Cyanides

Discoverer Karl Wilhelm Sheele died from its vapors Commercial and home use Found in some fruit seeds Accidental poisonings from apricot kernels

Cyanides-Overview HCN and CK Highly volatile Easily dispersed as aerosols Readily soluble and stable in water Major route of toxicity is inhalation Aroma of bitter almonds or marzipan CK has cumulative effect on victims

Cyanides-Toxicity Inhibits oxidizing enzymes containing ferric iron, mainly cytochrome oxidase Interferes with aerobic respiration Lactic acid accumulates and cells die from a histotoxic anoxia Alters calcium metabolism

Cyanides-Toxicity Hydrogen Cyanide (HCN) 60 mgmin/m 3 - No serious symptoms 200 mgmin/m 3 - Fatal after 10 minutes Above 2,500 mgmin/m 3 - death within a minute

Cyanides-Toxicity Cyanogen Chloride (CK) Pulmonary irritant like phosgene 2.5 mgmin/m 3 - irritation after 10 minutes 5 mgmin/m 3 - intolerable at 10 minutes 400 mgmin/m 3 - fatal after 10 minutes

Protective Equipment Chemical protective clothing required Respirator filters containing silver oxide offer effective protection Change filter immediately after exposure

Detection Several analytical detecting methods are available Main method of laboratory detection is gas chromatography/mass- spectrometry

Decontamination First priority: remove victims from area Skin: wash well with soap and water Eyes: flush well with water or saline Decontamination of clothing or equipment is unnecessary

Signs and Symptoms Diagnosis History Abrupt onset of symptoms Bitter almond odor on the breath Mild HCN cases Headache Vertigo Nausea

Signs and Symptoms Low HCN concentrations Apprehension, dyspnea, headache, vertigo and a metallic taste are seen initially Convulsions and coma may follow and can last for hours or days

Signs and Symptoms Low HCN concentrations Prolonged coma, residual CNS damage may be seen Irrationality, altered reflexes, unsteady gait Nerve deafness also possible

Signs and Symptoms High concentrations Throat constriction, giddiness, confusion, decreased vision, vice-like gripping of the temples, and pain in the back of neck and chest If unconsciousness follows, further exposure can be fatal within 2-3 minutes

Signs and Symptoms Lower but still lethal concentrations Immediate, progressive sense of warmth, visible flushing Prostration ensues Nausea, vomiting, headache, dyspnea and chest tightness Unconsciousness & asphyxia will follow

Signs and Symptoms Very high concentrations Main initial symptom: hyperventilation Loss of consciousness, convulsions, and loss of corneal reflex Death by cardiac and/or respiratory arrest

Signs and Symptoms Effects are slower to develop to lethal amounts via ingestion or skin exposure Victim can survive minutes Antidote could be given

Signs and Symptoms CK exposure produces symptoms of cyanide poisoning and lung irritants Eye exposure Lacrimation and blepharospasm Respiratory exposure Irritation of the nose and throat, cough, dyspnea, and chest tightness

Signs and Symptoms Exposures>50 mgmin/m 3 produce pulmonary edema, followed by collapse, coma and death Liquid CK can cause 2º and 3º skin burns

Laboratory/ Diagnostics Useful lab findings include: High anion gap metabolic acidosis Elevated lactate, methemoglobin, and urinary thiocyanate levels

Laboratory/ Diagnostics EKG Atrial fibrillation Ectopic ventricular beats Abnormal QRS waves with the T wave originating high on the R wave

Treatment Victims asymptomatic after several minutes require no oxygen or antidotes Administer supportive care, oxygen and antidotes Acute effects (convulsions, dyspnea) Acute exposure (unconscious but breathing)

Treatment Treat irritation effects of CK Wash eyes with a weak boric acid solution Apply soothing lotions/compresses Assess and treat burns as you would thermal burns Control hypoxia with O 2 supplementation Consider early use of IPPB, PEEP or intubation

Treatment For ingestions Initiate gastric lavage with water 1:5000 solution of potassium permanganate if available Antidotes dissociate the cyanide ion from cytochrome oxidase

Treatment Goal: create methemoglobin, which binds to cyanide to form cyanmethemoglobin Sodium nitrite Amyl nitrite 4-dimethylaminophenol-hydrochloride (DMAP)

Treatment Other antidotes Cobalt in the forms of dicobalt edetate or hydroxocobalamin also combines with cyanide ions Hydroxocobalamin Dicobalt edetate

Treatment Therapies are life saving: not curative Follow these antidotes with sodium thiosulfate to aid the clearance of cyanide as non-toxic thiocyanate

Long-Term Medical Sequelae Low doses: no long-term problems At near lethal doses: lower intellect, confusion, loss of concentration and Parkinsonism

Long-Term Medical Sequelae Chronic poisoning: ataxic neuropathy No specific data on developmental and reproductive effects, mutagenicity or carcinogenicity

Environmental Sequelae HCN is highly volatile, removed from the environment in less than an hour CK is less persistent

Summary Hydrogen cyanide (HCN) and cyanogen chloride (CK) Cyanide gases Military and terrorist potential Inhalation main route of exposure Decontamination is possible with soap and water but must be done immediately

Summary Cyanide inhibits aerobic respiration at the cellular level Symptoms are immediate Supportive care and antidotes are required