Hemorragia Intestina

ETIOLOGY OF UGIB
There are several causes of UGIB, with age playing a role in determining potential etiologies.
The elderly are more likely to present with bleeds secondary to peptic ulcer disease, esophagitis, and gastritis. Together these account for 70% to 90% of hospital admissions for UGIB in this age group.12 Younger patients account for a larger percentage of cases secondary to causessuch as Mallory-Weiss tears, gastrointestinal varices, and gastropathy, which are all less likely in older adults. Common causes of UGIB with prevalence are summarized in Table 1. Peptic ulcer disease (PUD) is the most common cause of UGIB, accounting for approximately half of all cases.3 PUD occurs secondary to erosion of the gastric or duodenal tissue with symptoms of a gnawing epigastricdiscomfort and pain that worsens after eating and with lying down. Nausea and vomiting, along with anorexia and concomitant weight loss, are symptoms that are consistent with a diagnosis of PUD. Symptoms are often treated with the use of a proton pump inhibitor or H2 receptor antagonist. Infection with helicobacter pylori is the most common cause of PUD, with nonsteroidal anti-inflammatory drug (NSAID)use coming in second. Aspirin use, history of PUD, smoking, and alcohol use are all risk factors for PUD.
Zollinger-Ellison syndrome, a disorder resulting in excess production of the hormone gastrin, is an uncommon cause of PUD. Although the overall prevalence of PUD as a cause of UGIB has decreased, an increase in PUD incidence secondary to NSAID use is noted in the elderly.14 Varices areresponsible for approximately 10% to 25% of UGIB overall and 60% of UGIB in patients with cirrhosis.15 Cirrhotic patients develop portal hypertension secondary to blockage of the portal venous system, which lends itself to portosystemic collaterals, such as varices, and variceal bleeding. In patients with liver disease, the incidence of new esophageal varices is linear over time with a rate ofapproximately 9% per year.16 In addition, 30% of patients with portal hypertension and cirrhosis have bleeding secondary to these varices. Patients with portal hypertension– related bleeding, which includes esophageal and gastric varices and portal hypertensive gastropathy, have mortality rates of greater than 50% as compared
with a 4% rate with bleeding from PUD.2 O her common causes of UGI bleeds areinflammatory pathologies, such as gastritis and duodenitis, and Mallory-Weiss tears. Less common causes include angiodysplasia and Dieulafoy lesions, which are large tortuous arterioles in the gastric wall that can erode and bleed.3
ETIOLOGY OF LGIB
LGIB has decreased morbidity in comparison to UGIB and is often self-limited. Similar to UGIB, there are several factors that may be responsible for thebleed. The most common cause of LGIB is colonic diverticulosis, which presents with painless hematochezia. It is estimated that more than two-thirds of the population over the age of 80 are affected by diverticular disease. Approximately 60% of diverticular bleeds are found in the left aspect of the colon on colonoscopy.17 The recurrence rate of diverticular bleeds is 25% after 4 years.5 Aftercolonic diverticulosis, angiodysplasia, colitis, and postpolypectomy bleeding follow in frequency of LGIB causes. Angiodysplasia is responsible for both acute and chronic LGIB but those are often asymptomatic because they do not frequently bleed. Patients taking NSIDs, aspirin, and anticoagulants as well as coagulopathic patients or patients with platelet dysfunction are more likely to present withLGIB from angiodysplasia.17 Although there are poor data on the incidence of ischemic colitis, it is proposed that the disease is becoming more prevalent secondary to an increase in elderly patients with cardiovascular disease.17 Ischemic colitis is caused by a decrease in mesenteric blood flow as a result of hypotension or vasospasm, and patients often present with sudden onset of abdominal...