Pulmonary toxicology Flashcards
Examples of simple asphyxiants
N2, noble gases, methane, carbon dioxide
simple asphyxiant mechanism and symptoms
displace oxygen -> CNS symptoms and hypoxia
irritant mechanism of action
forms a chemical reactions as a reactive compound
H20 soluble irritant examples
ammonia, chlorine, sulphur dioxide
H20 soluble irritant symptoms
sensitisation in the upper respiratory airway
H20 insoluble irritant examples
oxides of nitrogen, phosgene
H20 insoluble irritant symptoms
lower respiratory tract -> pulmonary oedema and fibrosis
hydrocarbon aspiration symptoms
hypoxia, choking, dyspnea
acute lung injury, necrosis of epithelium, inflammatory cascade, loss of surfactant
methemoglobin inducer examples
nitrates, aromatic amines, chlorates
benzocaine, dapsone
methemoglobin inducer mechanism
Hb iron oxidised to Fe3+:
1. unable to bind to oxygen -> decrease oxygen transport
2. increases affinity for oxygen at other sites -> decrease release of oxygen
carbon monoxide mechanism
- bind to Hb -> impair delivery of oxygen
- bind to iron in myoglobin and mitochondria -> oxidative stress + lipid peroxidation + inflammatory cascade
cyanide mechanism
inhibit cytochrome oxidase -> O2 cannot act as final electron acceptor -> induce chemical suffocation of cell -> disrupt enzymatic processes
nitrite role in cyanide antidote kit
convert Hb to MetHB which has higher affinity for cyanide
sodium thiosulfate role in cyanide antidote kit
convert cyano-MetHB to sodium thiocynate to be removed from renal processes
paraquat toxicity
pulmonary fibrosis
