Introduction
Poisons are chemical or physical agents that produce adverse responses in biological systems.
Poisoning on the other hand is the ingestion by, or exposure of a patient to excessive doses of a medicine or other substances that may cause harm.
Carbon monoxide poisoning results from inhalation of smoke, car or generator fumes caused by incomplete combustion in a confined space.
Carbon monoxide reversibly binds to
haemoglobin, myoglobin and mitochondria, inhibiting cellular respiration
Clinical features of carbon monoxide poisoning
- Respiratory system: Dyspnoea
- Tachypnoea
- Headache
- Emotional liability
- Confusion
- Impaired judgement
- Clumsiness
- Syncope
- Nausea, vomiting and diarrhoea may occur
- Ischaemic chest pain,
- Arrhythmias,
- Heart failure and hypotension may occur
In severe poisoning:
- Coma and cerebral oedema may occur
- Pulmonary oedema
- Respiratory depression
- Cherry-red colour of skin and mucus membranes (rarely cyanosis)
Investigations
- Full Blood Count and ESR
- Serum Urea, Electrolytes and Creatinine
- Liver function tests
- Acid-base status.
- Blood gases
Non-drug treatment
- Remove from carbon monoxide exposure, move to fresh air
Drug treatment
- Oxygen administration: face mask in conscious patients and endotracheal intubation in comatose patients after clearing the airways
- Treat hypotension & arrhythmia
- Mannitol (10-20% ; 250 ml intravenously over 30 minutes. May repeat every 8 hours)