Anaphylaxis

Question 1

You have been called to see a patient on the Acute Medical Unit. The nurse is concerned that the patient has worsening shortness of breath and is wheezy. The patient was admitted earlier in the day with cellulitis. IV antibiotics have been prescribed and the nurse has just given the patient their first dose. The patient’s blood pressure is currently **110/64 **with a HR of 96.

How would you respond to this call?

Answer 1

If still on the call, I would ask the nurse to stop the antibiotics immediately. I would be mainly worried about anaphylaxis 2nd to antibiotics.

A
- Ensure patent airway, if alert and talking, can assume so
- Be mindful that this can change quickly if anaphylaxis
- If tongue or throad swelling, stridor, hoarse voice, airway oedema - put out an **arrest call **immediately - pt will likely will need intubation

B
- Monitor SpO2, RR
- Give high flow oxygen via NRB, aim for 94-98%
- Look for increased work of breathing, wheeze, cyanosis, falling SpO2
- Auscultate chest, scenario said wheezy, so I would look for bilateral air entry and wheeze

C
- Look for signs of shock: pale / clammy/tachycardia/hypotension
- Monitor HR and BP and ask the nurse to repeat this continually (cardiac monitor)
- 12-lead ECG
- Establish IV access (large bore cannula)
- Give IV fluid challenge if hypotensive (500-1000)

D
- Assess blood sugar, temperature
- GCS/AVPU

E
- Expose appropriately and check for any signs of an urticarial rash and oedema or mucosal changes

Ask for any allergies, review patient’s allergies

Question 2

Give your differential diagnoses for the patient’s symptoms

Answer 2

1. Anaphylaxis
2. Acute asthma
3. Bronchitis
4. Hereditary angioedema
5. ACE inhibitor-induced angioedema
6. Cardiac wheeze (2nd to pulmonary oedema)
7. Pulmonary eosionophilia

Question 3

The patient is able to inform you that he is allergic to penicillin. He has been given an IV dose of 2g flucloxacillin. How you manage this patient?

Answer 3

Stop the ABx if not stopped yet

Reassess ABCDE

If signs of airway compromise, put out an emergency call immediately and put on a high flow O2 via NRB.

I would look for signs of shock, give IV fluids

I would then give IM adrenaline to the anterolateral aspect of the thigh

Repeat ABC

Give another IM adrenaline after 5 minutes if needed
Repeat IV fluid bolus

If no improvement despite 2 doses of IM adrelinaline&raquo_space; follow REFRACTORY ANAPHYLAXIS ALGORITHM

Antihistamines are considered a third-line intervention and should not be used to
treat Airway/Breathing/Circulation problems during initial emergency treatment.

Corticosteroids (e.g. hydrocortisone) are no longer advised for the routine
emergency treatment of anaphylaxis

Question 4

Despite your initial treatment with IM adrenaline, the pt continues to deteriorate. There is evidence of stridor and the patient is now hypotensive at 86/52 with a HR of 130 despite fluid challenge.

Answer 4

As mentioned, I would have put out a call when first signs of airway compromise. If there were not, I would put out an arrest call now.

The patient will need to be intubated urgently

• Give IM adrenaline every 5 min until adrenaline infusion started
• IV fluid boluses

If the patient would go into cardiorespiratory arrest, start CPR and follow the ALS resuscitation pathway

Question 5

What features suggest acute life threatening anaphylaxis?

Answer 5

• Airway: swelling, hoarse voice, stridor
• Breathing: wheeze, SOB, respiratory arrest
• Circulation: pale, clammy, tachycardia, cardiac arrest, shock

Question 6

What are some common causes of anaphylaxis?

Answer 6

• Drugs and IV infusions - antibiotics, blood products, contrast mediums
• Insect bites
• Food - e.g. nuts, sea food
• Other common causes: latex, hair dye

Question 7

How could this patient’s airway be maintained in an emergency situation when intubation is not immediately possible?

Answer 7

An emergency cricothyroidotomy can be performed in an emergency setting where intubation fails or cannot be undertaken.

A 14G needle and insufflation with 100% oxygen can be used as a temporary measure until a definitive airway can be achieved.

Question 8

The patient is intubated and taken to ITU. Fortunately, the pt makes a good recovery. The patient’s penicillin allergy had been documented on the admission documents but not on the drug chart. How should this be managed?

Answer 8

• Duty of candour towards the patient
  Make aware of the error and apologise
• Clinical incident form / datix filed
• Highlight to the team

Question 9

How would you class anaphylaxis as a hypersensitivity reaction?

Answer 9

Anaphylaxis, atopy and asthma attacks = type 1 hypersensitivity reaction
* IgE mediated
* Fast response in minutes, rather than hours or days
* **Activated mast cells degranulate **and result in the secretion of pharmacologically active mediators (histamine, leukotrienes and prostaglandings) that act on the surrounding tissue
* Principal effect&raquo_space; vasodilation and smooth muscle contraction

Question 10

You put out an arrest call for this patient. Please demonstrate how you would communicate the situation to the resuscitation team as they arrive.

Answer 10

S – This 56 year old male is having a likely anaphylactic reaction to penicillin.

B – He was admitted with cellulitis earlier today and started on flucloxacillin despite a known penicillin allergy.

A – He has developed stridor and hypovolaemic shock. He has received a stat dose of adrenaline and is on high flow oxygen and IV fluids.

R – He needs definitive airway management and admission to ITU. He is at risk of cardiac arrest.