Gastrointestinal bleeding

Gastrointestinal Bleeding (GIB) — 
Definition and Overview

Gastrointestinal bleeding (GIB) refers to any form of blood loss originating from the gastrointestinal tract, ranging from the esophagus to the rectum. It is a common clinical emergency that varies in severity from occult (hidden) bleeding to massive, life-threatening hemorrhage. Clinically, GIB is broadly classified into upper and lower bleeding depending on its location relative to the ligament of Treitz.

Definition

• Gastrointestinal bleeding = blood loss from GI tract
• Can be:
  • Overt (visible)
  • Occult (hidden)

Classification

• Upper GI bleeding (UGIB) → proximal to ligament of Treitz
• Lower GI bleeding (LGIB) → distal to ligament of Treitz

Pathophysiology Overview

Gastrointestinal bleeding occurs when there is disruption of mucosal integrity or damage to blood vessels within the GI tract. This may result from ulceration, inflammation, vascular abnormalities, or malignancy. The severity depends on the size of the vessel involved and the underlying condition.

Mechanisms of Bleeding

• Mucosal erosion (e.g., ulcers)
• Vessel rupture
• Inflammation
• Vascular malformations
• Tumor invasion

Upper Gastrointestinal Bleeding (UGIB)
Definition

Upper GI bleeding originates from structures proximal to the ligament of Treitz, including the esophagus, stomach, and duodenum.

Etiology

The most common causes of upper GI bleeding include peptic ulcer disease, esophageal varices, and gastritis.

Causes of Upper GI Bleeding

• Peptic ulcer disease (most common)
• Gastritis / erosions
• Esophageal varices
• Mallory-Weiss tear
• Esophagitis
• Gastric cancer

Pathophysiology

Peptic ulcers erode into submucosal vessels, causing bleeding. In portal hypertension, increased pressure in the portal venous system leads to dilation of esophageal veins (varices), which are prone to rupture. Mucosal inflammation in gastritis can also lead to superficial bleeding.

Clinical Presentation

Upper GI bleeding commonly presents with hematemesis (vomiting blood) or melena (black, tarry stools). Severe bleeding may result in signs of hypovolemia such as tachycardia, hypotension, and dizziness.

Symptoms of UGIB

• Hematemesis (bright red or coffee-ground)
• Melena (black stools)
• Epigastric pain
• Signs of shock:
  • Hypotension
  • Tachycardia

Diagnosis

Endoscopy is the gold standard for diagnosing upper GI bleeding, as it allows both visualization and therapeutic intervention.

Diagnosis

• Upper endoscopy (EGD) – gold standard
• CBC → anemia
• BUN ↑ (due to blood digestion)
• Coagulation profile

Management

Management involves initial stabilization followed by definitive treatment of the underlying cause.

Management

Initial stabilization

• Airway, breathing, circulation (ABC)
• IV fluids
• Blood transfusion (if needed)

Medical therapy

• Proton pump inhibitors (PPIs)
• Octreotide (for varices)

Endoscopic therapy

• Band ligation (varices)
• Cauterization / clipping (ulcers)

Lower Gastrointestinal Bleeding (LGIB)
Definition

Lower GI bleeding arises from sources distal to the ligament of Treitz, typically involving the small intestine, colon, or rectum.

Etiology

Lower GI bleeding is often caused by diverticular disease, angiodysplasia, or colorectal malignancy.

Causes of Lower GI Bleeding

• Diverticulosis (most common)
• Angiodysplasia
• Colorectal cancer
• Hemorrhoids
• Inflammatory bowel disease (IBD)
• Infectious colitis

Pathophysiology

Bleeding in the lower GI tract often results from rupture of small vessels within diverticula or vascular malformations. Inflammatory conditions such as ulcerative colitis can also damage the mucosa and lead to bleeding.

Clinical Presentation

Lower GI bleeding typically presents with hematochezia (bright red blood per rectum). The severity can range from mild intermittent bleeding to massive hemorrhage.

Symptoms of LGIB

• Hematochezia (bright red blood)
• Abdominal pain (variable)
• Change in bowel habits
• Signs of anemia

Diagnosis

Colonoscopy is the preferred diagnostic tool for evaluating lower GI bleeding.

Diagnosis

• Colonoscopy – first-line
• CT angiography (active bleeding)
• Radionuclide scan
• CBC → anemia

Management

Treatment depends on the cause and severity of bleeding.

Management

• Stabilization (fluids, transfusion)
• Endoscopic therapy
• Angiographic embolization
• Surgery (if uncontrolled bleeding)

Upper vs Lower GI Bleeding Upper and lower GI bleeding differ in etiology, presentation, and diagnostic approach, although both require prompt evaluation and management.

Upper vs Lower GI Bleeding

Feature	Upper GI Bleeding	Lower GI Bleeding
Location	Above ligament of Treitz	Below ligament of Treitz
Main symptom	Hematemesis, melena	Hematochezia
Common causes	Ulcers, varices	Diverticulosis, angiodysplasia
Diagnosis	Endoscopy (EGD)	Colonoscopy

Severity & Clinical Importance The severity of gastrointestinal bleeding ranges widely. Acute massive bleeding can lead to hypovolemic shock and requires immediate intervention, whereas chronic low-grade bleeding may present only with iron-deficiency anemia.

Severity

• Mild → occult bleeding (anemia)
• Moderate → visible bleeding
• Severe → hemorrhagic shock

Warning Signs

• Hypotension
• Tachycardia
• Syncope
• Altered mental status