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Gastrointestinal systemPart I

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Function of G I system

The Primary Digestive Functions are

1. Break down food particles to absorbable

forms2.  Absorb the small molecules into the

bloodstream

3. Eliminate waste products & undigestedfood

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Impaired Esophageal Motility

(Achalasia) Achalasia: characterized by impaired peristalsis

of smooth muscle of esophagus and impaired

relaxation of lower esophageal sphincter 

Manifestations:

1. Dysphagia

2. chest pain (pyrosis)

3. Sensation of food stick in lower esophagus

4. Food regurgitation

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Gastroesophageal

Reflux Disease(GERD)

Gastroesophageal reflux

is the backward flow of gastric content into the

esophagus

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Gastroesophageal Reflux Disease (GERD)

2.Pathophysiology a. Gastroesophageal reflux results from transient

relaxation or incompetence of lower esophagealsphincter, or increased pressure within stomach

b. Factors contributing to Gastroesophageal reflux1.Increased gastric volume (post meals)

2.Position pushing gastric contents close toGastroesophageal juncture (such as bending or lying

down)3.Increased gastric pressure (obesity or tight

clothing)

4.Hiatal hernia

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Gastroesophageal Reflux Disease

(GERD)

Manifestations1. Heartburn after meals, while bending over, or 

recumbent

2. Dyspepsia or indigestion3. Regurgitation of sour materials

4.  Atypical chest pain

5. Sore throat with hoarseness

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Hiatal Hernia

Part of stomach protrudes through theesophageal hiatus of the diaphragm intothoracic cavity

Types

1. Sliding hiatal herni

2. Paraesophageal hiatal hernia:

( hernia can become strangulated; maydevelop gastritis with bleeding)

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Gastritis1.Definition: Inflammation of stomach lining from

irritation of gastric mucosa.

2.Types:

A. Acute Gastritis: Disruption of mucosal barrier 

allowing hydrochloric acid and pepsin to havecontact with gastric tissue: leads to irritation,inflammation, superficial erosions.

Gastric mucosa rapidly regenerates (self-limitingdisorder)

B.Chronic Gastritis: Progressive disorder beginning with superficial inflammation and leadsto atrophy of gastric tissues (prolong Gastritis)

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Gastritis

Causes of acute gastritis a. Irritants include aspirin and other NSAIDS,

corticosteroids, alcohol, caffeine b.Ingestion of corrosive substances: acid

c.food contamination (microorganisms)

Manifestations Epigastric discomfort

abdominal pain, nausea, vomiting

Heart burn , &sour taste in mouth If perforation occurs, signs of peritonitis

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gastritis

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Peptic Ulcer Disease (PUD)

Definition: Break in mucous lining of GI tract comes into

contact with gastric juice , referred to as gastric,duodenal , or esophageal ulcer 

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Peptic Ulcer Disease (PUD)

2.Pathophysiology

a. Acute Ulcers or breaks in mucosa of GI tractoccur with

1.H. pylori infection (spread by oral to oral,fecal-oral routes) damages gastric epithelialcells reducing effectiveness of gastric mucus

2.Use of NSAIDS: interrupts prostaglandinsynthesis which maintains mucous barrier of gastric mucosa

b. Chronic with spontaneous remissions andexacerbations associated with trauma, infection,physical or psychological stress

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Peptic Ulcer Disease (PUD)

Manifestations Pain is classic symptom: burning, occurs when

stomach is empty (pain: food: relief pattern)

Vomiting , nausea , constipation &diarrhea

presenting symptom may be complication: GIhemorrhage or perforation of stomach or duodenum

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Peptic Ulcer Disease (PUD)

Treatment Pharmacologic therapy

1. H2 receptor antagonist

2. Proton pump inhibitors3.  Antacid

Stress Reduction & Rest

Smoking Cessation

Dietary Modification

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 Acute Inflammatory Intestinal Disorders

(Appendicitis)

Pathophysiology:

Obstruction of the appendix lumen by faecolith,

enlarged lymph node, worms, tumour, brings about a

raised intra-luminal pressure, which causes the wall of the appendix to become distended. invasion by

bacteria found in the gut normally.

Clinical Manifestations

Rt Lower Quadrant pain, Fever, nausea , vomitinganorexia, tenderness, rebound tenderness.

Complications:

perforation peritonitis or abdominal abscess

,occurs after 24 hrs after onset of symptoms

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Irritable Bowel Syndrome (IBS)

Definition

a. Functional GI tract disorder without

identifiable cause characterized byabdominal pain and constipation, diarrhea,

or both

b. Affects up to 20% of persons in Western

civilization; more common in females

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Irritable Bowel Syndrome (IBS)

Pathophysiology a.  Appears there is altered CNS regulation of 

motor and sensory functions of bowel

1.Increased bowel activity in response to food

intake, hormones, stress

2.Increased sensations of chyme movementthrough gut

3.Hypersecretion of colonic mucus

b. Lower visceral pain threshold causingabdominal pain and bloating with normal levels of gas

c. Some linkage of depression and anxiety

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Irritable Bowel Syndrome (IBS)

Manifestations

a. Abdominal pain relieved by defecation

b. Altered bowel habits, abdominal bloating,

excess gas c. Nausea, vomiting, anorexia, fatigue,

headache, anxiety

d. Tenderness over sigmoid colon uponpalpation

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Peritonitis

Inflammation of peritoneum, lining that coversabdominal wall (parietal peritoneum) and organsof abdominal cavity (visceral peritoneum)

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Peritonitis

Pathophysiology: a. Peritonitis results from contamination of normal

sterile peritoneal cavity with infections or chemicalirritant.

b. Release of bile or gastric juices initially causeschemical peritonitis; infection occurs when bacteriaenter the space.

c. Bacterial peritonitis usually caused by thesebacteria (normal bowel flora): Escherichia coli,

Klebsiella, Proteus, Pseudomonas. d. Inflammatory process causes fluid shift into

peritoneal space (third spacing); leading tohypovolemia, then septicemia.

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Peritonitis

3. Manifestations

Presents with ³acute abdomen´

1.Abrupt onset of diffuse, severe abdominal pain

2.Pain may localize near site of infection3.Intensifies with movement

Entire abdomen is tender with board like rigidity

paralytic ileus

Systemically: fever, malaise, tachycardia«.

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Inflammatory Bowel DiseaseInflammatory Bowel Disease

Includes:

Ulcerative colitis

Crohn¶s disease.

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Ulcerative Colitis

Pathophysiology 1. Inflammatory process usually confined to

rectum and sigmoid colon

2. Inflammation leads to mucosal hemorrhages

and abscess formation, which leads to necrosisand sloughing of bowel mucosa

3. Mucosa becomes red, friable, and ulcerated;bleeding is common

4. Chronic inflammation leads to atrophy,narrowing, and shortening of colon

Manifestations

Bloody Diarrhea with mucus

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Ulcerative Colitis

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Crohn¶s Disease (regional enteritis)

Pathophysiology 1. Affect any portion of GI tract, but terminal ileum

and ascending colon are more commonly involved

2. Inflammatory ulceration of mucosa andsubmuscosa develops into ulcers and fissures that

involve entire bowel wall 3. Fibrotic changes occur leading to local

obstruction, abscess formation and fistula formation

4. Fistulas develop between loops of bowel, bowel

& bladder and bowel & skin. 5. Absorption problem (protein loss and anemia)

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Crohn¶s Disease

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Intestinal Obstruction

Definition

a. May be partial or complete obstruction

b. Failure of intestinal contents to move through

the bowel lumen; most common site is smallintestine

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Intestinal Obstruction

Pathophysiology

a.Mechanical

1.Problems outside intestines: adhesions (bands of scar tissue), hernias

2.Problems within intestinal wall: tumors

3.Obstruction of intestinal lumen (partial or complete)

a. Intussusception: telescoping bowel

b. Volvulus: twisted bowel c. Foreign bodies

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IntussusceptionVolvulus

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Adhesions

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Intestinal Obstruction

Functional1.Failure of peristalsis to move intestinal contents: 

(paralytic ileus, ileus) due to neurologic or muscular impairment

2.Causes include a. Post gastrointestinal surgery

b. Tissue anoxia or peritoneal irritation fromhemorrhage, peritonitis, or perforation

c. Hypokalemia

d. Medications: narcotics, anticholinergic drugs,antidiarrheal medications

e. Renal colic, spinal cord injuries, uremia

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Intestinal Obstruction

Manifestations Small Bowel Obstructionb.Colicky abdominal pain

c.Vomiting

1. Proximal intestinal distention stimulates

vomiting center  2. Distal obstruction vomiting may become

feculent

d.Bowel sounds

1. Mechanical obstruction: borborygmi may havevisible peristaltic waves

2. Paralytic ileus, diminished or absent bowelsounds

e.Signs of dehydration