CBRNE - Incapacitating Agents, Opioids/Benzodiazepines - Diagnosis and Differentials
Clinical
History: An event involving an opioid or benzodiazepine aerosolized incapacitating agent would probably create confusion and panic; cause multiple serious injuries or fatalities; and necessitate a major emergency medical service, police, and/or military response.- Large numbers of casualties could overwhelm any community's emergency response services.
- Chaos may occur following such an event.
- In the early phases of an emergency response, the agent would probably be unknown, and the history may be misleading and inaccurate.
- Physical examination is the key to identifying the causative agent.
Physical: Following exposure to either an aerosolized opioid or benzodiazepine incapacitating agent, the presentation would be a syndrome consistent with opioid or benzodiazepine toxicity, respectively. These syndromes can vary, depending on the opioid or benzodiazepine agent used. In addition, findings may vary, depending on the patient's preexisting medical problems, the treatment provided by first responders, and the potential complications of the intoxication. For example, if hypoxic brain injury occurs, the characteristic miosis seen in an opioid syndrome may be replaced by fixed dilated pupils.
- Opioid intoxication
- Respiratory depression manifesting as hypoventilation, apnea, and airway occlusion may be present.
- Central nervous system depression manifesting as fatigue, somnolence, ataxia, and/or coma may be present.
- Miosis may be present. Intoxication with the opioids meperidine and propoxyphene does not typically cause miosis, and normal papillary size is regularly maintained; however, neither of these agents has been associated with aerosolization. Mydriasis may occur in patients with severe toxicity because of anoxic brain injury. Miosis may be limited by preexisting medical conditions, such as a history of previous cataract surgery.
- Cardiovascular manifestations of opioid toxicity may include hypotension secondary to arteriolar and venous dilation. Both tachycardia secondary to hypotension or hypoxia and bradycardia secondary to a reduction of direct central nervous system stimulation may be observed. If hypoventilation becomes prominent, hypoxia-induced cardiac arrhythmias may occur.
- Benzodiazepine intoxication
- Respiratory depression manifesting as hypoventilation, apnea, and airway occlusion may be present.
- Central nervous system depression manifesting as drowsiness, somnolence, ataxia, nystagmus, and/or coma may be present.
- Cardiovascular manifestations of benzodiazepines may include hypotension, tachycardia, and bradycardia. Hypoxia-induced cardiac arrhythmias may occur.
Differentials
CBRNE - Chemical Warfare Agents
CBRNE - Cyanides, Hydrogen
CBRNE - Incapacitating Agents, 3-Quinuclidinyl Benzilate
CBRNE - Incapacitating Agents, Agent 15
CBRNE - Incapacitating Agents, Cannabinoids
CBRNE - Incapacitating Agents, LSD
CBRNE - Nerve Agents, Binary: GB2, VX2
CBRNE - Nerve Agents, G-series: Tabun, Sarin, Soman
CBRNE - Nerve Agents, V-series: Ve, Vg, Vm, Vx
Toxicity, Barbiturate
Toxicity, Benzodiazepine
Toxicity, Clonidine
Toxicity, Cyanide
Toxicity, Gamma-Hydroxybutyrate
Toxicity, Hallucinogen
Toxicity, Narcotics
Toxicity, Organophosphate and Carbamate
Workup
Lab Studies:- The use of laboratory studies in the treatment of patients potentially exposed to opioid or benzodiazepine incapacitating agents should initially focus on the potential complications associated with those sedatives. Additional laboratory tests can also be conducted in an attempt to identify the diagnosis of the incapacitating agent if the specific agent is unknown to the clinicians.
- Rapid urine drug screenings (immunoassays) are available and may assist health care professionals in making a diagnosis. However, these immunoassays do have a number of limitations. Opioid immunoassays are directed toward morphine. Many synthetic opioids, such as fentanyl, show no cross-reactivity with these assays. Testing for benzodiazepines is complicated because numerous benzodiazepines have substantially different structures. Results may be positive for diazepam, but negative for other benzodiazepines (eg, clonazepam).
- Performing a complete blood count, electrolyte tests, clotting studies, and renal and liver function tests is reasonable in any person who has potentially been exposed to an incapacitating agent.
- If the patient is comatose, performing a urine myoglobin and/or creatine phosphokinase test is warranted to exclude rhabdomyolysis. Hyperkalemia, hyperphosphatemia, and hypocalcemia may occur in association with rhabdomyolysis. The lactate level may also be elevated in these patients.
- If the incapacitating agent is unknown, obtain extra blood and urine samples. Subsequent testing can be performed to confirm the causative agent.
- A patient who has potentially been exposed to an opioid or a benzodiazepine incapacitating agent and who is comatose may be at risk for aspiration pneumonia. Obtain a chest radiograph.
- If the etiology of a patient's altered mental status is uncertain, performing a head CT scan to exclude other intracranial processes is reasonable.
Other Tests:
- Both opioids and benzodiazepines may be associated with bradycardia. However, stress occurring in response to a situation associated with an exposure to aerosolized opioids or benzodiazepines may lead to tachycardia. Patients who are exposed to these agents and have preexisting cardiac disease may be at risk for cardiac ischemia. Perform an ECG to exclude these potential problems.
| « Previous Page | Section 2 of 4 |
|
||||
Bibliography
- Booij LH: [The agent used to free the hostages in Moscow and the insufficient Dutch preparations in case of a terrorist chemical disaster]. Ned Tijdschr Geneeskd 2002 Dec 14; 146(50): 2396-401[Medline].
- Coupland RM: Incapacitating chemical weapons: a year after the Moscow theatre siege. Lancet 2003 Oct 25; 362(9393): 1346[Medline].
- Enserink M, Stone R: Toxicology. Questions swirl over knockout gas used in hostage crisis. Science 2002 Nov 8; 298(5596): 1150-1[Medline].
- Gudmundsdottir H, Sigurjonsdottir JF, Masson M, et al: Intranasal administration of midazolam in a cyclodextrin based formulation: bioavailability and clinical evaluation in humans. Pharmazie 2001 Dec; 56(12): 963-6[Medline].
- Hung OR, Whynot SC, Varvel JR, et al: Pharmacokinetics of inhaled liposome-encapsulated fentanyl. Anesthesiology 1995 Aug; 83(2): 277-84[Medline].
- Ljungman G, Kreuger A, Andreasson S, et al: Midazolam nasal spray reduces procedural anxiety in children. Pediatrics 2000 Jan; 105(1 Pt 1): 73-8[Medline].
- Loftsson T, Gudmundsdottir H, Sigurjonsdottir JF, et al: Cyclodextrin solubilization of benzodiazepines: formulation of midazolam nasal spray. Int J Pharm 2001 Jan 5; 212(1): 29-40[Medline].
- Mather LE, Woodhouse A, Ward ME: Pulmonary administration of aerosolised fentanyl: pharmacokinetic analysis of systemic delivery. Br J Clin Pharmacol 1998 Jul; 46(1): 37-43[Medline].
- Rieder J, Keller C, Hoffmann G: Moscow theatre siege and anaesthetic drugs. Lancet 2003 Mar 29; 361(9363): 1131[Medline].
- Schiermeier Q: Hostage deaths put gas weapons in spotlight. Nature 2002 Nov 7; 420(6911): 7[Medline].
- Stone A: Chemical weapons. U.S. research on sedatives in combat sets off alarms. Science 2002 Aug 2; 297(5582): 764[Medline].
- Wax PM, Becker CE, Curry SC: Unexpected "gas" casualties in Moscow: a medical toxicology perspective. Ann Emerg Med 2003 May; 41(5): 700-5[Medline].
- Worsley MH, MacLeod AD, Brodie MJ, et al: Inhaled fentanyl as a method of analgesia. Anaesthesia 1990 Jun; 45(6): 449-51[Medline].
- Xi LY, Zheng WM, Zhen SM, Xian NS: Rapid arrest of seizures with an inhalation aerosol containing diazepam. Epilepsia 1994 Mar-Apr; 35(2): 356-8[Medline].
Synonyms And Related Keywords
incapacitating agent; opioid; fentanyl; carfentanil; alfentanil; sufentanil; benzodiazepine; diazepam; chemical warfare agents; chemical, biological, radiological, nuclear, and explosive threat agents; chemical weapons; benzodiazepine toxicity; opioid toxicity
