Dealing with emergencies in general practice:  Anaphylaxis

Recognising and responding promptly to anaphylaxis can make the difference between full recovery and fatality, so practice nurses should familiarise themselves with signs, symptoms and emergency treatment

Approximately 20 people will die every year from anaphylaxis so in 2011, the National Institute for Health and Care Excellence (NICE) produced guidelines on the identification and management of anaphylaxis.¹

Anaphylaxis is a severe allergic reaction which involves both circulatory and respiratory changes, often accompanied by skin changes. It can be fatal if not diagnosed, addressed and treated quickly and correctly. According to the Anaphylaxis Campaign2 the main signs and symptoms of anaphylaxis include:

• Generalised flushing of the skin
• Urticaria
• Breathlessness
• Sense of impending doom
• Swelling of throat and mouth
• Alterations in heart rate
• Gastro-intestinal symptoms
• Hypotension
• Collapse and unconsciousness

The Resuscitation Council has suggested that anaphylaxis can be recognised by the following ABC criteria:³

• Life-threatening Airway and/or Breathing and/or Circulation problems
• Skin and/or mucosal changes (flushing, urticaria, angioedema) in up to 80% of cases
• Sudden onset and rapid progression of symptoms

The Council suggests that exposure to a known allergen for that patient will further support the diagnosis.

PATHOPHYSIOLOGY

When an allergen is detected by the body, immunoglobulin E (IgE) binds with it which then activates mast cells and basophils. This leads to degranulation and the release of histamine, leukotriene and prostaglandin amongst other substances. These mediators lead to contraction of bronchial smooth muscle, causing bronchoconstriction. The effect of the mediators on the cardiovascular system leads to bradycardia, vasodilation and hypotension.

RECOGNISING ANAPHYLAXIS

According to the World Allergy Organization,⁴ anaphylaxis can be diagnosed primarily by the presence of skin or mucosal changes plus hypotension and/or dyspnoea. However, other symptoms such as vomiting or diarrhoea may also occur.

ASSESSMENT AND DIFFERENTIAL DIAGNOSIS

It can sometimes be unclear initially if a patient is sufffering from an anaphylactic reaction or has simply fainted. In Dr Jones's case, he had become unwell within minutes of eating sushi and the history of previous allergic reaction to fish and the presentation of facial flushing, urticarial, dyspnoea and collapse soon after exposure to an allergen would be compatible with anaphylaxis. However, the case of the practice manager was slightly different — she had signs and symptoms that were more compatible with a faint, such as pallor and sweating after exposure to emotional distress and she would require completely different management.

IMMEDIATE MANAGEMENT OF ANAPHYLAXIS

The patient can be cared for in the most comfortable position for them. If breathing is impaired sitting upright may help; low blood pressure and collapse may be better addressed by having the patient lying flat, possibly with legs elevated. Dr Jones's attempt to leave the room could have had disastrous consequences as standing during anaphylaxis may be linked to an increased risk of cardiac arrest.⁴ The most important intervention at this stage is to give adrenaline (epinephrine) intramuscularly as soon as possible. [See box for dosage] If there is any doubt about the diagnosis but anaphylaxis is suspected, adrenaline should be administered without delay as there is potentially more harm from not giving adrenaline in a person who is having an anaphylactic reaction than giving a dose of adrenaline to someone who is not. Anaphylaxis can be fatal so immediate assessment of the patient's airway, breathing and circulation should be carried out and a 999 call should be made, stating that the patient is having an anaphylactic reaction. Life support should be carried out as necessary.⁵ If possible and practical, blood pressure, pulse oximetry and ECG can all be monitored.

While Dr Smith called the ambulance, the practice nurse had located a vial of adrenaline, a needle and syringe in the emergency kit and administered this immediately. Within a few minutes, Dr Jones started to respond. Meanwhile, the practice manager had already regained consciousness and was feeling much better, albeit somewhat embarrassed at all the fuss. As Dr Jones's condition started to improve, he too felt embarrassed at the turn of events. He stated that as he felt much better and he knew why the episode of anaphylaxis had occurred, the paramedics were unnecessary and he would require no further follow up.

ONGOING CARE

The NICE guidelines on anaphylaxis are quite clear that any patient who has suffered an anaphylactic reaction should be reviewed in secondary care immediately following the event. This is because of a phenomenon known as the late allergic response, which can lead to something called a biphasic anaphylactic reaction, where the initial event is followed by another reaction several hours later. For this reason it is vital that the patient who has had an anaphylactic reaction is seen in hospital even though they seem to have made a full recovery. This observation should continue for 6-12 hours following the onset of symptoms. A record should be made of the event and any possible cause. In the case of a suspected drug reaction this will need to be reported as an adverse event using the yellow card scheme at http://yellowcard.mhra.gov.uk/ .

The Anaphylaxis Campaign has a care plan for patients who are newly diagnosed; this could be useful to have in schools or workplaces or for individuals to keep on them. Amongst other things, this care plan discusses the role of automatic injection pens in anaphylaxis.

INJECTION DEVICES

There are three types of pen available in the UK"”the Anapen, the Epipen and the Jext pen. They are all activated via a spring loaded mechanism which allows a single measured dose of adrenaline to be delivered when pressure is applied. The Jext pen also has an integrated needle shield to protect against sharps injury. The EpiPen and Jext come in a 0.3mg dose suitable for adults and children over 30kg. The 0.15mg dose is suitable for people who weigh between 15kg and 30kg..

The Anapen is produced in three strengths. Anapen 500 is approved for patients weighing 60kg or more, Anapen 300 is recommended for people weighing 25-60kg and Anapen Junior 150 is recommended for children weighing 15-25kg.

Patients who are given pens to use in the event of an emergency should also be given education regarding the recognition of anaphylaxis, use of the pen, and advice on seeking further medical help.

SUMMARY

Anaphylaxis is a severe allergic reaction with life-threatening symptoms which may compromise the airway and breathing causing bronchospasm with tachypnoea; it may also affect the circulation leading to hypotension and/or tachycardia and possible collapse. Other signs and symptoms include urticaria, itching and nausea. Immediate recognition of the possibility of anaphylaxis is vital so that the correct treatment can be initiated without delay. Other conditions which may mimic anaphylaxis include fainting and panic attacks. Once the diagnosis has been made, adrenaline should be given without delay and an ambulance should be called. Life support should be commenced if required. Adrenaline can be repeated if there is no response. All patients should be seen in hospital post anaphylaxis even if they have fully recovered. Referral to an allergy specialist is then recommended. Ongoing education should then be provided and this should include advice allergen avoidance and the use of automatic injectable devices for adrenaline.

REFERENCES

1. NICE. Anaphylaxis. NICE clinical guidelines 134. 2011. Available at: http://guidance.nice.org.uk/CG134 Accessed April 2013

2. Anaphylaxis Campaign. Anaphylaxis signs and symptoms. 2012. Available at http://www.anaphylaxis.org.uk/what-is-anaphylaxis/signs-and-symptoms#1 Accessed April 2013

3. Resuscitation Council UK. Emergency treatment of anaphylactic reactions: Guidelines for healthcare providers. 2012 update. Available at http://www.resus.org.uk/pages/reaction.pdf Accessed April 2013

4. Simons FE, World Allergy Organization. World Allergy Organization survey on global availability of essentials for the assessment and management of anaphylaxis by allergy-immunology specialists in health care settings. Annals of allergy, asthma & immunology 2010;104(5):405—12.

5. Bostock-Cox B. Emergencies in general practice. Practice Nurse 9 November 2012;42(17):22-25