Gastrointestinal Bleeding

Written by A/Prof Viraj Kariyawasam, Gastroenterologist

1. What is Gastrointestinal Bleeding?

Gastrointestinal (GI) bleeding refers to any bleeding that occurs within the digestive tract, from the oesophagus to the rectum. The severity can range from mild, hidden blood loss to severe, life‑threatening bleeding.

GI bleeding is broadly classified based on its location (upper or lower GI tract) and how it presents (overt or occult). Identifying the source and type of bleeding is essential for appropriate management.

2. Causes & Risk Factors

Upper gastrointestinal bleeding originates from the oesophagus, stomach, or first part of the small intestine. Common causes include stomach or duodenal ulcers, oesophagitis, varices, gastritis, and upper GI cancers.

Lower gastrointestinal bleeding arises from the small bowel beyond the duodenum, colon, or rectum. Common causes include diverticular disease, haemorrhoids, inflammatory bowel disease, polyps, bowel cancer, and angiodysplasia.

Risk factors for GI bleeding include increasing age, use of blood‑thinning medications, non‑steroidal anti‑inflammatory drugs, liver disease, alcohol excess, and chronic medical conditions.

3. Symptoms & How It May Present

Overt gastrointestinal bleeding is visible and may present as vomiting blood, black tarry stools (melaena), or passing fresh blood per rectum.

Occult gastrointestinal bleeding is hidden and not visible to the naked eye. It often presents with iron deficiency anaemia, fatigue, shortness of breath, or a positive faecal occult blood test.

Symptoms may also include dizziness, weakness, abdominal pain, or collapse in severe cases.

4. How Is It Diagnosed?

Diagnosis depends on the severity and suspected location of bleeding. Blood tests are used to assess anaemia and overall stability.

Gastroscopy is the primary test for suspected upper GI bleeding, while colonoscopy is used to investigate lower GI bleeding. Capsule endoscopy or specialised imaging may be required when the source is unclear.

5. Treatment & Management Options

Management depends on the cause and severity of bleeding. Mild bleeding may resolve with treatment of the underlying condition.

Endoscopic therapies can be used to stop active bleeding, remove lesions, or treat ulcers. Severe bleeding may require hospital admission, blood transfusion, medication, or surgery.

6. Living With / Managing Gastrointestinal Bleeding

Long‑term management focuses on treating the underlying cause and reducing recurrence risk.

This may include medication review, treatment of ulcers or inflammatory bowel disease, management of liver disease, and regular surveillance where indicated.

7. Prevention & Risk Reduction

Reducing risk factors such as unnecessary NSAID use, careful use of blood‑thinning medications, and treatment of underlying gastrointestinal conditions can reduce the risk of GI bleeding.

Bowel cancer screening and surveillance colonoscopy play an important role in preventing bleeding related to polyps or cancer.

8. When to Seek Medical Advice

Urgent medical attention is required for vomiting blood, black stools, heavy rectal bleeding, dizziness, collapse, or severe weakness.

Medical review is recommended for unexplained iron deficiency, fatigue, or a positive faecal occult blood test, even in the absence of visible bleeding.