Updated: Jan 22, 2022
In the previous article, I talked about the physiology behind the signs and symptoms that we see in Anaphylaxis.
Let us talk about the management and prevention of Anaphylaxis.
In any emergency, the first priority is to make sure that blood circulation, airway and breathing is fine so that there is no permanent brain damage or death of the patient.
In anaphylaxis, blood circulation and airway are of major concern.
Because of generalised vasodilation and increased vascular permeability, there is hypotension leading to shock.
Because of upper (Laryngeal Edema) and lower (Bronchospasm) respiratory blockage, there is hypoxia. This hypoxia, if present for a longer duration, will lead to IHD and death.
So, when Anaphylaxis is suspected, we need to administer a drug that can counter these two aspects of Anaphylaxis.
Epinephrine is one drug that causes immediate vasoconstriction and it is also a potent bronchodilator.
Vasoconstriction caused by Epinephrine prevents further progression of edema and hypotension.
Remember, I said it prevents further progression of edema. It does not reverse it.
So, if there is laryngeal edema then we will have to manage it surgically (more on this later).
If there is marked hypotension then it has to be managed with administration of IV fluids such as Normal saline.
Epinephrine being a potent bronchodilator will lead to dilation of bronchioles, hence reversing bronchospasm caused by anaphylaxis.
Also, Epinephrine causes decrease in release of the chemical mediators from the mast cells.
Epinephrine is the only drug that addresses and (to some extent) reverses the life-threatening aspects of anaphylaxis.
Hence, Epinephrine is the drug of choice for management of Anaphylaxis.
Multiple studies have shown that it is crucial to administer Epinephrine as early as possible. A delay in administering Epinephrine increases the chances of death.
Once the circulation and airway are stabilized, then we move to the definite management of anaphylaxis with drugs like Antihistamines, Steroids, IV fluids and Oxygen.
Let us enumerate the steps in the management of Anaphylaxis.
Once you have diagnosed the emergency as Anaphylaxis, ask your assistant to call for Emergency Medical Services, then you go on to manage the emergency while the EMS in on their way.
Position of the patient depends on his level of consciousness.
If conscious - any comfortable position with legs elevated.
If unconscious - supine with legs elevated.
IM Inj. Epinephrine 0.3 ml 1:1000 (0.15 for children). Preferred site for intramuscular epinephrine is Vastus lateralis.
If no improvement within 10 mins, administer another dose. Usually one or a maximum of two doses are required.
Additionally Epinephrine Auto-injectors are also available which are ready to use and easier to administer.
If there is laryngeal edema then you will have to perform an Emergency Cricothyrotomy to facilitate air exchange in the lungs.
Watch this video to know about Cricothyrotomy in details.
Once the patient stabilizes, he will have the signs and symptoms of Fight or Flight Response like anxiety, restlessness, headache, dizziness, palpitations, pallor, and tremor.
Then we move to the other definitive drugs as mentioned below.
Bronchodilator (Albuterol, Salbutamol) via inhaler is used to further improve the air exchange in case of bronchospasm.
Administer Oxygen - At a flow rate of 15 liters/minute to increase oxygen saturation in the blood.
IV Corticosteroids (100 mg hydrocortisone sodium succinate) - to reduce the edema (Angioedema, laryngeal edema)
IV Anti-histaminic (50 mg diphenhydramine or 10 mg chlorpheniramine) - to prevent further progression of the signs.
Antihistaminics cannot be used in place of Epinephrine as they just prevent further progression of the symptoms and does not reverse them.
Administering Intravenous Antihistaminics is not an option as their rapid infusion will lead to further worsening of hypotension.
Also, these oral antihistaminics take 30-40 minutes for the onset of action, which is way too much while managing a life threatening emergency.
Also, Monitor vital signs like blood pressure, heart rate, oxygen saturation and respiratory rate, all throughout the emergency.
The only way to prevent anaphylaxis is to avoid exposure to the allergen.
And to avoid exposure to the allergen, one should know about the allergy.
For that a thorough medical history is important.
If the patient is visiting your clinic for the first time then ask if he has received local anesthesia injection in the past.
If he had been exposed to local anesthesia in the past then ask about his experience, whether he had any adverse reaction or not. Also ask about the number of times he has received local anesthesia.
As we know that allergy symptoms develop after the first exposure, so the patient would not experience any symptoms of allergy at the first instance he received local anesthesia.
Hence, always check for allergy by Intradermal injection at the first and second instance of the patient receiving local anesthesia.
Intradermal Allergy test involves injecting 0.1 ml drug just below the skin epithelium (in this case Local Anesthetic solution) and then wait for the signs of allergy to appear at the site of injection.
Even during Intradermal allergy test, you should be well equipped and prepared to manage Anaphylaxis.
Remember, Anaphylaxis is not dose dependent. It can occur even with a test dose of 0.1 ml.
So now you know what anaphylaxis is and how to prevent it.
Let me know in the comment section, whether you have experienced any such complication and how you managed it.
Also, do let me know what topics would you want me to write about next. The topics can be from local anesthesia, Oral & Maxillofacial Surgery or Medical emergencies.