Malabsorption

Question 1

What is the definition of malabsorption?

Answer 1

“Defective mucosal uptake and transport of adequately digested protein, fat, carbohydrates or nutrients”

Question 2

What is intraluminal digestion?

Answer 2

Pancreatic enzyme secretion and emulsification by bile salts

Question 3

What is terminal digestion?

Answer 3

Enzymatic hydrolysis in brush border of small intestine

Question 4

What is transepithelial transport?

Answer 4

Nutrients, fluid and electrolytes transported across epithelium

Question 5

What can disturbance in electrolyte absorption lead to?

Answer 5

Osmotic diarrhoea

Question 6

What are proteins, starches and triglycerides digested to?

Answer 6

Proteins → peptides
Starches → α-dextrins and disaccharides
Triglycerides → fatty acids and monoglycerides

Question 7

What are a-dextrins and disaccharides hydrolysed by?

Answer 7

α-dextrins and disaccharides are hydrolysed by brush border enzymes and absorbed into cells

Question 8

What do amphipathic bile salts form?

Answer 8

tiny spheres called micelles

Question 9

What do long chain fatty acids require for absorption?

Answer 9

bile salts

Question 10

What happens when Fatty acids and monoglycerides reach the epithelial cells of the villi?

Answer 10

Fatty acids and monoglycerides reach the epithelial cells of the villi and diffuse into the cells, leaving micelles behind in chyme

Question 11

Where are bile salts reabsorbed?

Answer 11

the terminal ileum (enterohepatic circulation)

Question 12

How do you identify steatorrhoea?

Answer 12

Stools may float in the pan – difficult to flush

Oily appearance and be foul smelling.

Question 13

Which vitamins are fat soluble?

Answer 13

Vitamins A, D, E and K are fat-soluble

If fat absorption is impaired, deficiencies in these vitamins may occur

Question 14

How does vitamin D deficiency affect calcium absorption?

Answer 14

Calcium absorption is greatly reduced in vitamin D deficiency and sometimes in generalized malabsorption

Question 15

What is osteoporosis?

Answer 15

reduced bone density, inc risk of fragility fractures

Question 16

What are some causes of osteoporosis?

Answer 16

Anorexia, smoking, alcoholism, malabsorption, steroid therapy, vitamin D/ calcium deficiency

Question 17

How is osteoporosis diagnosed?

Answer 17

WHO osteoporosis criteria, DEXA bone scan T-SCORE -2.5 or worse

Question 18

What is Osteomalacia and what causes it?

Answer 18

Definition:
Normal amount of bone but its mineral content is low.

Causes:
Vitamin D deficiency - inadequate sunlight, malabsorption (coeliac, intestinal resection, cholestasis), renal disease.

Question 19

What can vitamin A deficiency cause?

Answer 19

blindness (begins with inability to produce tears)

Question 20

What can vitamin B1 (thiamine) deficiency cause?

Answer 20

Beriberi; Wernickes

Question 21

What can vitamin B2 deficiency cause?

Answer 21

angular stomatis; cheilitis

Question 22

What can vitamin B6 deficiency cause?

Answer 22

polyneuropathy

Question 23

What can vitamin B12 deficiency cause?

Answer 23

anaemia, SCDC

Question 24

What can vitamin C deficiency cause?

Answer 24

scurvy

Question 25

What can vitamin D deficiency cause?

Answer 25

osteomalacia

Question 26

What can vitamin E deficiency cause?

Answer 26

bleeding disorders

Question 27

What can vitamin K deficiency cause?

Answer 27

bleeding disorders

Question 28

What can lead to B12 deficiency?

Answer 28

Gastric mucosal atrophy (pernicious anaemia) and terminal ileal disease

Question 29

What does B12 require for absorption?

Answer 29

intrinsic factor

Question 30

What is folate necessary for?

Answer 30

efficient thymidilate synthesis and production of DNA.

Question 31

3 things to consider in deficiencies

Answer 31

Is the patient - not getting enough in not absorbing enough losing too much

Question 32

3 mechanisms of iron deficiency

Answer 32

iron intake (dietary) ↓ iron absorption (principally in the duodenum) ↑ iron loss (sloughed mucosal cells, bleeding)

Question 33

What is coeliac disease?

Answer 33

Inflammatory condition of the small intestinal mucosa induced by an autoimmune reaction to the ingestion of gluten

Question 34

What can be seen in coeliac disease from a histology point of view?

Answer 34

Villous atrophy/ intraepithelial lymphocytosis

Question 35

How common is coeliac disease?

Answer 35

1 in 100 in the UK

Question 36

What is the clinical presentation of coeliac disease in infants?

Answer 36

impaired growth, diarrhoea, vomiting, abdominal distension

Question 37

What is the clinical presentation of coeliac disease in older children?

Answer 37

anaemia, short stature, pubertal delay, rickets, recurrent abdominal pain or behavioural disturbance

Question 38

What is the clinical presentation of coeliac disease in adults?

Answer 38

chronic/recurrent iron deficiency anaemia, diarrhoea, abdominal pain, bloating, isolated nutritional deficiencies, reduced fertility, osteoporosis, osteomalacia abnormal liver function tests

Question 39

How is Coeliac disease diagnosed?

Answer 39

Clinical history Serological tests – endomysial (EMA) and tissue transglutaminase (tTG) antibodies Duodenal biopsy via upper GI endoscopy

Question 40

How is coeliac disease treated/managed?

Answer 40

gluten-free diet

Question 41

What can lead to B12 deficiency?

Answer 41

Gastric mucosal atrophy (pernicious anaemia) and terminal ileal disease

Question 42

What does B12 require for absorption?

Answer 42

intrinsic factor

Question 43

What is folate necessary for?

Answer 43

efficient thymidilate synthesis and production of DNA.

Question 44

3 things to consider in deficiencies

Answer 44

Is the patient - not getting enough in not absorbing enough losing too much

Question 45

3 mechanisms of iron deficiency

Answer 45

iron intake (dietary) ↓ iron absorption (principally in the duodenum) ↑ iron loss (sloughed mucosal cells, bleeding)

Question 46

What is coeliac disease?

Answer 46

Inflammatory condition of the small intestinal mucosa induced by an autoimmune reaction to the ingestion of gluten

Question 47

What can be seen in coeliac disease from a histology point of view?

Answer 47

Villous atrophy/ intraepithelial lymphocytosis

Question 48

How common is coeliac disease?

Answer 48

1 in 100 in the UK

Question 49

What is the clinical presentation of coeliac disease in infants?

Answer 49

impaired growth, diarrhoea, vomiting, abdominal distension

Question 50

What is the clinical presentation of coeliac disease in older children?

Answer 50

anaemia, short stature, pubertal delay, rickets, recurrent abdominal pain or behavioural disturbance

Question 51

What is the clinical presentation of coeliac disease in adults?

Answer 51

chronic/recurrent iron deficiency anaemia, diarrhoea, abdominal pain, bloating, isolated nutritional deficiencies, reduced fertility, osteoporosis, osteomalacia abnormal liver function tests

Question 52

How is Coeliac disease diagnosed?

Answer 52

Clinical history Serological tests – endomysial (EMA) and tissue transglutaminase (tTG) antibodies Duodenal biopsy via upper GI endoscopy

Question 53

How is coeliac disease treated/managed?

Answer 53

gluten-free diet replace nutritional deficiencies monitor bone density

Question 54

What are investigations for chronic pancreatitis?

Answer 54

Faecal elastase-1 Produced by pancreas and passed in stool largely unaltered Plain abdominal X-ray Ultrasound/ CT MRCP vs ERCP

Question 55

What are some clinical features of pancreatic disease?

Answer 55

epigastric pain, often radiating to the back, food or alcohol may exacerbate the pain, weight loss.

Question 56

How is chronic pancreatitis managed?

Answer 56

``` Remove precipitant (eg. alcohol) Pain control Treat diabetes (often need insulin) Pancreatic enzyme supplements – Creon Lipase, protease, amylase Vitamin supplementation ``` Nerve plexus blocks Endoscopic stenting of strictures, surgery

Question 57

What is cholestasis?

Answer 57

Cholestasis is the impairment of bile formation / bile flow

Question 58

What is Primary sclerosing cholangitis (PSC)?

Answer 58

Inflammatory/ fibrotic process affecting intra/extrahepatic bile ducts Leads to bile duct strictures Aetiology unknown, but ~80% associated with IBD Presents as pruritis, fatigue, jaundice Ultimately leads to cirrhosis and liver failure - only proven treatment is liver transplantation

Question 59

What drug can cause malabsorption?

Answer 59

orlistat - inhibits gastric and pancreatic lipase