Presenting Complaint:

Jo has developed acute shortness of breath, wheezing, generalised itching, and facial swelling shortly after receiving IV antibiotics.

Allergies:

• NKDA .
• No known food allergies.

Proceed straight into A-E examination and management.

A-E examination:

General inspection

• Alert but anxious and distressed.
• Flushed with periorbital and lip swelling.
• Audible wheeze and difficulty speaking in full sentences.
• Urticarial rash over limbs and trunk.
• Penicillin IV drip running.

Airway

• Partially patent, stridor developing.
• Tongue mildly swollen.

Interventions

• Immediately stop and disconnect IV antibiotic infusion.
• Immediately administer adrenaline IM 500 mcg / 0.5ml of 1:1000 at this point to the anterolateral aspect of the middle third of the thigh. Repeat the intramuscular dose of adrenaline if there is no improvement after 5 minutes.
• Immediately call for senior assistance, the crash/emergency medical team (call 2222), and the crash trolley.
• Position the patient in a supine or semi-recumbent position, consider elevating legs.
• If the patient becomes obtunded and/or the airway deteriorates and becomes severely compromised, consider airway maneuvers, adjuncts and fast-bleep anaesthetics.

Breathing

• Respirations: 28 breaths/min.
• Oxygen Saturation: 86% on Air.
• Use of accessory muscles.
• Bilateral widespread wheeze.
• Reduced air entry.
• No obvious cyanosis developed yet.

Investigations

ABG

Interpretation: This ABG shows a pattern of type 1 respiratory failure, with acute severe hypoxaemia, low PaCO₂ and a borderline alkalaemia likely secondary to acute airway obstruction from anaphylaxis and hyperventilation. Elevated lactate indicates tissue hypoperfusion in keeping with anaphylaxis-induced shock.

Portable CXR

Interpretation: Left lower lobe opacity obscuring the left hemidiaphragm (silhouette sign) with air bronchograms consistent with pneumonia. Central trachea, no evidence of pneumothorax, bony injury or pneumoperitoneum.

Case courtesy of Henry Knipe, Radiopaedia.org, rID: 31388 https://radiopaedia.org/cases/31388 (1)

Interventions

• Start 15L O2 via a non-rebreather mask and titrate to target saturations (>94%).
• Due to presence of wheezing and PMH asthma, administer bronchodilator nebulisers e.g. salbutamol. 
• Consider nebulised adrenaline if marked stridor persists.

Circulation

• Blood Pressure: 82/45 mmHg.
• Pulse: 162 bpm.
• Cool peripheries.
• CRT >3 seconds.
• Radial pulse tachycardic, regular.
• JVP not elevated.
• No peripheral oedema.

Investigations

ECG

Interpretation: ECG shows sinus tachycardia at 162 bpm, regular rhythm, nil axis deviation and no acute signs of ischaemia such as ST segment changes or T wave inversion. P waves are visible although slightly obscured in some leads by the preceding T wave (2).

• Bloods – Mast cell tryptase, FBC, U&E, LFT, CRP, consider Wells Score / D-dimer if suspecting PE.

Interventions

• IV access – insert 2x wide-bore cannulas into the antecubital fossae – and give STAT 500 ml bolus of 0.9% saline.
• Re-assess BP after administration of bolus and re-administer if required.

Disability

• Consciousness (AVPU): Alert, anxious.
• Cap glucose 5.8 mmol/L.
• Pupils 6mm, equal and reactive to light.
• Nil intervention required.
  

Exposure

• Temperature: 36.9°C.
• Generalised urticaria over trunk and limbs.
• No signs of meningism or trauma.
• Nil intervention required.
  

NEWS Total Score: 13

Re-assessment (A–E) – Post-Adrenaline Administration

A – Airway:

• Airway patent.
• No stridor or upper airway swelling noted.
• Patient able to speak in full sentences, indicating a maintained airway.
  

B – Breathing:

• Respiratory rate: 22 breaths/min.
• Oxygen saturation: 97% on 15L O₂ via non-rebreather mask.
• Bilateral air entry present with no wheeze or added sounds.
• Improvement in work of breathing since adrenaline administration.
  

C – Circulation:

• Pulse: 96 bpm, regular.
• Blood pressure: 110/70 mmHg (previously 85/50 mmHg).
• Capillary refill time: <2 seconds.
• Peripheral perfusion improved.
• No further urticarial rash developing.
  

D – Disability:

• Alert and oriented (GCS 15).
• No signs of confusion or reduced consciousness.
• Blood glucose: 6.4 mmol/L.
  

E – Exposure/Everything else:

• Rash (urticarial) now settling.
• No signs of angioedema or further cutaneous involvement.
• Temperature: 37.2°C.
• No signs of ongoing infection-related deterioration at this time.

After initial treatment

• Reassess following initial A-E for improvement or deterioration (as above), administering further treatment (e.g. adrenaline doses, fluid boluses) as required. If respiratory or cardiovascular symptoms persist despite two doses of intramuscular adrenaline (refractory anaphylaxis), seek urgent expert help (likely critical care team) to allow for a low-dose, intravenous adrenaline infusion to be started.
• Give a non-sedating oral antihistamine (e.g., cetirizine) after initial resuscitation.
• Do not use corticosteroids routinely to treat anaphylaxis, however consider after initial resuscitation for refractory cases, ongoing asthma or shock.
• Ensure patient allergies are updated on medical records.
• Take a brief history including allergies, PMH, medications, and check previous clinical notes and drug chart.
• Monitor patients for a return of symptoms (biphasic reaction) for a minimum of 6 to 24 hours, depending on the severity of the reaction and other factors. Consider monitoring in a higher level care setting e.g. HDU/ITU if very severe reaction.

Choose EITHER Examiner Viva Questions OR Patient Questions

Patient Questions:

1. “Am I going to be okay?”

Possible Answer: “This is a serious allergic reaction, but you’re in the right place, and we’ve already started treatment to help your breathing and blood pressure. Most people make a full recovery with prompt treatment like you’re getting now.”

2. “Why did this happen?”

Possible Answer: “It’s likely your body reacted to the penicillin. With an allergy, your immune system overreacts and causes a cascade of symptoms like breathing difficulty, swelling and rash. Even if you’ve never had it before, this can sometimes happen.”

3. “Will I need to carry anything for the future to stop it happening again?”

Possible Answer: “Yes. After you’ve recovered, we’ll refer you to an allergy specialist. You’ll be given an adrenaline auto-injector (like an EpiPen) to carry in case of future emergencies, and you’ll need to strictly avoid all penicillin-type antibiotics.”

Examiner Questions:

1. “What are your key differentials?”

• Anaphylaxis – Rapid onset respiratory compromise, hypotension, urticaria following exposure to a known allergen (penicillin). Most likely.
• Severe asthma exacerbation – Considered but no prior active asthma or trigger present.
• Septic shock – Possible but reaction occurred acutely after antibiotic administration; sepsis tends to be more gradual.
• Angioedema without urticaria e.g. Bradykinin-mediated angioedema (BMA) – Possible, but urticaria present here makes anaphylaxis more likely. BMA is due to hereditary C1-esterase inhibitor deficiency and can be triggered by ACE inhibitors. Facial and perioral swelling can be life-threatening, but patients with BMA tend not to have urticaria or haemodynamic instability and do not respond to adrenaline.
• PE or pneumothorax – Unlikely; timing and rash point away.

2. “What is the immediate management of suspected anaphylaxis?”(5)

3. “What follow-up does this patient require?”

• Full documentation of the reaction and allergy on notes and alert systems.
• Referral to allergy clinic.
• Training and provision of an adrenaline auto-injector.
• Education about avoidance, recognition of symptoms, and emergency action plan.
• Review and amend antibiotic prescribing for pneumonia accordingly.