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Chapter 13: Digestive System Patho

Terms in this set (69)

Gastritis
inflammation of the lining of the stomach
Acute gastritis
-Usually due to ingestion of biological or chemical irritants
-Often causes vomiting and diarrhea
-May be associated with mucosal ulceration or bleeding
-Self-limited inflammation of short duration
Damage is usually minimal with rapid healing of the mucosa
chronic gastritis
-Often associated with Helicobacter pylori colonization of mucosa
-Recurring exposure to irritating substances
*Alcohol
*Aspirin
*NSAIDs
-Pernicious anemia
From nonsteroidal anti-inflammatory drugs (NSAID) that inhibit cyclooxygenase (COX) enzyme:
aspirin, ibuprofen, naproxen
-COX-1: promotes synthesis of prostaglandin that protects gastric mucosa
-COX-2: promotes synthesis of prostaglandin that mediate inflammation
*Drugs that selectively inhibit COX-2 increase risk for heart attack and stroke
Alcohol
a gastric irritant; stimulates gastric acid secretion
H. Pylori Gastritis
-Small, curved, gram-negative organisms that colonize surface of gastric mucosa
-Grow within layer of mucus covering epithelial cells
-Produce urease that decomposes urea, a product of protein metabolism, into ammonia
-Ammonia neutralizes gastric acid allowing organisms to flourish; organisms also produce enzymes that break down mucus layer
H. Pylori Gastritis (cont)
-Common infection that increases with age (50% by age 50)
-Spreads via person-to-person through close contact and fecal-oral route
-Increased risk of gastric carcinoma: intestinal metaplasia
-Increased risk of malignant lymphoma (mucosa-associated lymphoid tissue, MALT)
Gastritis symptoms
-Epigastric pain
-Indigestion
-Nausea
-Belching
-Loss of appetite
-Bleeding can occur
Gastritis treatment
-Curing H. pylori infection with antibiotics often rapidly resolves the gastritis
-Eliminating irritants
-Antacids, H2 blockers, PPIs, antiemetics
-Vitamin B12 injections for chronic gastritis
peptic ulcer
sore or lesion in the muscous membrane
peptic ulcer pathogenesis
-Digestion of mucosa due to increased acid secretions and digestive enzymes (gastric acid and pepsin)
-Helicobacter pylori injures mucosa directly or through increased acid secretion by gastric mucosa
-Common sites: distal stomach or proximal duodenum
Peptic ulcer symptoms
-Epigastric pain that varies from a gnawing, dull, aching, hungerlike pain to intense pain
Eating or antacids usually relieves pain
-Heartburn, indigestion
-Anorexia
-Nausea, vomiting
Peptic Ulcer Complications
-hemorrhage
-Perforation leading to peritonitis
-Obstruction from scarring
Peptic Ulcer Treatment
-Histamine (H2) receptor blockers (Pepcid, Tagamet, Zantac) or proton pump inhibitors (Prilosec, Prevacid) to reduce gastric secretions
-Antacids to reduce gastric acidity
-Sucralfate to coat and protect the mucosa
-If H. pylori is the cause, antibiotics (clarithomycin or azithomycin), combined with a PPI and sucralfate
-Any nonhealing ulcers should be evaluated by endoscopy to rule out cancer (especially gastric ulcers)
-Surgery in severe cases
Acute enteritis
-self-limiting
-caused by many organisms and bacterial toxins
acute enteritis symptoms
-Nausea, vomiting
-Abdominal discomfort
-Loose stools
Inflammatory bowel disease
-chron's disease
-ulcerative colitis
etiology of inflammatory bowel disease
-unknown
-genetic predisposition
-Evidence that immune or autoimmune mechanisms contribute
inflammatory diseases of the intestines
-Impaired ability to regulate the immune response
--The intestinal epithelium is less able to resist invasion of normal intestinal bacteria
*Intestinal bacteria can penetrate the epithelium and extend into deeper tissues
**Intestinal bacteria invade the bowel wall causing T cell activation that leads to inflammation and necrosis
Chrohn's disease
-Chronic, relapsing inflammatory disorder of the gastrointestinal tract
*Chronic inflammation and ulceration of mucosa with thickening and scarring of bowel wall
-Can affect any portion of the GI tract from mouth to anus
Most commonly in distal ileum
*Diseased segments separated by normal bowel in a characteristic distribution called skip lesions
Chrohns disease symptoms
-Chronic diarrhea along with crampy, intermittent abdominal pain
-Fever
-Weight loss
-Malaise, nausea, anorexia
crohn's disease treatment symptoms
No cure, therapy has 2 goals: treat acute disease flare-ups and maintain remission
-Anticholinergics and narcotic agents to relieve cramping and diarrhea
-Sulfasalazine because it has both antibacterial and anti-inflammatory properties
-Steroids and immunosuppressive drugs to decrease inflammation and promote healing
-When bowel obstructions, GI hemorrhage, abscesses, or perforations develop, surgery to remove affected portions
ulcerative colitis
-Chronic, diffuse, continuous inflammation of the rectum and colon (large intestines)
-Inflammation is limited to mucosa, bowel not thickened unlike in Crohn's
ulcerative colitis symptoms
Intermittent episodes of bloody diarrhea, abdominal cramping, urgency to defecate, and mucoid stools
Weight loss, fever, malaise
ulcerative colitis complications
-Perforation: from extensive inflammation with leakage of intestinal contents into peritoneal cavity
-Long-standing disease may develop cancer of colon and/or rectum
ulcerative colitis treatment
Goal is to induce and maintain remission and to improve quality of life
-Avoid foods that cause irritation, anticholinergics, sulfasalazine, steroids
-Patient is examined annually because it is associated with an increased risk of colon cancer
-In severe cases, removal of the colon and rectum
Pseudomembranous enterocolitis (antibiotic-associated colitis, C. diff)
Acute inflammation with a plaque-like adhesion of necrotic debris and mucus adhered to the damaged superficial mucosa of the small and large intestine
Pseudomembranous enterocolitis (antibiotic-associated colitis, C. diff): etiology
Often related to broad-spectrum antibiotic use
-Destroy the body's protective natural intestinal flora and allows an infection with Clostridioides (formerly Clostridium) difficile to develop
-The bacteria produces powerful toxins that cause the bowel wall to become inflamed, ulcerated, and necrotic
Pseudomembranous enterocolitis (antibiotic-associated colitis, C. diff): Symptoms
-Greenish, foul-smelling watery diarrhea (up to 30 per day)
-Fever
-Weakness
-Abdominal cramping and tenderness
-Nausea and vomiting
Pseudomembranous enterocolitis (antibiotic-associated colitis, C. diff): treatment
-Milder cases, cholestyramine (Questran) is given to bind the toxins produced by the bacteria
-Usually, oral vancomycin or metronidazole (Flagyl) is used
appendicitis
-inflammation of the appendix
-most common inflammatory lesion of the bowel
appendicitis: etiology
-Narrow caliber of appendix may be plugged with fecal material (a fecalith)
-Secretions of appendix drain poorly, create pressure in appendiceal lumen, compressing blood supply
-Bacteria invade appendiceal wall causing inflammation
Appendicitis symptoms
-Begins with vague periumbilical abdominal discomfort
Then localizes as pain in right lower quadrant of abdomen (McBurney's point)
-Rebound tenderness
-Rigidity
-Guarding
-Nausea and vomiting
-Fever
-Diarrhea or constipation
appendicitis complication
Inflamed appendix may perforate and cause peritonitis
celiac disease (gluten enteropathy, celiac sprue): etiology
-Hypersensitivity to gluten (protein in wheat, rye, barley, oats)
*Immune-mediated damage to intestinal mucosa that results in atrophy of villi and impaired absorption
-Seems to have a genetic component and a link to early childhood viral infection
celiac disease: symptoms
-Chronic diarrhea impairing absorption of fats and nutrients
*Characteristic pale, greasy, foul-smelling stools
-Weight loss, vitamin deficiencies
-Anorexia
-Flatulence
-Abdominal distention
-Abdominal cramping
Celiac disease treatment
-Gluten-free diet
*Relieves symptoms
*Villi return to normal
-If no improvement, corticosteroids
Diverticulosis
Outpouches (diverticula) of mucosa penetrate weake points in muscular layer of large intestine
*occurs mostly in distal colon and sigmoid colon
Diverticulosis: etiology
-Linked to age and stool volume
-Diet low in fiber results in smaller, dryer stool
*Leads to higher intraluminal pressures
-High pressure squeezes mucosa through inner muscle layer
Diverticulosis: symptoms
-Usually asymptomatic
-Occasionally mild discomfort, irregular bowels
-Can sometimes can bleed
Diverticulosis: treatment
-Diet with adequate fluids and fiber to produce soft, formed, daily stools
-Some advocate for avoiding foods with kernels and seeds
Diverticulitis
inflammation and infection of diverticula
Diverticulitis etiology
-Plugging by fecalith leads to infection by colonic bacteria
-May cause bleeding or bowel perforation
Diverticulitis: symptoms
-Fever
-Nausea
-LLQ abdominal pain
-Episodes of diarrhea or constipation, or both
Diverticulitis:treatment
-Antibiotics
-Stool softeners
-Liquid diet
-Surgery for perforations, bleeding, or severe disease
Ileus
-Blockage of movement of contents of the GI tract
*Mechanical obstruction (mechanical ileus)
Physical blockage is responsible
*Parelytic ileus (adynamic ileus)
Result of stoppage of peristalsis

-Always considered as a serious condition
Severity depends on location of obstruction, completeness, interference with blood supply
Symptoms of obstruction
-Severe pain
-Nausea/vomiting
-Abdominal distention
-Obstipation - lack of fecal matter or gas evacuation
common causes of mechanical intestinal obstruction
-Adhesions
-Hernia
-Tumor
-Volvulus
-Intussusception
Adhesions
-adhesive bands of connective tissue may form after surgery or inflammation
-May cause loop of bowel to become kinked, compressed, twisted
* causes obstruction proximal to site of adhesion
Intestinal obstructions: hernia
Protrusion of loop of bowel through a small opening, usually in abdominal wall
Inguinal Hernia:
common in men; loop of small bowel protrudes through weak area in inguinal ring and descends downward into scrotum
Umbilical hernia
loop of bowel protrudes into umbilicus through defect in the abdominal wall
Femoral Hernia
loop of intestine extends under inguinal ligament along course of femoral vessels into the groin
Incisional hernia
loop of bowel protrudes through an incompletely healed surgical scar
Reducible hernia
herniated loop of bowel can be pushed back into abdominal cavity
*If not achieved promptly, can result in obstruction of intestinal contents
Incarcerated Hernia
cannot be pushed back
Strangulated hernia
: loop of bowel is tightly constricted obstructing the blood supply to the herniated bowel; requires prompt surgical intervention
*If not promptly corrected, will cause necrosis of tissue
Volvulus
rotary twisting of bowel impairing blood supply
Common site: sigmoid colon
Intussusception
telescoping of a segment of bowel into adjacent segment
-Result of vigorous peristalsis in children
-Caused by pedunculated tumor in adults
-Common site: terminal ileum
Tumor
carcinoma of colon may obstruct
-Common cause of low intestinal obstruction
Parelytic ileus (adynamic ileus)
A functional disorder that involves a loss of motility in the intestines
Parelytic ileus: etiology
Involves a neurogenic reflex that halts normal intestinal motility
-Triggered by various abdominal stimuli
*Pain
*Peritonitis
*Appendicitis
*Trauma (surgery)
*Acute distention of abdominal organs
Treatment of Obstruction
-NG tube to relieve distension
-NPO
-Colonoscopy may be attempted to correct some obstruction
-Surgery to remove or correct blockage
Colorectal cancer
A cancer that arises in any part of the colon or rectum
-3rd most commonly diagnosed cancer in US
-3rd most common cause of cancer deaths in US
colorectal cancer: etiology
-Most colorectal cancers arise from polyps over an average time of at least 10 years (could be as much as 10-20 years)
-Risk increases with age
-Other risk factors include consumption of red meat, obesity, sedentary lifestyle, alcohol, smoking, diabetes, inflammatory bowel conditions
-Factors that may be protective include a higher intake of fruits and vegetables, fiber, folic acid, and vitamin B6
colorectal cancer: symptoms
-Abdominal pain
-Change in bowel habits
-Weight loss
-Weakness
-Bloody stools, rectal bleeding
-Iron deficiency anemia
colorectal cancer:treatment
-Surgical resection with or without colostomy
-Chemotherapy
-Radiation
-Serum level of tumor marker CEA (carcinoembryonic antigen) is used to plan treatment and assess prognosis
-5-year survival is 64%
colorectal cancer prevention
-Regular screenings
*Currently recommended tests are either stool-based or those that visualize the colon
**No single test is clearly superior to the rest
**Getting people to undergo screening is more important then the test they choose
***Incorporating personal preferences may increase the likelihood that screening will occur
-Frequency of testing ranges from 1-10 years
Despite availbility and effectiveness of screening only
fewer than half of adults particpate
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