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Overview of Lower Gastrointestinal Bleeding

Definition and Etiology

• Lower gastrointestinal bleeding is defined as bleeding that occurs distal to the angle of Treitz, primarily due to diverticulosis in adults.

Characteristics of Diverticular Bleeding

• The most common source of lower GI bleeding is from diverticula, particularly on the right side (ascending colon). This type of bleeding is characterized as arterial, massive, painless, and self-limiting.

• In contrast, angiodysplasia causes venous bleeding that is also massive and painless but tends to be recurrent. Cancer can cause varying degrees of bleeding accompanied by pain.

Other Causes of Lower GI Bleeding

• Hemorrhoids are often mistaken for a primary cause; however, they typically result in minimal bleeding that does not compromise patient stability. Significant bleeds arise from diverticula or angiodysplasia and can lead to shock if severe.

• Additional causes include ischemic colitis, inflammatory colitis, infectious colitis (e.g., shigellosis), with children more likely experiencing anal fissures or intussusception leading to painful lower GI bleeding.

Diagnosis and Identification

Symptoms and Diagnostic Indicators

• Patients may present with bright red blood per rectum (hematochezia), indicating potential colon involvement or rectal bleeding (rectorrhagia). Chronic cases may lead to iron deficiency anemia or occult blood detected via fecal tests.

Diagnostic Procedures

• Colonoscopy serves as the initial diagnostic tool for identifying diverticula and malformations like angiodysplasia responsible for significant lower GI bleeds. If negative results occur but active bleeding persists, angiography may be warranted. For Meckel's diverticulum diagnosis, technetium-99m scintigraphy is preferred.

Treatment Approaches

Initial Management Strategies

• Initial treatment focuses on restoring hemodynamic stability through fluid resuscitation with crystalloids and possible transfusions based on hemoglobin levels.

Endoscopic Interventions

• Once stabilized, endoscopic therapy via colonoscopy can be employed for hemostatic treatments such as coagulation or clipping at the site of diverticular hemorrhage.

Advanced Treatment Options

• If endoscopic measures fail to control massive hemorrhaging from a diverticulum, arteriography with embolization may be attempted as an alternative intervention before considering surgical options like hemicolectomy as a last resort for refractory cases.