Anaphylactic shock following protamine administration

Area of Science:

• Immunology
• Cardiovascular Medicine
• Endocrinology

Background:

• Protamine is used clinically, often post-cardiac surgery or for heparin reversal.
• While cardiovascular effects of protamine are known, its immunologic mechanisms are less understood.
• Neutral protein Hagedorn (NPH) insulin contains protamine as a suspending agent.

Observation:

• A diabetic patient on NPH insulin experienced a severe anaphylactic reaction post-carotid endarterectomy after protamine injection.
• This reaction highlights a potential immunologic link between NPH insulin and protamine.
• The patient had a history of NPH insulin use, suggesting prior sensitization.

Findings:

• Protamine administration can trigger severe anaphylaxis in patients previously exposed, such as those using NPH insulin.
• Immunologic mediation of protamine's action, particularly in sensitized individuals, warrants further investigation.
• This case suggests a potential cross-reactivity or sensitization pathway.

Implications:

• Caution is crucial when administering protamine to patients with potential protamine sensitization.
• Diabetics using NPH insulin, blood donors, and prior cardiac surgery patients are at increased risk.
• Pre-administration screening, including skin testing and premedication, may be necessary to prevent adverse events.