2 - GI Patho Flashcards
What is achalasia?
lower esophageal sphincter fails to relax during swallowing
Food can’t get from the esophagus into the stomach
Caused by denervation of the myenteric plexus in the lower 2/3 of the esophagus
What is megaesophagus?
When achalasia is severe, the esophagus becomes distended and can hold up to one liter
food becomes putrid and infected while waiting to pass into the stomach
Loss of stomach secretions in individuals with chronic gastritis leads to ____ and ____
achlorhydria
pernicious anemia
What is achlorhydria
Stomach fails to secrete hydrochloric acid
A lack of acid also means pepsin is not secreted, and even if it is it isn’t activated into pepsinogen
How much Vitamin B12 is absorbed without intrinsic factor?
1/50th of the normal amount!
What is the usual cause of a peptic ulcer?
imbalance between rate of gastric secretion and degree of intestinal wall protection
What percentage of people with gastric ulcers have H. Pylori infections?
Why?
75%
bacteria burrows its way through the gastric barrier and releases ammonium that liquefies the barrier and stimulates secretion of hydrochloric acid
How long does an H. Pylori infection last?
A lifetime
Requires ABX treatment
What are three big modifiable factors that predispose people to peptic ulcers?
Smoking
Alcohol
Aspirin and NSAIDs
What are extreme measures that are used to stop ulcerative bleeding?
Removing portions of the stomach
Cutting the vagus nerves that supply PS stimulation to the gastric glands
What is the most common cause of pancreatitis?
What is the second?
Alcohol
Blockage of the papilla of Vater by a gallstone
What is Sprue?
Any disease that causes malabsorption in the SI mucosa
Compare tropical and non-tropical sprue
Tropical: caused by some sort of bacteria, but no one is sure which one
Non-tropical: celiac’s etc
What is steatorrhea?
Fatty stools
Sprue leads to fatty stools that are almost entirely composed of salts of fatty acids. What does this mean?
The problem isn’t in digesting fat. The bile salts are still doing their job, and the fats are still being broken down
they just aren’t being reabsorbed
that’s why sprue is a disease of malabsorption, not digestion
What is one cause of Hirschprung’s Disease?
lack of or deficiency of ganglion cells in the myenteric plexus in a segment of the sigmoid colon
How can patients with severed spinal cords control their bowel movements
Giving an enema at a specified time of day (in the morning) creates stimuli that will trigger the cord defecation reflex, and they can have a bowel movement
What is antiperistalsis?
Peristalsis up the GI tract (vomiting)
In the large intestine, what generates most of the gases?
Bacterial action
CO2
Methane
hydrogen
What is anorexia?
Lack of desire to eat despite physiologic stimuli that would normally produce hunger
What substances trigger vomiting in the CTZ?
Dopamine
Opioids
Ach
Substance P
serotonin
What is projectile vomiting?
Not preceded by nausea or retching
caused by direct stimulation of the vomiting center by neurologic lesions
OR
gastric outlet obstruction
What are the three main mechanisms of diarrhea?
osmotic
secretory
motility
Small volume diarrhea is usually caused by:
inflammatory disorder of the intestines (Crohn’s, UC, microscopic colitis)
Irritation and inflammation causes increased motility
What is motility diarrhea?
caused by resection of the SI,
surgical bypass,
fistula formation,
IBS,
diabetic neuropathy
laxative abuse
hyperthyroidism
Compare and contrast parietal and visceral pain
parietal pain arises from the peritoneum, visceral pain arises from the organs themselves
parietal is more localized and intense than visceral, which is diffuse and vague
parietal lateralizes and follows dermatomes, visceral may b e referred or nonspecific
parietal pain comes from A delta fibers, visceral comes from polymodal C fibers
Gallbladder pain sometimes is referred to the right shoulder. This is an example of ______ pain
visceral
What is a Mallory-Weiss tear?
tear at esophageal-gastric junction
caused by severe retching
What drugs put people at risk for GERD?
Ones that relax the lower esophageal sphincter:
anticholinergics
nitrates
calcium channel blocker
nicotine
What is eosinophilic esophagitis?
rare idiopathic inflammatory disease that causes infiltration of esinophils in the esophagus
manifestations look a little similar to GERD
What is a hiatal hernia?
protrusion of the upper stomach through the diaphragm into the thorax
Often asymptomatic except for GERD
Severe symptoms arise if strangulation occurs
Gastroparesis is most commonly associated with:
diabetes (form of neuropathy involving the vagal nerve and cells of cajal)
surgical vagotomy
fundoplication
What generally causes acquired pyloric obstruction?
PUD or nearby carcinoma
Why is prostaglandin inhibition such a problem for the stomach?
Prostaglandin usually stimulate the secretion of mucu and suppress inflammation
What is a curling ulcer?
What is a cushing ulcer?
From burns
From brain surgery/injury
What is dumping syndrome?
rapid emptying of hypertonic chyme from the fakey stomach into the SI 10-12 min after eating
Since the chyme is so extremely hypertonic, it pulls water into the lumen creating systemic dehydration
Causes rapid distention of the intestines, leading to pain and cramping, N/V
leads to diarrhea
What kinds of meals are ideal to prevent dumping syndrome?
frequent, small meals
high in protein
low in carbs
What are the four fat soluble vitamins?
A
D
K
E
Vitamin A deficiency results in:
night blindness
Vitamin D deficiency results in:
decreased calcium absorption/osteoporosis etc
Vitamin K deficiency results in
prolonged prothrombin
Vitamin E deficiency results in
testicular atrophy
neurologic defects in children
Conditions that decrease the production or secretion of bile include:
advanced liver disease (decreased production)
bile duct obstruction (decreased secretion)
intestinal stasis (permits overgrowth of bacteria that deconjugate bile salts)
resection/disease of the ileum (prevents reabsorption and recycling of bile salts)
_________ and _______ are chronic, relapsing idiopath inflammatory bowel disease
Ulcerative Colitis
Crohn’s Disease
What are the PRIMARY histological differences between UC and Crohn’s?
Crohn’s is transmural (full thickness), while UC is mucosal
Crohn’s effects portions of the entire bowel via skip lesions. UC is in the sigmoid colon and rectum
What are the most common sites of Crohn’s lesions?
ascending and transverse colon
What’s the difference between diverticulosis and diverticulitis?
Diverticulosis is asymptomatic presence of diverticula
Diverticulitis is inflammatory diverticula
Where in the GI tract do diverticuli occur?
can occur anywhere
most commonly in the left colon (western countries) and right colon (asian countries)
Where do diverticula form?
at weak points in the colon wall, where arteries penetrate the tunica muscularis to reach the mucosa
How does Laplace’s Law relate to diverticulitis?
Consuming a low-fiber diet results in reduced fecal bulk
This means the lumen of the intestines is smaller, which increases wall tension
Pressure can increase enough within the narrow lumen to cause bowel ischemia
What is the typical pain associated with appendicitis?
Epigastric or periumbilical pain!
The rebound RLQ pain is actually from inflammation of the surrounding tissues (the peritoneum)
Why is the small intestine more often the victim of acute mesenteric ischemia than the large?
The superior mesenteric artery has a more direct line of flow from the aorta
emboli enter it more readily than they enter the inferior branch, causing ischemia and necrosis of the SI
What happens when the intestines lose perfusion?
increased motility, N/V, diarrhea, distention
eventually mucosa can’t produce enough mucus to protect itself and start autodigesting
loss of fluid into the bowels
bacteria invade the necrotic intestinal wall, causing gangrene and peritonitis
What is normal portal blood pressure?
What is considered HTN?
3-5 mmHg
> 5 mmHg
What causes portal hypertension?
Anything that impedes blood flow through the liver:
Prehepatic (thrombosis/narrowing of portal vein)
Intrahepatic (vascular remodeling, fibrosis, hepatitis etc)
Posthepatic (R sided heart failure)
Hepatopulmonary Syndrome (HPS) is associated with:
Portopulmonary Hypertension (PPH) is associated with:
Both are respiratory complications caused by liver disease.
pulmonary vasodilation, shunting, and hypoxia
pulmonary vasoconstriction, vascular remodeling
What medications are used in preventing variceal bleeding?
nonselective beta blockers
Name five disease associated with ascites
- Liver Cirrhosis (most common)
- R heart failure
- Abdominal malignancies
- nephrotic syndrome
- malnutrition
What are three causes of jaundice?
- Obstructive (doesn’t pass from liver to intestine)
- Hepatocellular (not conjugated in the liver)
- Hemolytic (escessive destruction of RBCs)
What causes hepatorenal syndrome?
arterial vasodilation of the splanchnic vasculature reduces effective blood volume
also, renal vasoconstriction with advanced liver failure and portal hypertension
less fluid, and narrower afferent arteriole = decreased GFR
What is the incidence of gallstones in Native Americans?
60-70%!!!!!
it’s 15% in white adults
list some risk factors for gallstones
obesity, but also obese persons who have rapidly lost weight
Middle aged females
using contraceptives
What causes gallstones?
impaired metabolism of cholesterol, bilirubin, and bile acids
What are the three types of gallstones, and how common are they?
- Cholesterol 70-80%
- Pigmented
- Mixed
Cholesterol gallstones form in bile that is high in ______ and low in ______
cholesterol
bile acids and phospholipids
Pigmented gallstones are formed from:
calcium bilirubinate
fatty acid soaps
these bind with calcium
Pigmented gallstones are associated with:
biliary stasis
bacterial infections
biliary parasites
In obese persons, gallstones are usually caused by______
In nonobese persons, gallstones are usually caused by _____
cholesterol over-synthesis
decreased secretion of bile acids
When does biliary colic occur?
30 minutes after eating a fatty meal
What almost always causes cholecystitis?
A gallstone in the cystic duct
Cholelithiasis is a risk factor for developing _______
pancreatitis
Why is alcoholism related to pancreatitis?
pancreatic acinar cells metabolize ethanol and generate toxic metabolites that injure the acinar cells
Chronic alcoholism can also cause protein plugs in pancreatic duct and Oddi spasms
What is the most common cause of chronic pancreatitis?
Chronic alcohol abuse and smoking
Cleft ____ is more common in males
Cleft ____ is more common in females
lip
palate
Esophageal atresia is usually accompanied by:
a tracheoesophageal fistula
Which two syndromes are assoiated with esophageal atresia?
CHARGE
VACTERL
Increased secretion of ______ during the last trimester increases the incidence of pyloric stenosis
gastrin
What is the most common cause of intestinal obstruction in infants?
Pyloric Stenosis
Is pyloric stenosis more common in term or preterm infants?
term
How long after birth does pyloric stenosis manifest?
2-3 weeks after birth
forceful, non-bilious vomiting immediately after feeding
In the intestines, an atresia will cuase what?
a complete blockage
What is the most common congenital anomaly of the small intestine?
Intestinal malrotation
What is the other name for Hirschsprung disease?
Congenital Aganglionic Megacolon
What causes Hirschsprungs?
absence of PNS ganglia in the meissner and auerbach plexuses of the colon
What is the usual manifestation of Hirschsprung?
constipation or watery diarrhea 24-72 hours after birth
What causes a meconium ileus?
Formation of meconium in utero that is abnormally sticky
most common in children with CF d/t abnormal pancreatic enzymes
cause is usually unknown if not d/t CF
What is the most common cause of SBO in children?
Intussusception
Cystic fibrosis is caused by a dysfunction in which transmembrane receptor?
CFTR
What is the role of the CFTR protein in the epithelium?
regulates chloride and sodium ion channels
What is Kwashiorkor?
edematous malnutrition
usually occurs in infants or children 1-4 years old
high starch, protein deficient diet
What is marasmus?
starvation from lack of protein and carbs
can occur at any age, but more common in children <1 year
Often caused by early weaning to overdiluted commercial formula
Kwashiorkor and Marasmus are collectively referred to as:
Protein-Energy Malnutrition (PEM)
What is usually the underlying medical condition in infants with FTT?
80% of the time there isn’t one
