Pediatrics · Year 3 · from Pediatrics

Case 3: Pediatric Anaphylaxis

Patient Demographics

  • Age: 8-year-old male
  • Sex: Male

Chief Complaint

"He ate a cookie with peanuts and can't breathe."

History of Present Illness

An 8-year-old boy with a known peanut allergy is brought to the emergency department by his father. At a birthday party 20 minutes ago, he ate a cookie that he didn't know contained peanut butter. Within 5 minutes, he developed itchy hives on his arms and face. He then developed swelling of his lips and throat tightness. He has been coughing and wheezing. His father administered one dose of diphenhydramine at the party but did not have an epinephrine auto-injector available. The symptoms have been rapidly progressing.

Physical Examination

  • Vital Signs: HR 145 bpm, RR 36/min, BP 78/50 mmHg (low for age), SpO2 91% on room air
  • General: Anxious, appears in distress, hoarse voice
  • Skin: Diffuse urticarial wheals on trunk and extremities, flushed
  • HEENT: Angioedema of lips and tongue; oropharynx shows uvular edema
  • Respiratory: Stridor audible without stethoscope, bilateral wheezing, increased work of breathing with retractions
  • Cardiovascular: Tachycardic, weak peripheral pulses

Diagnosis

Anaphylaxis with respiratory and cardiovascular involvement

Clinical Reasoning

This patient meets criteria for anaphylaxis with involvement of multiple organ systems:

  1. Skin/mucosa: Urticaria, angioedema
  2. Respiratory: Stridor (upper airway), wheezing (lower airway), hypoxia
  3. Cardiovascular: Hypotension, tachycardia

The known peanut exposure provides the trigger. Anaphylaxis is a clinical diagnosis requiring immediate treatment. The presence of hypotension and respiratory compromise indicates severe anaphylaxis. Diphenhydramine alone is NEVER adequate treatment for anaphylaxis - EPINEPHRINE is the first-line and life-saving medication.

Management

Immediate Actions:

  1. EPINEPHRINE IM: 0.01 mg/kg of 1:1,000 (1 mg/mL)
  • Weight 25 kg x 0.01 mg/kg = 0.25 mg
  • Give 0.25 mg (0.25 mL) IM in lateral thigh
  • May repeat every 5-15 minutes if symptoms persist
  1. Position: Supine with legs elevated (unless respiratory distress requires upright position)
  1. Supplemental oxygen: High-flow oxygen via non-rebreather mask
  1. IV access and fluids: 20 mL/kg normal saline bolus for hypotension
  1. Adjunctive medications:
  • Albuterol nebulizer for persistent wheezing
  • H1 antihistamine (diphenhydramine 1 mg/kg IV)
  • H2 antihistamine (ranitidine 1 mg/kg IV)
  • Methylprednisolone 1-2 mg/kg IV (prevents biphasic reaction, but NOT first-line)
  1. Monitor: Continuous cardiac and respiratory monitoring
  1. Prepare for airway management: Have intubation equipment ready

Response to Treatment

After IM epinephrine:

  • HR decreased to 110 bpm
  • BP improved to 95/60 mmHg
  • Stridor resolved
  • Wheezing improved with albuterol
  • Urticaria beginning to fade

Disposition

  • Observation: Minimum 4-6 hours for biphasic reaction (can occur in up to 20%)
  • Discharge planning:
  • Prescription for 2 epinephrine auto-injectors
  • Demonstrate proper use before discharge
  • Anaphylaxis action plan
  • Referral to allergist
  • Medical alert bracelet recommended
  • School action plan

Clinical Image

Image Description: Demonstration of proper technique for intramuscular epinephrine administration using an auto-injector in the anterolateral thigh, the first-line treatment for anaphylaxis.

Source: Wikimedia Commons URL: https://commons.wikimedia.org/wiki/File:Epipen.jpg License: CC BY-SA 4.0

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