The Digestive system
L.3
Malabsorptive Disorders
Dr.Ghada Mansoor
Gluten-Sensitive Enteropathy (Celiac Disease)
It is an immune-mediated enteropathy caused by permanent sensitivity to gluten in
genetically susceptible individuals, in which the proximal small bowel mucosa is damaged
as a result of dietary exposure to gluten.
The most common period of presentation is between 6 mo and 2 yr of age.
Pathogenesis
Celiac disease develops only after dietary exposure to the protein gluten, which is found in
wheat, rye, and barley.
Oats???
A genetic predisposition is suggested by concordance in monozygotic twins approaching
100%.
An increased prevalence of gluten-sensitive enteropathy has been noted in children with
selective IgA deficiency, diabetes mellitus, chronic rheumatoid arthritis, thyroiditis,
hypothyroidism, Addison disease, pernicious anemia, alopecia, and Down syndrome.
Clinical Manifestations
Intestinal symptoms are common in children within the 1st 2 yr of life; failure to thrive,
chronic diarrhea, vomiting, abdominal distention, muscle wasting, anorexia, and irritability
are present in most cases.
Occasionally there is constipation, rectal prolapse, or intussusception.
As the age at presentation of the disease shifts to later in childhood, extraintestinal
manifestations without any accompanying digestive symptoms become recognized,
affecting almost all organs.
The most common extraintestinal manifestation of celiac disease is iron-deficiency anemia,
unresponsive to iron therapy.
Rickets &osteoporosis (Calcium/vitamin D malabsorption)
Short stature, arthritis and arthralgia.
Epilepsy, peripheral neuropathies, hypotonia, & cerebellar ataxia (Thiamine/vitamin B12
deficiency).
Ecchymoses and
,
nodosum(autoimmunity)
Dermatitis herpetiformis, alopecia, erythema
.
Edema (Hypoproteinemia)
petechiae (Vitamin K deficiency),
Weakness
Aphthous stomatitis.
Digital clubbing.
Pancreatic insufficiency
Amenorrhea, infertility.
,
Delayed puberty
Silent celiac disease:
No apparent symptoms in spite of histologic evidence of villous
atrophy. In most cases identified by serologic screening in at-risk groups.
Potential celiac disease: Subjects with positive celiac disease serology but without evidence
of altered jejunal histology.
Screening and Diagnosis
1. CBP: mild dimorphic anemia (iron deficiency with microcytic anemia & rare, a macrocytic
megaloblastic anemia); the blood smear may show target cells, Howell-Jolly bodies, & Heinz
bodies.
2. Hypoproteinemia, Hypoprothrombinemia can occur as a result of malabsorption.
3. Serologic markers:
The anti-endomysium IgA antibody and anti-tissue transglutaminase IgA & IgG antibody
tests are highly sensitive and specific.
*Antiendomysial antibodies, the sensitivity is nearly 100%, and the specificity is around
98%.
The tTG IgA assay has a specificity of 95-98% and a sensitivity of 92-94%.
4. Small Intestinal Biopsy
At least 4 fragments should be obtained from the descending part of the duodenum and at
least 1 from the duodenal bulb.
The characteristic histologic changes include partial or total villous atrophy, crypt
elongation, increased number of intraepithelial lymphocytes.
Small bowel biopsy returned to normal within 1-2 yr after starting a gluten-free diet
For children younger than 2 yr, and when the diagnosis is in question, a rechallenge is
recommended. This necessitates three biopsies: an initial biopsy at presentation, the 2nd to
document healing with gluten withdrawal, and the 3rd to show recurrent damage with
reintroduction of gluten.
Treatment
1. Lifelong, strict gluten-free diet. All wheat, rye, and barley products should be eliminated
from the diet (pure oats usually safe).
2. Vitamin and iron supplementation.
3. Pancreatic enzyme treatment: improve poor weight gain in the first months after
diagnosis.
*Celiac disease can also present as severe diarrhea, weight loss, hypocalcemia, and
hypoproteinemia, a condition known as a celiac crisis. Treatment of a celiac crisis is
supportive and includes the use of corticosteroids.
Osteopenia is usually reversed with a strict gluten-free diet.
Long-term complications:
Intestinal lymphoma, adenocarcinoma of the small intestine, of the pharynx, and of the
esophagus, especially with poor adherence to the strict gluten-free diet.
Non-Hodgkin
lymphoma is the main cause of death.
Constipation
A hard stool passed with difficulty every 3rd day.
Causes of Constipation
1. Nonorganic (functional)
2. Organic
*Anatomic: Anal stenosis, Imperforate anus
*Abnormal Musculature: Prune-belly syndrome, Down syndrome
*Intestinal Nerve abnormalities: Hirschsprung disease
*Spinal Cord Defects: Spinal cord trauma, Spina bifida
*Drugs: Anticholinergics, Narcotics, Lead
*Metabolic Disorders: Hypokalemia, Hypercalcemia, Hypothyroidism
*Intestinal Disorders: Celiac disease, Cystic fibrosis, Inflammatory bowel disease,
Cow's milk
protein intolerance
*Systemic lupus erythematosus, Anorexia nervosa.
Functional Constipation
(idiopathic constipation or fecal withholding)
It is associated with withholding behaviors, which may relate to social stressors or changes
in social situations. These often occur at the time of diet changes in infants and at the
initiation of toilet training for toddlers.
It is differentiated from constipation secondary to organic causes on the basis of a history
and physical examination.
History:
Functional constipation typically starts after the neonatal period.
The stool becomes firm,
smaller, and difficult to pass, resulting in anal irritation and anal fissure. Some children will
have a history of blood in the stool. Daytime encopresis is common.
Encopresis
:
involuntary fecal soiling in children. Occurs w
hen child's colon is full of
impacted stool, liquid stool can leak around the impacted stool and out of the anus,
staining the child's underwear.
Findings suggestive of underlying pathology include failure to thrive, weight loss, abdominal
pain, vomiting, or persistent anal fissure or fistula.
Physical examination: demonstrates a large volume of stool palpated in the suprapubic
area; rectal examination demonstrates a dilated rectal vault filled with a large fecal mass
.
Therapy for functional constipation
1. Patient education: regular bowel training program, including sitting on the toilet for 5–
10 min after meals,
2. Relief of impaction, and softening of the stool: If an impaction is present, an enema is
usually required to clear the impaction while bowel softeners are started as maintenance
medications.
Typical regimens include the use of polyethylene glycol preparations, glycerin
suppositories, lactulose (1 mL/kg/day – 3 mL/kg/day in divided doses), or mineral
oil.
3. Dietary modification
*A balanced diet that includes whole grains, fruits and vegetables is recommended.
*Carbohydrates (especially sorbitol) found in prune, pear and apple juices can cause
increased frequency and water content in stools.
*Adequate fluid intake with a bulking agent such as fiber.
2