Nem’s Notes…
Phase 2 Year 2
GASTROENTEROLOGY 3 (page 1 of 4)
The Small Intestine
Coeliac Disease (also called Gluten-sensitive Enteropathy).
Epidemiology
(Coeliac Disease)
(a) Common in Europe
1 in 1500 (UK)
1 in 300 (Ireland)
(b) Rare in Black Africans
(c) Increased incidence (10-15%) in first-degree relatives
(d) Increased incidence (30%) in monozygotic twins
(e) Linked to specific HLA types (90% have HLA DQ2)
Therefore a mixture of genetic and environmental factors
Pathogenesis
(Coeliac Disease)
Pathology
(Coeliac Disease)
Uncertain pathogenesis and may be due to a variety of possible factors such as:
(a) Toxicity of α-Gliadin (a peptide product of gluten)
(b) Immunogenetic factors (due to high incidence with specific HLA types)
(c) Environmental factors (possibly a viral infection)
Affects the mucosa of the proximal small bowel, but decreasing in severity from
jejunum to ileum (since the gluten is broken down to smaller non-toxic fragments).
(a) Absence of villi at the mucosal surface
(b) Elongated crypts
(c) Chronic inflammatory cells found in lamina propria
Causes of
Subtotal (Flat)
Villous Atrophy
Partial (Convoluted)
Clinical
Features
(Coeliac Disease)
(a) Coeliac Disease
(b) Dermatitis Herpetiformis
(c) Zollinger-Ellison Syndrome (rare)
(d) Hypogammaglobulinaemia (rare)
(a) Tropical Sprue
(b) Giardiasis
Coeliac disease can present at any age. Symptoms are very variable & non-specific:
(a) Tiredness and malaise
(b) Diarrhoea or Steatorrhoea
(c) Abdominal discomfort or pain
(d) Weight Loss
(e) Intermittent Mouth Ulcers
(f) Intermittent Stomatitis
Rare complications might include tetany, osteomalacia, gross malnutrition with
peripheral oedema.
Increased incidence of atopy and autoimmune disease such as thyroid disease and
IDDM. Other associated diseases are inflammatory bowel disease, chronic liver
disease.
There are usually few physical signs and are related to anaemia and malnutrition.
Investigation
(a) Endomysial antibodies (IgA)
(Coeliac Disease)
(b) Jejunal biopsy
(c) Anti-reticulin antibodies
(d) Haematology
Antibodies very specific and sensitive to coeliac
disease and is carried out using
immunoflouresence on monkey oesophagus for
transglutamase antigen.
The mucosal appearance of the biopsy
is diagnostic for Coeliac Disease.
Antibodies also very sensitive but also present in
other GI diseases such as Crohn’s.
Mild/moderate microcytic or macrocytic anaemia
in 50% of cases
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Nem’s Notes…
Phase 2 Year 2
GASTROENTEROLOGY 3 (page 2 of 4)
The Small Intestine
Treatment
(Coeliac Disease)
Complications
(Coeliac Disease)
Malabsorption
The removal of gluten from diet results in rapid clinical and morphological
improvement in patients with Coeliac Disease.
(a) Intestinal lymphoma
(b) Ulcerative jejunitis
(c) Carcinoma
Malabsorption is the reduced absorption of food due to either:
(a) intraluminal maldigestion (deficiency of enzymes)
(b) mucosal malabsorption (due to decreased surface area)
(c) postmucosal lymphatic obstruction (prevents uptake due to lymphatic blockage)
SEE Gastroenterology 6 (page 2 of 5)
Protein Losing Excessive loss of protein into the gut lumen sufficient to cause hypoproteinaemia
Enteropathy
Causes: (a) With mucosal erosions/ulcerations
(i) Crohn’s Disease
(ii) Ulcerative Colitis
(iii) Oesophageal, Gastric, Colonic Ulcer
(iv) Lymphoma
(v) Radiation Damage
(b) Without mucosal erosions/ulcerations
(i) Ménétrier’s Disease
(ii) Bacterial Overgrowth
(iii) Coeliac Disease
(iv) Tropical Sprue
(v) Eosinophilic gastroenteritis
(vi) SLE
(c) With lymphatic obstruction
(i) Intestinal lymphangiectasia
(ii) Constrictive pericarditis
(iii) Lymphoma
(iv) Whipple’s Disease
Bacterial
Overgrowth
SEE Gastroenterology 6 (page 2 of 5)
Causes of Bacterial Overgrowth
Hypo/Achlorhydria
Decreased Motility
Structural Abnormality
Impaired Immunity
Pernicious anaemia
Partial gastrectomy
Scleroderma
Diabetic autonomic neuropathy
Gastric surgery (blind loops)
Jejunal diverticulosis
Enterocolic fistulae
Strictures
Hypogammaglobulinaemia
more online at http://homepage.virgin.net/nemonique.sam/noteindx.htm page 2 of 4
Nem’s Notes…
Phase 2 Year 2
GASTROENTEROLOGY 3 (page 3 of 4)
The Small Intestine
Intestinal
Resection
Effects:
(a) 30-50% resection can be tolerated
(b) Gastric hypersecretion
(c) Gallstones
(d) Decreased fat absorption
(e) Hyperplasia/hypertrophy of bowel (adaptation)
(f) Increased bile salt synthesis (due to decreased absorption)
(g) Pernicious anaemia (decreased B12 absorption)
(h) Short gut syndrome
Investigation:
(a) SBFT
(b) B12 measurement
(c) Bile salt measurement
(d) Fat absorption tests
Treatment:
(a) B12 replacement
(b) Low fat diet for steatorrhoea
(c) Cholestyramine or aluminium hydroxide for diarrhoea
(d) Parenteral nutrition in short gut syndrome
Whipple’s
Disease
This is a rare disease usually affecting males who present with steatorrhoea, weight
loss, abdominal pain and fever.
Villi are stunted and contain periodic acid-Schiff (PAS) positive macrophages
(diagnostic). On electron microscopy bacilli can be seen within the macrophages.
Treatment is with penicillin, tetracycline and sulphonamides.
Radiation
Enteritis
Radiation over 50 Gy will damage the intestine (usually the ileum and rectum due to
pelvic irradiation). Symptoms of diarrhoea and abdominal pain usually improve within
6 weeks. Chronic radiation enteritis is diagnosed if symptoms persist for longer than 3
months.
There is muscle atrophy, ischaemic ulceration & obstruction due to fibrosed strictures.
Malabsorption and bacterial overgrowth can occur. Treatment is symptomatic.
Meckel’s
Diverticulum
Most common abnormality of the GI tract affecting 2-3% of the population where a
diverticulum projects from the wall of the ileum. It is usually asymptomatic but 50%
contain mucosa which secrete hydrochloric acid. Peptic ulceration and bleeding can
occur. Acute inflammation may also occur which is indistinguishable from appendicitis.
Treatment is surgical removal.
Amyloid
Systemic amyloidosis may cause amyloid deposits in the GI tract. Deposits in the
small intestine result in diarrhoea.
Connective
Tissue
Disorders of the connective tissue can affect the GI tract. Systemic sclerosis most
commonly affects the oesophagus although occasionally the small bowel and colon. It
is frequently asymptomatic but diarrhoea and steatorrhoea may occur due to bacterial
overgrowth secondary to decreased motility, dilatation and presence of diverticulae.
Rheumatoid arthritis and SLE may also cause GI problems.
Tumours
Benign
Adenomas
Leiomyomas
Lipomas
Hamartomas
Malignant
Adenocarcinomas
Carcinoid Tumours
Leiomyosarcoma
Lymphoma
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Nem’s Notes…
Phase 2 Year 2
GASTROENTEROLOGY 3 (page 4 of 4)
The Small Intestine
Lymphoma
Carcinoid
Tumour
Predisposing Factors:
(a) Coeliac Disease
(b) Crohn’s Disease
(c) Immunoproliferative Small Intestine Disease
Pathological Features:
(a) Most frequently found in ileum
(b) Most common is B-cell derived lymphoma (from MALT)
(c) Annular or polypoid masses
(d) T-cell lymphomas are ulcerated plaques or proximal
bowel strictures
Clinical Features:
(a) Abdominal pain
(b) Diarrhoea
(c) Anorexia
(d) Weight loss
(e) Anaemia
(f) May have a palpable mass
Investigation:
(a) SBFT
(b) USS
(c) CT
Treatment:
(a) Surgery
(b) Radiotherapy
(c) Chemotherapy
Pathological Features:
(a) Originate from enterochromaffin cells of intestine
(b) Common sites are appendix, terminal ileum and rectum
Clinical Features:
(a) Small bowel obstruction
(b) Intestinal ischaemia
(c) Hepatic metastases (pain, hepatomegaly, jaundice)
(d) Flushing/wheezing
(e) Diarrhoea
(f) Cardiac involvement
(g) Facial telangiectasia
Investigation:
(a) USS
Treatment:
(a) Octreotide relieves flushing and diarrhoea
(b) Surgical resection
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