Gastrointestinal bleeding

Overview

Gastrointestinal bleeding (GI bleeding) refers to any form of bleeding that occurs in the gastrointestinal tract, which extends from the mouth to the anus. It is a symptom of various underlying conditions rather than a disease itself. GI bleeding can range from microscopic bleeding, which is detectable only through laboratory tests, to massive bleeding that can be life-threatening. The bleeding can be classified as either upper or lower gastrointestinal bleeding, depending on its source.

Classification

Upper Gastrointestinal Bleeding

Upper gastrointestinal bleeding originates from the esophagus, stomach, or duodenum. Common causes include peptic ulcers, esophageal varices, Mallory-Weiss tears, and gastritis. Symptoms may include hematemesis (vomiting blood), melena (black, tarry stools), and less commonly, hematochezia (bright red blood in stools).

Lower Gastrointestinal Bleeding

Lower gastrointestinal bleeding originates from the small intestine, colon, rectum, or anus. Common causes include diverticulosis, inflammatory bowel disease (IBD), colorectal cancer, and hemorrhoids. Symptoms often include hematochezia and, less commonly, melena.

Etiology

Peptic Ulcer Disease

Peptic ulcer disease (PUD) is one of the most common causes of upper GI bleeding. It involves the formation of ulcers in the stomach or duodenum due to the erosion of the mucosal lining. Risk factors include Helicobacter pylori infection, nonsteroidal anti-inflammatory drugs (NSAIDs), and excessive alcohol consumption.

Esophageal Varices

Esophageal varices are dilated submucosal veins in the esophagus, primarily resulting from portal hypertension due to liver cirrhosis. These varices are prone to rupture, leading to significant bleeding.

Diverticulosis

Diverticulosis involves the formation of small pouches (diverticula) in the colon wall. When these pouches bleed, it can result in lower GI bleeding. The exact cause of diverticulosis is not well understood, but it is associated with a low-fiber diet and aging.

Inflammatory Bowel Disease

Inflammatory bowel disease, including Crohn's disease and ulcerative colitis, can cause chronic inflammation and ulceration of the gastrointestinal tract, leading to bleeding. The bleeding may be intermittent and vary in severity.

Colorectal Cancer

Colorectal cancer is a significant cause of lower GI bleeding, particularly in older adults. The bleeding is often occult (hidden) and may present as iron-deficiency anemia.

Pathophysiology

The pathophysiology of GI bleeding varies depending on the underlying cause. In peptic ulcer disease, the erosion of the mucosal lining leads to exposure and damage of blood vessels. In esophageal varices, increased pressure in the portal venous system causes veins to dilate and become susceptible to rupture. In IBD, chronic inflammation leads to mucosal damage and ulceration, which can bleed.

Clinical Presentation

The clinical presentation of GI bleeding depends on the location and severity of the bleeding. Common symptoms include:

Hematemesis: Vomiting of fresh blood or "coffee-ground" material.
Melena: Black, tarry stools indicating upper GI bleeding.
Hematochezia: Passage of bright red blood per rectum, typically indicating lower GI bleeding.
Fatigue and weakness: Due to anemia from chronic blood loss.
Abdominal pain: May be present depending on the underlying cause.

Diagnosis

The diagnosis of GI bleeding involves a combination of clinical evaluation, laboratory tests, and imaging studies.

Clinical Evaluation

A thorough history and physical examination are essential. The history should include questions about the onset, duration, and characteristics of the bleeding, as well as any associated symptoms. Physical examination may reveal signs of anemia, such as pallor and tachycardia.

Laboratory Tests

Laboratory tests include a complete blood count (CBC) to assess hemoglobin and hematocrit levels, coagulation studies, and liver function tests. A fecal occult blood test (FOBT) may be used to detect hidden blood in the stool.

Endoscopy

Endoscopy is the primary diagnostic tool for GI bleeding. Esophagogastroduodenoscopy (EGD) is used to visualize the upper GI tract, while colonoscopy is used for the lower GI tract. Endoscopy allows for direct visualization of the bleeding source and enables therapeutic interventions.

Imaging Studies

In cases where endoscopy is inconclusive, imaging studies such as a CT angiography or a tagged red blood cell scan may be used to localize the bleeding source.

Management

The management of GI bleeding involves stabilization of the patient, identification of the bleeding source, and therapeutic interventions.

Initial Stabilization

Initial stabilization includes securing the airway, breathing, and circulation (the ABCs). Intravenous access should be established for fluid resuscitation and blood transfusions if necessary. Oxygen therapy may be administered, and vital signs should be closely monitored.

Pharmacologic Therapy

Pharmacologic therapy depends on the underlying cause of the bleeding. Proton pump inhibitors (PPIs) are commonly used for peptic ulcer disease to reduce gastric acid secretion and promote ulcer healing. Octreotide may be used for variceal bleeding to reduce portal pressure.

Endoscopic Therapy

Endoscopic therapy includes techniques such as injection therapy, thermal coagulation, and mechanical hemostasis (e.g., clipping). These methods can be used to control active bleeding and prevent rebleeding.

Surgical Intervention

Surgical intervention may be necessary for patients who do not respond to medical and endoscopic treatments. Surgical options include resection of the bleeding segment, oversewing of bleeding ulcers, and portosystemic shunt procedures for variceal bleeding.

Prognosis

The prognosis of GI bleeding depends on the underlying cause, the severity of the bleeding, and the patient's overall health. Early diagnosis and appropriate management are crucial for improving outcomes. Patients with variceal bleeding or malignancy generally have a poorer prognosis compared to those with peptic ulcer disease or diverticulosis.

Prevention

Preventive measures for GI bleeding include:

Avoiding NSAIDs and other medications that can irritate the GI tract.
Managing risk factors for peptic ulcer disease, such as H. pylori infection and excessive alcohol consumption.
Regular screening for colorectal cancer, especially in high-risk individuals.
Managing chronic conditions such as liver disease and IBD to prevent complications.

References

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