Sodium Azide Poisoning at a Restaurant

Dallas County, Texas, 2010

Evan S. Schwarz, MD; Paul M. Wax, MD; Kurt C. Kleinschmidt, MD; Kapil Sharma, MD; Elizabeth Todd, PhD; Erin Spargo, PhD; Wendy M. Chung, MD; Gabriela Cantu, MPH; Mariama Janneh, MPH; Juan Rodriguez, MPH; Taye Derse, MD; Joshua G. Schier, MD

Disclosures

Morbidity and Mortality Weekly Report. 2012;61(25):457-460.

Abstract and Introduction

Introduction

In April 2010, Dallas County Health and Human Services (DCHHS) staff members investigated reports of acute-onset dizziness among patrons in a local restaurant. Symptoms, which included fainting resulting from low blood pressure, occurred within minutes of consuming food from the restaurant and were consistent with chemical poisoning. Toxicologic and epidemiologic investigations were begun to determine the cause of the poisonings and identify potentially exposed persons. This report summarizes the results of those investigations, including a case-control study that identified iced tea as the likely contaminated food or drink (odds ratio [OR] = 65; 95% confidence interval [CI] = 2.4–3,292). Approximately 5 months after the incident, extensive laboratory testing identified sodium azide (NaN₃) and hydrazoic acid (formed when sodium azide contacts water) as the toxic agents in the iced tea. All five ill restaurant patrons recovered from their symptoms. For rapid-onset foodborne illnesses, chemical poisons should be considered as a potential cause, regardless of negative initial toxicologic screening tests. Although unusual chemicals can be challenging to detect, a multidisciplinary approach involving public health officials and forensic and medical toxicologists can lead to appropriate testing. In the absence of an identified agent, epidemiologic tools are valuable for active case-finding and confirming suspected contaminated food vehicles.

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Next Section

Table 1. Exposure and clinical characteristics for five persons poisoned with sodium azide at a restaurant — Dallas County, Texas, 2010*
Characteristic	Patient 1	Patient 2	Patient 3^†	Patient 4	Patient 5
Exposure
Food	One bite of a sandwich	Cookie	One bite of a sandwich	Cookie	Two bites of a sandwich
Drink (iced tea)^§	Two sips	8 oz	1/4 cup	4 oz	Two sips
Signs and symptoms
Headache	Yes	No	Yes	No	No
Fainting	Yes	No	Yes	Yes	Yes
Vomiting	Yes	Yes	Yes	Yes	Yes
Diaphoresis	Yes	Yes	Yes	Yes	Yes
Sense of impending doom	Yes	Yes	No	Yes	No
Initial heart rate (bpm)	72	110	62	127	94
Initial blood pressure (mmHg)	92/64	110/68	84/42	89/54	86/54
Treatment	Normal saline	Normal saline Lorazepam Ondansetron Promethazine	Normal saline Ondansetron	Normal saline Ondansetron Promethazine Morphine	Normal saline Lorazepam Ondansetron Promethazine
ED disposition	Discharged	Admitted	Discharged	Admitted	Discharged

Abbreviation: ED = emergency department.
* The five patients ranged in age from 32 to 52 years; three were women. Among the five, comorbidities included hypertension, anemia, hypothyroidism, hyperlipidemia, and a bicuspid aortic valve condition.
^† This patient left the initial ED before receiving medical evaluation. After evaluation by another physician, the patient was sent to another ED for further treatment.
^§ None of the patients reported drinking anything other than iced tea.

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