Lecture 30 Small Intestinal Disorders and Investigation Flashcards
Functions of the small intestine
Digestion
Absorption
Barrier function
Endocrine and neuronal control function
Digestion of starch in stomach enzymes
o Salivary amylase
o Pepsin
Digestion of proteins process
o Broken down to oligopeptides & amino acids
o Trypsin activates chymotrypsin by cleaving peptidic bonds
o Final hydrolysis and absorption at brush border
Digestion of fat process
o Pancreatic lipase
Absorption of glycerol and free fatty acids
via lacteal and lymphatic system
Digestion of carbohydrate process
o Pancreatic amylase
Breakdown to disaccharides
Final digestion by brush border disaccharidase
What makes the small intestine a toxic environment
Digestive enzymes
Bile salts
Presence of IgA etc.
How does the small intestine maintain a barrier against pathogens
Immune sampling
Translocation of bacteria
Gut Associated Lymphoid Tissue
What are the tests of structure
• Small bowel biopsy
o Endoscopy
• CT Scan- not very sensitive to small bowel
• MRI enterography- Gold standard- no ionizing radiation
• Capsule enterography
What is the Gold standard for imaging for small bowel
MRI enterograohy
Name other assorted tests for the small bowell
• Small bowel biopsy
o Endoscopy
• CT Scan- not very sensitive to small bowel
• MRI enterography- Gold standard- no ionizing radiation
• Capsule enterography
Symptoms of small bowel disease
• Weight Loss • Increased appetite • Diarrhoea o Usually watery o Sometimes steatorrhoea • Bloating • Fatigue
Define Steatorrhea
- Fat malabsorption
* High fat content in stool
Signs of small bowel disease
- Signs of weight loss
* Low or falling BMI
Signs of Vitamin A deficiency
Night blindness
Signs of vitamin K deficiency
Raised Prothrombin
Signs of Vitamin B deficiency
Memory, dementia
Signs of Niacin deficiency
Dermatitis, unexplained heart failure
Signs of vitamin C deficiency
Scurvy
What is clubbing a sign of
Crohn’s, Coeliac disease
What is scleroderma a sign of
Systemic sclerosis
What is Aphthous ulceration and what disease are they seen in
Coeliac, Crohn’s
What is Dermatitis Herpetiforms
• Cutaneous manifestation of coeliac disease o Blistering o Intensely itchy o Scalp, shoulders, elbows, knees o IgA deposit in skin
Tests for coeliac disease
Serology
IgA test more reliable for IgG but only if you make IgA as 0.1 to 1% of population have IgA deficiency
Confirmatory tests for coeliac disease
Distal duodenal biopsy for villous atrophy (partial, subtotal, total), increased intra-epithelial lymphocytes
What test is a good exclusion test for coeliac disease
HLA status
97% of coeliac are either HLA DQ2 or DQ8 positive
What is Gliadin
Fraction of gluten which is responsible for the inflammatory response
Treatment for coeliac disease
- Stop eating gluten
* Must refer to a state registered dietician
Associated conditions with coeliac disease
- Dermatitis herpetiformis
- IDDM- Insulin-Dependent Diabetes Mellitus, now known as Diabetes mellitus type 1, an autoimmune disease resulting in the destruction of insulin-producing cells
- Autoimmune thyroid disease
- Autoimmune hepatitis
- Primary Biliary Cholangitis
- Autoimmune gastritis
- Sjogren’s syndrome
- IgA deficiency
- Down’s Syndrome
Complications of Coeliac Disease
- Refractory coeliac disease
- Small bowel lymphoma
- Oesophageal carcinoma
- Colon cancer
- Small bowel adenocarcinoma
Infections that can cause malabsorption
Tropical sprue HIV Giardia lamblia Whipple's Disease Amyloid Systemic sclerosis Diabetes Pseudo obstruction Iatrogenic
Treatment for small bowel bacterial overgrowth
◦ Rotating antibiotics Metronidazole Tetracycline Amoxicillin Each for 2 weeks ◦ Vitamin and nutritional supplements
