GI Flashcards
What is achalasia? What are the problems?
Loss of intrinsic inhibitory innervation of lower esophageal sphincter (LES) causing aperistalsis, incomplete relaxation of LES, and increased resting tone of LES.
The pt feels like they took a huge bite of food, swallowed too much, gets kind of stuck, painful, and relief when the food passes
Problems: dysphagia, mucosal inflammation and ulceration, and squamous cell carcinoma
Hiatal hernia symptoms
Heartburn and regurgitation due to pressure on the lower esophagus
GERD contributing causes and problems?
Causes: obesity, hiatal hernia, vagal nerve abnormalities
Problems: heartburn, Barrett esophagus (long-standing GERD, replacing normal stratified squamous mucosa with metaplastic columnar epithelium with goblet cells) -> Adenocarcinoma
Esophageal cancer: squamous cell carcinoma vs. adenocarcinoma
Squamous cell carcinoma: cancer of normal esophageal tissue caused by smoking, alcohol, achalasia, or very hot tea (China)
Adenocarcinoma (more common in US) is cancer of the metaplastic tissue (bottom of esophagus) caused by Barrett esophagus
Symptoms: dysphagia and obstruction, typically occur late in cancer progression
Parietal cells secrete ____ to the stomach and ____ to the blood.
HCl to the stomach and HCO3 to the blood
Chronic gastritis is usually caused by what and causes what problems? What’s a good blood test to diagnose?
Caused by H Pylori
Problems: Gastric Ulcers! N/V, pain
H. Pylori secretes ammonia to buffer the stomach acid, so the best test for this is an ammonia level! Most people with H. Pylori DON’T get ulcers, so it doesn’t make sense to go after that with treatment/tests.
What aggravates peptic ulcers? What are the problems?
Aggravating causes: NSAIDs, smoking, alcohol, corticosteroids, high stress personality
Problems: epigastric pain, N/V, hemorrhage, perforation
Impairs quality of life without shortening life (doesn’t lead to cancer)
Where are peptic ulcers?
98% in proximal duodenum and stomach (4:1)
Chronic vs. Acute gastritis?
Chronic leads to peptic ulcers that form scar tissue, fibrosis, not reversible
Acute leads to stress/gastric ulcers, if the problem is fixed, the mucosa can recover completely
Acute gastritis causes and problems?
Causes: NSAIDs, alcohol, smoking, cancer chemotherapy, uremia, systemic infection, severe stress (trauma, burns), ischemia, shock, ingestion of acids/bases, mechanical trauma (NG intubation)
Problems: epigastric pain with N/V, hematemesis, melena
Gastric/stress ulcer causes?
Focal, acute gastric mucosal defects resulting from severe stress
Causes: trauma, burns, gastric irritants (NSAIDS), head bleed
Gastric carcinoma causes? (2nd leading cancer death to lung cancer)
Intestinal-type adenocarcinoma from nitrates (preservative for meat), smoked food, pickled food, salt, chronic gastritis, H pylori, decreased by fruit and vegetables
Diffuse carcinoma causes are poorly understood, but doesn’t include H pylori
Where do disaccharides break down to monosaccharides?
Brush-border membrane Sucrose = fructose + glucose Maltose = glucose + glucose Lactose = glucose + galactose Only monosaccharides go through to the capillaries
What part of the GI tract is most at risk of not getting perfusion when the patient is hypovolemic?
Splenic flexure (between transverse colon and descending colon)
What is hirschsprung (congenital megacolon)? What are the 3 problems?
Caudal migration of neural crest cells fail to reach the anus, leaving an ganglionic segment of the distal colon lacking Meissner and Auerbach myenteric plexuses, peristalsis can’t take place at the distal colon.
Problems: obstruction, enterocolitis, and perforation
Progression of ischemic bowel disease?
Mucosal infarction (heals in 2 weeks) Mural infarction (one side of muscle of GI wall) Transmural infarction (whole muscle of GI wall)
What are causes of ischemic bowel disease? Note: mortality is 90%!
Arterial thrombosis/embolism
Venous thrombosis
Nonocclusive ischemia (cardiac failure, shock, dehydration, vasoconstrictive drugs)
Mechanical obstruction (volvulus, stricture, herniation)
What are hemorrhoids and what are the top causes for hemorrhoids?
Persistently elevated venous pressure in the hemorrhoidal plexus causing vatical dilations
Caused by straining (men), pregnancy (women), and hepatic portal hypertension
What is secretory diarrhea? What’s an example?
Vibrio cholerae (cholera)- spreads in infected water sources Bacteria that causes mucosal epithelial cells to lose Cl, then we don't take up Na, then we don't take up water, then we dump water into the intestine instead of absorbing. Death by dehydration, they lose 1 L/hour
What is osmotic diarrhea? What’s an example?
Gut lavage (golytely) We don't have enzymes to break down the polyethylene glycol, so as it moves through the GI tract it continues to hold water
What is exudative diarrhea? What’s an example
Shigella, salmonella, campylobacter
Destruction of the epithelial layer of the GI tract causes lousy absorption
What is malabsorptive diarrhea? What’s an example?
Giardia, lymphatic obstruction, defective absorption, lactose intolerance
You consume something that can’t be broken down or absorbed, bacteria overgrows
What’s an example of deranged motility diarrhea?
Surgery, hyperthyroidism
Idiopathic inflammatory bowel disease: What is the difference between Crohn’s and Ulcerative Colitis?
Crohn’s: skip lesions, anywhere in GI tract, fissures instead of ulcers, fever, maybe rectal bleed, abdominal pain/mass, fistulas
UC: ulcers start at anus and goes back, pseudopolyps, rectal bleed, maybe abdominal tenderness
Crohn’s/ UC symptoms?
Diarrhea, loss of appetite, weight loss, fatigue, painful and frequent BMs
Diverticulitis/diverticulosis: what is it? What are the problems? What can someone do to prevent this?
Diverticula are pouches protruding out of the bowel, occurs in half of people over 50, increases with age
Problems: LLQ pain, bleeding, perforation, fistula formation after perforation
Treatment/prevention: eat more fiber
What are 4 ways that bowel obstruction can occur mechanically?
Hernia
Adhesion
Intussusception (in kids, bowel folds into itself)
Volvulus (twists off)
What are 3 types of pseudo-obstructions
Paralytic ileus
Bowel infarction
Myopathy, neuropathy (Hirschsprung)
What is a polyp?
Tumorous mass protruding into the lumen
Pedunculated vs sessile
Pedunculated: has a stalk (of tissue)
Sessile: not having a stalk
Hyperplastic vs. Neoplastic
Hyperplastic: increased number of cells, not cancer
Neoplastic: abnormal disorganized growth, can be cancer
Adenoma vs. adenocarcinoma?
Adenoma: neoplastic polyps arising from epithelial proliferation and dysplasia
Adenocarcinoma: cancer arising from adenomatous polyps (98% of colorectal cancers). It becomes invasive when it penetrates the muscularis mucosae and enters the submucosal layer.
Colorectal cancer remains asymptomatic for a year, then what are the symptoms?
Pain obstruction, changes in bowel habit
Left side: blood in stool, LLQ pain
Right side: fatigue, weakness, iron deficient anemia (especially post-menopausal women with anemia)
Colorectal carcinoma: _____ cases per year; _____ deaths in the USA; lifetime risk: 6% incidence; 2% death
150,000 cases per year
50,000 deaths
