Notes on Gastrointestinal Disorders

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Cleft lip:

• Failure of fusion of facial processes.

Infections in AIDS patients:

• Candidiasis, apthous ulcers, hairy leukoplakia, Kaposi sarcoma.

Dental caries:

• S. mutans.

Treatment:

• Fluoride.

Erythema multiforme:

• Hypersensitivity reaction against Mycoplasma, drugs.

• AKA Stevens-Johnson syndrome.

Peutz-Jeghers syndrome:

• Melanin pigmentation of lips and oral mucosa.

Addison's disease:

• Increased ACTH causes melanocyte stimulation.

Lead poisioning:

• Lead deposition along gingival margins.

Leukoplakia and erythroplakia:

• Lesion doesn't wipe off.

Causes:

• Irritation, alcohol, tobacco, HPV.

Benign: Squamous papillomas:

• Most common tumors of oral cavity.

Malignant: oral cavity tumors:

• Smoking, tobacco.

• HPV; irritation from dentures.

Sjogren's syndrome:

• Autoimmune destruction of salivary glands.

Esophageal disorders:

Heart burn:

• Caused due to GRD.

Dysphagia:

• Caused due to obstructive lesion.

Tracheoesophageal fistula:

• Distal esophagus arises from trachea; proximal esophagus ends blindly.

• Stuff swallowed ends up in trachea.

• Food regurgitates in mouth.

Plummer-Vinson syndrome:

• Iron deficiency.

• Dysphagia for solids only.

Esophageal diverticulum:

• True, false, Zenker's.

• Painful swallowing, halitosis (trapped food).

Gastroesophageal reflux disease: GERD:

Caused by:

• Smoking, alcohol, caffeine, chocolate, hiatal hernia.

Findings:

• Chest pain, cough, asthma, heartburn, acid injury to enamel, Barrett's esophagus.

Barrett's esophagus:

• Complication of GERD.

• Glandular metaplasia in distal esophagus.

• Ulceration, glandular dysplasia; adenocarcinoma risk.

Infectious esophagitis:

• Complication of AIDS.

• Caused due to: HSV, CMV, Candida.

Esophageal varices:

• Dialated submucosal left gastric veins.

• Caused due to: cirrhosis.

• Vomiting blood.

Mallory-Weiss syndrome:

• Mucosal tear in esophagus and stomach.

Boerhaave's syndrome:

• Rupture of distal esophagus.

Achalasia:

• Incomplete relaxation of LES.

• Absent ganglion cells of myenteric plexus.

• No peristalsis.

Causes:

• Chagas disease.

• Abnormal barium swallow: beak-like (bird-beak) tapering at distal end of esophagus.

Esophageal tumors:

Leiomyoma:

• Most common benign tumor.

Adenocarcinoma:

• Most common primary cancer of esophagus.

Squamous cell carcinoma:

• Common primary cancer in developing countries.

• Smoking, alcohol.

• Plummer-Vinson syndrome.

• Findings: dysphagia, weight-loss.

Congenital pyloric stenosis:

• Projectile vomiting.

• Hypertrophy of muscles in pyloric sphincter.

Gastroparesis:

• Decreased stomach motiliy.

Acute hemorrhagic gastritis:

• Ulcers.

Causes:

• NSAIDS, AIDS, CMV, alcohol, smoking, burns.

Findings:

• Hematemesis, melena, iron deficiency.

Chronic atrophic gastritis: Type A:

• Due to pernicious anemia.

Chronic atrophic gastritis: Type B:

• Due to H. pylori.

• Tests to detect H. pylori: urease, urea breath test, serologic tests, stool antigen test.

• Chronic inflammation, intestinal metaplasia.

Chronic atrophic gastritis:

Menetrier's disease:

• Giant rugal folds.

• Due to hyperplasia of mucus-secreting cells.

Findings:

• Hypoproteinemia.

• Risk for adenocarcinoma.

Peptic ulcer disease:

• H. pylori.

• Gastric ulcers.

Zollinger-Ellison syndrome:

• Tumor most likely located on the pancreas.

• Excess secretion of gastrin, which causes acid secretion by parietal cells and increased parietal cell volume.

• Hyperacidity.

• Gastric pain, weight loss.

• Maldigestion of food.

• Increased BAO, MAO, and BAO/MAO ratio.

Gastric polyps:

• Due to gastritis and achlorhydria.

• Most common: hyperplastic polyp.

Gastric tumors:

Leiomyoma:

Intestinal type of gastric adenocarcinoma:

• H. pylori.

• Nitrosamines, smoked foods, lack of fruits/vegetables.

• Gastritis, Menetrier's disease.

Diffuse type of gastric adenocarcinoma:

• No H. pylori association.

• Infiltration of malignant cells in stomach.

• Produces Krukenberg tumors in ovaries.

• Weight loss, metastasis to left supraclavicular node.

• Spreads to liver, lung, ovaries.

Primary gastric malignant lymphoma:

• H. pylori related.

Findings in small bowel disease:

• Colicky pain: pain occurs in intervals.

• Diarrhea.

• Anemia: malabsorption of iron, folate, vitamin B12.

Findings in large bowl disease:

• Diarrhea.

• Pain.

• Iron deficiency.

• Hematochezia: massive blood loss.

Diarrheal screening tests:

• Fecal smear for leukocytes.

Stool osmotic gap:

• Less than 50 mOsm/kg = secretory diarrhea.

• Greater than 100 mOsm/kg = osmotic diarrhea.

Malabsorption:

Pancreatic insufficiency:

• Pancreatitis, diminished lipase and trypsin activity.

• CT scan of pancreas shows dystrophic calcification.

Bile salt deficiency:

• Inadequate bile salt production or blockage.

• Bacterial growth in SI.

• Excess binding of bile salts.

Small bowel disease:

• Malabsorption.

• Micelles are excreted.

• Lymphatic obstruction.

Screening:

• D-Xylose test.

• Lack of absorption = disease.

• Fat in stool.

Findings:

• Steatorrhea, vitamin deficiencies, anemias, ascites and pitting edema.

Vascular disorders:

• Small Intestine more likely to have ischemic damage.

• Small Intestine supplied by superior mesenteric artery.

• Splenic flexure is a water-shed area.

Infarctions:

Transmural:

• Full-thickness; superior mesenteric artery occlusion.

Mural and mucosal:

• Occur in shock.

Causes of acute ischemia in small intestine:

• Embolism from left side of heart to superior mesenteric artery.

• Thrombosis of superior mesenteric artery.

• Heart failure.

• Shock.

• Mesenteric vein thrombosis.

Findings:

• Abdominal pain, absent bowel sounds, no rebound tenderness, leukocytosis, increased amylase.

• Thumbprint sign.

• Bowel distention with air/fluid.

Ischemic colitis:

• Involves splenic flexure of large intestine.

• Atherosclerotic narrowing of superior mesenteric artery and inferior mesenteric artery.

• Pain after eating so patient doesn't eat.

• Bloody diarrhea.

Angiodysplasia:

• Dilation of mucosal and submucosal venules in cecum and right colon.

• Elderly.

• Hematochezia.

Small bowel diverticula:

Meckel diverticulum:

• 2 inches long; 2 feet from ilecocecal valve; 2% of population; 2% symptomatic.

Findings:

• Fecal material in umbilical area.

• Bleeding.

• Diverticulitis.

Diagnosis:

• 99m Tc nuclear scan.

Pulsion diverticula:

• Duodenum.

Complications:

• Divertilucitis, bacterial overgrowth.

Pulsion diverticula:

• Sigmoid colon.

• Low-fiber diet.

• Present in Marfan syndrome and Ehler-Danols syndrome.

• "left-sided appendicitis."

Inflammatory bowel disease:

Ulcerative colitis:

• Most common.

• Ulcerations.

Crohn's disease:

• Granulomatous, ulceroconstrictive disease.

• Discontinuous spread throughout entire GI tract.

Irritable bowel syndrome:

• Alternating bouts of diarrhea and constipation.

Small bowel malignancy:

Primary adenocarcinoma:

• Duodenum, most common site.

Carcinoid tumor:

• Most common small bowel disorder; neuroendocrine tumor.

If located on tip of vermiform appendix:

• Too small to metastasize

If located on terminal ileum:

• Metastasis to liver; 5-HIAA in urine.

• Bright yellow tumor.

Carcinoid syndrome:

• Syndrome produced with liver metastasis.

• Increased serotonin; flushed skin, diarrhea; tricuspid regurgitation; pulmonary stenosis.

• Increased urine 5-HIAA.

Non-neoplastic (hamartomatous) polyps:

Bowel polyps: Hyperplastic polyp:

• Majority in sigmoid colon.

• Sawtooth appreance.

Juvenile (retention) polyp:

• Common in children.

• Rectum.

• Cronkhite-Canada syndrome.

Peutz-Jeghers polyposis:

• AD disease.

• Mucosal pigmentation of buccal mucosa, and lips.

Neoplastic polyps:

• AKA adenomas.

Bowel polyps:

Tubular adenoma:

• Most common.

• Looks like a mushroom.

Tubulovillous adenoma:

• Stalked polyp.

Villous adenoma:

• Secrete protein and potassium-rich mucus.

Familial polyposis:

• AD disease.

• Adenomatous polyposis coli (APC) suppressor gene inactivated.

Gardner's syndrome:

• AD polyposis syndrome.

• Brain tumors.

Colon cancer:

• Increasing age.

• Low-fiber diet.

• Smoking.

• Familial polyposis, ulcerative colitis.

• Mutant APC, RAS, TP53.

• Common location: rectosigmoid.

• Test: fecal occult blood test, colonoscopy, barium enema.

• Constipation and diarrhea with or without bleeding.

• Spreads to: liver (common), lungs, bone, brain.

Acute appendicitis:

• Children: lymphoid hyperplasia.

• Adults: fecalith obstruction of proximal lumen.

• Initial colicky periumbilical pain.

• Nausea, vomiting, fever.

• Tenderness at McBurney's point (Blumberg's sign).

• Laboratory: neutrophilic leukocytosis.

• Diagnosis: CT scan.

• Complications: periappendiceal abscess; pylephlebitis.

• Treatment: appendectomy.

Anorectal disorders:

internal hemorrhoids:

• Dilated superior hemorrhoidal veins in mucosa and submucosa.

• Blood coats stool.

External hemorrhoids:

• Dilated inferior hemorrhoidal veins.

• Painful.

Rectal prolapse:

• Intussusception of rectum through anus.

Anal carcinoma: squamous cell carcinoma:

• Homosexual men; HPV association.

Additional Reading:

Basic Pathology

1. Cell Injury
2. Inflammation and Repair
3. Immunopathology
4. Water, Electrolyte, Acid-Base, Hemodynamic Disorders
5. Genetic and Developmental Disorders
6. Environmental Pathology
7. Nutritional Disorders
8. Neoplasia
9. Vascular Disorders
10. Heart Disorders
11. Red Blood Cell Disorders
12. White Blood Cell Disorders
13. Lymphoid Tissue Disorders
14. Hemostasis Disorders
15. Blood Banking and Transfusion Disorders
16. Upper and Lower Respiratory Disorders
17. Gastrointestinal Disorders
18. Hepatobiliary and Pancreatic Disorders
19. Kidney Disorders
20. Lower Urinary Tract and Male Reproductive Disorders
21. Female Reproductive and Breast Disorders
22. Endocrine Disorders
23. Musculoskeletal Disorders
24. Skin Disorders
25. Nervous System Disorders
26. Notes on Tissue Regeneration
27. A Table of Bleeding Disorders
28. FAQ on Structure and Function of Red Blood Cells
29. FAQ on Components of Blood
30. Notes on Hemostatic Mechanisms
31. What is Fever?
32. What is Edema?
33. FAQ on Blood Pressure
34. FAQ on principles of fluid and flow dynamics of Blood
35. Causes of Thrombocytopenia
36. Squamous cell carcinoma of head and neck mucosa
37. Four tumors which never metastasize to the brain
38. What is caustic injury?
39. What causes Peripheral Edema?

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