[A life-threatening anaphylactic reaction following mannitol]

Area of Science:

• Anesthesiology
• Clinical Immunology
• Pharmacology

Background:

• Mannitol is commonly used as an osmotic diuretic and for managing intracranial pressure.
• Anaphylactoid reactions, while rare, can occur with various medications administered during anesthesia.

Observation:

• A 39-year-old male experienced severe hypotension and cardiac arrest 80 minutes after initiating general anesthesia and infusing 20% mannitol.
• The patient developed ventricular fibrillation, requiring immediate and extensive resuscitation measures including fluid resuscitation, vasopressors, antiarrhythmics, and defibrillation.
• Post-event allergologic studies, including skin tests and in-vitro leukocyte histamine release, showed a specific positive reaction to mannitol.

Findings:

• The patient's reaction, characterized by profound hypotension and cardiac arrest, was directly linked to mannitol administration.
• Allergy testing confirmed mannitol as the causative agent, with negative results for other perioperative drugs.
• Hemodynamic instability and plasma sequestration were key features of the anaphylactoid response to mannitol.

Implications:

• This case highlights the potential for severe anaphylactoid reactions to mannitol, even in non-atopic individuals.
• Clinicians should maintain a high index of suspicion for mannitol-induced anaphylaxis in patients presenting with unexplained hypotension and cardiovascular collapse during anesthesia.
• Prompt recognition and appropriate management, alongside specific diagnostic testing, are crucial for patient survival and preventing recurrence.