Malabsorption

Question 1

Define malabsorption

Answer 1

Failure to fully absorb nutrients from the GI tract

Question 2

Pathology of malabsorption

Answer 2

1. Insufficient intake
2. Defective intraluminal digestion
3. Insufficient surface area
4. Lack of digestive enzymes
5. Defective epithelial transport
6. Lymphatic obstruction
7. Infection

Question 3

Causes of defective intraluminal digestion

Answer 3

1. Pancreatic insufficiency - pancreatitis, CF
2. Defective bile secretion - biliary obstruction, ileal resection (decreased bile salt uptake)
3. Bacterial overgrowth - PPI + DM = RF

Question 4

Causes of insufficient surface area

Answer 4

1. Coeliac - villous atrophy and crypt hyperplasia

2. Crohn’s

Question 5

Causes of lymphatic obstruction

Answer 5

1. Lymphoma
2. TB
   Means digested nutrients can’t get into the bloodstream

Question 6

Infections causes malabsorption

Answer 6

1. Giardia
2. Cryptosporidium
3. Whipple’s disease

Question 7

Signs and symptoms of malabsorption

Answer 7

1. Diarrhoea, weight loss, lethargy, steatorrhoea, bloating
2. Anaemia - b12 and folate deficiency
3. Bleeding disorder - vit K deficiency
4. Metabolic bone disease - vit D deficiency
5. Oedema - protein deficiency

Question 8

Management of malabsorption

Answer 8

1. Treat the cause

2. Supplements

Question 9

Define coeliac disease

Answer 9

Autoimmune inflammatory disease in which immune response is triggered by gliadin in the small bowel. Characterised by villous atrophy and crypt hyperplasia

Question 10

Epidemiology of coeliac

Answer 10

1. 1 in 100 in the UK
2. Peaks in children and 50s
3. FHx predisposes
4. Usually diagnosed in adulthood

Question 11

Pathology of coeliac disease

Answer 11

1. Gliadin binds to IgA in the small intestine
2. IgA-gliadin crosses the epithelium via transferrin
3. Tisse transglutaminase (tTG) removes amide group from gliadin
4. Deaminated gliadin is engulfed by macrophages
5. MHC II (HLA DQ2/8) present gliadin on surface causing immune response from T cells
6. T helper cells release inflammatory mediators and activate B plasma cells -> anti-tTG, anti-gliadin, endomysial antibodies
7. T killer cells damage the epithelium

Question 12

Investigations for coeliac disease

Answer 12

1. Anti-tTG - preferred test, also anti-endomysial and anti-gliadin antibody
2. Bloods - low Hb, B12, ferritin
3. Endoscopy and biopsy
4. HLA DQ2/8 genotyping

Question 13

Symptoms of coeliac disease

Answer 13

1. Abdominal pain/discomfort
2. Diarrhoea, steatorrhoea
3. Bloating
4. Weight loss
5. Failure to thrive

Question 14

Signs of coeliac disease

Answer 14

1. Anaemia (iron deficiency
2. IBS
3. Osteoporosis/osteomalacia
4. Infertility
5. Chronic fatigue
6. Severe mouth ulcers
7. Dermatitis herpetiformis
8. Angular stomatitis

Question 15

Management of coeliac

Answer 15

1. Lifelong gluten free diet - monitor response by symptoms and serology
2. Supplements initially
3. DEXA scan for OP risk

Question 16

Complications of coeliac

Answer 16

1. Anaemia
2. OP
3. Dermatitis herpetiformis
4. Hyposplenism
5. Increased risk of malignancy