Hypovolemic shock

Losing more than 15 to 20 percent of the normal amount of blood in your body causes hypovolemic shock.

Blood loss can be due to:

• Bleeding from serious cuts
• Bleeding from other injuries
• Internal bleeding, such as in the gastrointestinal tract

The amount of circulating blood in your body also may drop when you lose too much body fluid from other causes. This can be due to:

• Burns
• Diarrhea
• Excessive perspiration
• Vomiting

Symptoms may include:

• Anxiety or agitation
• Cool, clammy skin
• Confusion
• Decreased or no urine output
• Generalized weakness
• Pale skin color (pallor)
• Rapid breathing
• Sweating, moist skin
• Unconsciousness (lack of responsiveness)

The greater and more rapid the blood loss, the more severe the symptoms of shock.

A physical exam will show signs of shock, including:

• Low blood pressure
• Low body temperature
• Rapid pulse, often weak and thready

Tests that may be done include:

• Blood chemistry, including kidney function tests and those tests looking for evidence of heart muscle damage
• Complete blood count (CBC)
• CT scan, ultrasound, or x-ray of areas known or suspected to be injured
• Echocardiogram - sound wave test of heart structure and function
• Electrocardiogram
• Endoscopy - tube placed in the mouth to the stomach (upper endoscopy) or colonoscopy (tube placed through the anus to the large bowel)
• Right heart (Swan-Ganz) catheterization
• Urinary catheterization (tube placed into the bladder to measure urine output)

In some cases, other tests may be done as well.

Get medical help right away. In the meantime, follow these steps:

• Keep the person comfortable and warm (to avoid hypothermia).
• Have the person lie flat with the feet lifted about 12 inches (30 centimeters) to increase circulation. However, if the person has a head, neck, back, or leg injury, do not change the person's position unless they are in immediate danger.
• Do not give fluids by mouth.
• If person is having an allergic reaction, treat the allergic reaction, if you know how.
• If the person must be carried, try to keep them flat, with the head down and feet lifted. Stabilize the head and neck before moving a person with a suspected spinal injury.

The goal of hospital treatment is to replace blood and fluids. One or more intravenous (IV) lines will be placed to allow blood, blood products, or fluids to be given.

Medicines such as epinephrine or norepinephrine may be needed to increase blood pressure and the amount of blood pumped out of the heart (cardiac output).

Symptoms and outcomes can vary, depending on:

• Amount of blood/fluid volume lost
• Rate of blood/fluid loss
• Illness or injury causing the loss
• Underlying chronic medical conditions, such as diabetes and heart, lung, and kidney disease, or related to injury

In general, people with milder degrees of shock do better than those with more severe shock. Severe hypovolemic shock may lead to death, even with immediate medical attention. Older adults are more likely to have poor outcomes from shock.

Complications may include:

• Kidney damage (may require temporary or permanent use of a kidney dialysis machine)
• Brain damage
• Gangrene of arms or legs, sometimes leading to amputation
• Heart attack
• Other organ damage
• Death

Hypovolemic shock is a medical emergency. Call the local emergency number (such as 911) or take the person to the emergency room.

Preventing shock is easier than trying to treat it once it happens. Quickly treating the cause will reduce the risk of developing severe shock. Early first aid can help control shock.

Shock - hypovolemic

Angus DC. Approach to the patient with shock. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 92.

Dries DJ. Hypovolemia and traumatic shock: nonsurgical management. In: Parrillo JE, Dellinger RP, eds. Critical Care Medicine: Principles of Diagnosis and Management in the Adult. 5th ed. Philadelphia, PA: Elsevier; 2019:chap 26.

Maiden MJ, Peake SL. Overview of shock. In: Bersten AD, Handy JM, eds. Oh's Intensive Care Manual. 8th ed. Philadelphia, PA: Elsevier; 2019:chap 15.

Puskarich MA, Jones AE. Shock. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 3.

Updated by: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.