Small Intestinal Disorders and Investiation Flashcards
What are the functions of the small intestine?
Digestion
the breaking of food into its components
Absorption
The passage of nutrients into the body
Endocrine and neuronal control functions
Controlling the flow of material from the stomach to the colon
Barrier functions
Regulating what stays in and gets out.
Maintaining a barrier against pathogens
Immune sampling
Monitoring the presence of pathogens
Translocation of Bacteria
Gut Associated Lymphoid Tissue (GALT)
What contributes to the low bacterial population in the small intestine?
Toxic environment
Digestive enzymes
Bile salts
Presence of IgA etc
How are proteins broken down?
- Breakdown to oligopeptides & amino acids
- Trypsin, chymotrypsin
- Final hydrolysis and absorption at brush border
How are fats digested?
Pancreatic lipase
Absorption of glycerol and free fatty acids
via lacteal and lymphatic system
How are carbohydrates digested?
Pancreatic amylase
Breakdown to disaccharides
Final digestion by brush border disaccharidase
What are symptoms of small intestine malabsorption syndrome?
- Weight Loss
- Increased appetite
- Diarrhoea - Usually watery - Sometimes steatorrhoea
- Bloating
- Fatigue
What is steatorrhoea?
Fat malabsorption
High fat content in stool
Stool less dense and floats
Pale
Foul smelling
May leave an oily mark or oil droplets
What are signs of malabsorption?
Signs of weight loss
Low or falling BMI
What are signs of Ca2+, Mg2+ and Vitamin D deficiency?
Tetany and osteomalacia
Tetany: a condition marked by intermittent muscular spasms, caused by malfunction of the parathyroid glands and a consequent deficiency of calcium.
Osteomalacia: softening of the bones, typically through a deficiency of vitamin D or calcium.
What is the specific sign of vitamin A deficiency?
Night blindness
What is the specific sign for vitamin K deficiency?
Raised PTR (prothrombin time)
What is the specific sign of vitamin B complex deficiency?
Thiamine: (often on refeeding)
Memory, dementia
Wernicke-Korsakoff syndrome - Wernicke encephalopathy and Korsakoff syndrome are different conditions that often occur together. Both are due to brain damage caused by a lack of vitamin B1 (thiamine)
Niacin:
Dermatitis, unexplained heart failure
What is the specific sign for vitamin C deficiency?
Scurvy
What are signs of coeliac disease and Crohns?
Clubbing and Apthous ulceration
What can scleroderma be a sign for?
Systemic sclerosis
What is the cutaneous manifestation of coeliac disease?
Dermatitis herpetiformis:
Blistering
Intensely itchy
Scalp, shoulders, elbows, knees
IgA deposit in skin
What are the tests of structure of the small intestine?
Small bowel biopsy
Endoscopy
Small Bowel Study
Barium
CT Scan
MRI enterography
Capsule enterography
White Cell Scan
What are the tests for coeliac disease?
IgA tests (althogh a significant number of people don’t make IgA)
IgA anti-endomysial antibodies are detected by immunofluorescence.
IgG antibodies must be analysed in patients with IgA deficiency
Tissue transglutaminase is now recognised as the autoantigen for anti-endomysial antibodies often used in serological diagnosis
Distal duodenal biopsy: Gold standard, villous atrophy, sometimes the villi may appear normal but there are excess numbers of intraepithelial lymphocytes present.
HLA status
97 % of coeliacs are either HLA DQ2 or DQ8
But so are 30% of the population.
Useful to exclude but not to confirm coeliac disease
What is the prevalence of coeliacs disease?
1 in 200 although 50% of these patients will be asymptomatic
What part of gluten are coeliacs allergic to?
Gliadin
Found in Wheat, Rye, Barley
Absent from rice and maize
Not found in oats but most oat products are contaminated with wheat
What is the pathology of coeliacs disease?
Produces an inflammatory response
Thought to be via tissue Transglutaminase
Partial or subtotal villous atrophy
Increased intra-epithelial lymphocytes
Gold standard diagnosis is still a distal duodenal biopsy
What is diagnosis of coeliacs disease?
Distal duodenal biopsy
Serology
Anti endomysial IgA
Anti Tissue transglutaminase
Both 95% specific and sensitive
[Anti gliadin may help in children but not diagnostic in adults]
What is treatment for coeliacs disease?
Withdraw Gluten
What are the conditions with coeliacs disease?
Dermatitis herpetiformis
IDDM (insulin dependant diabetes mellitus)
Autoimmune thyroid disease
Autoimmune hepatitis
Primary Biliary cirrhosis
Autoimmune gastritis
Sjogren syndrome
IgA deficiency
Downs Syndrome
What are complicatinos associated with coeliacs disease?
Refractory Coeliac Disease
Small bowel lymphoma (T-Cell)
Oesophageal carcinoma (squamous)
Colon Cancer
Small bowel adenocarcinoma
What are the inflammatory and infectious causes of malabsorption?
Inflammation
- Coeliac disease
- Crohns
Infection
- Tropical sprue
Folate deficiency
Responds to antibiotics
- HIV
- Giardia Lamblia
What is tropical sprue?
Chronic progressive malabsorption
Patient is in or from the tropicsassociated with abnormalities of small intestinal structure or function.
Occurs mainly in west indies and in asia including southern india. Infective agent may be involved, no single bacterium has been isolated - condition often begins with acute diarrhoel illness. Small bowel bacterial overgrowth with E.Coli, enterobacter and klebsiella is frequently seen.
What are the fewatures of Giardia Lamblia?
Unicellular parasite
Contaminated water
Responds to Metronidazole
Hypogammaglobulinaemia
Several other causes of malabsorption
Whipples disease
- Middle aged men
- Skin, brain, joints and cardiac effects
- Weight loss
- Malabsorption
- Abdominal pain
- PAS material in villi
Tropheryma whippelii - Causative organism
Infiltration
- Amyloid
Impaired motility
- Systemic sclerosis
- Diabetes
- Pseudo obstruction
Iatrogenic
- Gastric surgery
- Short bowel syndrome
- Radiation
Pancreatic
- Chronic pancreatitis
- Cystic fibrosis
When can bacterial overgrowth occur?
In any condition that affects motility, gut structure and immunity
H2 Breath test
BUT: very unreliable.
If in doubt give a course of rotating antibiotics.
