关于胃呕吐论文的文献

IntroductionBackgroundGastritis includes a myriad of disorders that involve inflammatory changes in the gastric mucosa, including erosive gastritis caused by Helicobacter pylori bacterial infections, other infectious gastritises, nonsteroidal anti-inflammatory drugs (NSAIDs), noxious irritants, reflux gastritis from exposure to bile and pancreatic fluids, infectious gastritis, and gastric mucosal atrophy.Peptic ulcer disease (PUD) refers to a discrete mucosal defect in the portions of the gastrointestinal tract (gastric or duodenal) exposed to acid and pepsin secretion. Presentations of gastritis and PUD usually are indistinguishable in the ED, and thus the ED management is generally the same. Emergent complications include hemorrhagic shock and peritonitis secondary to a perforated ulcer. The clinician should be concerned about other life-threatening conditions (eg, acute coronary syndromes and aortic aneurysms), which can mimic the presentation of gastritis.For more information, see Medscape's Peptic Ulcer Disease Resource Center.PathophysiologyThe mechanisms of mucosal injury in gastritis and PUD are thought to be mainly caused by H pylori infections, coupled an imbalance of aggressive factors, such as acid production or pepsin, and defensive factors, such as mucus production, bicarbonate, and blood flow.Erosive gastritis usually is associated with serious illness or with various drugs. Stress, ethanol, bile, and nonsteroidal anti-inflammatory drugs (NSAIDs) disrupt the gastric mucosal barrier, making it vulnerable to normal gastric secretions.Infection with H pylori, a short, spiral-shaped, microaerophilic gram-negative bacillus, is the leading cause of PUD and is associated with virtually all ulcers not induced by NSAIDs. H pylori colonize the deep layers of the mucosal gel that coats the gastric mucosa and presumably disrupts its protective properties. H pylori is thought to infect virtually all patients with chronic active gastritis. Eradication of H pylori was thought to be the pathway to curing ulcer disease, but that has proven increasingly challenging.NSAIDs and aspirin also interfere with the protective mucus layer by inhibiting mucosal cyclooxygenase activity, reducing levels of mucosal prostaglandins. Many people with known H pylori colonization or who are taking NSAIDs do not suffer from gastritis or PUD, which indicates other important causative factors must be involved.FrequencyUnited StatesApproximately 10% of Americans eventually develop PUD, and about 10% of patients presenting to the ED with abdominal pain are diagnosed with PUD. Prevalence has decreased in the United States over the last 30 years.InternationalFrequency of PUD is decreasing in the developed world but increasing in developing countries.Mortality/MorbidityComplications of gastritis include PUD and, rarely, extensive bleeding. PUD accounts for more than 50% of all causes of upper gastrointestinal bleeds in the United States.Complications of peptic ulcer disease include bleeding, occasionally massive, and perforation leading to peritonitis and sepsis (rare).The mortality rate is low.SexMale-to-female ratio of gastritis is approximately 1:1Male-to-female ratio of PUD is approximately 2:1AgeAn estimated 60% of Americans older than 60 years harbor H pylori.Duodenal ulcers usually occur in those aged 25-75 years.Gastric ulcer prevalence peaks in those aged 55-65 years.ClinicalHistoryPatients typically present with abdominal pain that has the following characteristics:Epigastric to left upper quadrantFrequently described as burningMay radiate to the backUsually occurs 1-5 hours after mealsMay be relieved by food, antacids (duodenal), or vomiting (gastric)Typically follows a daily pattern specific to patientNSAID-induced gastritis or ulcers are usually silent.Sudden onset of symptoms may indicate perforation.Gastritis may present as bleeding, which is more likely in elderly patients.Symptoms consistent with anemia (eg, fatigue, dyspnea) may manifest.PhysicalEpigastric tenderness is present and usually mild.Bowel sounds are normal.Signs of peritonitis or GI bleeding may be manifest. Perform a rectal examination and Hemoccult testing.CausesH pylori (most common cause of ulceration)NSAIDs, aspirinGastrinoma (Zollinger-Ellison syndrome)Severe stress (eg, trauma, burns), Curling ulcersAlcoholBile refluxPancreatic enzyme refluxRadiationStaphylococcus aureus exotoxinBacterial or viral infection