Diamine Oxidase Deficiency as a Proposed Mechanism for Anaphylaxis After the Third Stage of Labor: A Case Report [2B

Abstract

INTRODUCTION: Previous case reports have demonstrated post-partum anaphylaxis associated with breast-feeding, thought to be due to destabilization of mast cells, but none associated with delivery of the placenta. The histamine-degrading enzyme diamine oxidase is produced in large amounts by the placenta as a metabolic barrier preventing bioactive histamine from entering the maternal or fetal circulation. METHODS: Case report. RESULTS: A 29 yo G5P3 admitted at 39w1d with ruptured membranes. Her obstetrical history is significant for 3 vaginal deliveries with subsequent anaphylaxis after delivery of the placenta, unrelated to narcotic administration. Medical history includes sensitive skin, seasonal allergies, and negative allergy testing. During her first two deliveries, she experienced angioedema (eye and lip swelling) after delivery of the placenta. After her third delivery, she required supplemental oxygen, steroids and epinephrine secondary to laryngeal edema refractory to diphenhydramine. With her fourth delivery, the patient was given 125 mg IV Solumedrol 2 hours prior to delivery, in addition to IV diphenhydramine. Two hours after delivery, she complained of eye and lip swelling and throat “itchiness” but remained hemodynamically stable. She did not improve with a second dose of IV Diphenhydramine. Due to her history, 0.3 mg Epinephrine IM was given with full resolution of symptoms. CONCLUSION: A proposed mechanism of decreased diamine oxidase after delivery of the placenta may provide insight into the maternal–fetal immune system interface in our unusual case. In retrospect, a proposed prevention of anaphylaxis in this patient would be diamine oxidase supplementation in the third trimester.