Disorders of the GI system
- Constipation/Fecal Impaction - defined as fewer than three bowel movements per week; sacral nerve stimulation, laxatives, enema, fiber/water, exercise, surgery are treatment options
- Constipation can be caused by megacolon, low residue diet, dehydration, opiates, anticholinergics, antacids, hypothyroidism, diabetic neuropathy, abdominal muscle weakness
- Diarrhea - three or more bowel movements a day, with increased volume and weight
- 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)
- Clinical manifestations of diarrhea include - dehydration, electrolyte imbalance, metabolic acidosis
- Treatment for diarrhea includes rehydration, medications (loperamide or atropine), fiber, fecal transplant, or probiotics in the case of Clostridium difficile
- Dysphagia - difficulty swallowing - could be mechanical, functional, idiopathic
- Functional disorders causing dysphagia incude vagal/pharyngeal nerve damage (stroke), infectious diseases, autoimmune disorders (Sjogren's, SLE, Myasthenia Gravis, Multiple Sclerosis)
- Diagnosis of dysphagia - x-ray, barium swallow, manometry, fiberoptic endoscopy
- 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
- 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
- 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
- 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)
- 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
- LES hypertension - loss of inhibitory motor neurons, odynophagia, progresses to achalasia, treated with smooth muscle relaxants
- Diffuse esophageal spasm - dysphagia, chest pain
- Nutcracker esophagus (hypertensive peristalsis) - where esophageal waves > 180 mm Hg, causes dysphagia, odynophagia
- 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)
- 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
- 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
- Pyloric (gastric outlet) obstruction - can be congenital (infantile hypertrophic pyloric stenosis) from thickening of circular muscle or less longitudinal muscle
- Can be acquired from malignancy, infection, tumors
- Treated with pyloromyotomy in neonates, gastric drainage or surgery or medications (H2 antagonists) in adults
- Sphincter incontinence - caused by collagen diseases (most common cause of GERD), neuropathy, eosinophilia, xerostomia (lack of protective HCO3-)
- Gastroparesis - delayed gastric emptying - less severe pyloric obstruction; caused by excessive tone, neuropathy, less gastric compliance, bradygastria (low gastic waves)
- Treated with endoscopic dilation, artificial pacemaker (bradygastria)
- Most common adult gastric motility disorder
- 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
- 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
- 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
- Irritable Bowel Syndrome - more common in women, correlates with increased intestinal motility, mimics bowel infection
- Hydrogen breath test reveals mouth to cecum time - treat IBS with anti-diarrheal drugs or fiber
- Inflammatory Bowel Disease (IBD) - Crohn's and Ulcerative Colitis - treated with antiinflammatory and immunosuppressing medication
- Crohn's disease due to excessive helper T response, TNF increases mucosal permeability, damage often deep
- Ulcerative colitis due to anti colonic antibodies - accumulation of CD8+ cells in lamina propria, damage restricted to mucosa and submucosa
- Crohn's affects any GI area and can skip area, leads to shortened villi and deep lesions
- UC affects colon, especially descending and sigmoid, continuous damage area and pseudopolyps
- Four causes of intestinal obstruction - herniation, adhesion, intussusception, volvulus
- Volvulus - twisting or axial rotation of bowel, relived by decompression and needs surgery to prevent iscehmia
- Bilious vomiting (yellow/green) is characteristic of intestinal obstruction below duodenal papilla
- Rectal prolapse - full thickness or internal prolapse - has full concentric rings