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Gastrointestinal Disorders . Disorders of Nutrition. Alterations in: Ingesting Digesting Absorbing Eliminating. Anorexia Pica
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Gastrointestinal Disorders
Disorders of Nutrition Alterations in: Ingesting Digesting Absorbing Eliminating
Anorexia Pica Nausea & Nausea Esophageal Atresia Tracheoesopheal fistula Cleft lip/palate Anorexia Nervosa Pyloric Stenosis Projectile Vomiting Ingestion
Maldigestion • Lactic Deficiency • Pancreatitis • Cystic Fibrosis
Malabsorption • Intestinal Parasites • Gastrectomy Loss of Stomach as Reservoir for Food Dumping Syndrome Loss of Intrinsic Factor • Celiac Disease (Sprue) • Cholecystitis/Cholelithiasis • Regional Enteritis (Crohn’s Disease)
Elimination • Diarrhea Osmotic Changes Secretory Changes Mucosal Damage Altered Motility • Crohn’s Disease • Ulcerative Colitis
Basic Structure of the GI tract PSNS SNS longitudinal muscle Myenteric plexus Circular muscle Submucosal plexus Submucosa Lumen
Enteric Nervous System Influenced by ANS PSNS SNS Pelvic nerves NE Ach ENTERIC NERVOUS SYSTEM Myenteric Submucosal Smooth muscle Secretory Cells Endocrine Cells Blood Vessels
Gastric Motility LES fundus pylorus receptive relaxation Antrum approx 3 contractions per minute
Control of Gastric Emptying PSNS SNS + - GASTRIC EMPTYING - - secretin - CCK Duodenal acid Duodenal fats Duodenal hypertonicity
Small and Large Bowel Motility • Small Intestine • 2-4 hours to traverse • Segmental contractions to mix • Peristaltic waves to move forward • Large Intestine • Slow progression at 5-10 cm per hour • Segmental contractions produce haustra • 1-3 mass movements per day
Secretion in the Stomach • Parietal Cells • HCL • Intrinsic Factor • Chief Cells • Pepsinogen • Surface epithelia and mucous cells • HCO3- and mucus
Control of Acid Secretion VagusMast CellsG cells Ach Histamine Gastrin muscarinic receptor H2 receptor gastrin receptor Gastric Parietal Cell Acid Secretion
Secretion in the Small Intestine • Secretions from Pancreas • HCO3-, Proteases, Lipases, Amylases • Secretion from Gallbladder • Bile acids, pigment, phospholipid • Secretions from intestinal epithelia • Brush border enzymes
Brush Border Enzymes Lactase: lactose glucose, galactose Sucrase: sucrose fructose, glucose Dextrinase: cleaves amylose branch points Glucoamylase: maltose glucoses Only Monosaccharides are Absorbed
Digestion and Absorption of Proteins • Pepsin: 15% of peptide bonds broken • Pancreatic proteases • Trypsin • Chymotrypsin • Carboxypeptidases • Brush Border • Peptidases cleave into 1 to 4 aa chains
Digestion and Absorption of Fat • Bile salts are amphipathic molecules that break up large fat globs into droplet • Lipase are water soluble - only work at surface of droplet • Triglycerides --------> FFA and glycerol • Bile forms micelles with FFA to keep soluble. • FFA are lipid soluble so absorb directly
Reabsorption of Bile • Bile is reabsorbed at terminal ileum • Passive diffusion and active transport • Transported to liver via portal blood • ALL reabsorbed bile is taken up on first pass by liver • Entire bile pool circulates 2 to 5 times per meal. 5-10% lost per day in stool
Dysphagia • Neuromuscular: pharynx • Stricture or tumor: Progressive solid food dysphagia • Achalasia: esophageal motility disorder, loss of peristalsis in lower 2/3 plus impaired LES relaxation • Mallory-Weiss syndrome: mucosal tears at distal esophagus, bleeding, pain
Nasal regurgitation Airway obstruction with eating Coughing when swallowing Immediate regurgitation Hoarse voice No airway distress Late regurgitation Chest pain @ meals Frequent heartburn Presence of collagen disease Presence of Left supraclavicular node Oropharyngeal vs Esophageal
Dyspepsia • Present with heartburn, indigestion, epigastric distress • Up to 2/3 will have no identifiable cause • One-half will have relief from placebo • Symptom profile does not differentiate between GERD, PUD, and non-ulcer dyspepsia (functional) • Physical exam is rarely helpful
Diagnosis • NSAID: suspect PUD and treat • Helicobacter pylori: urea breath test or biopsy during endoscopy • GERD: Trial of H2 therapy • Functional: may improve with agents that increase motility • Zollinger-Ellison syndrome: gastrin level
PUD with H. pylori • H. pylori is nearly always a factor in non-NSAID peptic ulcer disease • Conventional therapy with H2 blockers or H+ pump inhibitors has a 75-80% one-year recurrence rate • Treatment for H. pylori reduced recurrence rate to less than 5%
Acute Infectious Diarrhea High fever? Bloody diarrhea? NO YES Noninflammatory Inflammatory watery large volume periumbilical pain small volume LLQ pain + fecal leukocytes Shigella, Salmonella, C. difficile, E. coli (bad) Campylobacter, HIV- associated Viral: rotavirus, Norwalk S. aureus food poisoning Giardia Rehydrate, symptomatic Culture and treat
Chronic Diarrhea: Stool Studies • Stool Osmolality: normal gap < 50 • Laxative screen: Mg, PO4, SO4 • Fecal leukocytes: Inflammatory disease • Ova and parasites: Giardia, cryptosporidium • Fecal Fat analysis: > 10 g/24 hrs indicates malabsorption • Fecal weight: > 1000 g is secretory
Osmotic Diarrhea: Lactase Def. • Incidence • 90% of Asian Americans • 95% of Native Americans • 50% of Mexican Americans • 60% of Jewish Americans • 25% of other Caucasians • DX: empiric trial of lactose-free diet for two weeks
Inflammatory Bowel Disease • Ulcerative Colitis • Involves only the colon and rectum • Mucosal layer is affected • Hallmark is bloody diarrhea and lower abdominal cramps • Associated with increased cancer risk after 8-10 years of disease
Assess UC Disease Severity • Number of stools per day • Hematocrit • Sed rate • Albumin level
Crohn Disease • Intermittent bouts of fever, diarrhea, and RLQ pain • May have RLQ mass, tenderness • Can affect any portion of GI tract • 30% are small bowel only • 50% are small and large bowel • 15-20% are large bowel only
Crohn Disease • Transmural process in the intestinal wall predisposes to fistula formation • If suspected, obtain upper GI series with small bowel follow through plus either colonoscopy or barium enema • Suggestive findings are ulcerations, strictures, and fistulas • RX: stop smoking, drugs similar to UC
Crohn’s Disease “Skip” Lesions (granulomatous) Terminal ileum Diarrhea/Constipation Alternates – Less Bloody Malignant Potential(not totally determined) Proned to Develop Abcesses & Fistula formation Ulcerative ColitisContinuous ulcerationof mucosa of colonColon, rectum – distalWatery diarrhea – has mucus/pus – may be bloody – commonProned to develop colon carcinomarare abcess/fistula formation Compare and Contrast – CD & UC
Motility Diarrhea: IBS • Irritable bowel syndrome is a chronic (>3months) functional disorder with no identifiable pathology • Fluctuations in stool frequency and consistency (no nocturnal diarrhea) • Perceived abd distention, bloating, pain • Often associated with anxiety or depression
IBS • It is not IBS if fever, bloody stools, nocturnal diarrhea, or weight loss are present • Consider checking CBC, sed rate, albumin, and stool for occult blood to rule out inflammatory disease, consider lactose-free trial. • RX: restrict caffeine, gas producing food, high fiber. Rx depression
Occult GI Bleeding • Detected by FOBT: worry colorectal CA • Indicated for iron deficiency anemia in males or postmenopausal females • Unless S&S suggest Upper GI etiology (heartburn, dyspepsia PUD) start with colonoscopy (or barium enema) • If no source, follow with endoscopy
Acute Abdominal Pain • Tension: spasm, associated with intense peristalsis (irritant, infection, obstruction) • Ischemia: intense constant pain (bowel strangulation, volvulus adhesion) • Inflammation: first localized to serosa covering inflamed part then extends to abdominal wall causing reflex muscle spasms (rigidity, involuntary guarding)
Assessment of the Pain • Is it nongastric? consider aortic aneurysm, ectopic pregnancy, PID, kidney • Is it an acute surgical abdomen? • Involuntary guarding, rigidity • Absent bowel sounds • Is there shock
Localization of Abdominal Pain • Stomach, duodenum: mid epigastric • Small bowel: periumbilical • Colon: low abdomen, midline • Rectum: sacrum and perineum • Gallbladder: mid epigastric radiates to RUQ or right scapula • Pancreas: mid epigastric radiate to back • Appendix: RLQ, but variable
Bowel Obstruction • Presentation • Pain, distention, vomiting, obstipation • Evaluation • Flat and upright abdominal film • Small bowel: less urgent • intestinal tube, decompression • Large bowel: urgent, danger of cecal perf • immediate surgical consult
Mechanical Obstruction * Adhesions * Tumors * Impaction * Strangulated Hernia * Volvulus “Twisting” * Intussusception (telescoping) Functional Obstruction * Bowel Manipulation (surgery) * Narcotic Anesthesia * Peritonitis Types of Bowel Obstruction
“Itis” from TOP to BOTTOM “itis” Etiology Clinical Findings esophagitis reflux (GERD) - pain after meals - “heartburn” gastritis -PUD ASA, ETOH - epigastric pain H. pylori regional enteritis ? Etiology - diarrhea with (Crohn) blood and mucus ulcerative colitis ? Etiology - bloody diarrhea
“Itis” from TOP to BOTTOM “itis” Etiology Clinical Findings diverticulitis low fiber diet low abdominal pain, fever appendicitis obstruction - RLQ pain, fever “fecalith” - rebound pain peritonitis perforation - severe pain, ileus bowel ischemia - guarding, rigid pancreatitis biliary disease - pain to back, shock ETOH - high lipase, amylase
“Itis” from TOP to BOTTOM “itis” Etiology Clinical Findings cholecystitis cholelithiasis - RUQ pain - steatorrhea hepatitis viral, acute ETOH - jaundice, big liver - high AST, ALT - flu-like symptoms
Appendicitis • Etiology: • Obstruction by fecalith, inflammation • Presentation: • RLQ pain (classic, but may be anywhere), N&V, fever, diarrhea, RLQ tenderness • Evaluation: CBC, abdominal ultrasound • RX: immediate surgical consult
Diverticulitis • Etiology: • Microperforation with peridiverticular inflammation • Presentation: • Elderly with LLQ pain, severe constipation, nausea, fever • Evaluation: • CBC, abd film, CT if peritoneal signs • Rx: NPO, antibiotics, IV fluids
Acute Pancreatitis • Etiology: unknown • Associated with ETOH, biliary disease • Presentation: • Severe epigastric and back pain • Evaluation: • CBC, glucose, calcium, electrolytes, amylase, lipase (renal studies) • Severity index
During first 48 hours HCT drop of >10% BUN rise >5 mg/dl PaO2 < 60 Calcium < 8 mg/dl Fluid sequestration of > 6 liters Severity Scale: Pancreatitis Initially • Age over 55 • WBC > 16,000 • Blood glucose > 200 • Base deficit > 4 • Serum LDH >350 • AST > 250
Pancreatitis Severity Number of criteria Mortality Rate 0-2 3-4 5-6 7-8 1% 16% 40% 100%
Cholecystitis • Etiology: • 95% associated with stone in cystic duct • Presentation: • Often obese female, fever, RUQ pain with scapular or epigastric pain, colicky, N&V • Evaluation: • CBC, RUQ ultrasound, HIDA scan • RX: Prompt cholecystectomy