Anaphylactic Shock

Anaphylactic Shock

Anaphylactic shock, also known as anaphylaxis, is a severe and potentially life-threatening allergic reaction that occurs rapidly after exposure to an allergen. An allergen is a substance that triggers an allergic response in individuals who are sensitive or allergic to it. Anaphylactic shock is an extreme and immediate immune system response that can affect multiple organs and systems in the body.

Anaphylactic shock requires immediate medical attention, as it can progress rapidly and become life-threatening if not treated promptly. The first-line treatment for anaphylactic shock is an injection of epinephrine (adrenaline), which helps to counteract the severe symptoms by constricting blood vessels, improving breathing, and reversing the allergic response. Individuals who are at risk of anaphylaxis often carry an epinephrine auto-injector (such as an EpiPen) for emergency use.

Common triggers for anaphylaxis include certain foods (peanuts, tree nuts, shellfish, etc.), insect stings or bites, medications (such as antibiotics and certain pain relievers), latex, and other environmental allergens. It’s important for individuals with known allergies to be aware of potential triggers and take appropriate precautions to avoid exposure.


The pathology of anaphylactic shock involves a complex and rapid immune system response to an allergen, leading to the release of various inflammatory mediators and chemicals. This response can cause widespread and severe effects on different systems within the body. Here’s an overview of the key pathological mechanisms involved in anaphylactic shock:


An individual becomes sensitized to a specific allergen through previous exposure. During this initial exposure, the immune system produces antibodies, particularly immunoglobulin E (IgE), which are specific to that allergen.

Subsequent Exposure

Upon subsequent exposure to the same allergen, the allergen binds to IgE antibodies attached to mast cells and basophils (a type of white blood cell) throughout the body.


The widespread inflammation and leakage of fluids can disrupt normal blood flow. Blood vessels may become dilated, leading to poor circulation and reduced blood pressure. At the same time, blood clotting mechanisms can be activated, leading to the formation of small blood clots that can block blood vessels and impair oxygen delivery to organs.

Vasodilation and Increased Permeability

Histamine and other mediators cause blood vessels to dilate (widen) and become more permeable. This results in a drop in blood pressure and fluid leakage from the blood vessels into surrounding tissues, leading to swelling and a decrease in circulating blood volume.

Cardiovascular EffectsCollapse

The drop in blood pressure (hypotension) can lead to decreased perfusion of vital organs, including the brain and heart. The heart may respond by increasing its rate to compensate for the decreased blood pressure.

Respiratory Effects

Bronchoconstriction and increased mucus production in the airways can lead to difficulty breathing, wheezing, and coughing.Bronchoconstriction and increased mucus production in the airways can lead to difficulty breathing, wheezing, and coughing.

Systemic Effects

The release of inflammatory mediators can also affect other organ systems, leading to gastrointestinal symptoms (nausea, vomiting, abdominal cramps), neurological symptoms (anxiety, confusion), and skin reactions (hives, itching, swelling).

Cytokine Storm

In severe cases, the immune response can become dysregulated, leading to a systemic inflammatory response known as a cytokine storm. This can further contribute to the shock state and organ dysfunction.

In this condition, the pericardium (the sac surrounding the heart) becomes thickened and rigid, impairing the heart’s ability to expand and contract properly.

Signs and Symptoms


  • Feeling of impending doom
  • Anxiety or restlessness
  • Confusion or dizziness
  • Weakness or fatigue


  • Difficulty breathing or shortness of breath
  • Wheezing or noisy breathing
  • Coughing
  • Tightness in the chest
  • Rapid, shallow breathing

Heart Rate

  • Rapid or weak pulse
  • Low blood pressure (hypotension)
  • Fainting or loss of consciousness
  • Palpitations (rapid, strong, or irregular heartbeat)

Blood Pressure

Low Blood Pressure (Hypotension)

As the blood volume drops, blood pressure may decrease, leading to reduced perfusion of vital organs.

Skin Condition

  • Hives (raised, itchy welts on the skin)
  • Swelling of the face, lips, tongue, or throat (angioedema)
  • Flushing (redness and warmth of the skin)

Gastrointestinal Symptoms

  • Nausea and vomiting
  • Abdominal pain or cramping
  • Diarrhea

Other signs and Symptoms

  • Metallic taste in the mouth
  • Itchy or scratchy throat
  • Swelling of the eyes
  • Sense of warmth or flushing

It’s important to note that not all individuals experiencing anaphylactic shock will exhibit all of these symptoms, and the severity of symptoms can vary. However, any combination of the above symptoms, especially when occurring rapidly and together, should raise suspicion of anaphylactic shock. Immediate medical attention and intervention, including administration of epinephrine, are crucial to reverse the reaction and prevent further complications.

Treatment – Obstructive Shock

Assess and Prioritize

Quickly assess the patient’s condition and prioritize interventions based on their level of distress and medical history.

Assess Airway, Breathing, and Circulation (ABCs)

Perform a systematic primary survey, ensuring a patent airway, adequate breathing, and circulation. If necessary, initiate advanced airway management techniques.

Administer Epinephrine

Epinephrine is the first-line treatment for anaphylactic shock. Paramedics will administer epinephrine through an intramuscular injection, usually in the thigh. The epinephrine injection helps reverse the allergic reaction by constricting blood vessels, relaxing the airways, and counteracting the effects of histamine and other inflammatory mediators.

Initiate Oxygen Therapy

Paramedics may provide supplemental oxygen to help improve oxygenation and alleviate respiratory distress.

Intravenous Access and Fluid Management

In cases of severe hypotension, paramedics may administer intravenous fluids to help restore blood pressure and circulation.


In some cases, paramedics may administer bronchodilator medications (such as albuterol) to help open the airways and alleviate wheezing.

Antihistamines and Corticosteroids

Paramedics may administer antihistamines (e.g., diphenhydramine) and corticosteroids (e.g., methylprednisolone) to further reduce allergic reactions and inflammation. These medications may help prevent a recurrence of symptoms after the initial epinephrine treatment.

Continuous Reassessment

Continuously reassess the patient’s response to interventions and adjust treatment strategies as needed. Document changes in clinical status, vital signs, and interventions administered.

Transport Decision and Communication

Collaborate with the receiving medical facility to discuss patient condition, interventions performed, and estimated time of arrival.

Communication and Documentation

Continuously communicate with your team and provide detailed documentation of your assessment, interventions, and the patient’s response to treatment.

It’s important to note that paramedic protocols and procedures may vary based on location and medical protocols. The above steps provide a general overview of the treatment approach for anaphylactic shock. In all cases of anaphylaxis, seeking emergency medical assistance is critical, and paramedics are trained to provide immediate and life-saving care to individuals experiencing this serious allergic reaction.

Why is epinephrine import in Anaphylactic Shock

Epinephrine (also known as adrenaline) is a critical and life-saving medication in the treatment of anaphylactic shock. It is considered the first-line treatment and is administered as an injection to rapidly counteract the severe and potentially fatal symptoms of anaphylaxis. Here’s why epinephrine is important in anaphylactic shock:

  1. Vasoconstriction: Epinephrine causes blood vessels to constrict (narrow), which helps to counteract the drop in blood pressure that occurs during anaphylaxis. Vasoconstriction increases blood pressure and improves blood flow to vital organs, including the brain and heart.
  2. Bronchodilation: Epinephrine relaxes and opens up the airways in the lungs (bronchodilation), making it easier for the individual to breathe. This helps to relieve wheezing, shortness of breath, and other respiratory symptoms associated with anaphylaxis.
  3. Reduced Swelling: Epinephrine helps to reduce swelling and edema by decreasing the permeability of blood vessels, which can prevent or alleviate swelling of the face, lips, tongue, and throat (angioedema). This is important for maintaining a patent airway and preventing airway obstruction.
  4. Stabilization of Heart Rate and Rhythm: Epinephrine can help stabilize the heart rate and rhythm, preventing potential arrhythmias (abnormal heart rhythms) that can occur during anaphylaxis.
  5. Counteracting Allergic Cascade: Epinephrine acts quickly to counteract the release of inflammatory mediators like histamine and other chemicals that trigger anaphylactic reactions. By doing so, it helps to halt the progression of the allergic cascade and mitigate the severity of symptoms.
  6. Rapid Onset of Action: Epinephrine works rapidly, often within minutes of administration, making it an essential tool for addressing the immediate and potentially life-threatening nature of anaphylactic shock.

Administering epinephrine promptly is crucial because anaphylactic shock can progress rapidly and lead to severe complications, including loss of consciousness, cardiac arrest, and organ failure. Individuals who are at risk of anaphylaxis due to known allergies are often advised to carry an epinephrine auto-injector (such as an EpiPen) at all times and to be trained in its proper use. Proper use of epinephrine, along with seeking emergency medical care, can greatly increase the chances of a positive outcome for someone experiencing anaphylactic shock.