— Mark Di Stefano 🤙 (@MarkDiStef) February 19, 2017
Filed under: Uncategorized Tagged: Uluru
As the History Channel video above indicates, nerve agents are potent acetylcholinesterase inhibitors that utilize the same mechanism as organophosphate insecticides such as parathion. Conceptually, the effect of VX exposure is simple: wherever in the body acetylcholine acts as a neurotransmitter, nerve agents cause unregulated, chaotic activity. There are generally 3 such sites:
The effects of nerve agents on these sites are predictable:
Victims exposed to nerve agents die of respiratory failure, due to a triple-whammy: airway obstruction and bronchospasm, dysfunction of voluntary muscles of respiration, and loss of central drive to breathe. With 3 separate types of effects, there are fittingly 3 antidotes:
Despite the announcement that VX was identified, there are still some puzzling details that don’t seem to fit. Video of Mr. Kim after he was exposed to the agent does not seem to show muscle weakness, fasciculation, or copious secretions. Also, given that VX is often called one of the deadliest substances on the planet, the attackers did not seem to suffer serious effects. (It is not clear if they were wearing gloves, and a recent report suggests that one of the young women seen on the video vomited.) There has also been speculation that a binary weapon was involved, in which two harmless chemicals might have been combined to produce VX.
[Addendum: 2/24/17 14:32 CST]
According to emedicine.com, after dermal exposure of V-series agents onset of symptoms may be delayed for hours. I remember from the time I taught in the Department of Defense Domestic Preparedness Program that Dr. Fred Sidell, one of the nation’s experts on chemical weapons, stated that symptoms might not develop until 18 (!) hours after skin exposure to VX. This would be consistent with what we know about the attack on Mr. Kim. However, if the agent got in his eye, I would expect meiosis to produce markedly decreased vision.
Note also that VX is quite viscous, having high persistence and low volatility. Whereas the G-series nerve agents (tabun, soman, sarin) have approximately the consistency of water, VX is more like motor oil.
Originally published at CoreEM.net, who are dedicated to bringing Emergency Providers all things core content Emergency Medicine available to anyone, anywhere, anytime. Reposted with permission.
Written by: Latrice Triplett, MD // Edited By: Anand Swaminathan, MD
History and Physical
Take Home Points
Berbari EF, Kanj SS, et al. Executive Summary: 2015 Infectious Disease Society of America (IDSA) Clinical Practice Guidelines for the Diagnosis and Treatment of Native Vertebral Osteomyelitis in Adults. Clin Infect Dis 2015 Sept 15;61(6):859-63. PMID: 26316526
Boody B, et al. Vertebral Osteomyelitis and Spinal Epidural Abscess: An Evidence-based Review. J Spinal Disord Tech. 2015 Jul;28(6):E316-27 PMID: 26079841
Chowdhury V, Gupta A, Khandelwal N. Diagnostic Radiology: Musculoskeletal and Breast Imaging. 3rd ed. New Delhi: JP Brothers Medical Ltd; 2012
Della-Guistina, D. Evaluation and Treatment of Acute Back Pain in the Emergency Department. Orthopedic Emergencies 2015 May; 33(2) 311-26. PMID: 25892724
Gouliouris T, et al. Spondylodiscitis: update on diagnosis and management. J Antimicrob Chemother. 2010 Nov;65 Suppl 3:iii 11-24 PMID: 20876624
Mylona E, et al. Pyogenic Vertebral Osteomyelitis: A Systematic Review of Clinical Characteristics. Semin Arthritis Rheum. 2009 Aug; 39(1):10-7. PMID: 18550153
Pruitt CR, Perron AD. Specific Disorders of the Spine. In: Sherman SC eds. Simon’s Emergency Orthopedics. 7th ed. New York, NY: McGraw-Hill; 2014
Winters ME, Kluetz P et al. Back Pain Emergencies. Med Clin North Am, 2006 May;90(3):505-23. PMID: 16473102
Zimmerli W. Vertebral Osteomyelitis. N Engl J Med 2010 Mar; 362(11)1022-9. PMID: 20237348
*Thanks to Dr. Clark Owyang for following this “case” with me!
On February 13, Kim Jong-un, son of Kim Jong-il and half-brother of current North Korean leader Kim Jong-un, was poisoned at Kuala Lumpur airport in Malaysia. He died shortly after. Yesterday, the Malaysian police reported that Kim Jong-nam died of exposure to VX gas.
The UK first synthesized VX gas in 1952 in the UK, and then gave it to the U.S. for military development. It is an organic phosphorous compound, and the most potent nerve gas ever developed. The aerosolized dose causing mortality in 50% of humans (LD50) is only 10 mg/minute/m3. Because of its low volatility, it poses a higher risk for dermal exposure than respiratory exposure. Via this dermal route, death generally occurs within several hours.
VX is an acetylcholinesterase inhibitor, meaning that it prevents degradation of acetylcholine bound at the neuromuscular junction. It works at muscarinic, nicotinic, and central receptors. Muscarinic effects include the SLUDGE symptoms we all know: salivation, lacrimation, urination, defecation, GI cramping, and emesis. Nicotinic effects include muscle fasciculations, weakness, and paralysis. Centrally, this agent may cause seizures (prior to the flaccid paralysis caused by nicotinic activation) and respiratory depression.
In an aerosol exposure, the eyes are affected first. Symptoms include miosis (due to direct contact of nerve gas with the eye), blurring of vision, and ciliary spasm that causes eye pain. Next, the patient may experience rhinorrhea, increased airway secretions, and bronchial constrictions.
Self-protection is of the utmost importance. Don your own protective equipment before treating patients. The first treatment step is always decontamination. Clothing exposed to nerve gas may continue to release the toxic agent in fumes. Remove all the patient’s clothing and place it in an airtight receptacle. Next, the patient should be showered. Consider using a solution that releases chlorine, like household bleach or other alkaline substances. These substances hydrolyze and inactivate nerve gas. To make bleach application safe for skin, dilute household bleach in water to make a 1:10 solution. If bleach or an alkaline substance cannot be obtained rapidly, regular soap and water should be used.
Both the muscarinic and nicotinic effects of nerve gas must be addressed. Atropine is an anticholinergic, and should be used to reverse muscarinic symptoms. The standard dose determined by the military is 2mg, but severely poisoned adults should get a first dose of 5-6 mg. Titrate atropine to effect. The endpoint is drying of bronchial secretions. Tachycardia is expected. Do not stop administering atropine to a tachycardic patient who is still experiencing bronchial secretions.
Pralidoxime chloride (pyridine-2-aldoxime, or 2-PAM) reverses the nicotinic (i.e. neuromuscular) effects of nerve gas. It re-activates acetylcholinesterase. If “aging” (i.e. irreversible dealkylation) of the nerve gas-acetylcholinesterase has already occurred, 2-PAM won’t work. VX has an aging half-life of 48 hours.
Pediatric infectious diseases have been a common topic for the PedEMMorsels and rightfully so as kids love to collect numerous viral and bacterial infections (ex, Measles, Flu, Mumps, Omphalitis). With that being said, pneumonia is often the topic of conversation in the Peds ED and, thus, deserves special attention. We have discussed pneumonia several times previously (ex, Pneumonia Detective, Round Pneumonia, Penicillin for Pneumonia, and CAP), but recently our friends at the Section on Emergency Medicine at the AAP published a easy to follow guide to Community Acquired Pneumonia (displayed below). Let is take another moment to ensure we are up to date with current recommendations for Pediatric Pneumonia.