Disorders of the GI system

  1. Constipation/Fecal Impaction - defined as fewer than three bowel movements per week; sacral nerve stimulation, laxatives, enema, fiber/water, exercise, surgery are treatment options
  2. Constipation can be caused by megacolon, low residue diet, dehydration, opiates, anticholinergics, antacids, hypothyroidism, diabetic neuropathy, abdominal muscle weakness
  3. Diarrhea - three or more bowel movements a day, with increased volume and weight
  4. Three types of diarrhea - osmotic (water drawn into lumen by nonabsorbable substance), secretory (excessive chloride or bicarbonate rich fluid, or inhibition of sodium absorption), and motility (excessive motility causes less fluid absorption)
  5. Clinical manifestations of diarrhea include - dehydration, electrolyte imbalance, metabolic acidosis
  6. Treatment for diarrhea includes rehydration, medications (loperamide or atropine), fiber, fecal transplant, or probiotics in the case of Clostridium difficile
  7. Dysphagia - difficulty swallowing - could be mechanical, functional, idiopathic
  8. Functional disorders causing dysphagia incude vagal/pharyngeal nerve damage (stroke), infectious diseases, autoimmune disorders (Sjogren's, SLE, Myasthenia Gravis, Multiple Sclerosis)
  9. Diagnosis of dysphagia - x-ray, barium swallow, manometry, fiberoptic endoscopy
  10. Oropharyngeal dysphagia - caused by brainstem stroke (nucleus ambiguous), cranial nerve or C1-3 neuropathy/compression, skeletal muscle disorders
    • Symptoms include dysphagia within 2 seconds of swallowing, sticking in throat
    • Typically irreversible
  11. Cricopharyngeal (UES) - UES spasm, lump in throat, Zenker diverticulum (pouch in throat)
    • UES incontinence caused by swallowing of nitrogen (aerophagia) leading to flatus (or O2, CO2, H2, methane)
    • CO2 flatus caused by soft drinks or bicarbonate, methane and sulfur from malabsorption, hypermotility, or upper GI infection
    • Normal incidence 15+-7 times a day, with more volume for men than women
  12. Zenker's Diverticulum
    • Just above the cricopharyngeal muscle; a pseudodiverticulum that appears in the hypopharynx or an area know as Killian's triangle - more common in older people, very rare
    • Zenker's Diverticulum is a discoordination of pharyngeal and esophageal phases or UES spasm - interferes with closer of glottis and UES, treated surgically
    • Endoscopic treatment causes shorter length of hospitalization, earlier diet introduction, lower rates of problems, but higher recurrence
  13. Aspiration - contents enter trachea - increased likelihood with neuropathy, age, collagen disease, etc. - CO2 levels increase
    • Complications include respiratory arrest or obstruction (immediate), pulmonary edema (hours), pneumonia (days)
  14. Esophageal dysphagia caused by stroke, vagal neuropathy, smooth muscle myopathies, connective tissue disease
    • Damage to enteric nerves or loss of ENS function can be causal, as can eosinophilia
    • Symptoms include dysphagia > 2 sec after swallowing, sticking in chest, secondary swallowing reflex, thumping senstation in chest
    • Evaluated with barium contrast media and typically irreversible - pain killers may help
    • Focal dermal hypoplasia of squamous papillomas of the esophagus can cause dysphagia; treatment is not required but largest lesions can be used endoscopically - does not predispose to esophageal cancer
  15. LES hypertension - loss of inhibitory motor neurons, odynophagia, progresses to achalasia, treated with smooth muscle relaxants
  16. Diffuse esophageal spasm - dysphagia, chest pain
  17. Nutcracker esophagus (hypertensive peristalsis) - where esophageal waves > 180 mm Hg, causes dysphagia, odynophagia
  18. Achalasia - failure of LES relaxation, progression of LES tonicity, due to damage to ENS; barium swallow reveals bird's beak at LES - functional disorders treated with smooth muscle relaxants or Botox, structural disorders require dilation (pneumatic dilator)
  19. Gastro Esophageal Reflux Disease (GERD) - affects 1/3 of population - main symptom heartburn
    • Primarily LES disorder, lack of tone
    • Spincter injury secondary to gastric ulcer or hiatial hernia
    • Barret esophagus in 20% of GERD patients - characterized by epithelial dysplasia and can lead to esophageal cancer
    • Stretta procedure is in middle of medication and surgery - radiofrequency energy to LES
    • GERD can cause loss of enamel, dental decay, dry mouth - red wine may prevent tooth decay and gum disease
  20. Hiatal hernia - protrusion of upper part of stomach through diaphragm into thorax
    • Type I - sliding, most common - GE junction displaced above diaphragm
    • Type II - Fundus above diaphragm
    • Type III - GE junction and part of stomach above diaphragm
    • Only types II and III cause necrosis, strangulation
    • Treated with surgery or gastric anti-secretory therapy
  21. Pyloric (gastric outlet) obstruction - can be congenital (infantile hypertrophic pyloric stenosis) from thickening of circular muscle or less longitudinal muscle
  22. Can be acquired from malignancy, infection, tumors
  23. Treated with pyloromyotomy in neonates, gastric drainage or surgery or medications (H2 antagonists) in adults
  24. Sphincter incontinence - caused by collagen diseases (most common cause of GERD), neuropathy, eosinophilia, xerostomia (lack of protective HCO3-)
  25. Gastroparesis - delayed gastric emptying - less severe pyloric obstruction; caused by excessive tone, neuropathy, less gastric compliance, bradygastria (low gastic waves)
  26. Treated with endoscopic dilation, artificial pacemaker (bradygastria)
  27. Most common adult gastric motility disorder
  28. Dumping Syndrome or Rapid Gastric Emptying
    • Damage to pyloric sphincter by Helicobacter pylori, gastric bypass surgery, tachygastria
    • Early phase symptoms - diaphoresis, vomiting
    • Late stage symptoms - rebound hypoglycemia, malabsorptive diarrhea
  29. Paralytic ileus - common following abdominal surgery; presents with abdominal distension and minimal pain; bowel sounds are minimal unlike with mechanical obstructions - managed with nasogastric suction, correction of electrolyte imbalance
  30. Hirschsprung disease (congenital aganglionic megacolon) - polygenic due to improper differentiation of myenteric plexus and submucosal plexus in distal colon; absence of enteric ganglion causes failure to pass meconium at birth, treated with surgical resection of aganglionic megacolon
  31. Irritable Bowel Syndrome - more common in women, correlates with increased intestinal motility, mimics bowel infection
  32. Hydrogen breath test reveals mouth to cecum time - treat IBS with anti-diarrheal drugs or fiber
  33. Inflammatory Bowel Disease (IBD) - Crohn's and Ulcerative Colitis - treated with antiinflammatory and immunosuppressing medication
  34. Crohn's disease due to excessive helper T response, TNF increases mucosal permeability, damage often deep
  35. Ulcerative colitis due to anti colonic antibodies - accumulation of CD8+ cells in lamina propria, damage restricted to mucosa and submucosa
  36. Crohn's affects any GI area and can skip area, leads to shortened villi and deep lesions
  37. UC affects colon, especially descending and sigmoid, continuous damage area and pseudopolyps
  38. Four causes of intestinal obstruction - herniation, adhesion, intussusception, volvulus
  39. Volvulus - twisting or axial rotation of bowel, relived by decompression and needs surgery to prevent iscehmia
  40. Bilious vomiting (yellow/green) is characteristic of intestinal obstruction below duodenal papilla
  41. Rectal prolapse - full thickness or internal prolapse - has full concentric rings