Malabsorption & Coeliac Disease Flashcards
What is Coeliac Disease?
An autoimmune condition where the immune system recognises gluten as something foreign
Is Coeliac common?
Yes, 1 in 100 people in European derived populations
What causes Coeliac to develop?
Genetics: links have been found with Coeliac and certain HLA IIs
What part of gluten is the body intolerant to?
Alpha-gliadin is the toxic bit of gluten
What’s the pathogenesis of Coeliac?
Epithelium is damaged by infection for example
Gliadin moves from the lumen through the epithelium
APC’s recognise gliadin as foreign, and presents it to T cell
T cells stimulate plasma cells to make antibodies against gliadin
T cells release cytokines that damage epithelial cells
What age does Coeliac usually present?
Infancy
Second peak around age 40-50
But can present at any age
Clinical features of Coeliac disease.
Diarrhoea + steatorrhoea
Stools with offensive smell
Abdominal pain + distension
Nausea + vomiting
Weight loss, fatigue, failure to thrive
Anaemia + nutritional deficiency
Investigations for Coeliac disease.
Serum antibodies: anti-gliadin
(they need to keep eating gluten until you do this test!)
Low Hb, ferritin + folate
Endoscopy: look for damage
Jejunal biopsy: villous atrophy + crypt hyperplasia
Why do Coeliac patients get anaemia?
They can’t absorb iron from their food as well as they should
Where in the body does Coeliac affect?
Mainly small intestine
Skin: dermatitis herpeteformis
Cerebellar dysfunction (rarely)
What does dermatitis herpeteformis look like?
Red, raised patches with blisters that burst with scratching
Severe itching and stinging
Elbows, knees, buttocks
What happens to the enterocytes in Coeliac?
Villous atrophy
Crypt hyperplasia
Why does Coeliac cause malabsorption?
Loss of villi and damage to enterocytes mean they can’t absorb nutrients from the gut as effectively
Management of Coeliac?
Gluten-free diet for life
Symptoms will disappear if gluten is removed completely
What cancers are Coeliac patients more at risk of?
T cell lymphomas
Gastric, oesophageal, bladder many more
What is malabsorption?
Problems with absorption of food nutrients across the gastrointestinal tract
What are the clinical features of malabsorption?
Weight loss despite eating normally
Diarrhoea + steatorrhoea
Anaemia
General malnutrition
When faced with a patient you suspect of malnutrition what should you first rule out?
Whether they are eating enough, think of things like anorexia
What are the 5 different types of causes of malabsorption?
- Defective intraluminal digestion
- Insufficient absorptive area
- Lack of digestive enzymes
- Defective epithelial transport
- Lymphatic obstruction
What could cause defective intraluminal digestion in the small bowel?
Intraluminal digestion = occurs in the lumen, before absorption
- Pancreatic insufficiency: lack of enzyme production
- Cystic fibrosis: enzymes can’t get from pancreas to lumen due to excess mucus
- Defective bile secretion: would lead to lack of fat solubilisation
- Bacterial overgrowth
What could cause insufficient absorptive area in the small bowel?
Coeliac disease: villous atrophy
Crohn’s: scarring + fibrosis
Giardia Lamblia: parasites absorb nutrients before the gut can
What is an example of lack of digestive enzymes that could cause malabsorption?
Lactose intolerance: lack of lactase
What is another name for Coeliac disease?
Gluten sensitive enteropathy
What could cause defective epithelial transport in the small bowel?
Primary bile acid malabsorption: mutations in bile acid transporter protein
Abetalipoproteinaemia: rare genetic problem with absorption of fat and fat soluble vitamins
What could cause lymphatic obstruction?
Lymphoma
TB
Investigations for malabsorption?
FBC: low iron, B12, folate
Stool: look for excess fat, infection
Endoscopy: look for Crohn’s, Coeliac
Biopsy
What is tropical sprue?
A disease that causes abnormal flattening of the villi and inflammation of the lining of the small intestine
Occurs in far and middle east and Caribbean
Unknown cause, thought to be due to a persistent infection
What are the symptoms of tropical sprue?
Same as Coeliac
Vitamin deficiency if left untreated
Treatment of tropical sprue?
Antibiotics: tetracycline
