Chapter 37 Notes

Signs and Symptoms Common to Gastrointestinal Disorders

• anorexia

• nausea

• vomiting

• gastrointestinal bleeding (GIB) - upper and lower

Anorexia, Nausea, Retching, and Vomittign

• anorexia, nausea, and vomiting are physiologic responses → common GI disorders

• retching → rhythmic spasmodic movements of the diaphragm, chest wall, and abdominal muscles

  • responses are protective to the extent that they signal the presence of disease

  • action of vomiting - removes noxious agents from GI tract

  • contributes to impaired intake or loss of fluids and nutrients

Vomiting and Neural Structures

• vomiting involves two functionally distinct medullary centers

  • vomiting center

  • chemoreceptor trigger zone

• action of vomiting thought to be a reflex integrated → vomiting center

  • vomiting center located in the reticular formation of the medulla near the sensory nuclei of the vagus

  • chemoreceptor trigger zone is located in a small area on the floor of the fourth ventricle

    • thought to mediate the emetic effects of blood=borne drugs and toxins

Swallowing

• mechanism

  • depends on the coordinated action of the tongue and pharyns

  • these structures are innervated by cranial nerves V, IX, X, and XII.

• alterations

  • dysphagia

    • difficulty in swallowing

  • odynophagia

    • painful swallowing

  • achalasia

    • failure of the esophageal sphnicter to relax

Gastroesophageal Reflux Disease (GERD)

• heartburn

  • 30 to 60 minutes after meals

  • evening onset

  • pain in the epigastric area that radiates to the throat, shoulder, or back

    • GERD symptoms easily confused for heart attacks in women and vice versa

• preventions

  • avoiding large meals

  • avoiding alcohol use and smoking

  • eating meals sitting up

  • avoiding recumbent position several hours after a meal

  • avoiding bending for long periods

  • sleeping with the head elevated

  • losing weight if overweight

Esophageal Cancer

• squamous cell carcinoma

  • alcohol and tobacco use

• adenocarcinoma

  • barrett’s esophagus

• signs and symptoms

  • dysphagia

  • weight loss

  • anorexia

  • fatigue

  • painful swallowing

Factors Contributing to the Protection of the Gastric Mucosa

• gastric mucosal barrier

  • an impermeable epithelial cell surface covering

  • mechanisms for the selective transport of hydrogen and bicarbonate ions

  • the characteristic of gastric mucus

Types of Mucus Protecting the Gastric Mucosa

• water-insoluble mucus

  • formats a thin, stable gel that adheres to the gastric mucosal

  • surface

  • provides protection from the proteolytic (protein-digesting) actions of pepsin

  • forms an unstirred layer that traps bicarbonate → forming an alkaline interface between the luminal contents of the stomach and its mucosal surface

• water-soluble mucus

  • washed from the mucosal surface

  • mixes with the luminal contents

  • its viscid nature makes it a lubricant that prevents mechanical damage to the mucosal surface

Major Causes of Gastric Irritation and Ulcer

• aspirin

• nonsteriodal anti-inflammaotry drugs (NSAIDS)

  • irritate the gatric mucosa and inhibit prostaglandin synthesis

• infection with Helicobacter pylori

  • thrives in an acid environment of the stomach

  • disrupts the mucosal barrier that protects the stomach from harmful effects of its digestive enzymes

Types of Gastritis

• acute gastritis

  • a transient inflammation of gastric mucosa

  • most commonly associated with local irritants such as bacterial endotoxins, alcohol, and asprin

    • can become chronic with long-term exposure

• chronic gastritis

  • characterized by the absence of grossly visible erosions and the presence of chronic inflammatory changes

  • leads eventually to atrophy of the glandular epithelium of the stomach

Helicobacter pylori

• colonize the mucus-secreting epithelial cells of the stomach

• produce enzymes and toxins that have the capacity to interfere with the local protection of the gastric mucosa against acid

• produce intense inflammation

• elicit an immune response

Methods for Establishing Presence of H. pylori infection

• C urea test using a radioactive carbon isotope

• stool antigen test

• endoscopic biopsy for urease testing

• blood tests to obtain serologic titers of H. pylori antibodies

Peptic Ulcer

• ulcerative disorders that occur in areas of the upper gastrointestinal tract that are exposed to acid-pepsin secretions

  • spontaneous remissions and exacerbation

• common causes

  • H. pylori

  • aspirin

  • age

  • warfarin

    • blood thinner

  • smoking

Complications of Peptic Ulcer

• hemorrhage

  • caused by bleeding from the granulation tissue or from erosion of an ulcer into an artery or vein

• obstruction

  • caused by edema, spasm, and or contraction of scar tissue and interference with the free passage of gastric contents through the pylorus or adjacent areas

• perforation

  • occurs when an ulcer erodes through all the layers of the stomach or duodenum wall

GI Tract Bleeding

• pyloric sphincter

  • valve between eh stomach and small intestine

• upper GI bleed

  • pre-pyloric sphincter bleed

  • digested coffee ground like consistency

  • stomach and above

• lower GI bleed

  • post-pyloric sphincter bleed

  • classic bloody appearance

  • small intestine and below

• hematemesis

  • blood in the vomitus

  • may be bright red or have coffee ground appearance

• melena

  • blood in the stool

  • ranges in color from bright red to tarry

  • may be occult (hidden)

Treatment of Peptic Ulcer

• eradicate the cause and promote a permanent cure for the disease

  • eradicating H. pylori

  • relieving ulcer symptoms

  • healing the ulcer crater

    • acid-neutralizing, acid-inhibiting drugs, and mucosal protective

    • antacids

    • proton pump inhibitors

Risk Factors for Development of Stress Ulcers

• large surface area burns

• trauma

• sepsis

• acute respiratory distress syndrome

• severe liver failure

• major surgical procedures

• zollinger-ellison syndrome

Risk Factors for Development of Gastric Cancer

• genetic predisposition

• carcinogenic factors int he diet

  • cancer causing

• autoimuune gastritis

• gastric adenomoas or polyps

Conditions Causing Altered Intestinal Function

• irritable bowel disease

• inflammatory bowel disease

• diverticulitis

• appendicitis

• alteration in bowel motility

• malabsoption syndrome

• cancer of the colon and rectum

Infection of the Intestine

• viral infection

  • rotavirus

• bacterial infection

  • Clostridium difficile (C. diff)

    • spore

    • must wash hands with soap and water

    • hand sanitizer does not destroy the pathogen

    • malodorous

    • distinct fecal odor and consistency → can cause infectious colitis

    • commonly caused by antibiotics that disrupt normal flora in the colon

    • meds

      • vancomucin (antibiotic)

      • flagul (antifungal)

  • E. coli

• protozal infection

  • E. histolytica

Characteristics of Irritiable Bowel Disease of Syndrome

• persistent or recurrent symptoms of abdominal pain

• altered bowel function

• varying complaints of flatulence, bloatedness

  • flatulence

    • flatus - gas

  • nasuea and anorexia

  • constipation or diarrhea

  • anxiety or depression

Inflammatory Bowel Disease

• crohn’s disease

  • a recurrent, granulomatous type of inflammatory response that can affect any area of the gastrointestinal tract from the mouth to the anus

  • autoimmune disease

• ulcerative colitis

  • a nonspecific inflammatory condition of the colon

Symptoms of Diverticulitis

• pain in the lower left quadrant

• nausea and vomiting (N/V)

• tenderness in the lower left quadrant

• a slight fever (pyrexia)

• an elevated white blood cell count (leukocytosis)

Appendicitis

• appendix → inflamed, swollen, and gangrenous

  • appendix eventually perforates if not treated

• appendicitis is related to intraluminal obstruction with following:

  • fecalith (i.e., hard piece of stool)

  • gallstones

  • tumors

  • parasites

  • lymphatic tissue

Types of Diarrhea

• large volume

  • osmotic

  • secretory

• small volume

  • inflammatory bowel disease

  • infectious disease

  • irritable colon

Clinical Manifestations of Celiac Disease

• classically, presents in infancy

• signs and symptoms

  • failure to thrive

  • diarrhea

  • abdominal distention

  • occasionally, severe malnutrition

Constipation

• a healthy adult should have at east 3 bowel movements in 7 days

• common causes of constipation

  • failure to respond to the urge to defecate

  • inadequate fiber in the diet

  • inadequate fluid intake

  • weakness of the abdominal muscles inactivity and bed rest

  • pregnanacy

  • hemorrhoids

Fecal Impaction

• painful anorectal disease

• factors if fecal impaction

  • tumors

  • neurogenic disease

  • use of constipating antacids or bulk laxatives

  • a low-residue diet

  • drug-induced colonic stasis

  • prolonged bed rest and debility

Internal Obstruction

• mechanical obstruction → result from post operative (surgery) causes

  • external hernia

  • postoperative adhesions

• paralytic (dynamic) obstruction → results from nuerogenic or muscular impairment of peristalsis

• (A) Intussusception

• (B) Volvulus

• (C) Inguinal Hernia

Peritoneal Cavity & Peritonitis

• permits rapid absorption of bacterial toxins

• favors the dissemination of contaminants

• greats inflammatory response

  • thick, fibrinous protective substance

• perforated peptic ulcer

• ruptured appendix

• perforated diverticulum

• gangrenous bowel

• pelvic inflammatory disease

• gangrenous gallbladder

• abdominal trauma and wounds

Peritonitis

• protective body mechanism to control peritonitis perforation

  • decreased peristalsis

  • formation of thick exudates to seal off the perforated bowel

Intestinal Malabsorption

• failure to transport dietary contents from the intestinal lumen → extracellular fluid

• causes

  • celiac disease

    • inflammatory reaction

  • neoplasm

  • colorectal cancer

• symptoms

  • diarrhea

  • steatorrhea (fat in stool)

  • flatulence

  • bloating

  • abdominal pain

  • cramps

  • weakness, muscle wasting

  • weight loss and abdominal distention

Colorectal Cancers

• risk factors

  • age

  • family history

  • crohn disease

  • ulcerative colitis

  • familial adenomatous polyposis

  • diet

• testing

  • stool occult blood test

  • digital rectal examination

  • x-ray studies using barium (e.g., barium enema)

  • flexible sigmoidoscopy and colonoscopy