Emergency department visits for concern regarding anthrax--New Jersey, 2001.

Introduction: In October of 2001, after letters processed in Trenton, New Jersey, resulted in multiple cases of anthrax, emergency departments (EDs) in New Jersey experienced an increase in visits from patients concerned about possible exposure to agents of biologic terrorism. Information about the effect of an actual biologic terrorism attack on the emergency department population might be useful in the design of biosurveillance systems, particularly with regard to their performance during the mitigation phase that occurs after an attack. In addition, such information might help identify issues that arise regarding the public health response in the ED setting.

Objectives: The objectives of this report were to identify and characterize ED visits, by patients concerned with exposure to biologic terrorism agents, in selected New Jersey hospitals after the anthrax attack in fall 2001.

Methods: A retrospective cohort design was used in this study. The setting was 15 New Jersey EDs within a 55-mile radius of Trenton. Participants were consecutive patients evaluated by ED physicians for the following four periods in 2001: 1 month before September 11; 1 month after September 11; 1 month after October 11; and for the second month after October 11. Percentages of visits were calculated with a concern for exposure (CE) visits by using International Classification of Diseases, Ninth Revision (ICD-9) descriptors: Feared Complaint-No Diagnosis (ICD-9 code v65.6) and Screening for Infectious Disease (ICD-9 code v75.9) for all hospitals and for Trenton versus non-Trenton hospitals as a percentage of ED visits. Charts were reviewed by using a structured data form.

Results: A total of 225,403 ED visits occurred during the 4 months, of which 698 were CE visits. The percentages of CE visits for the four periods were 0.06%, 0.06%, 0.92%, and 0.10%, respectively. For the peak third period, the percentage was increased for the two Trenton hospitals, 1.81%, versus 0.82% for the 13 non-Trenton hospitals. This report is a summary of the 508 visits associated with concern for anthrax exposure during the peak third period: 47% reported exposure to powder, 13% were postal workers, 4% received chest radiographs, 65% had a nasal swab for anthrax, 13% had ED decontamination, and 32% received antibiotics.

Conclusion: An increase in CE visits occurred during the 1-month period after October 11, 2001. During the peak month, a higher increase occurred in Trenton EDs. Considering the substantial variation in diagnostic evaluation and treatment, readily available guidelines are needed.