Chapter 29 Disorders of Gastrointestinal Function Essentials of Pathophysiology Chapter 29 Disorders of Gastrointestinal Function

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. T F

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 Reflex paralysis Inflammation and cell damage Obstruction Distension, ischemia Food does not pass through bowel at correct rate Decreased bowel function Malabsorption

Which symptom accompanies hemorrhage into the stomach? Hematemesis- Question Which symptom accompanies hemorrhage into the stomach? Hematemesis- Occult blood – Coffee-grounds vomitus – 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 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 - difficulty in swallowing inability of a circular muscle to relax, resulting in widening of the structure above the muscular constriction 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 inflammation of the stomach, especially of the mucous membrane of the stomach erosion of the mucous membrane caused in part by the corrosive action of the gastric juice 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

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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 normal Question: Explain her symptoms

Helicobacter pylori The major cause of ulcers Second most common cause is NSAIDs pylori damages stomach lining repair and ULCER healing increased risk of gastric cancer

Helicobacter Pylori

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.)

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? Enterocolitis Crohn disease Ulcerative colitis Diverticulitis

Answer b. Crohn disease Rationale: 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.

The bowel attempts to get rid of the infectious agent Enterocolitis The bowel attempts to get rid of the infectious agent Exudate to dilute toxins Hypermotility Vomiting Decreased intestinal function Food not absorbed Osmosis draws water into the bowel 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 Reflex paralysis Inflammation and cell damage Obstruction 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 False Rationale: 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 IV Question: Why are you taking fluids out of her GI tract and putting them into her veins?