Biologic Weapons, Emergency Medicine

Basics

Description

Defined as naturally occurring organisms or toxins that are purified and prepared for mass dissemination with intent of causing mass morbidity, mortality, and social disruption.
Organisms include bacteria, viruses, and fungi.
Over 400 potential or actualized etiologic agents capable of being used as biologic weapon:
- Characterized by their relatively low cost compared with other weapons of mass destruction (WMD), high potency, and their ability to be delivered in a stealthy manner
- Stealth quality of biologic weapons comes from organisms natural incubation period.
Easy to conceal and difficult to detect:
- Agents often invisible to naked eye, odorless, and tasteless
Patients typically present to various health care facilities with host of common complaints, adding to delay in recognition of covert release of biologic weapon.
Victims of biologic warfare agents are exposed either via direct cutaneous contact with agent, respiratory inhalation of aerosolized agent, or via GI tract after poisoning of food or water source.

Etiology

Bacteria:
- Anthrax: Bacillus anthracis
- Plague: Yersinia pestis
- Cholera: Infection from Vibrio cholerae:
  - Presents with severe GI symptoms and rapidly leads to profound dehydration
- Tularemia: Francisella tularensis
- Brucellosis: Organism in the Brucella genus
- Q fever: Coxiella burnetii
Viruses:
- Smallpox: Variola virus
- Viral encephalitides: Members of Alphavirus genus (Venezuelan equine encephalitis, Eastern equine encephalitis, and Western equine encephalitis)
- Viral hemorrhagic fevers: From 4 families of viruses, includes illnesses such as Ebola, Marburg, Lassa, and dengue fever
Toxins:
- Ricin
- Staphylococcal enterotoxin B
- Botulinum toxin
- Mycotoxins

Diagnosis

Signs and Symptoms

Health care providers need to be alert to detect illness patterns and diagnostic clues that indicate biologic weapon release.
Indications of intentional release of agent include:
- Geographic clustering of illnesses with individuals who live, work, or attended event in close proximity (if multiple people who work in same office develop pneumonia, it could potentially represent respiratory pathogen release)
- Unusual age distribution for common illness (chickenpox-like illness among adult patients could represent smallpox release)
- ≥2 patients presenting with similar unexplained illnesses (2 patients presenting with flaccid paralysis could represent botulinum toxin release)
- Single case of illness caused by uncommon agent (smallpox, inhalational anthrax)
- High volume of patients with similar presentation of symptoms associated with escalating morbidity and mortality

Anthrax

Inhalational anthrax:
- Fever
- Chills
- Fatigue, malaise, lethargy
- Cough, usually dry or minimally productive
- Nausea or vomiting
- Dyspnea
- Diaphoresis
- Chest pain
- Myalgias
- Tachycardia
- Fever
- Meningeal signs
Cutaneous anthrax:
- Skin lesion:
  - Painless pruritic papule
  - Turning into vesicle that ruptures forming necrotic ulcer
- Black eschar
- Surrounding gelatinous nonpitting edema

Plague

Abrupt onset
Fever, chills
Cough, hemoptysis, dyspnea
Headache
Vomiting
Swollen tender lymph nodes (buboes)
Skin lesions at site of inoculation (i.e., flea bite)
Confusion
Abdominal pain
Oliguria
Obtundation
Extensive ecchymosis
Acral gangrene (digits, nose, penis)

Tularemia

See "Tularemia"� chapter.
Typhoidal:
- Most likely form of disease when weaponized and delivered by aerosol
- Fever, headache, malaise
- Nonproductive cough
- 35% mortality if untreated

Q fever

Incubation period 10-40 days
Flu-like symptoms and pleuritic chest pain for 2-10 days
CXR shows patchy infiltrates
Definitively diagnosed serologically
Mortality:
- <1% even if untreated

Brucellosis

Incubation period 3-60 days
Flu-like symptoms and neuropsychiatric symptoms (headache, depression, fatigue, and irritability)
Focal infection of joints and GU tract may cause localized pain, particularly back pain.
Diagnosis by combination of serologic testing and cultures of blood or bodily fluids.
Mortality: <2%

Smallpox

Incubation period 7-17 days (average is 12 days)
Flu-like symptoms (fever, fatigue, myalgias, headache) for ~2-3 days followed by characteristic rash:
- Progresses from macules to papules to pustular lesions and crusted lesions
- Starts on face and extremities (including palms/soles) and spreads to trunk in 1 wk
- Scabs over in 1-2 wk
Mortality:
- 30% if untreated

Hemorrhagic Fevers

See "Hemorrhagic Fever"� chapter
Incubation period 1-3 wk
Starts as flu-like syndrome with fever, malaise, myalgias, headache, and sore throat
Afterward, infectious gastroenteritis syndrome, rash, and renal/hepatic dysfunction
Finally, hemorrhagic symptoms develop around the 5th day followed by shock and death:
- Mortality in 50-90% for Ebola if untreated

Essential Workup

Suspect bioterrorism if: �

Multiple cases of relatively young, healthy patients who present with flu-like syndrome and within days deteriorate rapidly
Typical cutaneous lesions appear

Diagnosis Tests & Interpretation

Lab

CBC
Electrolytes, BUN, creatinine
ABG
Cerebrospinal fluid (CSF):
- Anthrax: 50% with inhalation anthrax develop hemorrhagic meningitis.
Coagulation studies:
- Plague: Disseminated intravascular coagulation (DIC)
Blood cultures
Wound cultures
Alert lab personnel to potential concerns of clinicians.

Imaging
CXR: �

Anthrax: Mediastinal widening, pulmonary infiltrate/consolidation, pleural effusion
Plague: Bronchopneumonia

Differential Diagnosis

Anthrax:
- Influenza
- Bacterial pneumonia, bacterial meningitis
- Brown recluse spider bite
- Tularemia
- Streptococcal/staphylococcal skin infection
Plague:
- Tularemia, catscratch disease
- Lymphogranuloma venereum, chancroid
- Tuberculosis
- Streptococcal adenitis
- Meningitis, encephalitis, sepsis
Smallpox:
- Varicella
- Rash starts centrally on trunk and spreads outward:
  - Lesions in different stages of development
  - Rarely involves palms or soles
  - Disseminated molluscum contagiosum
- Monkeypox, drug eruptions
Toxins:
- Staphylococcal enterotoxin B:
  - Most common cause of food poisoning
  - Can be aerosolized in addition to being placed in food or water reservoir
  - When inhaled, produces febrile type of illness that can progress to septic shock picture
- Ricin:
  - Plant protein derived from castor beans
  - Causes rapid progression from upper respiratory congestion to cardiopulmonary collapse
  - Ingestion is less toxic because GI tract does not absorb it well, but it can lead to local cytotoxic death, shock, and death.
- Botulinum toxin:
  - Initially symptoms include cranial nerve dysfunction with descending paralysis that leads to respiratory failure.
- Mycotoxins:
  - Highly toxic compounds produced by certain species of fungus
  - Dermal, respiratory, or GI contact can rapidly lead to multiorgan system failure and death.

Treatment

Pre-Hospital

Universal precautions with N-95 mask �

Initial Stabilization/Therapy

ABCs
0.9% NS fluid bolus for hypotension
Supplemental oxygen for hypoxemia
Vasopressors for persistent hypotension
Respiratory and contact isolation for suspected cases

Ed Treatment/Procedures

All treatments include:
- Control fever with acetaminophen.
- Initiate therapy for specific disease.
Anthrax:
- Initiate antibiotics:
  - IV for inhalational or severe cutaneous
  - Antibiotic choice depends on susceptibility.
- Antibiotic options:
  - Ciprofloxacin: 1st line
  - Doxycycline
  - Rifampin
  - Clindamycin
  - Vancomycin
Plague:
- Antibiotics initiated within 24 hr minimizes mortality.
- 1st-line agents: Streptomycin or gentamicin
- Add chloramphenicol if signs of meningitis or unstable patient
- Prophylaxis: Doxycycline or ciprofloxacin
Brucellosis:
- Supportive therapy
- Start doxycycline 100 mg PO BID for 6 wk with the addition of streptomycin 1 g per day IM for the 1st 2-3 wk or rifampin 900 mg per day for 6 wk.
Q fever:
- Recovery occurs within 2 wk without treatment.
- Doxycycline shortens duration of illness.
Smallpox:
- Supportive therapy
- Vaccine given within 4 days of initial exposure decreases chances of contracting smallpox or developing severe symptoms.
- Vaccinate medical staff caring for patient.
- Treat secondary bacterial infection.
Tularemia:
- See "Tularemia."�
Hemorrhagic fevers:
- See "Hemorrhagic Fever."�

Medication

Chloramphenicol: 25 mg/kg IV q6h
Ciprofloxacin: 400 mg IV q12h or 500 mg PO BID (peds: 15 mg/kg BID PO)
Clindamycin: 900 mg IV q12h
Doxycycline: 100 mg (peds: ≥45 kg, 100 mg; if weight ≤45 kg, 2.2 mg/kg IV) PO/IV q12h
Gentamicin: 5 mg/kg IM or IV q24h (peds: 2.5 mg/kg IV/IM q8h)
Rifampin: 10 mg/kg IV not to exceed 600 mg/d
Streptomycin: 1 g (peds: 20-40 mg/kg) IM q12h
Vancomycin: 1 g IV q12h

Follow-Up

Disposition

Admission Criteria

Decision to treat patient as inpatient vs. outpatient will have to be made in context of overall disaster.
Toxic or hypoxic patients require admission.
Respiratory isolation

Discharge Criteria
Mild, noncontagious illness �
Issues for Referral

Contact local and state health departments for suspected or confirmed illness related to biologic weapons.
Infectious disease and toxicology consult for suspected illness

Follow-Up Recommendations

Postexposure prophylaxis and vaccinations should be continued based on the causative agent.
Exposed staff should have follow-up with employee health and infection control prior to returning to work.

Pearls and Pitfalls

Early diagnosis is difficult, and a high index of suspicion is required.
Failing to use personal protective equipment to protect self and staff is a pitfall.
Suspect biologic weapons etiology when there is geographic clustering of patients who live, work, or attended an event in close proximity.
Initiate therapy or prophylaxis early in suspected illness.

Additional Reading

Centers for Disease Control and Prevention (CDC). Recognition of illness associated with the intentional release of a biologic agent. MMWR Morb Mortal Wkly Rep. 2001;50:893-897.
Franz �DR, Jahrling �PB, Friedlander �AM, et al. Clinical recognition and management of patients exposed to biological warfare agents. JAMA. 1997;278(5):399-411.
US Army Medical Research Institute of Infectious Diseases. Medical Management of Biological Casualties Handbook. 6th ed. Fort Detrick, Frederick, MD, April 2005.

Useful Websites

emergency.cdc.gov/bioterrorism/
sis.nlm.nih.gov/enviro/biologicalwarfare.html

Codes

ICD9

V01.0 Contact with or exposure to cholera
V71.82 Observation and evaluation for suspected exposure to anthrax
V71.83 Observation and evaluation for suspected exposure to other biological agent
V01.3 Contact with or exposure to smallpox

ICD10

Z03.818 Encounter for observation for suspected exposure to other biological agents ruled out
Z20.09 Contact with and (suspected) exposure to other intestinal infectious diseases
Z20.810 Contact with and (suspected) exposure to anthrax
Z77.098 Contact w and expsr to oth hazard, chiefly nonmed, chemicals
Z20.89 Contact with and (suspected) exposure to other communicable diseases

SNOMED

418307001 Exposure to biological agent (event)
170475009 exposure to Bacillus anthracis (event)
409510007 Inhalational exposure to biological agent (event)
409511006 Exposure to biological agent by ingestion (event)
444351007 Exposure to Variola virus (event)
444381004 Exposure to Vibrio cholerae (event)

Home

Erectile Dysfunction

Doctor123.org