A SUDDEN COLLAPSE
History
Gregory is a 5-year-old boy who has been brought to the A&E department by ambulance after a friend’s parent dialled 999. While at their son’s birthday party he complained of tummy ache, started vomiting and then had profuse watery diarrhoea. He also became acutely wheezy and was struggling to breathe. His voice became hoarse and he was obviously scared. The ambulance crew report that when they arrived he was barely conscious, had severe stridor and markedly increased work of breathing. He is known to have asthma and eczema, both reasonably well controlled. His parents report that he had cow’s milk intolerance as a toddler, with vomiting and poor weight gain, and develops urticaria if he eats eggs. However, he has never had anything like this before.
Examination
Gregory is sitting up on the trolley with a salbutamol nebulizer in progress. There is obvious stridor with tracheal tug. His work of breathing is increased with subcostal and intercostal recession and he is using his accessory muscles of respiration. He is quiet but can say his name. His oxygen saturation is 92 per cent. His pulse is 160/min and his capillary refill time is 4 s. His heart sounds are normal. There is widespread expiratory wheeze. Abdominal examination is normal. He is flushed and his lips and face are swollen. He has widespread urticaria.
Questions
• The ambulance crew gave him life-saving drug treatment. What was it?
• How would you continue his immediate management?
• Once he has recovered, what investigations would you undertake?
Medicine
Gregory has had an acute anaphylactic reaction – presumably to something he ate at the party. The emergency drug treatment of anaphylactic shock is intramuscular 1/1000 (1 mg/mL) adrenaline (see Table 96.1). All health care professionals involved in procedures that could cause anaphylaxis, e.g. practice nurses giving immunizations, are trained to give this as first line. They do not need to wait for a doctor’s prescription.
Table 96.1 Dose of intramuscular adrenaline (epinephrine) for anaphylactic shock (UK Resuscitation Council)
Age Dose ( g) Volume (mL) 1/1000 adrenaline
Under 6 months 50 0.05
6 months–6years 120 0.12
6–12 years 250 0.25
12–18 years 500 0.5
The management of acute anaphylaxis is essentially ‘ABC’ – airway, breathing, circulation. Oxygen should be administered at all times. The stridor is evidence of upper airway obstruction and the wheeze indicates lower airway obstruction. If the stridor and respiratory distress are severe, he should receive nebulized adrenaline, repeated if necessary. If the stridor does not improve, the anaesthetist should be called. In severe cases, an ENT surgeon will also be required. Intravenous hydrocortisone will also help the stridor and wheezing but may take a few hours to work. Nebulized salbutamol should be continued as necessary to treat the acute bronchoconstriction. He is flushed and has urticaria and is therefore peripherally vasodilated. His capillary refill time is prolonged. His blood pressure should be measured. He should receive a 20 mL/kg bolus of intravenous 0.9 per cent saline plus a dose of antihistamine, e.g. chlorpheniramine. Once he is stable, further history should be obtained to try and identify the culprit food. Skin-prick tests and/or total IgE and RAST (radioallergosorbent test) to specific foods should be requested (but these need to be done a week or more after the last administration of an antihistamine or steroid). Peanuts and nuts are hidden in many foodstuffs and would be high on the list. Lifelong exclusion is required but inadvertent ingestion is a risk. He will need to have available at all times a pack for self (or carer) administration of intramuscular adrenaline from a pre-assembled syringe and needle, e.g. Epipen. Most importantly his family need advance instruction on how to use it. They should also have a supply of oral antihistamine. If he is found to be allergic to a specific food he will need referral to a dietician for specialist advice. Self-administered adrenaline is indicated for all those with a definite history of anaphylaxis and in children with asthma on inhaled steroids who have less severe reactions because they are at greater risk of anaphylaxis. Routine prescription for all children with a history of a peanut or nut allergy is controversial. Mild reactions to foodstuffs are very common and avoidance is the key.
KEY POINT
• Intramuscular adrenaline is the first-line treatment for acute anaphylaxis.
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