What are the 5 Possible Clinical Pathways for a Patient with Anaphylaxis?

Anaphylaxis is a severe and potentially life-threatening allergic reaction that can present in various ways. There are five primary clinical pathways that anaphylaxis can follow. However, it is important to note that a patient may start on one pathway and then transition to another.  

What Happens During Anaphylaxis? 

When anaphylaxis occurs, there is an uncontrolled and excessive release of the mediators of inflammation from the granules of the mast and basophil cells in the human body which triggers the anaphylactic cascade. In response, the individual releases other chemicals such as adrenaline, angiotensin II, and endothelin I to combat the anaphylaxis. It is like an internal war starts within the patient. Of course, we can also incorporate our own medical management into this battle.

The outcome of this internal war depends on several factors, including:

• The amount of the mediators of inflammation that are released
• The timeframe over which they continue to be released
• The rate at which they are broken down and
• The overall health of the patient

As a result, the situation is often in a state of constant flux.

Another crucial point to consider is the rapidity of onset and progression that can occur. In a clinical setting, when death does occur, the mean time to death is 5 minutes¹. This means that you need to be prepared to manage any one of the 5 pathways at the beginning of anaphylaxis.  

The 5 Potential Clinical Pathways

The five clinical pathways for a patient experiencing anaphylaxis are:

1. Self-Limiting Anaphylaxis 

This occurs when the patient wins the battle and effectively counteracts the mediators of inflammation internally without medical intervention.  This is still anaphylaxis, however, and the patient must be managed with observation, management plans, adrenaline autoinjector prescriptions, and referral to an immunologist; the same as for any of the other anaphylaxis pathways. 

2. Simple Anaphylaxis 

This is what many healthcare professionals associate with anaphylaxis. The patient is diagnosed, given a single dose of intramuscular adrenaline, the anaphylaxis resolves, and the patient gets better. 

3. Complex anaphylaxis 

Here, the patient either doesn’t respond to a single dose of adrenaline or only partially responds. This is where additional measures are needed which may include:

• Multiple doses of intramuscular adrenaline
• IV fluid replacement
• IV adrenaline infusion
• Nebulized adrenaline
• Nebulized salbutamol
• IV Glucagon (if a beta blocker is present)

Management here, when outside of a main hospital, needs to be under the supervision of an ED or ICU specialist who, if not physically present, may be on the phone. Management may need to be performed within the healthcare professionals’ own setting depending on the rapidity and severity of the progression of the anaphylaxis and the availability (or not) of paramedics to attend due to their many competing emergencies.

With complex anaphylaxis management it is essential that you have prior training in the potential management options.

This is best done in 2 separate parts. The first is by undergoing comprehensive education in advance, so that you are aware of the management strategies you may be called upon to undertake. I undertake this education in the various courses in my Understanding Anaphylaxis Training for Healthcare Professionals. Click here for further information on our comprehensive course

The second follows on from the first and is to undertake any relevant in-service training you require for practical skills. During an emergency is not the time to update or practice long-forgotten skills. Having a comprehensive education will allow you to recognise which in-services are appropriate for you in advance.

What you can and cannot do will depend on your skill set. For example, if you have intravenous access for your patient, you will be able to perform more of the complex management procedures than if you do not. That being said, there are certainly additional measures available without IV access.

It is also important to note that there are special considerations here for paediatrics and the pregnant patient

4. Overwhelming anaphylaxis (cardiac arrest)

This occurs when the patient is no longer able to compensate for the effects of the mediators of inflammation and has either a cardiac (most common) and/or a respiratory arrest. Again, management outside of a main hospital is best performed under the supervision of an ED or ICU specialist.

The protocols for CPR apply here; however, there are some very important differences:

• Firstly, this patient needs aggressive fluid replacement and adrenaline administration as per the advanced life support protocol.
• Secondly, basic breathing techniques are often successful in these cases
• Thirdly and very importantly, this patient qualifies for a prolonged resuscitation as they started out well.
  
  

5. Biphasic anaphylaxis

In up to 20% of cases, the anaphylaxis, once treated, re-occurs without any further exposure to the allergen. This is called the biphasic response, and it can manifest in any one of the above scenarios. Management of the biphasic response starts from scratch, all over again! 

Management Steps for Anaphylaxis

To effectively manage these five potential clinical pathways, there are seven prescribed steps in the management of anaphylaxis². The ASCIA Guidelines for Health Professionals: Acute Management of Anaphylaxis is the peak body protocol³

It is important to note that the management that I reference is appropriate for Australia and New Zealand only. Other areas may have their own management protocols that are appropriate for them to follow. My courses and resources are also only suitable for healthcare partitioners working in Australia and New Zealand.  

Please click here to download a copy of the 7 steps and my complementary Anaphylaxis Management form, which is a valuable resource which is designed to assist you in managing anaphylaxis.

How do I manage anaphylaxis?

When managing a patient with anaphylaxis, I always prepare for the worst and am appreciative if it does not occur. I approach each case with urgency, treating every instance as though it could imminently lead to a cardiac arrest, rather than adopting a "wait and see" attitude.

The critical aspect of management is to halt the progression of anaphylaxis before it gains momentum, as it becomes significantly more challenging to control once fully underway. This requires rapid diagnosis, prompt administration of adrenaline, and continuous monitoring of the patient's condition for any changes.

The old scout motto, "Be Prepared," perfectly encapsulates the approach to managing anaphylaxis.

For those looking to understanding how to manage anaphylaxis, click here to enrolling in my Anaphylaxis Management Courses. These online, guideline-based courses provide in-depth training, practical strategies and 19 real case studies to better equip you with the knowledge needed to respond effectively to any of the 5 possible anaphylaxis clinical pathways.

Writen By 
Dr Sue Flanagan