Distributive Shock

Overview

Shock is a medical emergency in which the body's organs do not get enough oxygen-rich blood. Distributive shock is one of the main types of shock. In this form, the total amount of blood may be normal, but the blood vessels relax and widen so much that pressure inside them drops and blood pools away from vital organs. As a result, the brain, heart, kidneys, and other tissues are starved of the blood flow they need.

Distributive shock is most often caused by overwhelming infection (septic shock), severe allergic reactions (anaphylactic shock), or damage to the nervous system that controls blood vessel tone (neurogenic shock). It is a true emergency and can become fatal quickly. Survival depends on recognizing it early and getting emergency treatment without delay.

Symptoms

Symptoms reflect both very low blood pressure and the underlying cause. Warning signs include:

• Very low blood pressure and a fast, weak pulse
• Confusion, agitation, drowsiness, or reduced alertness
• Rapid breathing or shortness of breath
• Skin that may feel warm and flushed early on, then cool and clammy as shock worsens
• Reduced or no urine output
• Fever or very low body temperature in sepsis
• Hives, swelling of the lips or throat, and wheezing in anaphylaxis

Any person who is confused, very weak, struggling to breathe, or collapsing needs emergency care immediately. Call emergency services without waiting.

Causes

Distributive shock results from conditions that cause widespread widening of blood vessels:

• Septic shock: A severe, body-wide response to infection that releases chemicals causing blood vessels to dilate and leak.
• Anaphylactic shock: A severe allergic reaction to foods, medicines, insect stings, or other triggers, releasing histamine and related substances.
• Neurogenic shock: Damage to the spinal cord or nervous system that removes the normal signals keeping blood vessels toned.
• Other causes: Certain toxins, severe adrenal gland failure, and some drug overdoses.

Risk Factors

• Serious infection or a weakened immune system
• Known severe allergies to foods, drugs, or insect stings
• Recent surgery, hospitalization, or invasive devices such as catheters
• Spinal cord injury or nervous system disease
• Very young or older age
• Chronic illnesses such as diabetes, cancer, or liver disease

Diagnosis

Distributive shock is diagnosed urgently using examination and tests performed in parallel with treatment:

• Vital signs: Blood pressure, heart rate, breathing rate, temperature, and oxygen levels.
• Blood tests: Lactate level (a marker of poor tissue oxygen), blood counts, kidney and liver function, and cultures to find infection.
• Cause-specific tests: Imaging or sampling to locate an infection, or assessment of allergy triggers and spinal injury.
• Monitoring: Continuous tracking of blood pressure and organ function, sometimes with specialized lines.

Treatment

Treatment is started immediately in an emergency or intensive care setting and targets both blood pressure and the underlying cause.

• Intravenous fluids: Rapid fluids help fill the widened blood vessels and raise blood pressure.
• Vasopressor medicines: Drugs such as norepinephrine tighten blood vessels to restore pressure when fluids alone are not enough.
• Treating the cause: Antibiotics and source control for sepsis; epinephrine (adrenaline) and supportive care for anaphylaxis; stabilization and support for neurogenic shock.
• Organ support: Oxygen or breathing support, and care for the kidneys and other organs as needed.

People with known severe allergies are often prescribed an epinephrine auto-injector to use at the first sign of anaphylaxis while emergency help is on the way.

Prevention

• Treat infections promptly and seek care early if you feel very unwell
• Carry and know how to use an epinephrine auto-injector if you have severe allergies
• Avoid known allergy triggers and wear medical alert identification
• Keep vaccinations up to date to reduce serious infections
• Follow safe care practices for catheters, wounds, and devices
• Manage chronic conditions that raise infection risk

When to See a Doctor

Distributive shock is a medical emergency. Call emergency services or go to an emergency department immediately if a person has:

• Confusion, extreme weakness, or loss of consciousness
• Very low blood pressure, fainting, or a rapid weak pulse
• Difficulty breathing, swelling of the lips or throat, or widespread hives
• High fever with rapid breathing, chills, and a sense of being gravely ill
• Little or no urine output with cold, clammy skin

Early treatment saves lives, so do not wait to see if symptoms improve.

Related Topics

Frequently Asked Questions

References

1. MedlinePlus, U.S. National Library of Medicine. Shock.
2. National Heart, Lung, and Blood Institute (NHLBI). Septic shock and sepsis.
3. Mayo Clinic. Anaphylaxis — Symptoms and causes.
4. Centers for Disease Control and Prevention (CDC). Sepsis.