Small Intestinal Disorders and Investigation Flashcards
State the common disorders affecting the small intestine with particular reference to malabsorption.
Inflammation;
- Coeliac disease
- Crohn’s disease
Infection;
- Tropical sprue: folate deficiency, responds to antibiotics
Infection;
- HIV
- Giardia lamblia: unicellular parasite, contaminated water, responds to metronidazole, hypogammaglobulinaemia
- Whipple’s disease
State the common disorders affecting the small intestine and the principles of their investigation.
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State the common disorders affecting the small intestine and the principles of their management.
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List the medical and surgical causes of the acute abdomen including approaches to diagnosis and management including fluid balance.
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Explain the concept of maldigestion.
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Explain the clinical presentation of maldigestion.
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Explain the management of maldigestion.
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Explain the concept of malabsorption.
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Explain the clinical presentation of malabsorption.
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Explain the management of malabsorption.
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Describe the functions of the small intestine.
- Digestion: the breaking down of food into its components.
- Absorption: the passage of nutrients into the body.
- Barrier functions: regulating what stays in and gets out.
- Endocrine and neuronal control functions: controlling flow of material from stomach to colon, motility.
Describe the signs of specific vitamin deficiencies.
- Iron: B12, folate
- Ca2+, Mg2+ and vitamin D: tetany, osteomalacia
- Vitamin A: night blindness
- Vitamin K: raised PT (blood will take longer to clot)
- Vitamin B complex: thiamine (often on refeeding), memory, dementia
- Niacin: dermatitis, unexplained heart failure
- Vitamin C: scurvy
Discuss the investigations and management of patients with acute abdominal pain (including conditions such as peritonitis, obstruction and pancreatitis).
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Compare and contrast pathophysiological causes of abdominal swelling and outline relevant investigations.
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Describe digestion in the small intestine.
- Decontaminates dirty food.
- Requires a lot of fluid.
- Controlled hydrolysis to avoid fluid shifts.
- Sophisticated control of motility.
- Absorption against gradients.
- Onward processing in the liver.
Commences in the stomach;
- Salivary amylase
- Pepsin
- Controlled breakdown to avoid osmotic shifts
Briefly describe the digestion of proteins, fat and carbohydrates.
Proteins;
- Broken down into oligopeptides and amino acids.
- Trypsin, chymotrypsin
- Final hydrolysis and absorption at brush border
Fat;
- Pancreatic lipase
- Absorption of glycerol and FFAs
- Via lacteal and lymphatic system
Carbohydrates;
- Pancreatic amylase
- Breakdown to disaccharides
- Final digestion by brush border disaccharidase
Describe absorption in the small intestine.
Large surface area;
- Villous architecture
- Constant turnover of cells in crypts and villi
Describe the barrier functions of the small intestine.
Low bacterial population (toxic environment);
- Digestive enzymes
- Bile salts
- Presence of IgAm etc.
Maintaining a barrier against pathogens;
- Immune sampling
- Monitoring the presence of pathogens
- Translocation of bacteria
- Gut Associated Lymphoid Tissue (GALT)
Describe small bowel investigations.
Tests of structure;
- Small bowel biopsy: endoscopy
- CT scan
- MRI enterography
- Capsule enterography
Other assorted tests;
- H2 breath test: lactulose or glucose substrate
- Culture a duodenal or jejunal aspirate
Describe the symptoms of small bowel diseases.
- Weight loss
- Increased appetite
- Diarrhoea: usually watery, sometimes steatorrhea
- Bloating
- Fatigue
Describe steattorhea.
- Fat malabsorption
- High fat content in stool
- Stool less dense (floats) and can be difficult to flush
- Pale
- Foul-smelling
- May leave an oily mark or oil droplets
Describe the signs of small bowel diseases.
- Signs of weight loss
- Low of falling BMI.
Clubbing and aphthous ulceration are non-specific signs of which illnesses?
- Coeliac disease
- Crohn’s disease
Scleroderma is a non-specific sign of which illness?
Systemic sclerosis.
Dermatitis herpetiformis is a non-specific sign of which illness?
Cutaneous manifestation of coeliac disease;
- Blistering
- Intensely itchy
- Scalp, shoulder, elbows, knees
- IgA deposit in skin
Describe the serology test for coeliac disease.
- 90% specific and sensitive
- IgA tests more reliable than IgG
- Selective IgA deficiency is relatively common (0.1-1% of norm, 2-3% of coeliacs)
- Thus, always check total plasma IgA as well
Describe the confirmatory tests for coeliac disease.
Distal duodenal biopsy;
- Villous atrophy (partial, subtotal, total).
- Produces an inflammatory response: thought to be via tissue transglutaminase.
- Increased intra-epithelial lymphocytes.
HLA status;
- 97% of coeliacs are either HLA DQ2 or DQ8 (so is 30% of norm)
- Useful to exclude but not confirm in adults
(Anti-gliadin may help in children but not in adults.)
State conditions associated with coeliac disease.
- Dermatitis herpetiformis
- IDDM
- Autoimmune thyroid disease
- Autoimmune hepatitis
- Primary biliary cholangitis
- Autoimmune gastritis
- Sjogren’s syndrome
- IgA deficiency
- Down’s syndrome
Describe the complications of coeliac disease.
- Refractory coeliac disease
- Small bowel lymphoma
- Oesophageal carcinoma
- Colon cancer
- Small bowel carcinoma
Describe the treatment of small bowel bacterial overgrowth.
- Rotating antibiotics: metronidazole, tetracycline, amoxicillin (each for 2 weeks)
- Vitamin and nutritional supplements
