Malabsorption

Question 1

Define malabsorption.

Answer 1

Defective mucosal absorption caused by:
defective luminal digestion
mucosal disease
structural disorders

Question 2

List some common and uncommon causes of malabsorption.

Answer 2

Common causes:
Coeliac disease
Crohn's disease
Post infectious
Biliary obstruction
Cirrhosis
Uncommon causes: 
Pancreatic cancer
Parasites
Bacterial overgrowth
Drugs
Short bowel (including resections)

Question 3

What are different malabsorptive states?

Answer 3

Protein
fat
carbohydrate
vitamins and minerals

Question 4

List some digestive causes of protein malabsorption.

Answer 4

Partial or total gastrectomy (poor mixing)
Exocrine pancreatic insufficiency
Trypsinogen deficiency
Congenital deficiency of intestinal enterokinase

Question 5

List some absorptive causes of protein malabsorption

Answer 5

Coeliac disease 
Tropical sprue
Short bowel syndrome
Jejunoileal bypass
Defects in neutral AA transporters (Hartsnup disease)
Cystinuria I-III
Oculocerebral syndrome of Lowe

Question 6

List some digestive causes of fat malabsorption.

Answer 6

Less time to mix: gastric resection, autonomic neuropathy, amyloidosis
Decreased micelle formation caused by a decreased bile acid synthesis/secretion: Cirrhosis, Biliary obstruction, CCK deficiency, small intestinal bacterial overgrowth
Decreased Lipolysis: Chronic pancreatitis, cystic fibrosis, Pancreatic/ampullary tumours, Low luminal pH, Excessive calcium ingestion, Lipase/co-lipase deficiency (rare)

Question 7

List some absorptive causes of fat malabsorption

Answer 7

Decreased chylomicron formation and/or mucosal absorption:
Coeliac disease
Chylomicron retention disease

Question 8

List some post-absorptive causes of fat malabsorption

Answer 8

Defective lymphatic transport:
Lymphoma
Whipple disease
Trauma

Question 9

Name a digestive cause of carbohydrate malabsorption

Answer 9

alpha-amylase deficiency

Question 10

Name some absorptive causes of carbohydrate malabsorption

Answer 10

Lactase deficiency
Coeliac disease
Crohn’s disease
sucrase-isomaltase deficiency

Question 11

List some causes of Vitamin B12 malabsorption

Answer 11

Deficiency of gastric intrinsic factor
Pancreatic insufficiency/Z-E syndrome (Reduced release of B12 from R-binding protein)
Ileal Crohn’s disease
Ileal resection

Question 12

List some causes of Folic acid malabsorption

Answer 12

Caused by diseases affecting the proximal small bowel
Coeliac disease
Whipple disease
Alcoholism

Question 13

What are the fat soluble vitamins?

What could cause malabsorption of these?

Answer 13

Vitamins A, D, E and K

Anything that disrupts fat absorption will result in one or more than one deficiency

Question 14

What are the clinical features of lactose malabsorption (i.e. lactase deficiency)

Answer 14

History of the induction of the diarrhoea, abdominal discomfort and flatulence following the ingestion of dairy products.

Question 15

How is lactase deficiency diagnosed?

Answer 15

It is diagnosed clinically, and confirmed using the lactose breath hydrogen test, or the oral lactose intolerance test.

Question 16

What is tropical sprue?

Answer 16

Colonisation of the intestine by an infectious agent or alterations in the intestinal bacterial flora induced by the exposure to another environmental agent.

Question 17

What are the clinical features of tropical sprue?

Answer 17

Diarrhoea
Steatorrhoea
Weight loss
Nausea
Anaemia

Question 18

What is the treatment for tropical sprue?

Answer 18

Tetracycline + folic acid

Question 19

What is whipple’s disease?

Answer 19

A rare infectious bacterial disease caused by Tropheryma whipplei.
There is multi-system involvement and increase in the frequency of HLA-B27.

Question 20

What are the clinical features of whipple’s disease?

Answer 20

Weight loss, diarrhoea, steatorrhea, abdominal distension, arthritis, fever, nutritional deficiency symptoms

Question 21

How is whipple’s disease diagnosed?

Answer 21

Biopsy and demonstration of T.whipplei in involved tissues by microscopy

Question 22

What is the treatment for Whipple’s disease?

Answer 22

Anti-microbial

Question 23

What are the clinical features of Crohn’s disease?

Answer 23

Abdominal pain and diarrhoea
Fever and weight loss
Abdominal tenderness, most commonly in the right lower quadrant

Question 24

How is Crohn’s disease diagnosed?

Answer 24

Endoscopy
Barium imaging of small bowel mucosal disease, including strictures, ulcerations and fistulae
CT
MRI

Question 25

What is the treatment for Crohn's disease?

Answer 25

Steroids, immunosuppressants (azathioprine), biological therapy (anti-TNF)

Question 26

What does Giardia lamblia/ giardia intestinalis cause? What are risk factors for contracting this parasitic infection? What are other intestinal parasites?

Answer 26

Giardiasis Risk factors are travel to areas where the water supply may be contaminated and swimming in ponds Other parasites: Coccidial, strongyloides

Question 27

What are the clinical features of giardiasis?

Answer 27

``` Diarrhoea Flutulence Abdominal cramps Epigastric pain nausea Significant malabsorption with steatorrhoea and weight loss may develop ```

Question 28

How is giardia lamblia confirmed in the lab?

Answer 28

Stool examination for ova and parasites | Three separate stool samples increases the yield of positive examinations to 80-90%

Question 29

How is giardiasis treated?

Answer 29

Metronidazole for 1 week

Question 30

Which pathogens cause small bowel overgrowth?

Answer 30

E. coli or Bacteroides.

Question 31

What are the symptoms of small bowel overgrowth?

Answer 31

Diarrhoea, steatorrhoea and macrocytic anaemia

Question 32

What lab results would be found in small bowel overgrowth?

Answer 32

low cobalamin and high folate levels. | aerobic and or anaerobic colonic-type bacteria in a jejunal aspirate obtained by intubation

Question 33

What is the treatment for small bowel overgrowth?

Answer 33

Surgical correction of an anatomical blind loop | Tetracyclines 2-3 weeks

Question 34

In which known disease states should you suspect malabsorption?

Answer 34

Those of the liver, pancreas and small bowel

Question 35

What features of past medical history should make you suspect malabsorption?

Answer 35

Gastric or small bowel resection Gastrointestinal diversion (bariatric) Radiation exposure Travel

Question 36

What questions should you ask about diarrhoea?

Answer 36

``` Duration Malabsorptive stool Fat globules Floating Hard to flush away Offensive ```

Question 37

What is easy bruising a sign of?

Answer 37

Vitamin C "scurvy" (deficiency) | VItamin K deficiency

Question 38

Name an autosomal recessive skin condition due to impaired zinc uptake. What are the signs of this? How is this treated?

Answer 38

Acrodermatitis Enteropathica. The signs are a perioral or acral rash, and alopecia. It is treated with lifelong zinc supplements.

Question 39

Which skin condition may indicate coeliac disease? How does it present? What causes it?

Answer 39

Dermatitis herpetiformis. It presents as itchy blisters on extensor surfaces. It is caused by sub-epithelial IgA deposition.

Question 40

What can glossitis and angular stomatitis be signs of?

Answer 40

Vitamin B deficiency | Iron deficiency

Question 41

What can spooned nails be a sign of?

Answer 41

Iron deficiency

Question 42

Which baseline investigations should be carried out?

Answer 42

``` FBC Coagulation LFTs Albumin Calcium/Magnesium Stool culture ```

Question 43

Which anatomical investigations can be done?

Answer 43

Endoscopy | Imaging

Question 44

What should the management of a malabsorption be?

Answer 44

Treat the underlying cause Replace the deficiency Support nutritionally