suggesting
involvement of the lower jejunum and the ILEUM).
Children who have celiac disease may also appear
malnourished, showing spindly limbs and protruding
bellies, despite adequate food consumption.
Biopsy of the intestinal mucosa in people who
have celiac disease tends to show marked structural
differences from normal intestinal mucosa.
Most significant is flattening of the mucosal tissue
from its normal “pleated” appearance, which
reduces the surface area available for nutrient
absorption. Lymphocytes and leukocytes are also
present within the mucosal tissue, evidence of the
inflammatory process. However, there are no
definitive tests to diagnose celiac disease. BLOOD