Tiêu đề 2. GASTRO ESOPHAGEAL REFLUX DISEASE.pdf ✅

PHARMD GURU Page 1 GASTRO ESOPHAGEAL REFLUX DISEASE INTRODUCTION:  GERD is a symptom or complication resulting from refluxed stomach contents into the esophagus or beyond into the oral cavity or lung.  GERD can be further classified as either symptom based or tissue injury based depending on how the patient presents.  Symptom based GERD may exist with or without esophageal injury and most commonly presents as heartburn, regurgitation or dysphagia. Less commonly odynophagia or hypersalivation may occur.  The absence of tissue injury or erosions is commonly termed nonerosive reflux disease (NERD).  Tissue injury-based GERD may exist with or without symptoms. The spectrum of injury includes esophagitis, Barrets esophagus (when tissue lining the esophagus is replaced by tissue similar to lining of the intestine), strictures, and esophageal adenocarcinoma. DEFINITION: Gastroesophageal reflux disease (GERD) occurs when refluxed stomach contents lead to troublesome symptoms and/or complications. Episodic heartburn that is not frequent or painful enough to be bothersome is not included in the definition. EPIDEMIOLOGY: Gastroesophageal reflux disease occurs in people of all ages but is most common in those older than age 40 years. Although mortality associated with GERD is rare, GERD symptoms may have a significant impact on quality of life. The true prevalence and incidence of GERD is difficult to assess because many patients do not seek medical treatment, symptoms do not always correlate well with the severity of the disease, and there GASTROINTESTINAL SYSTEM
PHARMD GURU Page 2 is no standardized definition or universal gold standard method for diagnosing the disease. However, 10% to 20% of adults in Western countries suffer from GERD symptoms on a weekly basis The prevalence of GERD varies depending on the geographic region but appears highest in Western countries. Except during pregnancy, there does not appear to be a major difference in incidence between men and women. Although gender does not generally play a major role in the development of GERD, it is an important factor in the development of Barrett esophagus. Barrett esophagus is most prevalent in white adult males in Western countries and may increase the risk for adenocarcinoma of the esophagus especially in white males. Alarmingly, adenocarcinoma of the esophagus has increased two- to sixfold over the past 2 decades. The relationship of adenocarcinoma to Barrett esophagus, or even just long- standing GERD, which may be an independent risk factor for esophageal adenocarcinoma, is not clear. Other risk factors and comorbidities that may contribute to the development or worsening of GERD symptoms include family history, obesity, smoking, alcohol consumption, certain medications and foods, respiratory diseases, and reflux chest pain syndrome. ETIOLOGY:  The lower esophageal sphincter (LES) is a circular band of muscle at the end of your esophagus. When it’s working properly, it relaxes and opens when you swallow. Then it tightens and closes again afterwards.  Acid reflux happens when your LES doesn’t tighten or close properly. This allows digestive juices and other contents from your stomach to rise up into your esophagus.
PHARMD GURU Page 3 PATHOPHYSIOLOGY: 1) DECREASED LOWER ESOPHAGEAL SPHINCTER PRESSURE:  Primary barrier to gastro esophageal reflux is the lower esophageal sphincter.  LES normally works in conjunction with the diaphragm.  If barrier disrupted, acid goes from stomach to esophagus. May be due to:  Spontaneous transient LES relaxations.  Transient increase in intra abdominal pressure.  An atonic LES.
PHARMD GURU Page 4 FACTORS AFFECTING LES TONE:  Drugs that reduce LES tone include calcium channel antagonists (e.g., nifedipine, verapamil, diltiazem), nitrates, anticholinergic agents(e.g.,tricyclic antidepressants , antihistamines), and oral contraceptives and estrogen.  Foods that reduce LES tone include chocolate, fatty foods, onions, peppermint, and garlic.  Smoking (nicotine) reduces LES tone. 2) DISRUPTION OF ANATOMICAL BARRIERS:  Associated with hiatal hernia.  The size of hiatal hernia is proportional to the frequency of LES relaxations.  Hypotensive LES pressures and Large hiatal hernia- more chance of GERD following abrupt increase in intra abdominal pressure. 3) ESOPHAGEAL CLEARANCE:  The GI acid produced spent too much time in contact with the esophageal mucosa.  Normally swallowing contributes to esophageal clearance by increasing salivary flow.  Saliva decreases with increasing age, so more often seen with elderly. 4) MUCOSAL RESISTANCE:  The mucus secreted by the mucus secreting glands involves in the protection of esophagus.  The bicarbonate’s moving from the blood to the lumen can neutralize acidic refluxate in the esophagus. On repeated exposure to the refluxate or due to some defect in normal mucosal defenses hydrogen ions diffuse into the mucosa, leading to cellular acidification and necrosis leading to esophagitis. 5) DELAYED GASTRIC EMPTYING:  An Increase In gastric volume may Increase both the frequency of reflux and the amount of gastric fluid available to be refluxed.