Anaphylaxis is an acute hypersensitivity reaction to substances to which the patient has been previously sensitised. These may be sera, local anaesthetic solutions, penicillin or other allergenic substances. Prevention is best effected by ensuring that all those with a history of allergy, asthma or hay fever do not receive drugs known to cause such reactions, particularly by injection.
Signs and symptoms
These usually begin within half an hour of introducing the foreign substance. The reaction is characterised by urticaria, particularly at the site of injection, by cyanosis, and dyspnoea due to bronchospasm and oedema, by sweating and a general feeling of faintness. These are accompanied by a raised pulse, a fall in blood pressure and the onset of circulatory collapse and death'.
This consists in laying the patient down with their feet well up, maintaining the airway and injecting at once 0.5-l- ml of adrenaline 1 :1,000 solution by intra-muscular injection. This should raise the blood pressure and dilate the bronchi. Where the hypotension persists, a further dose 10 minutes later using a different limb is given. Antihistamine (chlorpheniramine) given by slow intravenous injection may be helpful. The blood pressure is checked repeatedly and if hypotension is persistent an intravenous saline drip may be required.
Anaphylaxis shock Mx Protocol
Anaphylacxis Associated with Anesthesia
Mechanism Of Anaphylaxis
Use Of Epinephrine In Anaphylaxis
Features And Mx Of Anaphylaxis