Week 3 - G - Malabsorption - Coeliac's, Lactose, Tropical Sprue, Whipple's, Giardia, Small bowel bacterial overgrowth

Question 1

Malabsorption can be caused by
* Defective luminal digestion
* Mucosal disease
* Structural disorders
What are common causes of malabsorption? What are uncommon causes?

Answer 1

Common causes of malabsorption
* Corhn’s disease
* Coeliac disease
* Post infectious
* Biliary obstruction
* Cirrhosis
Uncommon causes - pancreatic cancer, parasites, bacterial overgrowth, drugs, short bowel

Question 2

Malabsorptive states as mentioned can be due to digestive or absorptive problems (mucosal/structural disease) affecting * Protein, Fat, Carbohydrates, Vitamins and minerals Specific diseases states we will discuss * Coeliac, Lactose malabsorption, tropical sprue, Whipple’s disease, Crohn’s. Parasitic infection, Small bowel bacterial overgrowth What are common symptoms of GI malabsorption?

Answer 2

Symptoms -
* diarrhoea,
* weight loss,
* lethargy,
* steatorrhea,
* bloating

Question 3

List some common signs of GI malabsorption?

Answer 3

Signs - Anaemia (Iron, B12, folate) Bleeding disorders (vitamin K) Oedema (protein) Meabolic bone disease Neurological features (B12) Peripheral neuropathy (B12, B6) Angular chelitis (B2, B12) Glossitis (atrophic -iron, beefy - B12, folate)

Question 4

What is coeliac disease? What HLA are involved?

Answer 4

Coeliac disease is an autoimmune condition caused by sensitivity to the protein gluten. Intestinal antigen presenting cells are present in people expressing HLA DQ2 (95%) and HLA DQ8 (the rest)

Question 5

What leads to the mucosal inflammation and damage in coeliac disease?

Answer 5

The intestinal antigen presenting cells in people expressing HLA-DQ2 and HLA-DQ8 bind with dietary gluten peptides (gliadin and glutenins) resulting in mucosal T lymphocytes cytokines causing inflammation and damage to the small bowel

Question 6

What does the intraepithelial T lymphocyte mediate damage cause to the small bowel mucosa?

Answer 6

This leads to villous atrophy of the small bowel, loss of surface area and a flat duodendal mucosal resulting in malabsorption as well as different symptoms

Question 7

What are the symptoms of coeliac disease?

Answer 7

Spectrum from asymtpomatic to malabsorption / nutritional deficiencies * Diarrrhoea * Weight loss * Excess flatus * Abdo discomfort * Stinking stools/ steatorrhea * Bloating * Aphthous ulcers

Question 8

What are different associations and complications of coeliac disease? (eg due to the malabsorption)

Answer 8

Associations - Dermatitis herpetiformis, ther autoimmune disease Complications * Anaemia - iron, floate B12 deficiencies (folate more common than B12 as stores last shorter) * Hyposplenism * Osteopenia/ossteoporosis * Increased risk of T cell lymphoma of GI tract * Increased risk of small bowel carcinoma

Question 9

Before testing for coeliac disease, what do you need to ask the patient to do with regards to eating gluten foods?

Answer 9

Confirm that the person has eaten gluten-containing foods (with wheat, barley, or rye as an ingredient) at least twice every day over the previous 6 weeks. Serological tests do not diagnose coeliac disease, but instead indicate whether further confirmative testing is needed

Question 10

What is the first line serological test carried out in the investigation of coeliac disease? What is second line? What is measured if there is an identified IgA subclass deficiency?

Answer 10

Use immunoglobulin (Ig)A tissue transglutaminase antibody (tTGA) and total IgA first-line. IgA endomysial antibody (EMA) can be used if IgA tTGA is unavailable, or in cases where it is weakly positive. If IgA deficiency is present, this will cause a false-negative specific IgA test, so test for specific IgG instead (IgG tTGA, IgG EMA)

Question 11

If the blood tests come back positive, what is the gold standard diagnostic test for coeliac’s disease? If the patient has dermatitis herpetiformis, a biopsy should be taken here, what would be seen on this skin biopsy?

Answer 11

Dudoendal biopsy is gold standard for diagnosing coeliac disease DH - Immunoflourescence reveals granular deposits of dermal papillary IgA against tissue transglutaminase Hallmark of the condition seen on histology is the presence of dermal papillary microasbcesses - mainly subepidermal disease

Question 12

What is the treatment of coeliac disease? Which treatment can be used to treat the itch and rash should dermatitis herptiformis be present? (failure to respond is very rare in this condition - almost a diagnostic treatment)

Answer 12

Treatment is a gluten free diet (avoid barley, rye and wheat) For dermatitis herpetiformis - daponse (an antibiotic) - very effective in treating itch/rash

Question 13

What causes lactose malabsoption? (disease is known as lactose inteorlerance) What is the presentation?

Answer 13

Lactose intolerance is characterised by reduced lactase enzyme concentration in the mucosal brush border of the small intestine The deficiency of the lactase enzyme results in the build up of lactose following ingestion of dairy products History of diarrhoea, abdo discomfort and flatulence following fairy product ingestion

Question 14

How is lactose interolance diagnosed and treated?

Answer 14

Diagnosis is usually clinical from trial of dietary elimination of lactose Can be confirmed by lactose hydrogen breath test Treatment is a lactose free diet

Question 15

What is tropical sprue and what is it caused by?

Answer 15

Tropical sprue is a malabsorption disease commonly found in tropical regions. - Far/Middle East and Caribbeans It is characterised by villi atrophy and inflammation of the lining of the small intestine. Whilst the aetiology is not fully clear it is thought to be infective in origin due to coloniszation of the intestine

Question 16

The symptoms of tropical sprue closely mimick that of coeliac disease Which patients should the diagnosis of tropical sprue be considered in? What are the symptoms?

Answer 16

Tropical sprue diagnosis should be considered in any patient with diarrhoea and signs and/or symptoms of malabsorption who has spent more than 2 weeks in a tropical region where the disease is endemic. Malabsorption symtpoms - steatorrhea, weirght loss, nausea, anorexia, anaemia, bloating

Question 17

What is the treatment of tropical sprue?

Answer 17

The treatment to tropical sprue involves tetracycline and folic acid

Question 18

What is whipple’s disease and what is it caused by? Who is it more common in?

Answer 18

Whipple’s disease is a rare mutli systemic disease featuring GI malabsorption It is caused by gramp positive bacterium Tropheryma whippelii infection. It is more common in those who are HLA-B27 positive and in middle-aged men.

Question 19

What are the main features of Whipple’s disease? (caused by Trophyeryma whipplei)

Answer 19

Main features * Arthralgia - seroneagtive arttropathy often HLA-B27 positive, affecting peripheral joints * GI malabsorptive sympotms - weight loss, diarrhoea, steatorrhea, bloating * Systemic symptoms such as fever, lymphadenopathy, skin hyperpigmentation Also CNS involvement may occur (demenia, ophthalmoplegia) Affected patients are typically middle-aged white men, who may present with weight loss, arthralgia, diarrhoea, and fever.

Question 20

How is Whipple’s disease diagnosed? How is it treated?

Answer 20

Diagnosis established by jejunal biopsy - shows macrophages in lamina propria which stain positive for periodic acid Schiff (PAS) Treatment is with Ceftriaxone IV (for 2 weeks) followed by Co-trimaxazole (for a year)

Question 21

Crohn’s disease will be discussed in more depth in a future flash card set - can affect anywhere of the GI tract from mouth to anus Which area of the GI tract does Crohn’s disease most commonly affect?

Answer 21

Terminal ileum is most commonly affected in Crohn’s disease

Question 22

What is the most common diagnosis for persistent traveller’s diarrhoea? (watery stools >/=3 times / day, lasting for greater than 14 days, starting during or shortly after foreign travel_ What type of infection is it and how is it spread?

Answer 22

Giardia lamblia (Giardisis) is a parasitic infection (flagellate protozaon) and is the most common diagnosis for persistent traveller’s diarrhoea It is spread via the oral faecal route by drinking infected drinking water/food where the supply may be contaminated

Question 23

What is the presentation of giardia lamblia? What is the incubation periods?

Answer 23

Incubation period is about 1-3 weeks Normally presents with Non-bloody diarrhoea, flatulence, bloating, pain, malabsorption symptoms eg steatorrhea/weight loss

Question 24

How is giardiasis diagnosed? How is treated?

Answer 24

Diagnosed via three separate stool samples for ova & parasites Treatment is with metronidazole for a week (or tinadazole as a single dose)

Question 25

What is small bowel bacterial overgrowth syndrome? What age group is it common in?

Answer 25

Small bowel bacterial overgrowth syndrome (SBBOS) is a disorder characterised by excessive amounts of bacteria in the small bowel resulting in gastrointestinal symptoms. It is spontaneous occurring but is especially common in the elderly

Question 26

What is the presentation of small bowel bacterial overgrowth syndrome?

Answer 26

Many overlapping features with irritable bowel syndrome Diarrhoea Bloating / flatulence Abdominal pain Also diverticula, fistulas and strictures may form Postop blind loops also common

Question 27

How is small bowel bacterial overgrowth syndrome diagnosed?

Answer 27

The diagnosis of bacterial overgrowth is made by a number of techniques, with the gold standard being an aspirate from the jejunum that grows in excessbacteria Treatment is usually tetracyclines or rifaximin (broad spectrum antibiotic) Post-op blind loops should be corrected