Disorders of Gastrointestinal Function Flashcards
What can cause anorexia?
-loss of appetite
-emotional factors
-drugs
-disease
-precursor to nausea
-can be stimulated or suppressed by smell
What is nausea stimulated by?
vomiting center in medulla
What can cause nausea?
distention of duodenum
What is retching?
spasms of diaphragm, chest, and abdominal muscles
What is vomiting?
sudden forceful removal of stomach contents
Why does retching and vomiting occur?
protects against ingested toxins
What is vomiting and chemoreceptor trigger zone?
medulla (this is why brain injury causes nausea/ vomiting)
What can vomiting lead to?
dizziness, hypotension, bradycardia
What is hematemesis?
vomiting blood
What is melena?
black, tarry stools (blood)
What is hematochezia?
bright red blood in stool
What is occult bleeding?
small amounts of blood in gastric secretions, vomitus, or stools not apparent by appearance; detectable by guaiac test
What happens when RBCs die in GI bleed?
they release protein from hemoglobin
What is the end product as protein is metabolized in a GI bleed?
nitrogen
This nitrogen resulting from blood cells in the gut leads to increased lab value of blood urea nitrogen
BUN
Onset of digestion starts in the stomach but mostly occurs where?
in the small bowel
What are enzyme deficiencies?
-lactase
-pancreatic enzymes
-cystic fibrosis
What can happen during lactase deficiencies?
undigested lactose leads to lactose intolerance with production of gas, abdominal cramping, and diarrhea
What are pancreatic enzymes?
released in inactive form, then activated once in the intestine
What can happen in cystic fibrosis?
obstruction and destruction of pancreatic ducts that are blocked by thick mucus in the ducts
What is an example of accelerated gastric motility?
dumping syndrome
What is dumping syndrome?
-rapid gastric emptying
-to compensate, large bowel brings in lots of fluid
-rapid change of fluid and electrolytes within the bowel
What is an examples of delayed or absent gastric motility?
gastroparesis
What can cause gastroparesis?
acute illness/ injury, neuropathy of any source
Gastrectomy
-loss of food reservoir
-loss of intrinsic factor from mucosal parietal cells decreases vitamin b12 absorption from the ileum of the small bowel
What is the turnover of GI mucous cells?
72 hours
What happens to tissue in GI Translocation?
it erodes from innermost to outermost layer
Where do pathogens go during GI translocation?
from inside gut structures into lymph vessels, blood vessels, and abdominal cavity causing peritonitis
What is translocation a source of?
multiple organ dysfunction syndrome which is highly fatal
What would be a common pathogen involved in bacterial translocation?
E. coli
GERD- Etiology
-relaxation of lower esophageal sphincter with back flow of gastric contents into esophagus
-acidity of gastric contents irritates esophagus
GERD in pediatrics
-resolves by age 6-24 months
-spitting up food
-bradycardia if aspirating food into lungs
GERD in adults
-heartburn after eating with chest pain that can radiate to throat, shoulders, back
-can lead to chronic inflammation and esophageal cancer
What is Esophagitis?
-irritation by gastric acid
-gastro: esophageal reflux
-chronic inflammation can lead to Barrett’s esophagitis (a precursor to esophageal cancer)
-hiatal hernia often present
What is gastritis?
acute or chronic disruption of mucosal barrier of stomach allows auto digestion of the mucosa by HCL
Gastritis- Etiology
aspirin, NSAIDs, H. pylori, alcohol, smoking, physiologic stress, hypersecretion of HCL
What is Peptic Ulcer Disease (PUD)?
ulceration of GI tract due to increased pepsin secretion in the stomach
Where does PUD occur?
Can occur in the esophagus, stomach, pylorus, or duodenum
What is the leading cause of PUD?
H. pylori infection
What leads to bleeding in PUD?
interruption of the stomach mucosal barrier
What protects mucosal layer of stomach?
overuse of aspirin, anti inflammatory, action of prostaglandin
PUD- Clinical Manifestation
-pain: epigastric region; relieved by food, antacids
-occult GI bleeding
-dark stools (melena)
What are the 2 types of inflammatory bowel disease?
Crohn and ulcerative colitis
Crohn disease
-can occur in any site of GI tract
-can erode through ALL tissue layers
Ulcerative colitis
-occurs only in the colon
-erodes only in the innermost layer of colon
What happens in Crohn Disease?
-inflammation, swelling, thickening of the involved tissue
-etiology often unknown but runs in families and stress
Crohn Disease Pathophysiology
-lesions identified by endoscopy
-often called skip lesions because they skip around the tissue
-areas can perforate and create fissures from the inside of the gut leading into bowel, skin, bladder, vagina
Crohn- Clinical Manifestations
-usually non bloody diarrhea
-anemia due to blood loss
-malabsorption of nutrients when small bowel involved
-weight loss
-lower abdominal pain
-frequent fistula formation
-increased risk of colon cancer
Ulcerative Colitis
-similar to crohns disease
-only involves innermost mucosal layer of colon
-inflammation and sloughing of tissue causes bleeding
Ulcerative Colitis- Pathophysiology
-rectum and sigmoid often affected
-mucosal edema and tissue erosion
-mucosal thickening
-bleeding
-perianal abscess
Ulcerative Colitis- Clinical Manifestations
-large volume of watery diarrhea with blood
-cramping or abdominal pain
-urge to stool
-increased risk for colon malignancy after 10 years
