Download 5._Malabsorption

Malabsorption
Dr. Adnan Hamawandi
Professor of Pediatrics
Malabsorption
Malabsorptive disorders are conditions that
cause insufficient assimilation of ingested
nutrients as a result of either maldigestion or
malsbsorption.
Malabsorption
Causes
Generalized defect: present with similar
signs and symptoms; abdominal distention;
pale, foul smelling, bulky stools; muscle
wasting; poor weight gain or weight loss; and
growth retardation.
A. Exocrine pancreas: cystic fibrosis,
chronic pancreatitis, chronic protein calorie
malnutrition, Shwachmann-Diamond
syndrome.
Malabsorption
B. Liver: biliary atresia, familial neonatal
hepatitis, other cholestatic states.
C. Intestine: massive resection, giardiasis,
celiac disease, cow milk protein intolerance,
immune deficiency, tropical sprue.
Specific defect: the clinical features of
these disorders typically differ from those of
generalized malabsorptive disorders, some
present without gastrointestinal disorders.
Malabsorption
A. Intestinal: abetalipoproteinemia, Hartnup
disease, disaccharidase deficiency, vit.B12
malabsorption, glucose - galactose
malsbsorption, Chloride losing diarrhea,
acrodermatitis enteropathica.
B. Drug induced: sulfasalazine(folate),
phenytoin (Calcium)
C. Pancreatic: Specific enzyme deficiency
like lipase, trypsinogen.
Celiac disease
Gluten sensitive enteropathy
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Environmental, genetic, and immunologic
factors, some of which are clear and others
that are only now beginning to come into
focus, are important in the pathogenesis of
celiac disease.
The disease activating proteins in wheat, rye,
and barely widely termed Glutens.
Celiac disease is strongly associated with
HLA class II genes on DQ locus. DQ2 &DQ8.
Celiac disease
Gluten sensitive enteropathy
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When susceptible individuals ingest gluten,
the antigen presenting cells can potentially
bind the gluten peptides and present them to
DQ2 or DQ8 restricted CD4+ T cells in the
small intestinal mucosa. The later release
gamma interferon and activate the release of
metalloproteinases that can damage the
intestinal mucosa.
Celiac disease
Clinical features
Most children show symptoms between nine
and 24 months , but the condition may occur
at any age. Malabsorption causing diarrhea,
failure to thrive, abdominal distention, and
muscle wasting is the classic presentation.
Also seen are vomiting, anorexia, irritability,
isolated abdominal distention, short stature,
unexplained iron deficiency anemia, rickets,
glossitis and angular stomatitis.
Celiac disease
Diagnosis
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Serological screening: antiendomyseal IgA
and IgG antibodies are recommended.
Antigliadin and Antireticulin antibodies can
also be of help.
If serological screening is positive a small
bowel biopsy should be performed.
Demonstration of inflammation, villous
atrophy and crypt hyperplasia is consistent
with the diagnosis. ”Marsh classification”
Celiac disease
Therapy
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Dietary: Life long provision of gluten free diet.
All wheat, rye, and barely should be
eliminated from the diet.
Initially while small intestinal mucosa heal,
restriction of lactose as well as vitamin and
iron supplementation may be necessary.
Improvement of mood and appetite is
followed by lessening of diarrhea usually
within 1 week of starting therapy.
Celiac disease
Prognosis
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Diabetes mellitus, IgA deficiency, and other
autoimmune disease have high incidence
among celiac patients.
The late development of bowel lymphoma in
long standing cases with poor adherence to
diet is possible.
No complications from long term gluten free
diet treatment are recognized.
Cow milk protein allergy
The precise mode by which cow’s milk
protein cause disease is unknown.
Sensitization may occur de novo or after a
bout of acute infectious enteritis.
Variable mucosal abnormalities may be found
in the stomach, small bowel, and colon.
Infants who are sensitive to cow’s milk protein
may also be sensitive to soy protein.
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Cow milk protein allergy
Clinical features
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Most symptoms develop in the first 3
months of life. 1. Diarrhea and vomiting are
the most common and if prolonged lead to
failure to thrive. 2. Rectal bleeding may be
seen if allergic colitis occur. 3. Edema
secondary to protein losing enteropathy,
often associated with anemia. 4. Wheezing,
rhinorrhea, and eczema may occur.
Cow milk protein allergy
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Diagnosis is usually made empirically once
symptoms resolve after elimination of cow’s
milk.
Therapy: elimination of cow’s milk from the
diet is usually curative although severely
affected infants may take weeks or months to
recover and may require IV alimentation until
the intestinal mucosa heals.
Lactose intolerance
Lactase deficiency
Lactose enzyme located on the brush
border membrane of the small bowel
epithelial cells, hydrolyses lactose into
glucose and galactose before their
absorption.
If this hydrolysis is incomplete the sugar will
accumulate in the distal intestinal lumen
where organic acids and hydrogen gas are
produced by bacteria.
Lactose intolerance
Lactase deficiency
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The excess intraluminal sugar and organic
acids draw water into the lumen leading to
osmotic diarrhea.
Lactase deficiency is a common cause of
diarrhea in childhood. Congenital absence of
lactase is rare while acquired lactase
deficiency is usually secondary to a diffuse
mucosal disease like infectious diarrhea or
celiac disease.
Lactose intolerance
Clinical manifestations
In response to ingestion of lactose (milk)
Explosive watery diarrhea is associated with
abdominal distention, borborygmi, flatulence,
cramping abdominal pain, and an excoriated
diaper area.
Lactose intolerance
Diagnosis
1. Breath hydrogen testing; is the most
accurate diagnostic test.
2. Stool PH; less than 5.6 and presence of
reducing substance + 2 and more suggest
carbohydrate malabsorption.
3. Intestinal biopsy; Direct assay of brush
border enzyme activity.
Lactose intolerance
Therapy
1. Elimination of cow’s milk and substitution
by lactose free milk.
2. Lactaid is a lactase preparation when
added to milk it allows asymptomatic
consumption of modest quantities of milk
incubated with the added enzyme.