GI Exam Study Guide

GI ANATOMY, DISEASES & ISSUES There are 2 esophageal sphincters: the lower and upper. - The upper directs food and liquids into the esophagus and prevents aspiration into the airway. Ingested food moves down the esophagus by peristalsis – the contraction and relaxation of the muscle of the esophagus, innervation of muscles through sensory neurons and moisture form the mucosal membranes. - Lower esophageal sphincter prevents gastric contents from coming up into the esophagus. - ISSUES… - GERD (gastroesophageal reflux)…the most common cause of GERD is a functional or mechanical problem that decreases muscular tone of the lower esophageal sphincter(LES). The inability of the LES to close correctly causes the acid in the stomach to backup into the esophagus. This damages the esophageal lining/epithelium. The gastric acid can quickly erode the mucosal epithelial layer and cause ulceration of the esophageal lining. If untreated it can cause metaplasia – which is a change of esophageal epithelial cells into stomach columnar cells = dysplastic cell changes….This change at the GE junction is called Barrett’s esophagus – a precancerous condition - and can lead to cancer. o Certain conditions, substances, foods or medications can weaken or hinder closure of the lower esophageal sphincter. These include: alcohol, chocolate, coffee, fatty meals, medications, nicotine, obesity, pregnancy. o Signs & Symptoms of GERS are: dysphagia, heartburn, epigastric pain, eructation (belching) regurgitation, a bitter or sour taste in the mouth, some people develop a chronic dry cough due to that irritation. Pain after eating fatty foods. - Dysphagia is swallowing difficulty. It is widely associated with disorders of the esophagus, such as the lack of a gag reflex. Lack of gag reflex occurs in degenerative neurological diseases and stroke (neuromuscular dysfunction and stroke). STOMACH - The vagus nerve (remember the cranial nerves???) stimulates the opening of the lower esophageal sphincter and the bolus is pushed into the stomach. Parietal cells in the stomach are responsible for gastric acid secretion which aids in the digestion of food, absorption of minerals, and control of harmful bacteria. HCL sterilizes and breaks down food. Intrinsic factor is required for absorption of vitamin B12 in the small intestine. Goblet cells reside throughout the length of the small and large intestine and are responsible for the production and maintenance of the protective mucus blanket by synthesizing and secreting high-molecular-weight glycoproteins known as mucins. GASTRITUS - Acute gastritis is also known as erosive gastritis and is an inflammation in the lining of the stomach. - It is caused by a number of medications and factors such as infection, allergy, acute stress, bile reflex, alcohol abuse, radiation, and direct trauma. Chronic use of aspirin, NSAIDs (Ibuprofin,steroids), or corticosteroids commonly cause gastritis. These medications suppress the inflammatory response and irritate the stomach lining by blocking gastric mucus production. They are known to frequently cause GI bleeding or PUD (peptic ulcer disease. - The wall of the stomach has 3 layers. Inflammation associated with acute gastritis is limited to the mucosa layer. An irritant to the mucosa triggers an inflammatory response. This causes WBCs to rush to the area and increase the blood supply, causing edema. The swelling creates increased pressure within the tissue layers and causes pain. - Although NSAIDS relieve the inflammation, they deplete the gastric mucus and impair the stomach’s protective mechanism. Without mucus, the gastric lining is exposed to acidic contents that increase the pain. - Clinical symptoms include complaints of heartburn, nausea and epigastric pain. Chronic Gastritis - Chronic gastritis is normally associated with an underlying disease or severe infection. The protective mechanisms of the intestinal mucosal barrier are damaged by H. pylori. The erosion in the mucosal lining of the stomach or duodenum permits HCL into the stomach wall and blood vessels causing inflammation with release of prostaglandins and histamines, ultimately causing ulcers to form. • It is different from acute because it causes atrophy of the glandular stomach lining (atrophic gastritis). The presence of H. pylori bacterium, which usually affects the fundus of the stomach, is the most common cause. It attacks the mucosal layer of the stomach wall and can cause erosion and death of cells which diminishes the production of pepsin, HCl and intrinsic factor. Chronic gastritis is different from acute gastritis because it causes atrophy of stomach lining, no absorption of iron and vitamin B12. • PUD (Peptic ulcer disease) - this is an inflammatory erosion of the stomach or duodenal lining causing ulcers. The most frequent causes of PUD include H. pylori and the use of NSAIDS or aspirin. The protective mechanisms of the intestinal mucosal barrier are damaged by H. pylori. The erosion in the mucosal lining of the stomach or duodenum permits HCL into the stomach wall and blood vessels causing inflammation with release of prostaglandins and histamines, ultimately causing ulcers to form. • S&S - Epigastric, abdominal pain - between meals, about 2 to 3 hours after eating; Pain is intense; a burning and gnawing sensation is present that can be slightly relieved by food and can be strong enough to awaken a person from sleep. SMALL INTESTINE - The small intestine is the main part of the intestinal tract that absorbs nutrients. There are 3 parts: Duodenum, Jejunum and the Ileus - - - The duodenum marks the beginning of the small intestine by connecting the stomach to the small intestine. In the duodenum – bile from the liver, enzymes from the pancreas and chyme from the stomach come together to complete the digestive process. Acidic stomach contents enter the duodenum gradually. This allows pancreatic bicarbonate to neutralize the acidic gastric contents. The jejunum is the middle section of the small intestine and is responsible for absorption of nutrients like amino acids, glucose, iron, calcium and vitamins A, D, E, and K. Last is the ileum, the longest segment of the small intestine. The primary function of the ileum is reabsorption of vitamin B12 and return of bile acids to the liver. The ileum then connects the small intestine to the large intestine. In addition – there are 3 pancreatic enzymes that break down: - Fats (lipids)…enzyme = lipase - Carbohydrates… enzymes = amylase - Proteins…enzyme = protease LARGE INTESTINE - The function of the large intestine is to absorb water and sodium and to store feces until defecation. It is made up of the: Cecum Ascending Transverse Descending and sigmoid colon These then lead to the rectum and anal canal. Throughout the ascending and transverse colon a large amount of water and electrolytes are absorbed from the intestinal contents. THEN a large amount of water is also reabsorbed within the descending colon. - ISSUES.. Constipation - Generally thought of having fewer than 3 bowel movements in a week. The diagnosis of constipation is based upon the presence of 2 or more of the following conditions (at least 25% of the time for 6 months): (1) straining, hard stools, sensation of incomplete evacuation, sensation of anorectal obstruction/blockage, manual maneuvers required to facilitate defecation or (2) fewer than 3 bowel movements per week. Fecal Impaction - when hard stool that cannot be passed is lodged in the sigmoid colon and rectum. Obstipation - This is a sensation to defecate with no passing of stool, liquid, or gas from the colon. Cathartic Colon - anatomical and physiological change in the colon that occurs with chronic use of stimulant laxatives. - S&S : Bloating, a feeling of fullness, abdominal pain, and incomplete fecal evacuation Cholecystitis – Murphy’s sign ACUTE ABDOMEN - When severe acute (sudden) abdominal pain and tenderness occurs, it is referred to as an acute abdomen. Anything that causes a tender abdomen, intense pain, and fever. It is considered a surgical emergency because some conditions can cause perforation of the bowel and peritonitis. KNOW THE SIGN & SYMPTOMS - Causes of acute abdomen depend on the abdominal quadrant – know what organs are in each quadrant: - RUQ = hepatitis, duodenal ulcer, acute cholecystitis - LUQ = Gastric ulcer, ruptured spleen, aortic aneurysm, Pancreatitis - RLQ = hernia, appendicitis, ovarian cyst, kidneys tone, pyelonephritis, ectopic pregnancy, salpingitis, mesenteric adenitis, bowel obstruction, diverticulitis, IBS - LLQ = hernia, diverticulitis, ovarian cyst, kidney stone, pyelonephritis, ectopic pregnancy, bowel obstruction, IBS - Abdominal pain, involuntary guarding, abdominal rigidity & rebound tenderness. Any female of child-birthing age should receive a pregnancy test and pelvic exam. Fecal occult blood testing to check for blood in stool. IBS – Irritable Bowel Disease TOXIC MEGACOLON • It is a complication of Crohn’s disease • • Extreme dilation of a segment of the diseased colon, commonly the transverse colon \It causes complete obstruction and impaired absorption of fluids and electrolytes. In toxic megacolon, life-threatening perforation and peritonitis can result. LIVER The liver is the largest internal organ in the body. It functions as an accessory organ of digestion, an endocrine organ, a hematologic organ and an excretory organ. Liver cells have a distinctive regenerative capacity that enables it to function until 80% of its cells are destroyed. Hepatitis is a systemic infection affecting the liver, usually caused by one of 5 viruses (Hepatitis A, B, C, D or E). Hepatitis is a general term used to describe inflammation of the liver. Liver inflammation can be caused by several viruses (viral hepatitis), chemicals, drugs, alcohol, certain genetic disorders or by an overactive immune system that mistakenly attacks the liver, called autoimmune hepatitis. General symptoms include: fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, light-colored stools, joint pain, and jaundice. - Hep A – caused by ingestion of contaminated food or water and/or contracted from person to person by the fecal oral route. Hepatitis A Vaccine endows immunity with one dose. - Hep B - HBV is a stable virus spread by blood products, body fluids, or sexual contact. Treatment is symptomatic (treat the symptoms) and usually supportive with rest. The HBV vaccine is recommended for all people. - Hep C - usually mild and chronic hepatitis occurs in at least 75% of patients. Transmission is via blood, as in IV drug use; sexual transmission is not as likely. HCV can live dormant in someone for years before symptoms develop. At this time there is no vaccine. ALCOHOLIC LIVER DISEASE Also called alcoholic cirrhosis. It develops over a long period of time and is permanent. It can be diagnosed by the presence of histopathological changes in the liver. It causes severe functional impairment. If alcohol ingestion ceases, it CAN resolve – but long term effects often remain. Portal Hypertension -Complication of Liver disease - The liver receives blood from 2 sources: - Hepatic artery - Hepatic portal vein - A major complication of cirrhosis that can lead to life-threatening side effects. As cirrhosis worsens, pressure within the portal vein increases, causing back up of pressure to the GI veins and collaterals. Dilated superficial veins become visible around the umbilicus (referred to as caput medusa). Increased venous pressure builds within the vasculature of the GI system causing splenomegaly, esophageal varices, rectal varices, and eventually ascites. Rupture of esophageal and rectal veins can occur.