How is IBS treated?
Low FODMAP diet
What are the red flags of IBS diagnosis?
What must be excluded before the diagnosis of IBS can be made?
How is the diagnosis of coeliacs made?
Positive transglutaminase abs - DGP (deamidated gliadin peptide)
Biopsy demonstrating villous atropy, crypt hyperplasia, and intraepithelial lymphocytes while on gluten diet
- and resolution of these when off the gluten
What does faecal elastase reflect?
Exocrine failure of the pancrease
What is the pathophysiology of IBS?
Serotonin is the key mediator - disordered intestinal motility
What causes secretory diarrhoea? What are the characterists of it?
Active secretion of anions by enterocytes typically due to bacterial toxin, hyperthyroidism
Large volume, persist during fasting
Calprotectin is normal
Where is iron absorbed?
In the proximal small intestine
Describe fluid absorption and secretion in the GIT
9L enters the tract
7L is absorbed in the SI
1.8L is absorbed in the large intestine
200ml passes in stool
Why might you get steatorrhoea in Crohn's?
Failure of bile salt reabsorption in the terminal ileum
How is IBS diagnosed?
Rome III crieria
- Symptoms > 3 months
- Recurrent abdominal discomfort associated with
> Relief with defaecation
> Change in stool colour and frequency
How do you test someone for coeliacs if they're already on a gluten free diet?
HLA-DQ2 and 8 genotype
6 week gluten challenge
What are some causes of increased intestinal motility?
What are some mechanisms of intraluminal maldigestion?
Mechanical failure of mixing eg post gastrectomy
Decreased nutrient availability
Defective nutrient hydrolysis - eg pancreatic insufficiency
Reduced fat solubilisation
What is faecal calprotectin a marker of?
What are the mechanisms of diarrhoea?
What the mechanism and cause of inflammatory diarrhoea and what are the characteristics of it?
Increased permeability of the mucosa causing exudate of blood, pus or protein
Invasive bacteria (eg Shigella, Salmonella), Entamoeba histolytica, CMV colitis, IBD
Small volume +/- blood and pus
Associated with tenesmus, urgency and constitual symptoms
What is a common cause of osmotic diarrhoea? What are the characterists of it?
Presence of excess unabsorbed carbohydrates
- eg Fermentable carbohydrate malabsorption - FODMAPs
Stops with fasting
Increased stool osmotic gap