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360 Cards in this Set
- Front
- Back
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What is a gastroscopy?
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A minimally invasive procedure in which a tube is inserted in the GI tract and the doctor can watch what is going on a TV screen
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What is the esophagus?
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It is the tube that food passes through between the pharynx and stomach
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What is the esophagus lined with?
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Squamous epithelium
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What is esophageal varices?
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Varicose veins in the esophagus, certain veins that are normally not visible are dilated and engorged with blood
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What is the primary cause of esophageal varices?
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Liver disease such as cirrhosis
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What is the principle behind why liver disease causes esophageal varices?
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Blood travels from the left gastric vein to the portal vein that supplies the liver (liver is important to analyze what we eat!)
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How does esophagueal varices develop in liver disease?
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If there is portal vein hypertension such as in liver disease due to something that impair blood flow through the liver, the blood is shunted through the esophageal plexus (collateral circulation).
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What is a problem with the blood shunting into these collateral vessels?
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These vessels are not designed for such a high pressure and are fragile, become distended. A hemorrhage can occur
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What controlls swallowing?
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Both the enteric and autonomic systems
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How is swallowing initiated?
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By the swallowing centre in the medulla
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How many sphincters are in the esophagus?
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Two: UES and LES
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What characterizes these sphincters?
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They are regions of high pressure and have circular muscle to keep them closed
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What is the role of the LES?
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To prevent gastric juice from going back up from stomach into the esophagus
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Which sphincter is most susceptible to being associated with disease?
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LES
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What is dysphagia?
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Difficulty swallowing
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How can a malfuncitoning LES result in dysphagia?
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If the LES cannot relax properly (ie. cannot open up), the material cannot get into the stomach
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How can dysphagia due to LES malfunction result?
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If you lose the inhibitory neuron function, the LES muscle is constantly stimulated and it can therefore not relax properly and therefore cannot open
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What is wrong with the LES during heartburn?
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The LES opens inappropriates or fails to close completely
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What is a consequence of the failure for the LES to close properly?
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The acid is not prevented from going back up to the esophagus
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What is a frequent cause of the LES opening inappropriately?
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Hiatus hernia
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What is a hiatus hernia?
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The abdominal esophaus or even stomach fundus slidies above the diaphragm through the esophageal hiatus into the thoracic cavity.
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What can a hiatus hernia result from?
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A tear or weakness in the diaphragm
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Why does a weakening or tear in diaphragm result in a hernia and how does this affect the LES?
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The diaphragm normally functions to help keep the LES closed. If the stomach pushes up against the diaphragm, it could push the LES through the esophageal hiatus and this normal control over the LES by the diaphragm is lost
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What is a sliding hiatus hernia?
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The stomach/LES rise and come back down
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What is a paraesophageal hiatus hernia?
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The LES stays in place, but a part of the stomach slides up next to it
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What are the two types of hiatus hernia?
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Sliding hiatus hernia
Paraesophageal hiatus hernia |
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What is the pain from in hiatus hernias?
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1) Pressure
2) acid coming into the esophagus |
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What is "reflux"?
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Term for the acid going back up into the esophagus
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What does the presence of acid in the esophagus lead to?
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-Hyperplasia of cells in the esophagus
-Fibrosis (caused by ulcers) -Stricture (scars impair contraction) -Dysphagia -Spasm -Metaplasia |
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What are some major contributors to reflux?
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-Obesity
-Posture -Smoking + eating junk food |
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What causes the risk of carcinoma in the esophagus?
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Alcohol and cigarettes
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What is gastritis?
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Inflammation of the stomach
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What can actute gastritis be caused by?
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Ethanol, NSAIDs, other drugs, food poisoning
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What can the mucosal layer of the stomach be affected by?
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Acute erosion and acute gastritis
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What is an ulcer?
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An erosion of the mucosa
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What is a peptic ulcer?
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An ulcer in the stomach or duodenom
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What are the layers of the stomach from the outside (facing lumen) to inside?
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Mucosa, PLexus, muscle, serosa
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Which cells secrete HCl?
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Parietal cells
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Which cells protect against HCl?
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Mucus cells (secrete mucous containing mucin)
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What property of mucous protects the epithelial cells?
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A high bicarbonate composition
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How do parietal cells secrete acid?
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Via a proton/potassium pump
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How can parietal cells be stimulated to secrete acid?
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Gastrin
Histamine Ach |
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How does a peptic ulce result?
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By an imbalance of the acid output and the mucosal defense
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To what level of the stomach lining does a chronic ulcer erode to?
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The serosa
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What are some consequences of chronic ulcers?
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Inflammation, scar tissue, hemorrhage, perforation, stricture, etc
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What are some ways this imbalance can occur?
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-Sympathetic NS
-Rate of emptying -Not enough bicarbonate |
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How can peptic ulcers be treated?
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-Neutralize the acid via antiacid
-Target H2 histamine receptor on parietal cell -Target proton pump |
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What is pyloric stenosis?
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A narrowing of the opening from stomach to intestines (pyloric sphincter) due to scar tissue (scar tissue can result as a consequence of the ulcer erosion)
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What is thought to be the cause of chronic peptic ulcers?
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Helicobactor pylori
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How does Helibactor pylori cause ulcers?
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They bind to the surface of epithelial cells and inject cytotoxins as well as neutrophil activating proteins
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What is VacA?
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A pore forming cytotoxin produced by H.pylori
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What is a consequence of H. pylori action on the epithelium?
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Intense inflammation, erosion
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What is the best way to treat chronic ulcers?
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Antibiotics (gets rid of H. pylori infection)
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What are acute gastric ulcerations caused by?
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Severe PHYSIOLOGICAL stress: ex car accident, operation, brain injury, burns, etc..
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Which layer of the stomach is disrupted in acute gastric ulcers?
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Mucosal barrier
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What is stomach cancer mostly caused by?
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Bacterial infection leading to chronic inflammation
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How has stomach cancer incidence been improved?
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-Better storage of food
-Development of antibiotics -Sanitation |
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Besides chronic ulceration, when can pyloric stenosis occur?
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Strictures, fibrosis, newborn
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What does pyloric stenosis lead to?
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Projectile vomiting
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What is vomiting?
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A protective mechanism against toxic compounds/doses
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What are the two areas in the brain related to vomiting?
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-Vomiting centre
-Chemoreceptor Trigger Zone |
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What does the CTZ send impulses to?
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Vomiting centre
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Where else does the vomiting centre get impulses from?
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Stomach, intestine, sympathetic NS
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Why can people vomit when they see something terrible?
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Due to the input from the cortex to the vomiting centre
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What can trigger vomiting?
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Alcohol, food poisoning, binge eating, migraines, food allergies, stress or travel
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What happens once the vomiting centre is stimulated?
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It sends impulses to the diaphragm, stomach, intestine and abdominal muscles resulting in reverse peristalsis
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What is the path of movement of the stomach material?
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The diaphragm and abdominal muscles contract forcibly, the LES relaxes, then the UES. The stomach is compressed and the material is expelled
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What type of effect do anticancer drugs, such as those for chemotherapy, have on the CTZ and vomiting centre?
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Chemotherapy can stimulate the CTZ which then in turn stimulates the vomiting centre
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What is the liver?
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It is the second largest organ and is located in the abdomen and is important in detoxification and digestion
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Why can the liver recover easily from alot of problems?
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The liver has a good regenerative ability and can replace the hepatocytes
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Why are liver disorders common?
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The liver is important for many things
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What type of blood supply does the liver have?
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Dual
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What is this dual blood supply that the liver receives?
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Blood comes into the liver via the hepatic artery as well as the portal vein
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Where does the portal vein come from?
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It drains the rest of the GI and flows through the liver
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What happens once blood flows through the liver?
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The hepatic artery and portal venous system combine into sinusoids and then to the central vein
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What important substance does the liver produce?
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Bile
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What are hepatocytes?
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Major cells that do the bulk of the work in the liver, they perform the metabolic work
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What are Kupferr cells?
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Liver cells that are phagocytic
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What is the portal triad?
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The section of the liver with the hepatic artery, portal vein meet and go into the central vein
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How is there easy communication between the blood and hepatocytes?
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The sinusoids provide little barrier between the blood and hepatocytes
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What do hepatocytes do to the blood?
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They scan the blood, chemically altering its constituents and manufacturing ingredients to be secreted into the blood
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What are some characteristics of sinusoids that allow them to provide this little barrier?
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They are line by endothelial cells and have alot spaces between these cells with little basement membrane
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What are stellate cells?
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They are quiescent but can become activated in diseased states to produce collagen scar tissue
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Where are stellate cells found and what is there normal function?
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In the perisinusoidal space and they function to store lipid droplets
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What is the livers involvement in nutrient metabolism?
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It is involved in the breakdown of fats, proteins, and carbohydrates
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How does the liver regulate blood glucose?
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It performs gluconeogenesis, glycogen formation, glyconeolysis, and insulin metabolism
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How does liver regulate protein?
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It metabolizes aa's
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How does the liver regulate absorption and transport of lipids?
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-Produces bile salts
-Produces lipoproteins |
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How do bile salts help in regulating fat?
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Bile salts are secreted into the GI and allow the absorption of fat
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How do lipoproteins help in regulating fat?
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They allow transport and absorption of fat
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Where is bile stored?
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In the gall bladder between meals
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What happens when we consume food?
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The gall bladder contracts and secretes bile through the common bile duct into the duodenum (small intestine)
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What is the main constituent of bile salts and lipoproteins?
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Cholesterol
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What is xanthoma?
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A problem with the liver that results in cholesterol deposits in the eye lids and palms of the hands
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What is the role of the liver in hormone metabolism?
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Insulin, thyroxin, androgens and estrogen needs to be inactivated once made
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What is a spider nevus?
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Altered hormone metabolism leading to expanded, dilated blood vessels
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What is albumin?
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A serum protein produced by the liver that is responsible for osmotic forces, retaining fluid in the circulation
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Why are there bleeding problems in liver disease?
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The liver produces coagulation factors
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Why would you be vulnerable to certain types of infection in liver disease?
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The liver produces COMPLEMENT ad therefore without this you would have a diminished immune response
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What is ascites?
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THe peritoneal cavity (abdomen) is full of fluid due to liver disease
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What is bilirubin?
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A breakdown of hemoglobin that the liver excretes
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How does the liver "see" bilirubin?
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Bound to albumin
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How does bilirubin get bound to albumin?
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Macrophages phagocytose RBCs at the end of their life span, releaseing bilirubin from the hemoglobin. Bilirubin is NOT water soluble and thus gets bound to albumin (albumin is able to travel in the blood)
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What does the liver do to bilirubin?
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It has an enzyme glucuronyl transferase, which conjugates GLUCURONYL ACID to bilirubin to get BILIRUBIN GLUCURONIDE
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Where does bilirubin glucuronide travel?
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It is water soluble, so it can travel to the kidney for excretion
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Therefore what is the overall role of the liver concerning bilirubin?
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Bilirubin excretion
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Why is urine yellow?
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When the bilirubin-glucuronide reaches the kidney, since it is water soluble it can be directly excreted and since it is yellow give sthe urine a yellow color
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Why is stool brown?
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When bilirubin reaches the intestine, it is acted on by colonic bacteria to form a brown derivative
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What is jaundice?
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When bilirubin is not handles properly by the liver it will not be excreted into the intestine/kidney and will form deposits in various locations turning the person yellow
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Where are the main sites of bilirubin deposit during jaundice?
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Skin and eyes
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What happens during extrahepatic biliary obstruction?
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WHen bilirubin leaves the liver it goes to the hepatic duct, but something could be blocking it from moving further so it is reabsorbed
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What are some causes od extrahepatic biliary obstruction?
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-Carcinoma of the bile duct
-Carcinoma of the ampula of Vater -Pancreatic carcinoma -ENlarged lymph nodes -Stricture -COngenial biliary atresia |
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How does pancreatic carcinoma result in extrahepatic biliary obstruction?
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It compresses the hepatic duct from the outside
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How do enlarged lymph nodes result in extrahepatic biliary obstruction?
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They also compress the hepatic duct
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What is congenial biliary atresia?
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Child born with a defective region of the bile duct
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What is hemolytic jaundice?
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There is an excess of unconjugated bilirubin presented to the liver (excess RBC breakdown)
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When would excessive breakdown of RBCs occur?
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In internal hemorrhage
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What is Gilbert's syndrome?
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A mutation in the promoter of the gene encoding glucuronyl transferase
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What is a result of this mutation in the promoter of GT in Gilbert's syndrome?
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Reduced transcription of GT leading to less conjugated bilirubin, which in turn leads to excessive presentation to the liver of unconjugated bilirubin, resulting in jaundice
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What is kernicterus?
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A complication of neonatal jaundice which occurs in newborns
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What is kernicterus characterized by?
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Deposits of bilirubin in the basal ganglia of the brain
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What does the bilirubin in the brain do?
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Besides deposition, targets basal ganglia, causes neuronal degeneration and necrosis
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Why is the UCB (unconjugated bilirubin) able to get so easily into the brain?
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The blood brain barrier is extremely permeable in the newborn
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Why do newborns tend to have higher levels of unconjugated bilirubin?
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They have underdeveloped functions that lead to increased RBC lysis and therefore increased unconjugated bilirubin
-Also, albumin synthesis by the liver is low in premature infants |
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What are some disorders of the liver?
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-Excess consumption of alcohol
-Hepatitis B and C -Autoimmune disorders -Gallstones -Iron overload -Cirrhosis |
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How is ethanol metabolized?
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It is broken down in the liver first to acetylaldehyde and then to acetic acid by aldehyde dehydrogenase
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Which product of ethanol metabolism is toxic?
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Acetylaldehyde
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Which product of ethanol metabolism can we get rid of?
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Acetic acid
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What is the first stage of alcoholic liver disease?
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Impaired ability of liver to handle fats (diminished oxidation of fatty acids) leading to accumulation of tryglycerides in the cell
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What does this accumulation of triglycerides within the cell lead to?
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A fatty liver
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Why is the accumulation of triglycerides bad?
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It impairs liver function and the liver is unable to make lipoproteins to carry the triglycerides out of the liver
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What is the next stage in alcoholic liver disease after the development of the fatty liver?
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Inflammation of the liver
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What happens to the hepatocytes following this inflammation of the liver in alcoholic liver disease?
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THey get damaged and expanded (are "ballooned")
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What are Mallory's hyaline material?
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Damaged liver cells in alcoholic liver disease contain these aggregates of intermediate filaments in the cytoplasm
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Why are there necrotic cells in alcoholic liver disease?
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Ethanol and acetaldehyde are toxic to the hepatocytes
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Where is alcoholic liver disease most prominent?
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Around the central vein
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What is the next stage after the inflammation of the liver?
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Cirrhosis
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What is cirrhosis?
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Inflammation accompanied by progressive scarring, laying down fibrous tissues and permanent damage to the liver
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What component of alcoholic liver disease is reversible?
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Accumulation of triglycerides within the hepatocytes
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What is a consequence of the fibrosis in the cirrhosis stage of alcoholic liver disease?
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It interferes with the normal blood flow resultig in hyperplasia of the surviving liver tissue
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What is the difference between micronodular cirrhosis and macronodular cirrhosis?
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-Macronodular cirrhosis is caused by massive necrosis of a NORMAL liver resulting in LARGE nodules
-Micronodular cirrhosis often develops from a FATTY LIVER and forms SMALL nodules |
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What follows the hyperplasia of liver cells?
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Dysplasia, increasing the risk for cancer
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What are some consequences of cirrhosis?
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-Portal hypertension
-Ascites -Enlarged spleen -Gastroesophageal varices -Portasystemic encephalopathy -Spider angiomas -Palmar eryhema -Clubbing of fingers -Testicular atrophy -Primary liver cancer |
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How does portal hypertension occur in cirrhosis?
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Since there is damage to the microvascular
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What is a consequence of portal hypertension in cirrhosis?
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The blood is shunted to esophagus, spleen, rectum
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What develops when blood is shunted to the rectum?
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Hemorrhoids
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What are hemorrhoids?
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Swelling and inflammation of veins in the rectum
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What are some consequences of portal hypertension?
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-Ascites (accumulation of fluid in the abdominal cavity)
-Impaired lymphatic flow through the liver -Stimulating effect on BP hormones leads to increased fluid retention by the kidneys |
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Why is there increased fluid retention by the kidneys?
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Since the high pressure of the portal circulaton leads to fluid accumulation in the peritoneal cavity, this sequesters the fluid and this causes the kidney to retain more fluid to compensate
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What also contributes to the ascites (osmotic pressure)?
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There is decreased osmotic pressure due to the defective albumin synthesis
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What are some terms for enlarged spleen?
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Splenomegaly or
Hypersplenism |
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What is portasystemic encephalopathy?
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-The accumulation of toxic substances in the blood due to liver failure (inability to detoxify) which reach the brain
-Sometimes, blood is diverted through other channels and completely bypasses the liver |
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What are the acute effects of portasystemic encephalopathy?
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CNS depressant (diminished function)
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What are the chronic effects of portosystemic encephalopathy?
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Neurotoxicity
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What is spider angiomas?
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Due to vascular changes
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What is palmar erythema?
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Changes in the blood flow to the hand, red patches
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What is the genome of most viruses that cause viral hepatitis?
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RNA genome
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What type of genome does HBV have?
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DNA
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In decreasing incidene, which hepatitis virus is more common?
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HCV, HBV, HAV
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How is HAV transmitted?
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Fecal-oral transmission (contaminated food or water)
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How does fecal-oral transmission work?
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A person ingests orally, the virsu crosses the intestines and gets into the blood, and it then causes inflammaiton in the liver and is excreted in bile, and stool resulting in contamination of water and food
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What are some symptoms of hepatitis?
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Jaundice/yellow eyes, diarrhea, dark urine, light colored stools, abdominal pain, malaise/fatigue, fever/chills, decreased appetite, abdominal, gastrointestinal and systemic problems
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What happens when the virus damages the hepatocytes?
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Necrosis of hepatocytes and release of enzymes into the blood, diminished coagulation (factors not being produced)
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How does jaundice occur during viral hepatitis?
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The virus damages the hepatocytes leading to disruption of the bile canaliculi, leading to the accumulation of bile in the blood
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What occurs in early stage viral hepatitis?
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Enlarged liver, Ballooning degeneration of hepatocytes, Necrosis, Inflammatory cells, inadequate bile flow
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What does necrosis variance depend on?
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Virus and severity of infection
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What is severe necrosis in hepatitis?
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Centrilobar necrosis
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What is centrilobar necrosis?
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Necrosis of hepatocytes surrounding the central venule of the liver
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What is the damage to the hepatocytes mediated by?
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-Cytopathic effect of virus (reproduction within hepatocyte)
-Immune mediated response (inflammatory response causes damage) |
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How does HAV resolve?
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After a few weeks, the infection is cleared by the immune system and the inflammatory cells move away, hepatocytes divide and begin to heal
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What are some morphological characteristics of the virus?
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It is circular, has specific surface antigens
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How is HBV transmitted?
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It is secreted in all body fluids, and is transmitted via sexual contact and intravenous drug use
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What is viremia?
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Virus is EVERYWHERE: blood, semen, saliva, vaginal secretions, mothers milk
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What is a problem caused by the surace Ags of HBV?
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Abs are produced against them, but this leads to immune complex deposition
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What can HBV infection lead to?
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Primary liver cancer, liver failure, chronic hepatitis/cirrhossis)
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How is HCV transmitted?
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Through blood
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How does the virus get into the hepatocyte?
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Binds to hepatocyte receptors, gets taken into an endosome, exhibits membrane fusion w/ endosomoe and the genome is released into the cell
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When does HCV replicate?
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During VLDL secretion
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How could tou prevent HCV infection?
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Target the receptor it binds to for endocytosis
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How is HCV treated?
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Through administration of interferon
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Which virus are people with chronic hepatitis most infected with?
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HCV
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What is unique about hepatitis D virus?
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It is a parasite on Hepatitis B (needs surface antigen of hepatitis B to replicate)
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What type of effect does HDV have?
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If co-infected with HBV, causes worse symptoms of hepatitis, increases risk for cirrhosis
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What is another name for HDV?
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Delta agent
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How does HDV replicate?
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It needs the surface antigen to bind to on HBV
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What is hepatitis E?
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Similar to Hep A (fecal oral, no chronic state)
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What is different between hep E and hep A?
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Hep E has a high risk in pregnancy and causes a 20% death rate
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What is viral hepatitis G?
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Causes mild hepatitis
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How are gall stones formed?
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Ingredients in bile may precipitate
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What are stones made of?
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Pigment
Cholesterol Calcium carbonate |
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What is the pigment in the gallstones?
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Billirubin
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Which ingredient sometimes exists on its own in gallstones?
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Sometimes gallstones only have one ingredient CHOLESTROL (however, most are mixtures)
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What are some causes of gallstones?
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-Low fiber, high fat diet
-Obestiy -Gastrointestinal disorders |
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How does obesity lead to cholesterol stones?
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Hyperinsulemia (associated with obesity) stimulates hepatic cholesterol
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How could gastrointestinal disorders lead to cholesterol stones?
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They could interfer with the enterohepatic circulation
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What is the frequency of gall stone?
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20% (common!)
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What are 5 consequences of gallstones?
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-Bilary colic
-Acute cholecystis -Cholestasis -Ulceration of gall bladder -Pancreatitis |
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What is another term for gallstone?
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Cholelithiasis
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What is biliary colic?
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Acute severe pain froms tone in the cystic duct, which often radiates to the right shoulder
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What is the cystic duct?
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Joins gallbladder to the common bile duct
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What is acute cholecystis?
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Inflammation of gallbladder following obstruction
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What are some possible complications of acute cholescystis?
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Infection, Abscess, Perforation, Peritonitis
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What is cholestasis?
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The bile stops flowing due to obstruction
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What can result from cholestasis?
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Obstructive jaundice because of choledocholithiasis (formation of stones in the duct)
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What can ulceration of the gall bladder lead to?
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A fistula developing from the gall bladder to the duodenom
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What is pancreatitis?
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Inflammation of the pancreas
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How does pancreatitis arise during cholelithiasis?
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A biliary stone may lodge in the pancreatic duct or ampulla of Vater and obstruct the pancreatic duct
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How are gallstones treated?
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By removal of the gallbladder, stone fragmentation, drugs to dissolve stones
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How can intestinal obstruction occur? (5 ways)
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1-Mechanical obstruction of the lumen
2-Volvulus or hernia 3- Intussusception 4-Paralytic ileus 5-Destruction or Lack of neuons in intestinal plexus |
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What can result in mechanical obstruction of the lumen?
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A tumor
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What is a volvulus?
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Twisting of the bowel to form a closed loop
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What is a hernia?
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A protrusion of an organ through cavity wall that contains it
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Where does a volvulus tend to occur?
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In areas where the mesentery is longer
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Which specific parts of the intestine can a volvulus occur in?
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Small ntestine, Sigmoid colon or cecum
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What is the cecum?
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Pouch, connects ileum with ascending colon
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What is the sigmoid colon?
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It is the portion of the colon closest to the rectum/anus
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What is an intussusception?
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Prolapse of part of the intestine into the adjacent segment
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What is a paralytic ileus?
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Temporary absence of peristalsis due to impaired neural control
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What can this impaired neural control be caused by in temporary absence of peristalsis?
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Abdominal surgery or peritonitis
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How can paralytic ileus be treated?
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Nasogastric tube, IV fluids allows recovery
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What would result in the paralytic ileus isnt treated?
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Accumulation of fluid and electrolytes in the intestine, leading to shock
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How does destruction of neuorns in the intestinal plexus aries?
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It can sometimes happen in inflammatory bowel disease
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How can one cure the obstruction causes by destruction of neurons?
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Removing the aperistaltic area
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What is diverticular disease characterized by?
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Formation of pouches (diverticular) in the colon
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Which area of the colon is most often affected by diverticular disease?
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The sigmoid region
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What is a colonic diverticulum?
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A herniation of the mucosa and submucosa through the muscular layers of the bowel
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Where does these buldges in colonic diverticulum tend to occur?
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Through gaps in smooth muscle where blood vessels penetrate the colonic wall
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What is the size range of a diverticula?
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1mm-5cm
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When is diverticulosis diagnosed?
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Radiologica examination following barium enema
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What is barium enema?
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Contrast material (barium) is put in the rectum
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How common is dvierticular disease in North America?
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1/2 of people over age 60
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What is the environmental cause considered to be?
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Inadequate fiber in the diet
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What does a diverticulum result in?
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It prolongs intestinal transit time and narrows lumen diameter, resulting in areas of high intraluminal pressure
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What are some consequences of diverticular disease?
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Intermittent lower abdominal pain, distention, discomfort, etc
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What are some more serious complications of diverticular disease?
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-Diverticulitis
-Bleeding |
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What is diverticulitis?
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Inflammation of the diverticulum
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What is the inflammation often due to in diverticulitis?
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Blockage of the diverticuli with fecal material
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What does this inflammation result in?
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Pain, leukocytosis, fever, absess, possible perforations, adhesions, fistulas, peritonitis, or septicemia
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What can severe inflammation as a result of diverticulitis lead to?
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Physical obstruction or paralytic ileus
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How is diverticulitis treated?
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Analgesics, antibitoics, antiinflammatory drugs
-or surgery if it becomes more severe (in the case of obstruction, fistula, or perforation) |
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How can bleeding result in diverticular disease?
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If the vessel ruptures
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What are two types of inflammatory bowel disease?
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1) Ulcerative colitis
2) Crohn's diseae |
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Where is the problem in ulcerative colitis?
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The problem is mostly in the mucosa
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Where is the problem in Crohn's disease?
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The abnormalities extend through the entire wall of the bowel
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What are some differences between crohn's and ulcerative colitis concernin the REGION of the GI affected?
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-Crohn's can occur anywhere in the GI but it often occurs in the small intestine and could extend to the colon
-Ulcerative colitis affects the colon and rectm ONLY |
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Where does ulcerative colitis begin?
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In the rectum/sigmoid colon and extends PROXIMALLY
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What are some differences between Crohn's and ulcerative colitis concerning the EXTENT OF INFLAMMATION?
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-Crohn's = transmural inflammation
-Ulcerative colitis = inflammation is restricted to the mucosa/submucosa |
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What is the difference between the LESION PATTERN between Crohn's and ulcerative colitis?
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Crohn's has characteristic SKIP LESIONS while in ulcerative colitis, the lesions are CONTINUOUS
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What are skip lesions?
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An area is inflamed, followed by a normal area, followed by another inflamed area, etc...
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What is the difference between ulcerative colitis and crohn's concerning a CURE for the disease?
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Ulcerative colitis can be cured with SURGERY but Crohn's is INCURABLE
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Why can't you cure Crohn's disease with surgery but you can cure ulcerative colitis?
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You can live without your colon but you can't live without the small intestine. Also, Crohn's disease lesions occur in multiple locations, and another lesion will usually appear somewhere else
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Since Crohn's cannot be cured, how is it treated?
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Using antiinflammatory drugs, dietary supplements to counteract malnutrition, surgery for complications (such as fistula)
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What are FIVE common features to Crohn's and ulcerative colitis?
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1-They are both chronic and debilitating
2-The cause is unknown 3-The age distribution is similar 4-Techniques for diagnosis are similar 5-Both may be associated with non-intestinal symptoms |
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What are some possible causes of Crohn's and ulcerative collitis?
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-Genetic predisposition
-Immune dysregulation -Bacterial -Viral triggers -Activated T cells |
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What is the typical age distribution of Crohn's and ulcerative colitis?
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10-30, and then 50-60
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What are the techniques for diagnosis of Crohn's and ulceraive colitis/
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Endoscopy, biopsy, barium x-rays and symptoms
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What are some non-intestinal symptoms that crohn's and ulcerative colitis might be associated with?
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Joints, liver, and skin may be affected
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What are some things that form in Crohn's that are abnormal?
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Granulomas
Fistulas |
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Why does malabsoprtion often occur in Crohn's disease?
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Villous atrophy in the small intestine
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Why does the ileum have a "cobble stone appearance" in Crohn's?
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Ulcerations
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What can ulcerations cause?
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Regional enteritis leading to possible obstruction
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What do Crohn's disease symptoms depend on?
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1-The region of the intestine involved
2-The severity of the inflammation |
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What are the most common regions affected in Crohns?
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1/3 small intestine only
1/3 colon only 1/3 in mixed regions |
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What are six consequences of inflammation in the small intestine?
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1) intermittent abdominal pain
2) Inflammation and fever 3) fibrosis 4)Anemia 5)Wieght loss 6)Diarrhea |
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Why is abdominal pain present in Crohn's when there is inflammation of the SI?
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THe pain may be due to partial obstruction of the intestine
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Why does anemia result during inflammation of the SI in Crohn's?
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Mucosal erosion + bleeding
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Why does weight loss occur in Crohn's?
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-Malabsorption
-Loss of protein from inflammed mucosa (due to increase cell turnover) |
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Why does diarrhea result in Crohn's?
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There is osmotically active ingredients in the intestine
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What are three consequences of inflammation in the LARGE intestine during crohn's?
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-Abdominal pain
-Diarrhea -Bleeding |
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Why does diarrhea occur in inflammation of the LARGE intestine during Crohn's disease?
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-One of the major functions of the large intestine is WATER ABSORPTION so without this we get diarrhea
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What is ileocolitis?
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Crohn's in which nflammation of both the large intestine and small (ileum)
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What are some POSSIBLE complications of Crohn's disease?
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1) Hemorrhage
2) Absess 3) Obstruction 4) Fistula formation 5) Perforation leading to peritonitis |
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How can kidney problems occur in Crohns?
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If there is a fistula to the bladder
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What can form at the base of the ulcer during healing?
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Granulation tissue
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What is granulation tissue?
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Perfused, fibrous connective tissue that replaces a fibrous clot in wound healing
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How are the extensive lesions formed in ulcerative colitis?
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The ulcers tend to fuse
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Are the lesions continually occuring in ulcerative colitis?
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There are acute "attacks" followed by periods of remission
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After an acute attack, does the lesion heal completely?
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No! There is some scarring, loss of mucosal folds, loss of secreting glands
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What are four symptoms of ulcerative colitis?
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1-Abdominal pain
2-Diarrhea 3-Bleeding 4-Tenesmus |
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What is tenesmus?
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Diffiulty or painful dfecation
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When would systemic symptoms result in ulcerative colitis?
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In severe cases, accompanied by fatigue, weight loss, and fever
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What are four possible complications of ulcerative collitis?
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1-Hemorrrhage
2-Perforation 3-Carcinoma 4-Toxic dilation of colon leading to a block in peristalsis |
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How is mild ulcerative colitis treated?
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Antiinflammatory medication
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How is severe ulcerative colitis treated?
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Removal of colon
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Once the colon is removed, how can you ensure normal bowel function?
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-Create a direct ileo-anal junction
-Ileostomy |
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What is an ileostomy?
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Emptying the ileum through an opening in the abdominal wall (collecting in a pouch)
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What happens to the function of the SMALL intestine following colon removal?
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It compensate by increasing its ability to absorb fluids
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What type of diet is acute apendicitis typially associated with?
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A low fiber diet
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What is a cause of appendicitis?
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Fecal obstruction, leading to infection, inflammation, and ischemic necrosis reuslting in perforation and peritonitis
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What does a rupture of the appendix result in?
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Peritonitis
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What are two symptoms of appenditcitis?
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Abdominal pain
Rigid abdomen |
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What type of pain is felt in appendicitis?
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Visceral pain (diffuse ache in the lower midline) which then progresses to parietal pain (another location)
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When pain is felt in the upper abdomen, which organs might be causing this pain?
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Liver, stomach, duodenum
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When pain is felt around the umbilics, what might this pain be due to?
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Jejunum, ileum, lower right colon
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When pain is felt in the lower abdomen, what might this be due to?
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Uterus, Colon, bladder
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How is visceral pain activated?
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By stretch receptors following obstruction or distortion
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Why is pain felt in the midline? (though it is located in the lower right)
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Fibers from these organs enter the spinal cord on both sides and the brain interprets this pain as central
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What is visceral pain often accompanied by?
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Sweating, nausea
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How does the parietal pain develop?
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The inflamation spreads to the outer part of the appendix, irritating the parietal peritoneum
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How is the parietal pain transmited?
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Via somatic sensory nerves resulting in localized pain
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How does rigid abdomen result?
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Often when there is intense sensory input from the intestine, this results in a reflex in the spinal cord stimulating the abdominal muscle to contract
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How is appendicitis treated?
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A combination of surgery and antibiotix
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How much fluid enters the GI per day?
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9L (98% is reabsorbed)
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How much fluid is secreted into the GI tract?
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7L
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How much fluid do we get from food and drink?
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2L
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What is acute diarrheo almost ALWAYS due to?
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Microbial infections (90% viral)
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What is diarrhea often accompanied by?
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Headache, fever, anorexia, and vomiting
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What are three mechanisms that cause diarrhea?
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1.Osmosis
2.Decreased absorption 3.Increased secretion |
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How does osmosis result in diarrhea?
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There is a nonabsorbed solute that will retain fluid within the intestine, therby stimulating peristalsis
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What is an example of when osmosis results in diarrhea?
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Lactase deficiency (Lactose accumulates in the lumen of the intestine and by osmosis retains fluid)
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How can lactase deficiency result?
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Viral infection, lack of consuming milk
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How does decreased absorption result?
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Injury or destruction of the epithelial cells by viral infections or other diseases
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What does this destruction of epithelial cells result in?
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Villus atrophy-> mucosal surface area is decreased which lowers the absorptive capacity
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What is a common misconception of a cause of diarrhea?
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Increased motility of the intestine- THIS IS WRONG
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How is increased secretion into the GI caused?
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Bacteria may release enterotoxins that stimulate intestinal fluid secretion
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What are two major bacteria that produce enterotoxins that lead to increased secretion and thus diarrhea?
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Cholera and E.coli
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How do enterotoxins result in increased secretion?
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They bind to specific receptors on epithelial cells and irreversibly activate enzymes producing cAMP
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What does this constant production of cAMP result in?
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Continuous stimulous to secrete H2O w/ Na
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What are three consequences of acute diarrheo?
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1-severe fluid loss
2-Loss of potassium 3-Metabolic acidosis |
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What is lost in severe fluid loss?
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5-10% of body weight in not just water but also ELECTROLYTES!
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What can such a drastic drop in blood volume lead to?
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-Drop in blood pressure
-Increase in BP (to try and compensate) -Shock (inadequate perfusion) -Kidney failure -Death |
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What can the loss of potassium lead to?
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Cardiac arrythmias
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How does metabolic acidosis arise?
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Losing alot of bicarbonate from the intestine leads to a drop in pH
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How is cholera transmitted?
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By ingesting water or food contaminated by faecal material
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What does chronic diarrhea lead to?
|
Malnutrition
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How is cholera induced diarrhea treated?
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By giving a solution of glucose/salt (since glucose and salt absorption is coupled)
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What is this treatment called?
|
Oral rehydration solution
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What is acute viral gastroenteritis caused by?
|
Contamination of objects, food, or water supply by fecal matter
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What is acute viral gastroenteritis caused by?
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-Contamination of objects, food, or water supply by fecal matter
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What are two common viruses that cause acute viral gastroenteritis?
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-Rotavirus
-Norovirus (Norwalk virus) |
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What is rotavirus the major cause of?
|
Severe pediatric diarrhea (afects 6-24 months)
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What type of virus is rotavirus?
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RNA virus
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Why does rotavirus infect younger people more?
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It attaches to intestinal villus receptors, and these receptors decrease with age
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How does rotavirus cause secretion?
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A virus protein promotes secretion from enterocytes
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How common is rotavirus infection causing diarrhea?
|
1/3 children under two will have this each year
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Why do adults have a higher protection against Rotavirus?
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They have higher IgA levels and decreased receptors that rotavirus can bind to
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What is the difference with norwalk/rotavirus?
|
Norwalk infects older children and adults
-Less severe symptons -Produces LACTOSE INTOLERANCE |
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What are the three main categories of food poisoning?
|
1-Salmonella
2-Staphylococcus 3-Traveller's diarrhea |
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What is the incidence of Salmonella infection?
|
1%
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Who is Salmonella infection dangerous to?
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Young children, elderly, and immunosuppressed
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What does Salmonella target?
|
Epithelial cells of the intestine
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How can Salmonella reach these cells (even though very acidic enviornment)?
|
Highly contaminated food or water provides SO many microbes
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How does Salmonella trigger an inflammatory response?
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Gets taken into a phagosome and goes to the lamina propria, where it triggers an inflammatory response
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How does diarrhea resutl during Salmonella infection?
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Toxins released by the bacteria and prostaglandins released during inflammation
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How does prostaglandin result in the symptoms of food poisoning?
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They promote secretion and motility of the intestine
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After ingesting contaminated food, how long does it take for Salmonella to penetrate the intestine?
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8-48
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What are some symptoms of Salmonella induced food poisoning?
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Headache, nausea, vomiting, diarrhea, and abdominal pain
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How is Salmonella induced food poisoning resolved?
|
Wait 2-3 days, drink fluids
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Why cant you take antibiotics or antimotlity drugs to treat Salmonella induced food poisoning?
|
They make the situation worse by damaging protective microflora and icnreasing chance of bacteremia
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What is a key difference between Staphylococcus and Salmonella?
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Staphylococcus are NOT MOTILE
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How does staphyloccous result in food poisoning?
|
THe release of a toxin into food (that was left at room temp- staph are inhibited at refrigerated temperatures)
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Where are staphylococci frequent residents?
|
Nasopharynx + skin = can easily contaminate food when handling
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What are the symptoms of staphyloccocus induced food poisoning?
|
Rapid onset of severe diarrhea
Pain Vomiting |
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How is vomiting induced?
|
The toxin acts on the intestine and the CNS
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What is the difference between who this food poisoning can affect?
|
Staphyloccocus resulting in food poisoning is due to a toxin and not a live microorganism and will thus afffect everyone (live microorganisms have particular preferences)
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What is the cause of traveller's diarrhea?
|
Pathogenic intestinal flora (Ex: enterotoxigenic E.coli)
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What are symptoms of travellers diarrhea?
|
Diarrhea, fatigue, fever, cramps, anorexia, vomiting
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How does enterotoxigenic E coli cause travellers diarrhea?
|
The enterotoxigenic E.coli colonzies the small intestine, liberating a toxin which causes secretion of fluid and electrolytes
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How would you treat traveller's diarrhea?
|
-Oral rehydration solutions
-Antibiotics -Codeine |
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What is special about E.coli O157?
|
It is ENTEROHEMORRHAGIC- directly damages intestinal epithelial cells, causing diarrhea, hemorrhage and ulceration
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