Gastroenterology

Small bowel disease

Coeliac disease

About

  • Common cause of malabsorption and needs a low threshold for testing

Aetiology

  • Gluten (alpha gliadin) Hypersensitivity causing malabsorption
  • Gluten is found in wheat, rye and barley
  • Commonest in West of Ireland 1 in 300 but UK is 1 in 2000 Aetiology
  • Chronic malabsorption due to subtotal villous atrophy in small intestine
  • T cell mediated chronic inflammatory response to epitopes 57-75 of gliadin
  • Gamma interferon mediated intestinal wall damage
  • 95% have HLA DQ2 and DQ8
  • Commoner in diabetics

Clinical Findings

  • Depends on the extent of the disease - presents at any age but usually childhood and adolescence
  • Abdominal pain, fatigue, arthralgia, headaches
  • Malabsorption due to villous atrophy in the small intestine and loss of absorptive cross sectional area
  • Anaemia, failure to thrive in infants
  • Osteomalacia and osteoporosis
  • Malabsorption of Fat soluble vitamins (ADEK), Iron, Folate
  • Steatorrhoea, Diarrhoea, altered bowel habit, Flatus
  • Dermatitis herpetiformis - itchy blisters on arms and elbows and wrist

Investigations

  • Microcytic anaemia - Iron deficiency - low ferritin
  • Macrocytic anaemia - Folate deficient (B12 deficiency uncommon)
  • Dimorphic with features of both
  • Low albumin
  • Low calcium and phosphate and raised alkaline phosphatase (Vitamin D and Calcium malabsorption)
  • Prolonged PT due to Vitamin K deficiency
  • Howell-Jolly bodies due to splenic atrophy
  • IgA anti tissue Transglutaminase (tTG) has 95% sensitivity and specificity.
  • Anti-endomysial antibodies. If negative and disease suspected measure Immunoglobulins as IgA deficiency not uncommon.
  • OGD - multiple distal duodenal biopsies needed as can be patchy and shows subtotal villous atrophy as well as lymphocytic and plasma cell infiltration of lamina propria.

Differential

  • Tropical sprue
  • Cystic fibrosis
  • Milk protein enteropathy
  • Giardiasis
  • Chronic pancreatitis
  • Abetalipoproteinaemia

Management

  • Lifelong Gluten free diet - no wheat rye or barley products
  • Steroids have been used in severe cases
  • Antibody levels fall with treatment which is a useful guide to adherence to Gluten free diet
  • Some would re-endoscope to see if there has been a histological improvement
  • Adherence to a gluten-free diet can reduce the risk of cancer
  • Consider screening family members

Complications

  • Infants - growth retardation, delayed puberty
  • Osteopenia
  • Mortality x 2
  • Small bowel adenocarcinoma
  • Hyposplenism
  • Oesophageal squamous cell
  • Non Hodgkin's Lymphoma
  • Decreased Breast cancer apparently
  • There is an increase incidence of various bowel malignancies (lymphomas, squamous cancer of oropharynx/oesophagus and adenocarcinoma of small bowel - new symptoms should be regarded seriously

Tropical Sprue

About

  • Small intestinal malabsorption seen in tropical areas
  • May occur years after leaving tropical area
  • Found in Southeast Asia and the Caribbean

Aetiology

  • Possibly infectious agent as responds to antibiotics

Clinical Findings

  • Diarrhoea, Fever
  • Weight loss, Oedema
  • Anorexia, Fatigue
  • Abdominal distension

Investigations

  • Anaemia - Iron, Folate and B12 deficiency
  • Fat malabsorption
  • Stool microscopy and cultures for Giardiasis

Management

  • Folic acid supplement
  • Tetracycline for 6 months
  • Nutritional supplementation - B12 and Iron

Whipple's disease

About

  • In 1907, Whipple described a medical missionary with a chronic illness characterised by episodes of arthritis, weight loss, cough, fever diarrhoea, abdominal discomfort, and anaemia.
  • Uniformly fatal until the 1960s, when antibiotic therapy provided a response in some patients.

Aetiology

  • Infection with Tropheryma whipplei
  • Acid fast negative PAS positive "foamy" macrophages
  • Increased HLA B27
  • Uncommon in Blacks and women
  • Malabsorption due to impaired local lymphatic drainage  

Characteristics

  • Gram positive bacterium
  • Culture is difficult

Clinical Findings

  • Malabsorption with steatorrhoea, bloating, flatus, cramps
  • Painful joints - may be inflamed
  • Pericarditis, Pleurisy and Peripheral neuropathy
  • Clubbing and lymphadenopathy
  • Dementia, myoclonus, ophthalmoplegia, encephalopathy
  • Oculomasticatory Myorhythmia - pathognomonic (eye moves with mastication)

Investigations

  • Low Potassium, magnesium, Calcium, Albumin, Carotene, Cholesterol
  • Prolonged Prothrombin time, raised alkaline phosphatase
  • Low B12, folate, ferritin
  • Histological - Acid fast negative PAS (Periodic acid -schiff) positive macrophages
  • Electron microscopy shows bacilli in affected organs 

Management

  • Treat with co-trimoxazole for 6-12 months
  • Replace nutrition

Terminal ileum disease/resection

Causes

  • Small bowel resection is required in Crohn's and other diseases
  • Sequelae depends on length of bowel removed Terminal Ileal disease/resection
  • Crohn's disease
  • Radiation treatment to gynaecological/rectal tumours
  • Ileal resection for urinary conduit

Aetiology

  • Loss of surface area for absorption
  • Loss of terminal ileum with specific uptake of B12 and Bile salts
  • Disruption of the enterohepatic bile salt cycle Clinical
  • B12 deficiency causes SACD, Megaloblastic anaemia
  • Bile salt uptake loss leads to diarrhoea and renal oxalate stones
  • Steatorrhoea
  • Severe cases - water loss
  • Oxalic acid in food (tea, spinach, chocolate etc) is effectively taken care of by calcium forming insoluble oxalate which is expelled with the faeces. Under normal conditions only small amounts of oxalic acid are therefore absorbed from the intestine. However in patients with steatorrhea the formation of insoluble calcium soaps interfere with this mechanism. Increasing amounts of oxalic acid are will be absorbed, and the concentration of oxalic acid in urine will increase. Patients with hyperoxaluria are at risk for developing renal oxalate stones.

Investigations

  • Megaloblastic anaemia
  • Low albumin
  • Hyperoxaluria - renal oxalate stones
  • Deficiencies of Vitamins ADEK
  • Other losses - Magnesium, Zinc, Calcium

Management

  • Low fat diet can help but with Nutritional support - ADEK, Minerals
  • Codeine/loperamide reduce diarrhoea
  • Cholestyramine may be useful in some but can make severe cases worse
  • MCT (Medium Chain Triglycerides (MCT) have been used by patients with malabsorption as they can be hydrolyzed and absorbed without previous emulsification.

Small Intestinal Bacterial overgrowth

About

  • Small intestine should be almost sterile
  • Bacterial overgrowth in the small intestine with > 100,000 bacteria per ml of fluid
  • Can lead to the syndrome of malabsorption

Normal Physiology

  • Colon < 1,000,000,000 bacteria per ml of fluid
  • Small intestine < 10,000 bacteria per ml of fluid
  • Bacterial produce Vitamin K and improve gut transit

Causes

  • Motility problems - autonomic neuropathy, amyloid, ileus, systemic sclerosis
  • Structural - previous surgery, Structure - diverticulae, blind loops
  • Loss of gastric acid - use of PPI's, H2 blockers, gastrectomy, atrophic gastritis /PA

Aetiology

  • High bacterial counts can cause symptoms
  • large numbers of gas-producing bacteria are present in the small intestine
  • Compete with the small intestine for sugars and carbohydrates and produce large amounts of gas
  • Can compete for nutrients which leads to deficiencies

Clinical Findings

  • Excess flatus
  • Diarrhoea
  • Bloating and abdominal discomfort

Investigations

  • Anaemia - raised MCV
  • B12 may be low Folate normal or high from bacterial production
  • Hydrogen breath test (HBT) or CO2 breath test
  • OGD and biopsy and perhaps sampling - exclude Coeliac disease
  • Proximal small bowel aspirates - increased coliforms or Bacteroides
  • Small bowel series to look for diverticulate and lesions

Differential

  • Coeliac disease
  • Irritable bowel syndrome

Management

  • Stop PPI/H2 blockers if not needed
  • Consider surgical management of structural lesions
  • Neomycin orally for 10 days, Augmentin, Cephalosporin, Metronidazole
  • Concern is development of resistance
  • Nutritional support B12, Calcium, Vitamin K, ADEK
  • Commercially available probiotics

Protein losing enteropathy

About

  • Abnormal serum protein loss e.g. Albumin across intestinal mucosa
  • Exceeds normal protein synthesis

Aetiology

  • Lymphatic obstruction
  • Abnormal Mucosal integrity
  • Localised ulceration

Causes

  • Crohn's disease and Ulcerative colitis
  • Menetrier's disease affects gastric mucosa
  • Coeliac disease
  • Lymphangiectasia
  • Amyloidosis
  • Pseudomembranous colitis
  • Tuberculosis
  • Sarcoid
  • Whipple's disease
  • AIDS

Clinical Findings

  • Anasarca and oedema
  • Cachexia

Investigations

  • Hypoalbuminaemia

Management

  • Protein supplementation
  • Treat cause
  • A low-fat diet with supplementation with medium-chain triglycerides is theoretically of benefit in patients with lymphangiectasia

Lactase deficiency

About

  • Deficiency of enzyme lactase to breakdown lactose

Aetiology

  • Results in a osmotic diarrhoea
  • Genetic, Seen in Asians and Blacks

Clinical Findings

  • Diarrhoea, Bloating, cramps

Investigations

  • Stool pH < 5.5
  • Assess response to lactose exclusion from diet
  • Equivalent of Glucose tolerance test but using a disaccharide shows a flat glucose response as not absorbed

Management

  • Avoid lactose
  • Lactase enzyme supplementation

Meckel's diverticulum

About

  • Results from incomplete obliteration of the omphalomesenteric duct.

Rule of 2s

  • Seen in 2% of population Males to females 2:1
  • Usually within 2 foot of caecum in the ILEUM small bowel and classically 2 inches long
  • May contain gastric type epithelium with HCl secreting parietal cells

Clinical Findings

  • Presentation commonest in those under 2 years of age
  • Lower GI bleeding from ulcerated small bowel epithelium
  • Intussusception

Investigations

  • Diagnosis can be confirmed with a radiolabelled technetium scan
  • 99 m technetium pertechnetate has an affinity for gastric mucosa.
  • Giving H2 blockers before the scan improves the sensitivity

Management

  • Surgical excision