Anaphylaxis: Symptoms, Diagnosis and Treatment [Micro Lecture]

In today’s micro-lecture, Australian Paramedical College Hon. Snr. Lecturer Sam Willis talks about Anaphylaxis, how it affects so many people and how to manage it in paramedic practice.

In today’s session, we’re going to talk about what anaphylaxis is, how it comes to affect so many people in such a terrible way, and how you as a paramedic can manage this.

Now, some of you may be very familiar with anaphylaxis in terms of its mechanisms, how it differs between a normal allergic reaction and this life-threatening acute condition of anaphylaxis, and others may not be familiar with it at all.

In this short lecture, we’re going to try and talk in some detail about anaphylaxis because it is something that you are going to see in your role as a paramedic.

Now, anaphylaxis is a condition whereby it’s an over response of the body’s immune system to something that is usually quite harmless. Now, the reality is anaphylaxis is something that’s very complex when you start to look at the processes of how, for example, they call it the IgE, immunoglobulin E, allows activation of the mast cell, and therefore the signs and symptoms of anaphylaxis.

But we’re going to try and keep it as simple as possible because at this level you need to know what it is, how it occurs, and how you as the paramedic can treat it. But just be mindful, those of you going on to university to study this, you are going to study this in a such minute detail that you become the experts at this.

We’re going to recognize the key signs and symptoms of anaphylaxis. You’ve probably already got an idea of this anyway through the readings that you’ve already been doing. We’re also going to help you differentiate between anaphylaxis and other allergies and identify the management principles of anaphylaxis. Generally speaking, they are the same, but we’re going to talk to you about what that actually looks like when you have that patient in front of you and they are having that severe acute life-threatening reaction. Okay?

Why don’t you think about this? You’ve been dispatched to a male complaining of being allergic to nuts and accidentally being exposed to them at a party. He reports he does not have his EpiPen. On arrival at the address, you are greeted by a panicked male who is struggling to breathe and scratching all over. He’s itching. His eyes are beginning to swell, and his lips are blue.

Now, when you first get this call from dispatch, knowing what you know about anaphylaxis, you need to make sure that you treat it as a life-threatening emergency because not all cases that come through the dispatch triple zero system actually are life-threatening emergencies, even though you must treat them as so.

Now, anaphylaxis is one of those situations where they usually are acute medical emergencies that need a really fast and rapid but safe response form you guys.

Now, imagine being allergic to something that you know is going to have a life-threatening alteration. In other words, something that could kill you and knowing that you have to carry an EpiPen around with you at all times and the sheer shock and horror of knowing that you’ve been exposed to that allergen. In other words, something that’s external that can come into your body and trigger you, and you don’t have your EpiPen on you. That would cause a lot of fear. And usually not only for you but also for the people around you as well who are observing this and witnessing this.

On arrival at the address, you are greeted by a panicked male, and rightly so. You would be panicked if you can feel your throat swelling and closing because you’re going to start becoming hypoxic. Who is struggling to breathe and scratching all over. On top of your throat swelling and becoming constricted, so the smooth muscles inside your upper airways and lower airways becoming constricted, you’re also getting this massive mast cell reaction of antihistamine that causes swelling. In other words, your body tries to create a redness and swelling and overheating to try and kill whatever it is that’s causing you the problem. His eyes are beginning to swell because you get a shift of fluid from one place to the next, and the lips are blue, which is caused the hypoxia. That’s typically how a real-life anaphylactic situation goes.

Anaphylaxis is a life-threatening condition and is not just an allergic reaction. Now, just understand guys that allergic reactions are designed to protect you from something that is outside and potentially causing you harm. Now, there is actually a fine line between a serious allergic reaction and life-threatening anaphylaxis. My advice to you, which is what is supported in the literature, is that if you’re not sure which side you’re sitting on because of the signs and symptoms and your experiences, always treat it as a life-threatening allergic reaction. Don’t ever be … if you’re unsure, just treat it with the adrenaline and the airway management in the time critical nature. Don’t ever be too concerned.

Now, the reason we say that is because there is a documentation that paramedics under treat life-threatening emergencies with the adrenaline, they under treat it, because they’re scared of the drug adrenaline for some strange reason. Now, yes adrenaline does cause tachycardia, which you have to be mindful of, but also completes reverses all of the things that are going to kill your patient too.

We’ve already said that it’s an overreaction of the body’s immune system to something that is not a threat to the body. Now, anaphylaxis and severe allergies and asthma and life-threatening asthma and psoriasis and other types of immune system allergic manifestations, they’re all part of the same problem. It’s an overreaction of your body’s immune system. There’s a family here. Make sure you do do your history taking appropriately.

But it all comes to this cell here, the mast cell M-A-S-T. When you’re doing your homework, take a look at the mast cell because the mast cell, which is found around your joints and in skeletal muscle and in a whole range of other places, they’re floating around waiting to be exploded to try and help your body when in fact all they’re doing is actually causing your body problems.

Now, adrenaline really is the drug that reverses all of these problems, okay? Just be mindful that when you see this person with life-threatening problems, upper airway obstruction, they’re struggling to breathe, they’re cyanotic, they’re just about to go into arrest, the first thing is the intramuscular adrenaline. Yes, they need airway management too, but in my experience of using this, it’s always been the adrenaline first that has reversed this.

And this is just a diagrammatic representation of what we’re talking about here. Imagine this being the mast cell. This is the cell that’s got all the histamine and the interleukins and the prostaglandins, and all these are things that are in there. These are things you can learn about on your own time.

Now, imagine that this antibody has actually stuck on the wall of your mast cell and that it’s been activated by this thing here. This allergen has actually attached itself to the receptor. This is what we call a receptor or an antibody. The allergen has attached itself into the antibody, and as a result of these two mechanisms, you end up with what’s called the degranulation. In other words, this mast cell has exploded just like this, and what’s happening with this explosion is that all the internal substances, the histamine and everything that we’ve just talked about has exploded out of it.

Now, when we talk about adrenaline, adrenaline actually stabilizes all of this and puts it back into this condition here. Adrenaline is a wonderful drug that actually needs to be given pretty quickly.

When we talk about anaphylaxis and you say, “Well, what are the signs and symptoms?” Let’s go through these together. Swelling of the face, neck, and tongue. Now, collectively they’re called angioedema. Any type of swelling in or around the mouth is angioedema. Swelling of the face includes the eyes, the nose, and the mouth. There are some great Google images when you type in angioedema. Go and take a look to see how large the tongue actually can swell up to. The neck, you can get swelling of the upper airways. In other words, you get seriously tight constriction of the smooth muscle in the trachea. And we’ve talked about the tongue.

Pallor and blue lips due to hypoxia. Pallor just meaning pale face and blue lips. You know that your patient’s in trouble when you see that.

Now, yes, you should be giving an oropharyngeal tube as quickly as possible into the upper airway, but one you needs to be drawing up the drug and giving the drug intramuscularly, and the other paramedic, when you’re working as a pair, should be putting the OP tube in. And, of course, when the tongue gets so big and the air starts to struggle past the occlusion, you’re going to get the snoring noise.

Low blood pressure is something you’ll always find. Now, you shouldn’t be rushing for the blood pressure cuff straight away because you need to be treating airway, breathing, circulation, and within that comes the intramuscular injection. But you will find that one of the other things that mast cell contents do is to make your blood vessels little. Now, that’s designed to allow everything to flow to where it needs to flow to. It’s an actual purpose. But you also lose a lot of fluid through this mechanism, meaning that you’re going to end up with a low blood pressure. Of course again, adrenaline stops that function as well.

Difficulty in breathing as well. Not just noisy but also difficulty. In other words, hah, having problems with ventilation, hah. Swelling and tightness in the throat. The patient will actually report that. And difficulty talking as well. They won’t be able to talk, so don’t make your patient talk.

If you’re also going to be getting constriction in your lower vessels, you’re also going to end up with an expiratory wheeze, which is why we treat with salbutamol. Persistent dizziness and/or collapse. Dizziness due to the hypoxia. Pale we’ve also talked about, and floppiness in young children.

Now, here’s a summary of the treatment. Now, the reason these are just the principles is because when you have that patient in front of you, a step wise approach doesn’t actually work that well. When your patient is reporting to you that they’re allergic to nuts and they’ve had nuts, you need to be giving adrenaline quickly. Now, whether that’s an EpiPen that’s already an auto-injected pen that’s already been designed, already been drawn up. Fantastic. Or if you’re the paramedic and not just the first aider and you’re drawing up one milligram and one mil of adrenaline, it doesn’t really matter. Now, of course is going to work much quicker and much better than 300 micrograms because there’s 1000 micrograms in a milligram. Adrenaline really fast. And like I said before, if you can combine giving the adrenaline with the airway management, fantastic.

Consider salbutamol depending on your guidelines, but as we’ve said, you get constriction of the vessels of the smooth muscle in the upper airway so opening that’s really great.

Maintain the open airway. Once you’ve given the drug, prioritize on the head tilt chin lift and the oropharyngeal tube and suctioning where possible. And, of course, actively promoting communication once your patient’s recovering. Hello, medic, ambulance. You’ve had an allergic reaction. It’s the ambulance, Stay nice and calm. Just try and relax. And, of course, high flow oxygen to try and treat the hypoxia as well.

Once they’ve started to recovery, then you can do the secondary survey. Lots of reassurance. Lots of communication. Expose their chest to have a look at their work of breathing. Have a listen to their chest. Full set of vital signs. Remember what we talked about in previous lectures and in the workshops and everything you read around secondary survey what is included in the secondary survey.

And, of course, conveying to hospital due to the possibility of secondary events because adrenaline really does wear off around five minutes. It’s got a half life of about two to three minutes.

Okay, what we’ve talked about here guys is the signs and symptoms of anaphylaxis, the differences between anaphylaxis and other allergies. Now, just remember even though the purpose of this session wasn’t to talk in any detail about allergies. Your ambulance service will have guidelines as to what constitutes an allergy verus anaphylaxis, and if you’re only looking at an allergic reaction, then you’re not treating it with adrenaline unless you can’t differentiate because it’s on that more serious side, you can give nowadays piriton over the counter, antihistamines, and a whole range of other like chlorpheniramine. Your service will give you those things to treat them. On most occasions, you can discharge your patient on the scene depending on if there’s any signs of hypoxia or anything that’s not affecting A’s, B’s, and C’s. And we’ve talked in some detail about the management of the principles for anaphylaxis.

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