Malabsorption Disease

Front 1

Describe the normal histology of the small bowel (layers, mucosa description, and absorptive cells)

Back 1

Layers

• Mucosa
• Submucosa
• Muscularis propria
• Subserosa
• Serosa

Mucosa

• Vili with central blood vessels, lymphatics and MALT
  

Absorptive Cells

• Have microvilli on luminal surface (brush border) and include enzymes

Front 2

What suggests a normal villous architecture on biopsy?

Back 2

4 normal vili in a row

Front 3

What is the function of the small bowel?

Back 3

1. Enzymatic digestion
   
2. Absorption of nutrients and water

• Duodenum: Iron + Calcium (DIC)
• Jejunum: Folate (Judge the Fool)
• Ileum: B12, Bile acids

Front 4

What are the 7 congenital problems of the small bowel?

Back 4

1) Merkel's diverticulum

Vitelli-intestinal duct persist
2) Intestinal atresia

Intestinal lumen fails to develop
3) Stenosis

Narrowing of lumen
4) Malrotation
5) Heteotopic Pancreas
6) Heterotypic Gastric mucosa

Cause obstruction, perforation, ulcer, bleed
7) Hirschsprung's disease

Causes enterocolitis (origin in colon)

Front 5

How does malabsorption present clinically?

Back 5

• Failure to thrive
• Weight loss
• Steatohhoea
• Anaemia

Front 6

What are small intestinal causes of malabsorption?

Back 6

• Crohn's
• Coeliac disease
• Dermatitis herpetiformis
• Giardiasis
• Whipple's disease

Disease usually leads to Villous atrophy

Front 7

What is the incidence of Coeliacs and what gene(s) associated?

Back 7

1 in 100 (RoI)

1 in 200 (UK/USA)

Peaking in infancy and 30-40 yrs

NB - rare in African

Genes: HLA DQ2 (90-95%)

HLA DQ8 (2-8%)

Front 8

Briefly, describe the pathologic features of Coeliac's

Back 8

• Atrophy of villi w/ elongation of crypts
  
• Chronic Inflammatory cell infiltrate
• Increase intraepithelial lymphocytes
• Sensitivity to gliadin fraction of gluten

Front 9

How does Coeliac disease present?

Back 9

1. Diarrhoea (rare constipation)
2. Anaemia (Iron > Folate > B12)
3. Aphthous ulcers, sore tongue/mouth
4. Dyspepsia, abdominal pain, bloating
5. Fatigue, irritability
6. Anxiety/Depression
7. Osteoporosis
8. Weakness
9. Pruritic Rash

Front 10

How is Coeliac's diagnosed?

Back 10

Small bowel biopsy

Also: IgG, IGA Tissue transglutaminase

Front 11

How is Coeliac's managed?

Back 11

1) Strict Gluten-free diet w/ monitoring

2) Supplement Iron, Folic acid, Calcium

3) DEXA bone scans

Front 12

What are complications of Coeliac's?

Back 12

• Lymphoma
• Adenocarcinoma
• Ulcerative jejunitis
• Stricture formation

Think what could happen with chronic inflammation? (Ulcers, Strictures, ROS damage --> Cancers)

Front 13

What is Dermatitis Herpetiformis?

Back 13

Pruritic skin rash with vesicles on extensor surfaces

Found in 10% of coeliac patients

Associated with HLA B8 and DR3

Front 14

What is Whipple's Disease and what is it characterised by?

Back 14

• Systemic Illness
  
• Caused by Tropheryma whippelii
• Infiltration of various organs by macrophages containing the organisms - lamina propria of small intestine, mesenteric lymph nodes and CNS
• Responds to antibiotic therapy

Front 15

What is Tropical Spruce and how does it present?

Back 15

Due to E. coli or Haemophilus , affecting tropics

Presents with malabsorption within weeks of an acute diarrhoea enteric infection

Front 16

What histological changed are seen with Tropical Spruce and how is it managed?

Back 16

Histopathology

• Variable villous atrophy (partial/none/total)
  
• Injury to entire small bowel
  
• Inflammatory infiltrate w/ crypt hyperplasia

Management

• Tetracycline
  
• Folic Acid
  
• Vit B12
  

Front 17

What is SIBO?

Back 17

SIBO = Small Intestine Bacterial Overgrowth

Front 18

What is the aetiology of SIBO?

Back 18

• Anatomical abnormalities
  
• Abnormal motility
• Multifactorial (Hypochlorhydria, EtOH, Cirrhosis, Chronic Pancreatitis, Advanced Age)

Front 19

What is the pathogenesis of SIBO?

Back 19

Excess anaerobic bacteria

1. Deconjugate bile salts
2. Metabolise B12
3. Metabolise Carbohydrates
4. Damage surface epithelium

End result: Malabsorption

May look like Coeliac on Bx and Endoscopy

Front 20

How do Adenocarcinomas present in the SI?

Back 20

Rare, usually in the Duodenum as a complication of Crohn's or Coeliacs

Front 21

How do Lymphomas (Primary) present in the SI?

Back 21

Commonest small bowel malignancy, but only 1-4% of all GI malignancies

• T-Cell - rare, specific for Coeliac's, will see lymphoma cells with eosinophils
• B-Cell - MALToma?

Front 22

How do Carcinoid Tumour present in the SI?

Back 22

From neuroendocrine cells throughout GIT

(think the 2nd brain)

Peak incidence in 60's and may be malignant

Usually asymptomatic, small, and slow to metastasise to liver (Carcinoid Syndrome)

Front 23

What is Carcinoid Syndrome?

Back 23

Carcinoid Tumours make and secrete factors (esp. Serotonin) Think SSRI s/e's of bowel

Hepatic Metastases of carcinoid tumour can lead to systemic symptoms

• Facial Flushing
• Intestinal hypermotility (diarrhoea/cramps)
• Bronchospasm