Small Intestinal Disorders and Investigation Flashcards
Functions of the small intestine?
- Digestion
- Absorption
- Barrier functions (control what gets out/in)
- Endocrine/neuronal control functions (motility control)
Where does protein breakdown occur?
- Commences in the stomach: pepsin
- Small intestine: trypsin/chymotrypsin, final hydrolysis and absorption at brush border
Where is fat broken down and how is it absorbed?
In the small intestine
Absorbed via the lacteal & lymphatic system
How does the bacterial population of the small intestine compare to that of the large intestine? Why is this?
Much smaller
Toxic environment in the SI:
- digestive enzymes
- Bile salts
- IgA
What are the barrier functions of the small intestine?
- Keep bacterial population low
- Maintain a barrier against pathogens (via immune sampling, gut associated lymphoid tissue)
Investigations for examining small bowel structure?
- Endoscopy + biopsy
- CT scan
- MRI enterography
- Capsule enterography
What is capsule enterography?
Inserting a capsule with lights, a lens and an imager into the small bowel of the patient to view the structure of the small intestine
How can you test for bacterial overgrowth in the small bowel?
- H2 breath test
- Culture a duodenal or jejunal aspirate
Signs of small bowel disease?
- Weight loss
- Increased appetite
- Diarrhoea (sometimes steatorrhoea)
- Bloating
- Fatigue
What is steatorrhoea?
It is a condition of the small bowel due to fat malabsorption, resulting in:
- High fat content in stool
- Less dense stool, floats
- Pale coloured, foul smelling stool that may leave an oily residue
Signs of calcium, magnesium and/or vitamin D deficiency?
Tetany
Osteomalacia
Signs of vitamin A deficiency?
Night blindness
Signs of vitamin K deficiency?
Raised prothrombin time
Signs of vitamin C deficiency?
Scurvy
Swollen, bleeding gums
Easy bruising
Fatigue & Irritability
Signs of vitamin B complex malabsorption?
Thiamine - Memory, dementia
Niacin - dermatitis, unexplained heart failure
What GI diseases is finger clubbing a sign for?
Coeliac Disease
Crohn’s
What is Aphthous Ulceration? What GI conditions is a sign of?
It is benign, non-contagious ulceration of the mouth
Coeliac disease
Crohn’s
What is dermatitis herpetiformis? What GI conditions is it a sign of?
It is areas of intensely itchy blistering on the skin (scalp, shoulders, elbows & knees) - IgA deposits in skin
Sign of coeliac disease
What is Coeliac Disease?
An autoimmune disease characterized by hypersensitivity to gluten - when gluten is consumed inflammation occurs in the small intestine causing malabsorption
Symptoms of coeliac disease?
Fatigue Bloating Variable stools (diarrhoea) Abdominal pain Anaemia
Tests for coeliac disease?
Gold standard is distal duodenal biopsy - villous atrophy?
Serology - IgA/IgG levels should be elevated (IgA more sensitive than IgG)
Bloods (malabsorption): Fe, Folate, Ca, B12
What is gliadin?
Subunit of gluten - often reason for hypersensitivity response
(found in wheat, rye and barley but not rice and maize)
Treatment of coeliac disease?
Gluten free diet - lifelong
Must refer patient to registered dietician
Conditions associated with Coeliac disease?
Dermatitis herpetiformis Diabetes mellitus Autoimmune thyroid disease Autoimmune hepatitis Autoimmune gastritis IgA deficiency Downs
Main complications of coeliac disease?
Refractory coeliac disease
Small bowel lymphoma
Small bowel adenocarcinoma
Osteopenia
Oesophageal carcinoma
Colon cancer
What is refractory coeliac disease?
Persistent or recurrent malabsorptive symptoms and villous atrophy despite strict adherence to gluten free diet for 6-12 months
Small bowel conditions causing malabsorption?
Coeliac disease
Crohn’s
Infection (tropical sprue)
What is giardisis? What parasite causes it?
Infection of the small intestine
- caused by Giardia Lamblia (contaminated water)
What is Whipple’s disease? What are its effects?
Bacterial infection - most affects joints and digestive system (also brain & cardiac effects)
Causes malabsorption which leads to weight loss, abdominal pain
Organism causing Whipple’s disease?
Tropheryma whippelii
If suspected bacterial overgrowth in the small bowel what is the recommended treatment?
Rotating antibiotics - metronidazole, tetracycline, amoxicillin
Each for 2 weeks
Important step in treatment of many small bowel disorders that you’re probs gonna forget?
Nutritional support
