Carl H. Schultz and Kristi L. Koenig

Perspective

Besides managing the injuries and illnesses from common disasters such as earthquakes and airplane crashes, emergency physicians should also have competence in treating victims generated by terrorist attacks with nuclear, biologic, chemical, or high-energy explosive weapons. Conventional explosives remain the most common weapon used by terrorists; however, the risk from nuclear, biologic, and chemical agents may increase over time. The nomenclature for these weapons remains controversial. Some authors have proposed the use of weapons of mass effect or weapons of mass disruption. The military uses the acronym CBRNE, pronounced “see-burn-ee,” referring to chemical, biologic, radiologic, nuclear, and explosive. This chapter uses weapons of mass destruction (WMD) because of its wide acceptance.

The results of an attack with WMD, although admittedly of low probability, are potentially catastrophic. According to a World Health Organization estimate, 50 kg of anthrax spores aerosolized above a city of 5 million people would result in 100,000 deaths, with an additional 150,000 people seriously infected. The cost of managing 100,000 cases of anthrax exposure is estimated at between $6.4 and $26.2 billion.¹ Given these considerations, most authorities believe that preparedness for such threats is a priority.

Children are particularly vulnerable to these weapons. They breathe at a faster rate than adults do, increasing their relative exposure to aerosolized agents. Some chemicals, such as sarin, are heavier than air, so they tend to accumulate at the level where children are more likely to inhale them. Children have a greater surface area–to–volume ratio and their skin is thinner. This makes them more susceptible to agents that act on or through the skin. They have smaller fluid reserves and higher metabolic rates. Therefore, they are more vulnerable to dehydration from vomiting and diarrhea and suffer increased toxicity from a given exposure, such as to radioactive iodine (¹³¹I).

The use of biologic and chemical agents dates to biblical times, although the threat from radiation and nuclear detonation is relatively new. Assyrians poisoned the wells of their enemies with rye ergot in the 6th century BC. The Mongols catapulted bodies infected with bubonic plague over the walls of Kaffa in the 14th century. The British Army gave American Indians blankets taken from individuals infected with smallpox during Pontiac’s Rebellion in 1763. During World War I, the Germans effectively used chlorine and mustard agent against the advancing Allied armies. The Japanese killed hundreds to thousands of Chinese citizens with bubonic plague during World War II by spraying towns with fleas infected with Yersinia pestis. Saddam Hussein used a mustard agent against the Iranians during the Iran-Iraq War in the 1980s.

The use of WMD has been predominantly by the military during times of conflict. In recent history, however, the use of these agents has taken an ominous turn. Nonaffiliated groups have begun using WMD directed at civilians to achieve political ends. The Bhagwan cult sprayed salad bars in Oregon with Salmonella in an attempt to influence an election in 1984.² The Aum Shinrikyo used the nerve agent sarin in an unsuccessful 1994 assassination attempt on three judges in Matsumoto, Japan. This same group used sarin again in the 1995 Tokyo subway attack that killed 11 people.³ The United States experienced multiple anthrax hoaxes during 1997 and 1998, motivated by personal or political agendas. Terrorists initiated an actual anthrax attack using the U.S. mail in 2001 that resulted in 11 deaths. No one has yet used radiologic or nuclear devices in a successful mass terrorist attack, but at least one attempt has occurred. In addition, several highly radioactive sources have been stolen from U.S. medical facilities, and a Russian dissident, Alexander Litvinenko, was assassinated with a radiologic agent (polonium-210) in 2006.

Many agents are potential candidates for weaponization, and some represent a substantial risk (Box 194-1). Management strategies for patients exposed to WMD are frequently similar to strategies for hazardous materials exposure. However, several features associated with WMD make these events unique (Box 194-2). Additional knowledge and skills are required in the evaluation and treatment of WMD victims. These plans represent only one small part of an overall comprehensive emergency management strategy for all hazards (see Chapter 193). Names of departments, bureaus, and agencies that can assist with planning and response to WMD events are listed in Table 194-1.

Nuclear and Radiologic Devices

Terrorists selecting radiation as a means to inflict casualties are unlikely to use nuclear weapons. These devices are heavily guarded, difficult to move because of their size and weight, and easy to detect. Although Russia acknowledges that 50 to 100 of its 1-kiloton “suitcase” nuclear weapons are missing, the problems of purchasing, moving, and detonating these devices are formidable. Sabotage at nuclear power stations is possible, but given tight security, multiple safety systems, and thick concrete housings surrounding the reactors, the threat is probably low.

Instead, simple radiologic devices, such as those used by hospitals for radiation therapy, are thought to be the source of choice. These sources are plentiful. They do not detonate on their own and give no warning of their presence unless they are dispersed by a conventional explosive (radiologic dispersal device). Thefts of radiotherapy sources have occurred in the United States. Accidental dispersion from a stolen hospital therapy source in Brazil resulted in the screening of 112,000 people for contamination. A total of 249 people were found to be exposed, 4 of whom ultimately died.² Placement of such a device at an information kiosk in a crowded mall during a busy holiday shopping season would silently expose countless persons to significant radiation.

Ionizing radiation, regardless of its type, causes injury at the cellular level, usually by damaging DNA. Rapidly dividing cells are the most sensitive. Patients have symptoms within hours to days, depending on the dose. Common syndromes associated with radiation exposure include dermal burns, bone marrow failure, and gastrointestinal dysfunction (e.g., vomiting and gastrointestinal bleeding) (see Chapter 146). A U.S. Department of Homeland Security task force developed an expert consensus document on medical treatment of radiologic casualties, and the results were subsequently published in the peer-reviewed literature.⁴

A basic emergency department radiation protocol must address decontamination, triage, staff safety, personal protective equipment (PPE), and diagnostic procedures that emphasize radiation monitoring. Victims presenting to the emergency department will suffer from three types of exposure: irradiation, internal contamination, and external contamination. Irradiated victims have been exposed to a beam of radiation, similar to someone undergoing a chest x-ray examination. They are not radioactive and pose no threat to emergency department personnel.

Contaminated patients are more challenging, and early involvement of the radiation safety officer is critical. This individual evaluates the degree of the victim’s contamination and monitors radioactivity levels throughout the decontamination process. Internally contaminated patients present a therapeutic challenge because they have radioactive material inside their bodies (e.g., lungs and gastrointestinal tract) or incorporated into their cells. They should be placed in an isolation room, where all secretions and body fluids can be collected. Various medications are available for administration to internally contaminated patients and can limit uptake or facilitate removal of certain radioactive elements. These medications include Radiogardase (Prussian blue) for cesium and thallium ingestions and diethylenetriaminepentaacetic acid (DTPA) for plutonium exposure. Health care providers can receive assistance by calling the Radiation Emergency Assistance Center/Training Site (REAC/TS; http://orise.orau.gov/reacts) at 865-576-3131 (emergency number: 865-576-1005).

Externally contaminated victims have radioactive material on their skin or clothing and are decontaminated by removal of clothing and washing with soap and water. Washing by protected personnel should continue until monitoring by the radiation safety officer demonstrates the absence of radioactivity. If wounds are present, they are decontaminated first. After the wounds are covered with a sterile, waterproof dressing, the remaining skin is washed. Hospitals must be prepared to decontaminate patients because historical data suggest that up to 80% of patients do not receive this intervention before arrival.² Decontamination before hospital entry is crucial because these individuals can expose caregivers to radiation and contaminate the entire hospital through the ventilation system. Removal of clothing and covering of the head with a surgical cap can reduce contamination by 80% to permit stabilization in the decontamination unit, but complete decontamination should occur before exposure of unprotected staff if the patient’s medical condition permits.

Initial triage of radiation casualties is based on their overall pathologic condition, not on exposure.⁵ Even patients who have received a lethal dose of radiation do not die immediately as a consequence of the ionizing exposure. Therefore, a patient in acute distress from a myocardial infarction or urosepsis would be triaged ahead of a radiation victim with stable vital signs, regardless of the dose received. If a radiation casualty also suffers a severe injury or illness, immediate intervention is required. Most of the immediate morbidity and mortality associated with a radiologic dispersion device is related to traumatic injuries from the explosion and not to radiation exposure.⁴

In addition to patient contamination, the radiation safety officer is responsible for monitoring of the exposure of hospital staff. All personnel involved in the care of contaminated patients should wear dosimeters, which measure the amount of radiation received by the wearer. The safety officer tracks the amount of radiation received by each staff member and can remove a health care worker from the area if the exposure is too high. Radiation monitoring is complex, and the radiation safety officer should be involved as early as possible. Hospitals should consider conducting disaster drills that include casualties suffering radiation injuries.

Although many radioactive elements are candidates for use in a terrorist attack, ¹³¹I and related isotopes deserve additional discussion because of heightened interest. ¹³¹I is found only after a nuclear detonation or in reactor fuel rods. Although it is not impossible, the probability that terrorists could tap either of these sources is very small. The use of ¹³¹I in a radiologic dispersal device is unlikely because of its short half-life (8 days). Even if such a device could be made, it is extremely unlikely that the radiologic dispersal device could disperse sufficient radioactive material to pose an immediate health hazard.⁶ Given these facts, the probability that any significant exposure of the population (especially children) to ¹³¹I will occur is equally small. The large number of childhood thyroid cancers that occurred after the accident at the Chernobyl nuclear power plant resulted, to a significant degree, from situations that will not occur in the United States. These include delayed reporting of a breach in the reactor containment vessel preventing timely evacuation of all exposed populations, failure to effectively quarantine contaminated milk and vegetables, and significant iodine deficiency in the exposed population.⁷ The risk to children in communities surrounding the Fukushima nuclear power plant is also an issue that will require long-term monitoring. Nonetheless, concern about treatment to prevent thyroid cancer after potential exposure to ¹³¹I remains. Current recommendations for treatment with potassium iodide, which blocks uptake of ¹³¹I by the thyroid, are listed in Table 194-2. Caveats for use of this table include increasing the amount of potassium iodide for adolescents approaching 70 kg to the adult dose (130 mg) and monitoring thyroid-stimulating hormone and free T₄ levels in neonates when possible. Nonpregnant adults older than 40 years are unlikely to benefit from this intervention.

Biologic Weapons

By convention, biologic weapons are divided into three groups: bacteria, viruses, and toxins. A characteristic shared by these agents is their ability to be dispersed as an aerosol. Because this is the most effective means to expose a large population, aerosol dispersal is the most likely route that terrorists will use to deploy such weapons. Therefore, victims will have respiratory signs and symptoms. Dermal contact and ingestion are also potential pathways for exposure, and some agents are effective by these routes. People infected in the 2001 U.S. anthrax attack were inoculated through aerosol and dermal exposures. However, it is logistically more difficult to produce large casualty numbers by nonrespiratory portals of entry, so agents spread primarily by injection or through the gastrointestinal tract are less likely candidates for wide deployment. If the goal is to disrupt the economy or to spread fear among the population, then almost any type of release will suffice, whether or not people actually die.

Patients exposed to biologic agents usually present with vague symptoms associated with an influenza-like illnesses. Unless a biologic attack is announced or suspected, the emergency department staff may not realize that they are treating victims. Indeed, it is not always possible to distinguish natural occurrences from engineered outbreaks of diseases. Examples of non-terrorist outbreaks of anthrax include cutaneous disease in intravenous heroin users in Europe and an outbreak of cutaneous anthrax in Bangladesh in 2010 with more than 400 cases. Because of the challenges in identifying the true etiology of acute events, personnel should be vigilant and at least consider the possibility, especially when warning signs are present (Box 194-3). For example, large numbers of patients suddenly presenting with “the flu” not during influenza season should cause concern. For these reasons, health surveillance will be paramount in identifying agents and potential sources. The emergency department should have a working relationship with local and state health departments as well as with local law enforcement and stay apprised of Centers for Disease Control and Prevention (CDC) and Department of Homeland Security guidelines.

Several infectious agents with potential for use as biologic weapons can spread in a hospital environment. Examples include Ebola and smallpox.2,8 Hospitals need protocols for PPE and patient isolation to ensure a safe environment.^9–12 Fortunately, such protocols are similar to those applied to other infectious diseases (Box 194-4). Implementation of such precautions is credited with halting of the in-hospital spread of the Ebola virus in the 1995 Zaire outbreak. Decontamination is not a priority unless the exposure is immediate. Standard (universal) precautions are generally sufficient, and special suits (e.g., levels A, B, and C) are unnecessary.¹³

Whereas the CDC lists six Category A (high threat) agents (www.bt.cdc.gov/agent/agentlist-category.asp), this chapter focuses on three biologic agents—anthrax, plague, and smallpox—that represent the greatest interest.¹⁴