Malabsorption

Question 1

What is the most common cause of malabsorption?

Answer 1

Coeliac Disease

Question 2

What are the three pathological subsets of chronic diarrhoea?

Answer 2

Osmotic
Secretory
Inflammatory

Question 3

What defines steatorrhea?

Answer 3

Stools with a fat contents of more than 6 g/day. It is offensive smelling and difficult to flush away.

Question 4

State some clinical features of malabsorption.

Answer 4

Muscle Wasting
Loss of Fat
Oedema/Ascites
Anaemia, skin lesions, hair loss, poor wound healing, purpura

Question 5

What constitutes a balanced diet?

Answer 5

FACE MTV
Fats
Amino Acids and Protein
Carbohydrates 
Electrolytes and Water 
Minerals
Trace Elements 
Vitamins

Question 6

What is the difference between malabsorption and maldigestion?

Answer 6

Maldigestion - reduced gastric tissue/secretion, loss of pancreatic tissue, impaired bile secretion, reduction in intestinal brush border enzymes.
Malabsorption - loss of functional enterocytes, pre- and post-mucosal effects, single gene disorders

Question 7

Describe breath and stool tests for malabsorption.

Answer 7

Breath Test: make the patient breathe in something that is radioactively labelled and is metabolised to release carbon dioxide. Measure the amount of radioactive carbon dioxide coming out to determine how much they are absorbing and how much is being broken down.
FECAL PANCREATIC ELASTASE 1 test:
Pancreatic elastase is involved in breaking down lots of things
Low fecal pancreatic elastase (< 200 mcg) indicates exocrine pancreas insufficiency

Question 8

What is the histological hallmark of coeliac disease?

Answer 8

Subtotal villous atrophy with crypt hyperplasia

Question 9

State two other common causes of malabsorption.

Answer 9

Small bowel bacterial overgrowth

Pancreatic insufficiency

Question 10

State some less common causes of malabsorption.

Answer 10

Short bowel syndrome
Lymphoma
Chronic infections

Question 11

State three common forms of malabsorption of particular nutrients.

Answer 11

Lactose
Vitamin B12
Bile Salts

Question 12

What is short bowel syndrome?

Answer 12

Usually occurs after surgery for Crohn’s disease, infarction or trauma.
< 200 cm of small bowel
Results in malabsorption, malnutrition, electrolyte imbalance and progressive weight loss

Question 13

State some symptoms of coeliac disease.

Answer 13

Malaise, fatigue, steatorrhoea, diarrhoea, weight loss, anaemia

Question 14

What test is used to diagnose coeliac disease?

Answer 14

tTG - Tissue Transglutaminase
This is a blood test that uses anti-TTG antibodies to measure the TTG levels. Elevated TTG levels are indicative of Coeliac disease.
You have to first measure whether people have IgA or not before you do this test - hereditary IgA deficiency is quite common.

Question 15

What populations have a greater prevalence of coeliac disease?

Answer 15

T1DM
Thyroid Disease
Anaemic Blood Donors
Irritable Bowel Syndrome
Osteoporosis

Question 16

What is the action of TTG?

Answer 16

tTG is an enzyme that breaks down a particular peptide in gluten. People with Coeliac disease have anti-tTG antibodies.

Question 17

What MHC haplotype increases risk of having coeliac disease?

Answer 17

HLA-DQ2
State some complications of coeliac disease.
Slow growth
Anaemia
Lymphoma/adenocarcinoma
Osteoporosis/osteopenia

Question 18

State some complications of coeliac disease.

Answer 18

Slow growth
Anaemia
Lymphoma/adenocarcinoma
Osteoporosis/osteopenia