Carbon Monoxide and Cyanide Poisonings

1. Carbon Monoxide and Cyanide Poisonings Working Version of Tutorial Presentation, Authors: MUDr. Petra Smolková, Clinic of Occupational Medicine, Faculty Hospital and Palacky University Olomouc

2. Carbon Monoxide Poisoning, Occupational Exposure boiler-rooms, coceries, thermal powerstations carbon monoxide colourless odourless gas product of incomplete combustion

3. Mechanisms of Toxicity toxicity inhalation 200-300x higher binding capacity to hemoglobin than oxygen development of carboxyhaemoglobinemia ? hypoxy, hypocapnia (=diminished oxygen-carrying capacity of the blood) oxyhemoglobin dissociation curve (is shifted to the left) ? impairment of oxygen delivery to tissues cytochrome oxidase ihibition

5. Clinical Symptoms immediate features headache, nausea, irritability, weakness, tachypnoea intermediate features dizziness, ataxia, agitation, impairment of consciousness, respiratory failure in seroius cases cerebral oedema, metabolic acidosis (less common) skin blisters, rhabdomyolysis, acute renal failure, pulmonary oedema, myocardial infarction, retinal haemorrhages, cortical blindness... late features neuropsychiatric features (after a few weeks), memory impairment, disorientation, apathy, inability to concentrate, personality changes, parkinsoninsm, incontinence ? very often total recover of symptoms within a year (or subtotal)

6. Indication of Severity acute neurological signs coma need for ventilation ECG changes acidosis initial carboxyhaemoglobin > 30 %

7. depends on the carboxyhaemoglobin level: 10% - light concentration impairment 20% - mild headache, vertigo 30% - headache, vomiting, dyspnea, fatigue 40-50% - persistent headaches, fuzziness, consciousness disorders, coma > 60% - deep coma, death

8. Treatment removal from exposure maintain a clear airway and ventilation oxygenotherapy (oxygen in as high amount as possible) transfer to hospital (serious states) metabolic acidosis correction (by oxygenotherapy) mannitol (if cerebral oedema is suspected) ECG monitoring measurement of carboxyhaemoglobin concentration > 30 % - severe exposure less than 30 % do not exclude significant poisoning!!! look for extrapyramidal features and retinal haemorrhages to assess the severity of CNS damage (in pacients with unconsciousness in anamnesis) controversial role of hyperbaric oxygen therapy...

10. Cyanide Poisoning, Professional Exposure hydrogen cyanide (HCN) and its gas, salts – potassium and sodium cyanide (KCN, NaCN); nitriles (R-CN) – solvents, manufacture of plastics industrial sources metal and ore treatment, processing, printing, electroplanting, photoengraving, electronics, production of acrylics, plastics, nylon, petrochemical industry fumigants, rhodenticides acrylic nail remover and metal polishes! combustion of polyurethane, rubber, nylon... tobacco smoke! drugs (sodium nitroprusside) natural sources cassava, some types of grasses, flax, lima beans, linseed

11. Mechanisms of Toxicity toxicity soluble salts are more toxic (NaCN, KCN, CaCN) ingestion of cyanide salts – hydrogen cyanide is producted by the contact with hydrochloric acid in stomach gas inhalation toxicity occures within a few seconds of HCN, death in minutes ingestion of soluble cyanide salts toxicity within minutes, absortion can cause toxicity for several hours dermal exposure large surface, onset may be delayed (several hours), epidermal necrosis eye exposure

12. lethal dosis for hydrogen cyanide is 50 mg, sodium/potassium salts – 150 – 300 mg cell breathing blockage (cytochromeoxidase), leads to metabolic acidosis, production od lactate, hypoxemia, venous blood is bright detoxication (in the organism): ionic binding with sulphur (with thiosulphate sulofontranspherase) to almost nontoxic thiocyanate

13. Clinical Symtoms acute poisoning: cyanide, cyanogen chloride, acetonitrile, other cyanide releasing substances: ingestion/inhalation, large amounts: cyanide concentration > 3 mg/l immediate unconsciousness convulsions death in 1 – 15 minutes ingestion/inhalation/ skin absorption, moderate amounts: cyanide concentration 1 – 3 mg/l dizziness, tachypnoe, vomiting, flushing, headache, drowsiness, hypotension, rapid pulse, unconsciousness death in convulsions in 4 hours (sodium nitroprusside – 12 hours) ingestion/inhalation/skin absorption, small amounts: cyanide concentration < 1 mg/l nausea, dizziness, drowsiness, hyperventilation, anxiety

14. acute poisoning: acrylonitrile, inhalation nausea, vomiting, diarrhoea, weakness, headache, jaundice absence of blood cyanide concentration – poisoning suggest: lactate > 7 mmol/l, elevated anion gap acidosis, reduced arteriovenous oxygen gradient

16. Treatment based on the affinity of cyanide ion to methemoglobin - antidotes: first aid clear airway, ventilation 100 % oxygen to all victims pulse, blood pressure, respiratory rate, oxygen saturation, cardiac rhythm monitoring rapid transfer to hospital

17. mild poisoning asymptomatic and mildly symptomatic patients observation at least for 6 hours (ingestion of cyanide salt) or 12 hours (ingestion of acetonitrile) natrium thiosulphate

18. moderate and severe poisoning critical care antidote therapy is necessary (if started in pre-hospital care the admitting hospital must be informed) I. grade immediately inhalation of amylium nitrosum (? methemoglobinemia cca 5 %) hydroxycobalamine inj. 4 – 10 g i. v. or 4-DMAP inj. (3,25 mg/kg), causes methemoglobinemia 30 % II. grade natrium thiosulphate inj., 4 – 12 g i. v. (could be administred without additional antidotes in mild poisonings) III. grade only at a case of a definet cyanide poisoning can be administred cobalt EDTA (Kélocyanor) – associated with severe allergic reactions correction of hypotension (legs elevation, expanding the intravascular volume) treatment of convulsions

19. Literature Fialová J. Vybrané kapitoly z nemocí z povolání II. Profesionální intoxikace. Vydavatelství Univerzity Palackého, 2000. 51 p. Pelclová D et al. Nemoci z povální a intoxikace. Univerzita Karlova v Praze – Nakladatelství Karolinum; 2nd edition, 2006. 207 p. Smedley J, Dick F, Sadhra S et al. Oxford Handbook of Occupational Health. Oxford University Press; 1st edition, 2007. 932 p.

20. Some cyanide, please... THANKS FOR YOUR ATTENTION!