GI Pharmacology Quick Review

Overview

Lecture covered GI pharmacology (laxatives, antidiarrheals), functional and inflammatory bowel disorders, appendicitis, diverticular disease, and accessory organ disorders (liver, gallbladder, pancreas), including diagnostics, management, and key nursing considerations.

Laxatives: Types, Uses, Side Effects

• All promote bowel movements; mechanisms differ; used for constipation and colon prep.
• Bulk-forming: psyllium (Metamucil) increases stool bulk, eases passage.
• Emollient: mineral oil softens stool; stool softeners like docusate ease passage.
• Hyperosmotic: lactulose pulls water; also used to reduce ammonia in cirrhosis.
• Stimulant/irritant: bisacodyl, senna stimulate intestinal lining.
• Saline: pull water into intestines to ease defecation.
• Bowel evacuants: polyethylene glycol (MiraLAX, GoLYTELY) for colonoscopy prep.
• Side effects: diarrhea, nausea, bloating, flatulence; risk of dependence with chronic use.
• Long-term use only with provider monitoring; taper if used chronically.

Antidiarrheals: Classes, Actions, Nursing Points

• Agents: loperamide, diphenoxylate, bismuth, probiotics.
• Probiotics restore normal gut flora; support healthy GI function.
• Mechanisms: reduce water absorption into lumen and/or slow peristalsis.
• Side effects: dry skin/mucous membranes, constipation if excessive.
• Nursing: encourage fluids; monitor for fecal impaction/obstruction.

Irritable Bowel Syndrome (IBS)

• Functional motility disorder; bowel moves too fast or too slow.
• More common in women; often diagnosed in younger patients; genetic tendency.
• Symptoms: chronic constipation with bouts of diarrhea; belching, flatulence; no weight/metabolic changes.
• Key feature: no detectable disease after excluding other GI conditions.
• Diagnosis: barium enema, colonoscopy to rule out other diseases.
• Management: lifestyle changes, high-fiber diet, food diary; anticholinergics (dicyclomine) to reduce spasms.

Inflammatory Bowel Disease (IBD): Crohn’s vs Ulcerative Colitis

• Chronic autoimmune inflammation; requires medical intervention; no cure, management only.
• Location: UC limited to large intestine/colon; Crohn’s can affect any GI segment, commonly ileum.
• Pattern: UC continuous inflammation (LLQ pain); Crohn’s patchy “skip” lesions (RLQ pain).
• Depth: UC mucosal layer; Crohn’s transmural, can tunnel/fistulize.
• Bleeding: common in UC; uncommon in Crohn’s.
• Diagnosis: stool cultures, CBC (anemia), barium enema, colonoscopy.
• Surgery: Crohn’s surgery does not change recurrence; UC may benefit from ileoanal pull-through anastomosis.

IBD Pharmacologic Management

• Aminosalicylates: sulfasalazine; oral, topical anti-inflammatory in bowel.
• Side effects: headache, abdominal pain, nausea.
• Nursing: avoid with aspirin allergy (cross-sensitivity); monitor labs in renal failure.
• Other: vitamin/mineral supplementation; corticosteroids (prednisone); immunomodulators and biologics to prevent flares.

Appendicitis

• Inflammation of vermiform appendix due to obstructed appendiceal sphincter.
• Common in adolescents/young adults; obstruction by inflammation, disease, or fecalith.
• Early pain generalized; localizes to McBurney’s point (RLQ between umbilicus and right iliac crest).
• Other signs: rebound tenderness, fever, nausea, vomiting, lumbar pain, dysuria with pressure.
• Rupture: paralytic ileus, diffuse pain, absent bowel sounds; pediatric patients often rupture before diagnosis.
• Diagnostics: leukocytosis with neutrophilia; CT or ultrasound.
• Management: antibiotics; appendectomy; avoid abdominal palpation if suspected.
• Post-op nursing: IV fluids, pain control, activity restriction despite rapid symptom relief.
• Geriatrics: atypical presentation; may lack classic RLQ pain.

Diverticulosis and Diverticulitis

• Diverticula: mucosal herniations forming pouches; fecal retention causes inflammation/infection.
• Diverticulosis: diverticula present, asymptomatic; diverticulitis: inflamed diverticula.
• Risks: low-fiber diet, chronic constipation, possible hereditary weakness of intestinal wall.
• Symptoms: constipation alternating with diarrhea; LLQ pain/tenderness; flatulence; maroon or currant jelly stools.
• Diagnosis: CT, barium enema, colonoscopy.
• Management: high-fiber diet (20–35 g/day) and/or bulk-forming laxatives (psyllium).
• Surgical: bowel resection for perforation; possible colostomy (less common).

Liver Disorders: Jaundice and Cirrhosis

• Jaundice is a symptom from bilirubin buildup due to impaired hepatic processing.
• Normal bilirubin: 0.2–1.3 mg/dL; jaundice typically >2.5 mg/dL.
• Best assessment sites: sclerae and palms; gums/hard palate also useful.
• Bilirubin types: direct/conjugated (processed by liver); indirect/unconjugated (unprocessed).

Cirrhosis: Etiology, Findings, Management

• Chronic degenerative liver disorder with diffuse cellular damage and fibrosis.
• Common causes: alcohol; also NASH (nonalcoholic fatty liver disease) related to diabetes, dyslipidemia, CAD.
• Complications: fat malabsorption, portal hypertension, esophageal varices, ascites, hepatic encephalopathy.
• Diagnostics: liver biopsy (fibrosis); elevated bilirubin and liver enzymes (AST/ALT/ALP/GGT); low RBCs, platelets, albumin.
• Goals: prevent deterioration; no cure; emphasize alcohol cessation.
• Diet: high protein, low sodium, calorie-dense frequent meals (unless contraindicated by encephalopathy).
• Lactulose: reduces ammonia; typically dosed to produce about three bowel movements daily.

Cirrhosis Complications

• Portal hypertension: scarring compresses portal vein, causing systemic portal congestion.

• Consequences: esophageal/gastric varices, splenomegaly, hemorrhoids; GI bleeding; ascites; thrombocytopenia.

• Treatment goals: reduce fluid volume and venous pressure.

• Esophageal varices:

  • Dilated esophageal veins; high bleeding risk, can be fatal.
  • Treatments: injection sclerotherapy; variceal band ligation.

• Ascites:

  • Peritoneal fluid accumulation; worsened by low albumin.
  • Symptoms: massive abdominal distention.
  • Treatment: paracentesis, diuretics, low sodium diet.
  • Nursing: measure abdominal girth at umbilicus to trend improvement.

• Hepatic encephalopathy:

  • Neurotoxicity from elevated serum ammonia.
  • Signs: disorientation, drowsiness, confusion; check ammonia level.
  • Prevention: adherence to scheduled lactulose; patient education crucial.

Hepatitis (A, B, C, D, E, G)

• Inflammation of liver; acute or chronic; most commonly viral.
• Transmission:
  • Hep A, E: fecal-oral (contaminated food/water).
  • Hep B, C: blood and sexual contact.
  • Hep D: superinfection with hepatitis B.
  • Hep G: associated with post-transfusion; uncommon.
• Phases: incubation (infectious, asymptomatic), prodromal (GI symptoms, malaise), icteric (peak symptoms), posticteric (recovery).
• Diagnostics: viral antibodies, PT/PTT, liver function studies.
• Management: supportive care; balanced diet, rest, IV fluids, vitamins.
• Advanced therapies: interferon and antivirals for B and C to achieve remission.
• Severe cases: risk of permanent liver damage requiring transplant.

Gallbladder Disorders: Cholelithiasis and Cholecystitis

• Cholelithiasis: gallstones; cholecystitis: inflammation/infection; often coexist.
• Risks: advanced age, female sex.
• Symptoms: belching, nausea, RUQ biliary colic pain.
• Diagnostics: CT, ultrasound, ERCP.
• Management: NPO initially; gradual low-residue diet; analgesics; NG decompression post-op as needed.
• Procedures: lithotripsy; laparoscopic cholecystectomy (preferred); open cholecystectomy in selected cases.

Pancreatitis

• Acute pancreatitis:

  • Enzyme backup causes autodigestion; mild to severe; can be fatal.
  • Causes: alcohol; metabolic disorders; trauma; infection; hereditary; refeeding; idiopathic.
  • Symptoms: severe upper abdominal pain worsened by eating; steatorrhea (fatty, foamy stools).
  • Diagnostics: amylase and lipase >200; elevated liver tests; CT/ultrasound.
  • Management: NPO, pain control; improvement usually within one week.

• Chronic pancreatitis:

  • Progressive; pancreas hardens; loss of function; alcohol most common cause.
  • Symptoms: severe pain, weight loss.
  • Diagnostics: similar to acute.
  • Management: abstain from alcohol; NSAIDs/opioids for pain; pancreatic enzyme replacement (e.g., pancreatase); insulin for hyperglycemia.
  • Severe cases: partial/total pancreatectomy.

Key Terms & Definitions

• McBurney’s point: RLQ point between umbilicus and right iliac crest; focal appendicitis pain.
• Biliary colic: RUQ pain from gallbladder disease.
• Ascites: fluid accumulation in peritoneal cavity due to portal hypertension and hypoalbuminemia.
• Steatorrhea: fatty, foamy stools due to malabsorption or pancreatic insufficiency.
• Variceal banding: rubber band ligation of varices to prevent bleeding.
• Ileoanal pull-through anastomosis: surgical creation of a new pouch after resection in UC.

Structured Comparisons and Key Values

Action Items / Next Steps

• Review differences between IBS and IBD; memorize UC vs Crohn’s comparison.
• Practice identifying appendicitis via McBurney’s point and associated signs.
• Know indications, examples, and nursing considerations for laxatives and antidiarrheals.
• Memorize bilirubin thresholds, best sites to assess jaundice, and cirrhosis labs.
• Understand portal hypertension complications and nursing assessments (abdominal girth for ascites).
• Study hepatitis transmission routes and supportive vs antiviral management.
• Review pancreatitis labs (amylase, lipase), symptoms, and acute vs chronic care.
• Prepare examples for stimulant, saline, and bulk-forming laxatives for test recall.