OVERVIEW

What is anaphylactic shock?

Anaphylactic shock refers to a condition where the body comes into contact with certain substances or medications that trigger an allergic reaction, causing plasma to leak into the interstitial tissues and leading to a rapid decrease in circulating blood volume, resulting in shock. Symptoms may include numbness in the hands and feet, throat itching, chest tightness, nausea and vomiting, restlessness, profuse sweating, pale complexion, cyanosis of the lips, throat obstruction, and other systemic manifestations. Some patients may experience a sense of impending doom, while severe cases may present with coma and incontinence.

Once anaphylactic shock occurs, immediate cessation of exposure to the potential allergen is necessary, along with close monitoring of vital signs. Emergency treatment such as epinephrine injections and glucocorticoids should be administered promptly, often leading to timely recovery. However, without prompt intervention, severe cases can result in death within 10 minutes.

In what situations is anaphylactic shock commonly seen?

Anaphylactic shock commonly occurs after the use (including intravenous infusion or oral administration) of certain sensitizing medications, insect bites or stings, or consumption of allergenic foods such as seafood or milk.

SYMPTOMS

What are the common manifestations of anaphylactic shock?

• The onset of this condition is often acute, with symptoms developing rapidly after exposure to the allergen.
• Early symptoms primarily include general discomfort, numbness in the face and extremities, itching in the throat, restlessness, dizziness, and may be accompanied by palpitations, chest tightness, nausea, and vomiting.
• As the condition progresses, symptoms such as profuse sweating, pale complexion, cyanosis of the lips, and throat obstruction may occur, with some patients experiencing a sense of impending doom.
• Severe cases may lead to coma and incontinence.

How does anaphylactic shock develop?

Anaphylactic shock often occurs rapidly after exposure to the allergen, with severe reactions typically developing within 15 minutes. In rare cases, reactions may occur 30 minutes or even several hours later. It is an extremely severe allergic reaction, and without prompt treatment, death can occur within 10 minutes in critical cases.

What are the complications of anaphylactic shock?

Patients with anaphylactic shock may experience complications such as infection, lactic acidosis, acute kidney failure, acute respiratory and circulatory failure, cerebral edema, multiple organ dysfunction syndrome (MODS), disseminated intravascular coagulation, and death. Therefore, immediate and aggressive treatment is essential once shock symptoms appear.

CAUSES

What are the common causes of anaphylactic shock?

When an antigen enters a sensitized body and binds with corresponding antibodies, a Type I hypersensitivity reaction occurs. Vasoactive substances are released, leading to systemic capillary dilation and increased permeability. Plasma leaks into interstitial tissues, causing a rapid decrease in circulating blood volume and triggering shock. Common antigens include:

• Foreign proteins: Such as insulin, vasopressin, proteases, antiserum, penicillinase, pollen extracts, and foreign proteins in food like egg whites, milk, and seafood.
• Medications: Such as antibiotics, local anesthetics, and chemical reagents.

Is anaphylactic shock contagious?

No.

Is anaphylactic shock hereditary?

No.

DIAGNOSIS

How is anaphylactic shock diagnosed?

The onset of this condition is rapid, so timely diagnosis is essential. When systemic reactions occur immediately after exposure (especially injection) to antigenic substances, certain medications, or bee stings, and cannot be explained by the pharmacological effects of the drug itself, the possibility of this condition should be considered immediately.

The diagnostic criteria for shock are as follows:

1. Presence of shock triggers (e.g., injection of certain medications or insect stings);
2. Impaired consciousness;
3. Pulse > 100 beats/min or undetectable;
4. Cold and clammy extremities, positive skin pressure test on the sternum (refill time > 2 seconds); mottled skin, pale or cyanotic mucous membranes; urine output < 0.5 ml/kg/h or anuria;
5. Systolic blood pressure < 90 mmHg;
6. Pulse pressure < 30 mmHg;
7. For patients with pre-existing hypertension, systolic blood pressure drops by more than 30% from baseline.

A diagnosis can be made if two of criteria 1, 2, 3, and 4, along with one of criteria 5, 6, and 7, are met.

What tests are needed to diagnose anaphylactic shock?

• Complete blood count (CBC): Assess the patient's general condition and evaluate hemoconcentration during shock and treatment efficacy.
• Urinalysis and stool test: Determine the impact of shock on renal function and aid in identifying causes and differential diagnosis.
• Blood biochemical tests: Pyruvate, lactate, pH, and CO₂ combining power help assess the degree of acidosis during shock; blood urea nitrogen (BUN) and creatinine reflect renal function; liver function tests evaluate hepatic status; cardiac markers indicate heart condition; electrolytes assess electrolyte imbalances; all assist in diagnosis and differential diagnosis.
• Coagulation function tests: Monitor shock progression and detect disseminated intravascular coagulation (DIC).
• X-ray: Identify underlying causes.
• Electrocardiogram (ECG): Evaluate myocardial blood supply and arrhythmias, aiding in differentiating cardiogenic shock.
• Hemodynamic monitoring: Central venous pressure (CVP), pulmonary artery wedge pressure (PAWP), cardiac output (CO), and cardiac index (CI) assess cardiac status and aid in differential diagnosis.
• Microcirculation examination: Evaluate the patient's microcirculation.

Which diseases can anaphylactic shock be confused with?

Anaphylactic shock may be confused with hypotension, septic shock, hypovolemic shock, neurogenic shock, and other conditions. Doctors need to differentiate based on the patient's medical history, clinical manifestations, and auxiliary examinations.

TREATMENT

Which department should I go to for anaphylactic shock?

In case of shock, emergency services should be called immediately, and the patient should be transferred to the emergency department for urgent treatment.

Can anaphylactic shock resolve on its own?

No.

What are the emergency measures for anaphylactic shock?

Death from anaphylactic shock can occur within minutes, making prompt treatment crucial. The key to initial treatment is maintaining airway patency and ensuring effective respiratory and circulatory function.

• Immediately stop exposure to potential allergens or triggers, such as discontinuing suspected medications and replacing infusion sets if a drug allergy is suspected.
• Place the patient in a shock position: lying down with the head and chest elevated 20°–30° and the lower limbs elevated 15°–20°.
• Monitor the patient's heart rate, breathing, pulse, blood pressure, urine output, and consciousness. Ensure an open airway and administer oxygen. If life-threatening airway obstruction occurs (e.g., stridor or respiratory arrest), perform immediate endotracheal intubation or bedside tracheostomy.
• When anaphylactic shock is suspected, administer epinephrine subcutaneously or intramuscularly immediately. If the patient's shock symptoms do not improve significantly, repeat the dose as soon as possible. Simultaneously provide fluid resuscitation and vasopressors to maintain blood pressure, along with corticosteroids and antihistamines for anti-allergic treatment.
• If the patient experiences cardiac or respiratory arrest, perform CPR immediately.

Does anaphylactic shock require hospitalization?

Yes.

Anaphylactic shock is a medical emergency and can be life-threatening if not treated promptly. Therefore, hospitalization is necessary if suspicious symptoms occur.

Can anaphylactic shock be cured?

Yes.

However, the success of a cure is closely related to the timeliness and standardization of treatment, as well as the availability of advanced medical facilities.

DIET & LIFESTYLE

What should patients with anaphylactic shock pay attention to in their daily life and diet?

Avoid exposure to medications, foods, or environments that may trigger allergies and take protective measures.

Does anaphylactic shock require follow-up examinations? How is anaphylactic shock re-examined?

Yes.

Assess the patient's general condition and re-examine indicators such as liver and kidney function, myocardial enzymes, and blood biochemistry to monitor organ recovery.

PREVENTION

Can anaphylactic shock be prevented? How to prevent anaphylactic shock?

Yes.

For known drug or food allergies, avoiding the administration of allergenic medications, refraining from consuming allergenic foods, and taking protective measures can effectively prevent it. For suspected drug allergies, necessary skin tests are also crucial.

How can patients with anaphylactic shock prevent complications?

Prompt diagnosis, immediate emergency treatment, timely medical intervention, close monitoring of the patient's condition, and symptomatic management.