Physiologic manifestations of human anaphylaxis

Area of Science:

• Immunology
• Allergy
• Critical Care Medicine

Background:

• Insect sting hypersensitivity can lead to severe systemic reactions.
• Anaphylaxis is a life-threatening allergic reaction.
• Understanding the pathophysiology of severe anaphylaxis is crucial for effective treatment.

Purpose of the Study:

• To evaluate different forms of immunotherapy for insect sting hypersensitivity.
• To characterize the clinical manifestations and physiological changes during severe systemic reactions.
• To assess the efficacy of standard anaphylaxis treatments.

Main Methods:

• Controlled study evaluating immunotherapy.
• Observation of subjects experiencing systemic cutaneous urticarial reactions and systemic anaphylaxis.
• Monitoring of cardiopulmonary changes, gas exchange, plasma histamine levels, coagulation factors, and complement system components.

Main Results:

• Anaphylaxis presented with severe hypotension and peripheral vasodilation.
• Two subjects experienced respiratory arrest requiring mechanical ventilation.
• Plasma histamine levels correlated with the severity and duration of anaphylactic shock.
• Severe shock cases showed intravascular coagulation and complement system abnormalities.
• Standard therapy with epinephrine and fluids was not immediately effective in reversing severe hemodynamic or respiratory abnormalities.

Conclusions:

• Severe anaphylaxis can involve complex pathophysiological changes beyond histamine release, including hypotension, respiratory compromise, intravascular coagulation, and complement activation.
• Standard treatments may have delayed effects in the most severe cases of anaphylaxis.
• Further research is needed to optimize the management of severe insect sting-induced anaphylaxis.