Emergency care for shock

Pathophysiology and Clinical Presentation

Anaphylactic shock is an acute allergic reaction that occurs after contact with a trigger (most commonly food or medications). A history of anaphylaxis is found in 1–2% of the population.

In essence, this is a generalized hypersensitivity reaction of the immediate type (Type I per Gell and Coombs). Pathophysiologically, the condition belongs to vascular (distributive) shock, standing alongside septic and neurogenic shock. Massive vasodilation, arteriovenous shunting, and increased capillary permeability lead to a sharp drop in total peripheral vascular resistance (TPVR) and critical redistribution of intravascular blood volume.

Key markers for the immediate initiation of therapy:

• Respiratory disorders: stridor, wheezing, pronounced dyspnea, respiratory distress syndrome.
• Hemodynamic failures: drop in blood pressure, collapse.
• Skin symptoms: urticaria may complement the clinical picture but is not mandatory for diagnosis.

Step-by-step emergency care algorithm

The strict rule of the "golden hour" applies: care must be provided immediately at the scene.

1. Basic measures. Immediately stop contact with the allergen (e.g., halt intravenous drug administration). Perform an initial assessment using the ABC system (airway patency, adequacy of breathing, and hemodynamics). If possible, start oxygen administration immediately.
2. Epinephrine administration. This is the foundational step. Standard administration involves a 0.1% solution intramuscularly at a dose of 0.01 mg/kg of body weight (the maximum single dose should not exceed 0.5 mg). In extremely severe cases, slow intravenous administration is permitted.
3. Dynamic monitoring. The effect is assessed after 5 minutes. If there is no improvement, intramuscular adrenaline injections are repeated every 5–10 minutes until vital functions are fully stabilized.
4. Volume support. If shock persists, start intravenous fluid infusion at a volume of 20 ml/kg.

Adjuvant and General Antishock Therapy

All other medications are used only after epinephrine and are adjuvant in nature. The use of diuretics (furosemide) or antibiotics is not a primary lifesaving measure.

• Glucocorticoids (GCs): dexamethasone or prednisolone administered intramuscularly or intravenously.
• Antihistamines: systemic H1-histamine receptor blockers are needed exclusively to relieve itching and skin manifestations.
• Bronchodilators: in cases of severe asphyxia and bronchoconstriction, nebulized salbutamol and topical GCs (budesonide) are added.

General principles of shock treatment also include the normalization of microcirculation using colloid solutions (gelatin, medium-molecular-weight dextran 30,000–40,000) and the use of other vasopressors (norepinephrine, ephedrine). In specific cases, antigen inactivation is possible—for example, the administration of the enzyme penicillinase (beta-lactamase) in shock induced by penicillin-class antibiotics.

Special Situations and Contraindications

In life-threatening anaphylaxis, there are no absolute contraindications to the administration of epinephrine. The lifesaving effect always outweighs the risks. The drug is administered even to patients with concurrent coronary artery disease or uncontrolled hypertension, despite the risk of tachyarrhythmias or a sharp rise in blood pressure.

Allergic laryngeal edema requires special attention. Its clinical markers include concomitant eyelid and lip edema, as well as urticarial rash. The management is similar: cessation of contact with the allergen, epinephrine, systemic GCs, and antihistamines for rapid edema reduction, followed by mandatory hospitalization.

For any severe or refractory reactions, an urgent evaluation by an anesthesiologist-resuscitator is necessary. If blood pressure changes during the administration of any trigger drug, the infusion must be stopped immediately, and the question of continuing it should only be addressed after complete stabilization of the patient's condition.

Class and exam questions

What else to study on this topic

• Mechanisms of distributive (vascular) shock development
• Assessment of vital functions using the international ABC system
• Calculation of infusion therapy dosages in acute hypovolemia
• Specific antigen inactivation (use of beta-lactamases)

Other topics in the "Additional Topics" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.