PGY 412Final Exam Study GuideGastrointestinal DisordersLecture 1: Overview and Esophagus - - Esophageal pathologyo Obstruction Inside – foreign object, tumor, ring, web Outside – lung cancer, enlarged lymph nodes (secondary to metastasis or tuberculosis) Symptoms – dysphagia (difficulty swallowing), regurgitation o Dysfunction of esophageal muscle or its innervation – failure to contract or to relax Achalasia- LES (Lower Esophageal Sphincter) remains constricted- Eventually esophageal walls become dilated and peristalsis is lost- “Bird’s beak” appearance on barium swallow- Faulty parasympathetic control Failure to contract – scleroderma, Chagas disease (destroy collagen) Failure to relax – diffuse esophageal spasm that mimics symptoms of anginao Diverticula (outpouchings) Distal obstruction leads to proximal esophagus contracting more forcefully Pulsion Diverticula – esophageal wall weakens leading to an outpouching Traction Diverticula – due to lymph nodes Zenker’s Diverticulum – just behind UES (Upper Esophageal Sphincter); regurgitation of undigested food; pulsion type of diverticulumo Gastroesophageal Reflux Disease (GERD) Most common disorder of esophagus Esophagitis – acid burn of lower esophagus  Hiatus Hernia – protrusion (or herniation) of the upper part of the stomach into the thorax through a tear or weakness in the diaphragm Increased gastric pressure opening LES due to decreased gastric emptying (obstruction or gastric paresis) Worsens when lying down or bending over Barrett’s Esophagus – lining of the is damaged by stomach acid and changed to a lining similar to that of the stomacho Esophageal cancer Adenocarcinoma caused by Barrett’s Esophagus  Squamous cell carcinoma caused by smoking and alcohol  Dysphagia Upper airway obstructiono Esophageal varices Dilations of esophageal veins associated with Portal Venous Hypertension  Esophageal veins are dilated due to collateral veins from Portal system  Delicate – bleed easily- Acute bleed: Undigested – red- Chronic bleed: Digested – dark (coffee grounds) Lecture 2: Stomach- The stomach can be divided into three parts: The fundus is the top portion, the body is the middle portion, and the antrum is the lower portion- The inside of the stomach contains many folds called rugae- The chief cells of the stomach secrete pepsinogen - The parietal cells of the stomach secrete HCl and intrinsic factor- The secretion of HCl involves neurocrine, endocrine, and paracrine stimulation as well asdirect and indirect stimulationo G-cell – secretes gastrino ECL = enterochromaffin-like- Blockers and inhibitors o H-2 receptor Tagamet Zantaco H/K ATPase pump Prilosec Nexium Aciphex- Turning off the G-cellso Low pH in the gastric lumen stimulates the secretion of somatostatin from the D-cell;somatostatin inhibits the G-cells from releasing gastrin- Turning on the G-cellso Vagus nerve sends acetylcholine to GRP neuron, which releases GRP and stimulates the G-cell to secrete gastrino Vagus nerve once again transmits acetylcholine, but this time it stimulates a cholinergic neuron which inhibits the D-cell with more acetylcholine, therefore allowing gastrin to be secretedo The presence of digested protein in the lumen of the stomach stimulates gastrin secretion - Turning off the parietal cells (decreasing HCl secretion)o Somatostatino Prostaglandins – help with mucus formation o Secretino VIP- Turning on the parietal cells (increasing HCl secretion)o Histamineo Gastrino Acetylcholine- Regulation by secretino S-cell – secretes secretin- Ulcero Most common cause is Helicobacter Pylori (H. Pylori) bacteria – damages the mucosal protective layer and causes inflammation that increases acid secretion o Decreases mucosal protection A decrease in prostaglandins creates a decrease in mucus secretion  NSAIDS and COX inhibitors block inflammation, but also block mucus secretion COX-2 inhibitors has specific targets that reduces the risk of developing an ulcer Alcohol and tobacco decrease mucus secretiono Physiological stress – shock, sepsis, burns, and trauma  Decrease in gastric blood flow decreases mucus protection o Increased acid secretion Ethanol Caffeine Zollinger-Ellison Syndrome – gastrin-secreting tumor in pancreas elevates plasma gastrin - Secretin test – administration of secretin should cause minimal/no change in gastrin levels with a normal pancreas since secretin inhibits gastrin; secretin will actually stimulate gastrin secretion in a gastrinomal pancreas o Signs and symptoms Pain Nausea Vomiting – either red (undigested blood) or brown (digested blood) Tarry stools (melena) Changes in appetite  Perforation of gastric/duodenal wall – x-ray shows air in peritoneal cavity  Timing - Gastric ulcers – pain occurs while eating- Duodenal ulcers – pain occurs much later after eating o Treatment Antibiotics – eradicate H. Pylori Magnesium/calcium salts or NaHCO3 – neutralize acid Decrease acid production- Rantidine – H2 receptor blocker- Omeprazole – H+/K+ pump blocker Increase mucus production- Sucralfate – viscous gel- Misoprostal – synthetic prostaglandin - Gastritis – inflammation of stomacho H. Pylorio NSAIDSo Stresso Alcoholo Caffeineo Radiationo Crohn’s Disease – autoimmune disease that causes lesions throughout GI tracto Reflux of bile and/ or pancreatic secretions- Loss of intrinsic factor – needed to absorb vitamin B12, which is used for red blood cell productiono Gastric resection – removal of a portion of the stomacho Autoimmune gastritis – antibodies against parietal cellso Leads to pernicious anemia – decrease in number of blood cells because they are notbeing produced due to absence of intrinsic factor (and vitamin B12)- Gastric obstruction o Pyloric sphincter – inside: foreign body, gastric polyp, gastric cancer o Pyloric sphincter – outside: pancreatic tumor o Pylorus can be scarred by acido Pyloric stenosis – stays closed; usually congenital- Gastroparesis – paralysis of the stomach o Vagus nerve dysfunction  Acetylcholine release CNS controlo Anticholinergic drugs – Atropine, psychotropic drugso Narcotic analgesics – Morphine, Demerol- Gastric cancero Most common in people of Asian descento H. Pylorio Irritants – alcohol, caffeine, smoked fish, capsaicin, radiationLecture 3: