Gastrointestinal bleeding

Gastrointestinal (GI) bleeding can range from occult (no symptoms, only found on occult blood test) to severe and life-threatening. It may manifest as haematemesis, haemodynamic instability, melena, or haematochezia.

Haematemesis refers to vomiting of fresh blood, clotted blood, or coffee grounds-like material. Haematochezia refers to fresh or clotted blood per rectum and is typically a sign of lower GI tract bleeding, while melena refers to passage of black tarry stool and is typically a sign of upper GI tract bleeding. However, large (> 1L) upper GI bleeding may cause haematochezia as well.

Haematemesis mostly occurs in large bleedings.

Acute GI bleeding requires hospitalisation and urgent assessment and treatment. Mortality is high, 5 – 20%. Upper GI bleeding is 5x more frequent than lower GI bleeding.

Gastrointestinal bleeding can be occult, meaning that blood is present in the stool but not visible to the naked eye. Occult, chronic, or intermittent GI bleeding can be a sign of gastrointestinal cancer.

Etiology

Upper GI bleeding (mostly haematemesis):

• Variceal bleeding
  • Due to portal hypertension, mostly due to cirrhosis
• Non-variceal upper GI bleeding
  • Peptic ulcer
  • Mallory-Weiss syndrome
  • Oesophagitis
  • Erosive gastritis

Melena:

• Peptic ulcer
• Oesophagitis
• Gastritis
• Oesophageal varices
• Angiodysplasia

Haematochezia:

• Diverticulosis (most common cause overall)
• Inflammatory bowel disease
• Infectious colitis (inflammatory diarrhoea)
• Colorectal cancer
• Angiodysplasia

Clinical features

If acute GI bleeding is suspected, the first evaluation should assess for features of severe bleeding and haemodynamic instability.

• Signs of severe but partially compensated bleeding:
  • Postural hypotension
  • Tachycardia
  • Signs of vasoconstriction
• Signs of haemorrhagic shock
  • Pulse rate (bpm) > systolic blood pressure (mmHg)

Elevation of serum urea can be present in upper GI bleeding, due to proteins in the blood being metabolised to urea.

Diagnosis and evaluation

Acute GI bleeding

In case upper GI bleeding is suspected, due to haematemesis or signs of haemodynamic instability, urgent upper endoscopy is indicated. Colonoscopy is the investigation of choice for haematochezia. Both colonoscopy and upper endoscopy allow for both diagnosis and, in some cases, treatment of the bleeding.

Obtaining the patient’s bleeding parameters, medication list, and previous history are important to determine the source. As examples, anticoagulants can be reversed, known cirrhosis increases the likelihood of the source being oesophageal varices, and so on.

Aspiration of gastric contents through a nasogastric tube allows for quick differentiation between upper and lower GI bleeding. The aspirate is bloody in case of upper bleeding and clear in case of lower.

The Blatchford scoring system may be used to assess the risk of an upper GI bleeding requiring intervention. It’s based on vital parameters, comorbidities, lab tests, and clinical features. It’s used to identify patients who are low-risk (score ≤1) and can be treated outpatient.

Occult, chronic, or intermittent GI bleeding

Occult, chronic, or intermittent melena and haematochezia warrants investigation for malignancy, usually beginning with colonoscopy. As part of colorectal cancer screening or to investigate suspected melena or haematochezia, one can test the stool for blood. This can be accomplished with faecal occult blood tests.

Treatment

In case of acute bleeding, urgent assessment and stabilisation are crucial. If the patient is haemodynamically unstable they must be stabilised first. This involves monitoring, replacing lost fluids, and blood transfusion. Blood transfusion is indicated at haemoglobin level < 70 g/L, with a target of 70 – 90 g/L.

Then, we should determine the source of the bleeding, stop it, treat the underlying condition, and prevent recurrent bleeding. This involves upper endoscopy.