Chapter 29 Disorders of Gastrointestinal Function
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Transcript of Chapter 29 Disorders of Gastrointestinal Function
CHAPTER 29DISORDERS OF GASTROINTESTINALFUNCTION
Essentials of Pathophysiology
PRE LECTURE QUIZ TRUE/FALSE Two of the major causes of gastric irritation and
ulcer formation are aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) and infection with Helicobacter pylori.
A peptic ulcer affects only a single layer of the stomach or duodenum.
Clostridium difficile and Escherichia coli are two types of viral infections that affect the gastrointestinal system.
Small-volume diarrhea is usually painless and watery and without blood or pus in the stool.
Appendicitis, a condition in which the appendix becomes inflamed, swollen, and gangrenous, is very uncommon.
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PRE LECTURE QUIZ __________ refers to difficulty in swallowing. Crohn disease and ulcerative colitis are two
related intestinal disorders that fit under the category of __________ bowel disease.
__________ is a condition that occurs primarily in the sigmoid colon, in which the mucosal layer of the colon herniates through the muscular layer.
__________ disease is an immune-mediated disorder triggered by ingestion of gluten-containing grains (including wheat, barley, and rye).
__________ is a common characteristic of both ulcerative colitis and Crohn disease.
Celiac
Diarrhea
Diverticulosis
Dysphagia
inflammatory
THE JOB OF THE BOWEL To digest food: involves a corrosive
solution and potentially pathogenic bacteria
To absorb the food into the blood while keeping the corrosive substances and the bacteria inside the gut
To keep the solution moving down the bowel at the right rate for digestion and absorption
INFLAMMATION AND DAMAGE TO THE BOWEL WALL
• Hemorrhage anemia• Perforation peritonitis• Decreased mucosal function
malabsorption• Decreased bacterial containment
sepsis
HEMORRHAGE Hemorrhage above the stomach: frank
hematemesis Hemorrhage into the stomach with partial
digestion of blood: coffee-grounds vomitus Hemorrhage in the intestine with blood
mixing into stools: occult blood Hemorrhage into the intestine with large
volumes of blood: melena Hemorrhage in the rectum: red blood
coating stools
THE VICIOUS CIRCLE: ONE KIND OF BOWEL PROBLEM CAN CAUSE ANOTHER
Inflammationand cell damage
Obstruction
Malabsorption
Reflex paralysis
Distension, ischemia
Decreased bowelfunction
Food does not pass through bowel at correct rate
QUESTION
Which symptom accompanies hemorrhage into the stomach?
a. Hematemesis-b. Occult blood – c. Coffee-grounds vomitus – d. Melena -
the vomiting of blood
blood in the stool
blood mixed w/ chime
black, tarry, bloody stools, usually resulting from a hemorrhage in the alimentary tract.
ANSWER
c. Coffee-grounds vomitus Rationale: Coffee-grounds vomitus is a
classic symptom of blood in the stomach (it mixes with chyme to give it the coffee-grounds color and consistency). Hematemesis occurs in hemorrhage above the stomach; occult blood is the result of blood mixing with stool in the small intestine; and melena occurs with large-volume hemorrhages in the intestine.
DISORDERS OF THE ESOPHAGUS Dysphagia - Achalasia -
Esophageal diverticulum - Gastroesophageal reflux
disease
Cancer of the esophagus -
inability of a circular muscle to relax, resulting in widening of the structure above the muscular constriction
difficulty in swallowing
mucosal layer herniated through the muscularis layer
a chronic condition in which acid from the stomach flows back into the lower esophagus, causing pain or tissue damage
malignant neoplasm
DISORDERS OF THE STOMACH Acute gastritis Chronic gastritis Ulcer disease
Peptic ulcer Zollinger-Ellison syndrome
Stress ulcers
Cancer of the stomach
a condition in which a gastrin-secreting tumor of the pancreas or small intestine causes excessive secretion of gastric juice, leading to intractable peptic ulcers
Acute peptic ulcers occurring in association with various other pathologic conditions
erosion of the mucous membrane caused in part by the corrosive action of the gastric juice
inflammation of the stomach, especially of the mucous membrane of the stomach
SCENARIO
Mrs. D. has pain in her stomach at night and vomits up blood.
She is pale and weak The doctor finds that her hematocrit is low Her blood contains large, pale
erythrocytes and some reticulocytes Bilirubin levels are normalQuestion: Explain her symptoms
HELICOBACTER PYLORI
• The major cause of ulcers
• Second most common cause is NSAIDs
H. pylori
damages stomach
lining
ULCER repair and healing
increased risk of gastric cancer
HELICOBACTER PYLORI
“In the US: The frequency of HP infection may be linked to race. White persons account for 29% of cases, and Hispanic persons account for 60% of cases.”
“Internationally: … At least half of all people are infected … HP may be detected in approximately 90% of individuals with peptic ulcer disease...”
(Santacroce, L., and Miragliotta, G. 2005. Helicobacter pylori infection. eMedicine. Retrieved April 2005 from http://www.emedicine.com/med/topic962.htm#top.)
Helicobacter Pylori
INFLAMMATIONS OF THE SMALL AND LARGE INTESTINES
Infectious enterocolitis Viral infections Bacterial infections
Inflammatory bowel disease Crohn disease Ulcerative colitis
Diverticular disease Appendicitis
Crohn’s disease – an autoimmune condition-a chronic inflammatory bowel disease that causes scarring and thickening of the intestinal walls and frequently leads to obstruction.
DISCUSSION
Think back to the last time you had enterocolitis.
Questions: List the things that happened to you Which of them were systemic signs
of inflammation? Which of them were caused by your
sympathetic system? Which of them helped you get over
the disease? Which of them could have caused
serious complications? Why?
QUESTION
Which intestinal disorder is an autoimmune disease?
a. Enterocolitisb. Crohn diseasec. Ulcerative colitisd. Diverticulitis
ANSWER
b. Crohn diseaseRationale: Crohn disease is an
autoimmune disorder that affects the mucous membrane lining of the bowel (it gets thicker and doesn’t function as it should), causing chronic malabsorption.
ENTEROCOLITIS
The bowel attempts to get rid of the infectious agent Exudate to dilute toxins Hypermotility
Vomiting Decreased intestinal function
Food not absorbedº Osmosis draws water into the bowel
º Osmotic (or explosive) diarrhea
INFLAMMATIONS THAT CANNOT BE EXPELLED
Pain and sympathetic nervous stimulation cause the bowel to freeze in position Reflex paralysis or paralytic ileus
Muscles of the abdominal wall tighten to protect the inflamed bowel Board-like abdomen
Diaphragm and accessory breathing muscle movements decrease Shallow breathing
ONE KIND OF BOWEL PROBLEM CAN CAUSE ANOTHER
Inflammationand cell damage
Obstruction Reflex paralysis
Distension, ischemia
INTESTINAL OBSTRUCTION
Mechanical Severe, colicky pain Borborygmus Audible, high-pitched peristalsis;
peristaltic rushes Awareness of intestinal movements
Paralytic Continuous pain Silent abdomen
RESULTS OF OBSTRUCTION
Vomiting fluid and electrolyte loss
Fluids move into intestinal contents
Gas accumulates Distension of bowel Compartment
syndrome ischemia, necrosis
Anaerobic bacteria produce endotoxin toxemia
QUESTION
Tell whether the following statement is true or false.
Paralytic intestinal obstruction causes audible paralysis.
ANSWER
FalseRationale: Mechanical obstruction
results in high-pitched peristalsis (bowel sounds); in paralytic obstruction, bowel sounds are inaudible (silent abdomen).
BOWEL DISTENSION AND COMPARTMENT SYNDROME
The blood vessels on the surface of the gut are covered and held in place by the inflexible peritoneum
When the gut lumen distends, it crushes the blood vessels between the gut wall and the peritoneum
Peritoneum = Serosa
COMPARTMENT SYNDROME
• An organ expands inside a membrane that will not expand
• The blood vessels feeding the organ are crushed between the organ and the membrane
• Blood supply is cut off
SCENARIO
Mrs. K. presents with acute abdominal pain.• She has a distended, board-like abdomen with no
bowel sounds. Blood pressure is low and heart rate elevated. Her skin is pale and cool with cold sweat. She is very restless and complains of acute abdominal pain.
• The pain came on over the last 8 hours. WBC count is elevated. Now she complains of nausea and begins throwing up, but there is no blood in her vomitus. She has had no bowel movements or urine production.
Question:• What adaptive responses and counterattacks are
evident?
SCENARIO (CONT.)
• Mrs. K. has begun to run a fever• Her skin is now flushed and warm, and her
abdomen is further distended • Her blood pressure has decreased further• The doctor has ordered nasogastric suction and
an isotonic IVQuestion:• Why are you taking fluids out of her GI tract and
putting them into her veins?