Haemorrhage

Haemorrhage is a loss of blood from damaged blood vessels that can occur inside or outside your body. While minor bleeding like bruises may resolve on their own, severe haemorrhage is a medical emergency that can lead to organ failure or death if not treated promptly.

Table of contents

• What is haemorrhage?
• Types of haemorrhage
• What causes haemorrhage?
• Symptoms and warning signs
• When is bleeding an emergency?
• Classification by blood loss
• Treatment approaches

What is haemorrhage?

A haemorrhage is bleeding from a damaged blood vessel. The bleeding can be trapped inside your body, which is called internal haemorrhage, or it can flow outside your body through a wound or body opening such as the mouth, nose, or vagina, which is called external haemorrhage. The blood loss can range from minor to major.^[1]

Because you have blood vessels throughout your entire body, haemorrhages can occur almost anywhere. Blood is essential to maintain adequate circulation, provide nutrients, and remove waste from the brain, vital organs, and tissues.^[2] Most haemorrhages are medical emergencies that require immediate attention.^[1]

Types of haemorrhage

There are many different types of haemorrhages based on where they occur in the body. Some of the main types include:^[1]

• Intracranial haemorrhage (brain bleed): This is uncontrolled bleeding inside your brain or within the layers between your brain and skull. When the bleeding is in your brain tissue itself, it’s called a haemorrhagic stroke. This type of stroke is especially severe and can get worse quickly. It’s different from an ischemic stroke, which happens when there’s a blockage of blood flow in your brain.
• Subarachnoid haemorrhage: This is bleeding in the area between your brain and the thin tissues that cover and protect it. This is a medical emergency that often causes sudden, severe headache.^[1]
• Hemothorax: This occurs when blood collects in the space between your lungs and rib cage. It can compress your lungs and cause difficulty breathing or chest pain.^[1]
• Postpartum haemorrhage: This is severe vaginal bleeding after childbirth. It’s a serious condition that can lead to death. It can occur right after delivery or up to 12 weeks after delivery.^[1]
• Subconjunctival haemorrhage: This is bleeding in the whites of your eye. The blood is trapped in your conjunctiva. It’s one of the few types of haemorrhages that usually aren’t serious.^[1]

Bruises, which are bleeding under your skin, are also examples of haemorrhages, though usually minor ones. A hematoma is a related term that refers to a pooling of blood in the tissues.^[1]

Haemorrhages can also be classified by the type of blood vessel affected. Blood is transported throughout the body by three types of blood vessels: arteries, veins, and capillaries. Arterial haemorrhage happens in arteries that carry oxygen-rich blood from the heart to the body and is the most serious and urgent form of bleeding due to rapid blood loss. Venous haemorrhage occurs when a vein is injured and gradually releases dark red blood. Capillary haemorrhage happens when the tiniest blood vessels are injured and is often slow, occurring in oozes or trickles.^[10]

What causes haemorrhage?

Many different things can cause bleeding inside and outside your body. The main causes include:^[5]

Traumatic injury is a common cause of bleeding. Haemorrhage secondary to traumatic injury is the leading cause of death of Americans from one to 46 years of age.^[2] Worldwide, severe trauma results in the death of over 5 million people annually, and haemorrhage accounts for approximately 35% of these deaths.^[2] Violence is the leading cause of these injuries, with traffic collisions being second.^[2]

Types of traumatic injuries that can cause bleeding include:^[5]

• Abrasions (scrapes) that don’t penetrate too far below the skin
• Hematomas or bruises
• Lacerations (cuts)
• Puncture wounds from items like needles, nails, or knives
• Crushing injuries
• Gunshot wounds

Medical conditions can also cause haemorrhage. Some conditions that may lead to bleeding include:^[5]

• Hemophilia, a condition where blood doesn’t clot normally
• Leukemia
• Liver disease
• Menorrhagia (heavy or prolonged menstrual bleeding)
• Thrombocytopenia (low blood platelet count)
• Von Willebrand disease
• Vitamin K deficiency
• Brain trauma
• Colon diverticulosis
• Lung cancer
• Acute bronchitis

Medications can also increase your chances of bleeding. Blood thinners, antibiotics when used long-term, radiation therapy, aspirin, and other NSAIDs (nonsteroidal anti-inflammatory drugs) may be responsible for bleeding.^[5]

Symptoms and warning signs

The way haemorrhaging makes you feel varies greatly depending on where it is and how severe it is.^[1]

For external bleeding, visible blood loss from wounds is the most obvious sign. You may also experience pain or discomfort at the injury site, swelling around the affected area, or bruising due to underlying tissue damage.^[10]

For internal bleeding, symptoms can be harder to recognize. Blood may pool inside the body or exit through natural openings such as the nose, anus, vagina, urethra, or mouth (in the form of vomit or stool).^[10] Symptoms vary depending on the location of the bleeding but may include:^[1]

For bleeding in the head: sudden onset severe headache, vision changes, confusion, and weakness on one side of your body.

For bleeding in the chest: difficulty breathing, chest pain, and coughing up blood.

For bleeding in the abdomen: swelling or a feeling of fullness, abdominal bruising, and bloody vomit, urine, or stool.

For bleeding in bones, joints, and muscles: bruising, swelling, and pain. Increased pressure in tissues due to bleeding in a closed space is a medical emergency as it can compress nerves and blood vessels, leading to permanent loss of function.^[1]

When is bleeding an emergency?

If bleeding is severe, seek help immediately. You should seek emergency help if you suspect internal bleeding, as this can become life-threatening. People who have bleeding disorders or take blood thinners should also seek emergency help to stop bleeding.^[5]

The symptoms that indicate you need emergency care depend on how much blood you’ve lost. Healthcare providers consider up to 15% of blood volume loss as a Class I haemorrhage. People with this amount of blood loss generally don’t have symptoms.^[1]

A Class II haemorrhage is a loss of 15% to 30% of your total blood volume. The first signs of this level of blood loss may include:^[1]

• Dizziness or lightheadedness (due to low blood pressure)
• Fatigue and weakness
• Nausea and vomiting
• Shortness of breath and increased breathing rate
• Increased heart rate (tachycardia)

Call emergency services or go to the emergency room if you or someone near you has these symptoms.^[1]

Losing more than 30% of your total blood volume can lead to severe symptoms and complications, including:^[1]

• Confusion
• Seizures
• Loss of consciousness
• Hypovolemic shock, a dangerous condition where the body doesn’t have enough blood volume to maintain proper circulation

Classification by blood loss

The classification of haemorrhage is often based on the volume of blood lost:^[10]

Class I haemorrhage occurs when there is a loss of up to 15% of total blood volume. People with this amount of blood loss generally don’t have symptoms.

Class II haemorrhage occurs due to a loss of 15% to 30% of blood. This may present symptoms such as lightheadedness, increased heart rate, and low blood pressure.

Class III and IV haemorrhages are more severe. They occur when blood loss is greater than 30%. These haemorrhages can lead to critical conditions that need immediate medical intervention, such as blood transfusions or surgical procedures to control the bleeding.^[10]

A typical healthy person can endure a loss of 10 to 15% of total blood volume without serious medical difficulties. By comparison, blood donation typically takes 8 to 10% of the donor’s blood volume.^[3]

Treatment approaches

The location of the bleeding and the intensity of your symptoms will determine your exact course of treatment. Minor bleeding can generally be treated with basic first aid steps. However, more serious bleeding requires medical intervention and treatment, including blood transfusions or surgery.^[10]

For severe external bleeding, first aid steps include:^[18]

1. Call emergency services if the wound is deep or you’re not sure how serious it is.
2. Remove any clothing or debris from the wound, but don’t remove large or deeply embedded objects.
3. Stop the bleeding by covering the wound with sterile gauze or a clean cloth. Press on it firmly with the palm of your hand until bleeding stops.
4. Wrap the wound with a thick bandage or clean cloth and tape.
5. Lift the wound above heart level if possible.
6. Help the injured person lie down and elevate their feet if you notice signs of shock.

The primary treatment of haemorrhagic shock is to control the source of bleeding as soon as possible and to replace fluid. The first fluid of choice for resuscitation is crystalloid solution. Healthcare providers may immediately administer 2 liters of isotonic sodium chloride solution or lactated Ringer’s solution in response to shock from blood loss.^[11]

Packed red blood cells should be transfused if the patient remains unstable after crystalloid resuscitation. For acute situations, O-negative blood that hasn’t been crossmatched should be administered.^[11]

Surgical intervention may be necessary to control the source of bleeding. The type of surgery depends on the location and cause of the haemorrhage. For example, procedures may include repairing damaged blood vessels, removing damaged tissue, or addressing underlying conditions causing the bleeding.^[11]

The stopping or controlling of bleeding is called hemostasis and is an important part of both first aid and surgery.^[3] Up to half of the deaths resulting from haemorrhage occur before reaching definitive care, which is why the “Stop the Bleed” campaign was launched in 2013 to reduce the morbidity and mortality associated with haemorrhage secondary to traumatic injury.^[2]