Small bowel and appendix Flashcards
Tumors of the appendix
Very rare (0.9% of apply specimens)
Carcinoid: 0.5% appendectomy specimens (Neuroendocrine tumor)
Metastasis rare if tumor
Malabsorption/Maldigestion
Syndrome of disordered or inadequate absorption of nutrients
Clinical signs: weight loss, diarrhea, steatorrhea, vitamin deficiencies
Pale, bulky, malodorous stool
Float, difficult to flush
Oily residue
Causes: surgery, bacterial overgrowth, medications, pancreatic insufficiency, liver disease, intestinal inflammation, ulceration, ischemia, infiltration
Pancreatic Insufficiency
Digestive enzymes: Lipase, Trypsin etc 90% of pancreas burned out Lipid maldigestion first Protein malabsorption Carbohydrate malabsorption rare Chronic pancreatitis Cystic fibrosis
Liver Disease
Can cause malabsorption
Bile necessary for the absorption of lipids Cirrhosis Decreased function of hepatocytes Decreased bile formation Biliary Obstruction
Gastric bypass
malabsorption by design
B12, Fe, Ca, Vit D deficiencies the most common
Vitamin C, Cu rare
Prevention: Multivitamin
Monitoring Recommended
Small Bowel Bacterial Overgrowth (normal number of organisms/ml, causes, and clinical signs)
Normal bacteria: (
Tests for small bowel bacterial overgrowth and treatment
Fat soluble vitamin and B12 deficiency
Bacteria de-conjugate bile salts
Bacteria consume B12
Folate levels will be normal to high
Bacterial production
Diagnosis:
Aspiration of duodenum with culture
Glucose-Hydrogen breath test
Empiric Treatment with Antibiotics
Treatment: Antibiotics (e.g. Ciprofloxacin)
Celiac sprue
Gluten-sensitive enteropathy Wheat, barley, rye Inflammatory disease of small intestine Loss of villi, crypt hyperplasia, IE Lymphocytes 0.5-1.0% of US population 80% asymptomatic Incidence increases with age
Typical Celiac Sprue Signs and Symptoms
Abdominal distension Abdominal pain Anorexia Bulky, sticky, pale stools Steatorrhea Diarrhea Flatulence Failure to thrive Weight loss Fatigue Vomiting
Atypical Celiac Sprue Signs and Symptoms
Iron deficiency Anemia Dermatitis Herpetiformis Liver function tests AST, ALT elevations Cerebellar ataxia Osteoporosis Oral apthous ulcers
Celiac Pathogenesis
Associated with autoimmune diseases
e. g. Thyroiditis, Type-I diabetes
Female:Male=2:1
HLA-DQ2, HLA-DQ8 (40% US)
APC-MHC-II, present gluten peptides
2-5% gene carriers develop disease
Other genes + environment
CD4+ T cell response (IELs)
All have antibodies to tissue transglutaminase
Celiac sprue diagnosis and treatment
Diagnosis: findings on small intestine biopsy
Serologic Tests: anti-tissue transglutaminases, anti-endomysial antibodies, anti-gliadin IgA and IgG
Treatment: Gluten free diet
Future: Wheat without gluten epitopes, degradation of epitopes, oral tolerance, hookworms..
Tropical sprue
Residents or visitors to tropics
Cause: bacterial toxins or colonization of aerobic coliform bacteria
Classic presentation: Megaloblastic anemia from B12 and folate deficiency
Diagnosis: intestinal biopsy with villous flattening and travel history
Treatment: Antibiotics, B12, and folate
Whipple’s disease (epidemiology, cause, signs, diagnosis, and treatment)
Rare:
Mesenteric Ischemia
Atherosclerosis, Clot, Radiation
Chronic: 2 of 3 major vessels occluded
post-prandial abdominal pain, weight loss, sitophobia, malabsorption
Acute: embolus, severe abdominal pain
Malabsorption diagnostic tests
Focused testing-clinical scenario Fecal Fat Vitamin levels CBC, albumin CT-small bowel, liver, pancreas, bile ducts Endoscopy
Small Intestinal Tumors
Very rare cause of primary tumors (despite 90% of gut surface area)
Two main causes of diarrhea
- Decreased absorption of fluid and electrolytes
2. Increased secretion of fluid and electrolytes
Classification Of Diarrhea Based On Stool Characteristics
Fatty
Malabsorption
Maldigestion
Watery
Osmotic
Secretory
Inflammatory/Exudative
Blood
FunctionalWatery Diarrhea–Osmotic
Carbohydrate malabsorption
-Lactose
-Sorbitol (chewing gum)
-Fructose (non-diet drinks and many commercial foods—high fructose corn syrup)
Osmotic laxatives
-Magnesium-containing
-Phosphate, sulfate (colonoscopy bowel preps)
How can you tell the difference between Osmotic and Secretory Diarrhea
Measure stool sodium + potassium
The normal stool osmolality is 290 mOsm
Osm gap =290-2(stool sodium + potassium)
If the difference is > 50 mOsm, then the diarrhea is osmotic; if
Lactose intolerance
Down-regulation of lactase after weaning
Lactose ingestion leads to diarrhea (osmotic), flatulence (colonic bacteria)
Mutations in lactase promoter result in lactase persistence in ~80% Northern European and nomadic populations
Causes of Watery Diarrhea–Secretory
Bacterial toxins
-V. cholerae, E. coli enterotoxins
Neuroendocrine tumors (rare) -gastrinoma, VIPoma, carcinoids, calcitonin
Ileal bile salt malabsorption
Stimulant laxatives
Disordered motility/regulation
-Diabetic neuropathy, postvagotomy, irritable bowel syndrome
Bile-acid induced diarrhea
bile salts stimulate colon and can cause diarrhea
Causes of fatty diarrhea
Malabsorption syndromes
-Mucosal diseases (Celiac disease, Whipple’s disease)
-Short-bowel syndrome
-Small bowel bacterial overgrowth
Maldigestion/Malabsorption
-Pancreatic insufficiency
-Inadequate luminal bile salt concentration (chronic liver disease, biliary obstruction)
Causes of Inflammatory Diarrhea
Infection Inflammatory Bowel Disease Crohn’s Disease Ulcerative Colitis Ischemia
How to test for fatty diarrhea
Sudan fat stain
Have pt eat high fat meal before
Inflammatory Diarrhea Diagnosis
Infection: Usually Stool Culture; Endoscopy
Ischemia: CT scan; Endoscopy-colon
Inflammatory Bowel Disease: Endoscopy
Irritable Bowel Syndrome (IBS): characteristics
Abdominal Pain and altered bowel habits in the absence of an organic cause
Pain improved with defecation
Pain onset with change in stool frequency
Pain onset with change in stool appearance
Constipation and/or Diarrhea
10-15% of the population North America
Possible mechanisms of IBS
Visceral hypersensitivity
Carbohydrate malabsorption (consider FODMAPS diet)
Low grade inflammation
