Cyanide

There was a chemical incident declared once because the pre-hospital team could smell almonds- they thought cyanide could be involved. Turns out someone had been baking... 

Cyanide is released by the incomplete combustion of nitrogen-containing materials, and metabolised from amygdalin. Amygdalin can be found in the pits of many fruits, such as apricots and papayas and raw nuts.

Cyanide is a colourless gas with a bitter almond smell, detectable by only 40% of people.

http://www.christem.com/storage/cyanide%20mechanism

CN blocks cellular respiration by blocking the cytochromes. Affected cells convert to anaerobic metabolism, and a lactic acidosis results. The CNS and the heart are most sensitive.

Symptoms

#fcem #toxicology #FOAMed #revision Features of cyanide toxicity. pic.twitter.com/1UYxjDrIPI
— Kirsty Challen (@KirstyChallen) July 15, 2014

Symptoms after exposure to high vapor concentrations may include the following:
Transient hyperpnea and hypertension 15 seconds after inhalation
Loss of consciousness in 30 seconds
Respiratory arrest in 3-5 minutes
Bradycardia, hypotension, and cardiac arrest within 5-8 minutes of exposure

Symptoms after exposure to lower vapor concentrations or after ingestion or liquid exposure may include the following:
Feelings of apprehension or anxiety
Vertigo
Nausea, with or without vomiting
Muscular trembling
Loss of consciousness
Headache
Dyspnea

Patients exposed to cyanogen chloride experience severe eye and mucous membrane irritation.Low-dose exposure results in rhinorrhea, bronchorrhea, and lacrimation. Inhalational exposure results in dyspnea, cough, and chest discomfort. Onset of symptoms after exposure to nitriles (acetonitrile and/or propionitrile) may be significantly delayed.

Physical findings of cyanide exposure are generally nonspecific. They classically have cherry red skin.

Laboratory Investigations
- Normal arterial oxygen tension, high venous oxygen tension = decreased AV difference (<10%)
- High anion gap metabolic acidosis
- Raised lactate

Antidotes

#REBELReview 67 Cyanide Toxicity Treatment http://t.co/Fo3oz5PIN2 #FOAMed #FOAMtox #MedEd #ABIM #EMBoardReview #USMLE pic.twitter.com/j6FlhcmlKs
— Salim R. Rezaie (@srrezaie) June 1, 2014

To accompany episode # 1.. a fabulous #FOAMed visual representation of the mech of action of cyanide antidotes http://t.co/RxRCsTmnci
— FOAMcast (@FOAMpodcast) May 24, 2014

Minimal symptoms that resolve spontaneously need observation only.

Other Factors
- Oxygen
- Consider sodium bicarbonate if severe lactic acidosis
- Treat haemodynamic instability and cerebral oedema

@Lmellick video on smoke inhalation injury https://t.co/SbhSGXZWZX #FOAMed
— Jasmin Hamzic (@jasmin_hamzic) January 11, 2015

#EMSqoD A:Cyanide can be the toxic agent in smoke. http://t.co/r2Hu7eFs & http://t.co/Tt439mpi So use cyanokit, 50% increase in ROSC #FOAMed
— Dr. Howie Mell (@DrHowieMell) January 4, 2013

Cyanide poisoning: key facts #FOAMed #Toxicology #FCEM pic.twitter.com/LYGWeNf451
— Natalie May (@_NMay) July 9, 2013

References
http://blog.clinicalmonster.com/2015/02/em-ccm-carbon-monoxide-and-cyanide-poisoning/
https://umem.org/educational_pearls/2675/
http://www.enlightenme.org/knowledge-bank/cempaedia/industrial-chemical-incidents