Diarrhoea and Malabsorption Flashcards
How is IBS treated?
Low FODMAP diet
What are the red flags of IBS diagnosis?
>45
Bloody diarrhoea
Nocturnal symptoms
Weight loss
What must be excluded before the diagnosis of IBS can be made?
IBD
Coeliacs
Colorectal cancer
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
No leukocytes
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?
Thyrotoxicosis
IBS
Diabetic neuropathy
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?
Gastrointestinal inflammation
