Anaphylactic deaths in Maryland (United States) and Shanghai (China): a review of forensic autopsy cases from 2004 to 2006.

Anaphylaxis is a life threatening allergic reaction that is rapid in onset and may cause sudden death. A retrospective study was performed using the database from the Office of the Chief Medical Examiner (OCME) in the State of Maryland and the Department of Forensic Medicine in Shanghai Medical College (DFM-SMC) to examine the etiology and forensic investigation findings of anaphylactic deaths from 2004 to 2006. Details of the medical history, agent responsible for the allergic reaction, death scene investigation and postmortem examination findings were reviewed for all cases. A total of 28 cases of anaphylactic death were identified for the study period, 17 from Maryland and 11 from Shanghai. Of the 17 Maryland cases, 6 (35%) involved allergic reaction to food, 5 (25%) to drugs, 2 to bee stings, 1 to hair dye, and 3 to unknown allergens. Investigation revealed that 9 of 17 cases had a history of asthma and 8 had previous allergic reactions to certain foods and / or drugs. In Shanghai, all 11 deaths resulted from anaphylactic reaction to antibiotics, 10 of which occurred in clinics illegally operated by unlicensed physicians. The interval between the onset of symptoms and death ranged from less than 1 min to 3 days after initially contacting the allergen. In the majority (68%) of cases, death occurred within 8h after the onset of symptoms. Postmortem findings were relatively non-specific, and included pharyngeal/laryngeal edema 14/28 (50%), mucus plugging in the airways 11/28 (39%), and pulmonary congestion and edema 28/28 (100%). Serum tryptase concentrations were measured in 14 cases in Maryland and the concentration ranged from 3.3 ng/ml to 200 ng/ml. There were significant differences with regards to allergen type and the circumstances of death between these two regions. Inappropriate use of antibiotics and illegal medical practices were the main causes of identified anaphylactic death in Shanghai. In Maryland anaphylactic deaths were mainly caused by food reactions. This study indicates that the postmortem diagnosis of anaphylactic death is usually based on exclusion and circumstantial evidence. Knowledge of the patient's history and circumstances of death is of major importance for the forensic pathologist when investigating suspected anaphylactic death.