Hymenoptera Stings in Pediatric Patients

Hymenoptera Stings in Pediatric Patients

Key Points

  • Leading cause of anaphylaxis in children
  • 5% of population develops systemic reactions
  • Higher risk of severe reactions in children
  • Multiple stings can cause toxic reactions
  • Requires long-term management strategy

Epidemiology

  • Incidence:
    • 56-94% lifetime risk of sting
    • 0.4-0.8% anaphylaxis risk in children
    • Peak age: 5-14 years
    • Male predominance (60%)
  • Risk Factors:
    • Previous systemic reactions
    • Atopic conditions
    • Outdoor activities
    • Rural residence
    • Family history of reactions
  • Mortality:
    • 40-50 deaths annually in US
    • Higher risk in children with asthma
    • Most deaths from delayed treatment
    • Underreported cases common

Species Classification and Venom Characteristics

Major Species

  • Apidae Family (Bees):
    • Honey bees (Apis mellifera)
      • Barbed stinger remains
      • Single sting capability
      • 9-140 μg venom/sting
    • Bumble bees (Bombus species)
      • Multiple sting capability
      • Less aggressive
      • 10-31 μg venom/sting
  • Vespidae Family:
    • Yellow jackets (Vespula species)
      • Most aggressive
      • Multiple stings
      • Ground nests
    • Hornets (Vespa species)
      • Aerial nests
      • Aggressive defenders
      • Large venom load
    • Paper wasps (Polistes species)
      • Less aggressive
      • Open paper nests
      • Territorial defense

Venom Components

  • Protein Components:
    • Enzymes:
      • Phospholipase A2
      • Hyaluronidase
      • Acid phosphatase
    • Peptides:
      • Melittin (bees)
      • Mastoparan (wasps)
      • Kinins
  • Cross-Reactivity:
    • High between vespids (60-70%)
    • Low between bees and vespids (<5%)
    • Species-specific components

Pathophysiology and Immunology

Immunologic Reactions

  • Type I Hypersensitivity:
    • IgE-mediated response
      • Mast cell degranulation
      • Basophil activation
      • Rapid onset (<30 minutes)
    • Mediator Release:
      • Histamine
      • Leukotrienes
      • Prostaglandins
      • Platelet-activating factor
  • Additional Mechanisms:
    • Complement activation
    • Direct mast cell activation
    • Cytokine cascade
    • Tissue factor release

Toxic Reactions

  • Direct Venom Effects:
    • Tissue damage
    • Hemolysis
    • Rhabdomyolysis
    • Organ dysfunction
  • Multiple Sting Syndrome:
    • Dose-dependent toxicity
    • Critical threshold: >50 stings
    • Systemic inflammatory response

Clinical Manifestations

Local Reactions

  • Immediate Response:
    • Pain and burning
    • Erythema
    • Wheal formation
    • Local edema
  • Large Local Reactions:
    • Progressive swelling
    • Peak at 48 hours
    • Duration 5-10 days
    • Risk factors for progression

Systemic Reactions

  • Cutaneous:
    • Generalized urticaria
    • Angioedema
    • Flushing
    • Pruritus
  • Respiratory:
    • Bronchospasm
    • Laryngeal edema
    • Rhinitis
    • Chest tightness
  • Cardiovascular:
    • Hypotension
    • Tachycardia
    • Arrhythmias
    • Shock
  • Gastrointestinal:
    • Nausea/vomiting
    • Abdominal pain
    • Diarrhea

Unusual Manifestations

  • Neurologic:
    • Seizures
    • Peripheral neuropathy
    • Encephalopathy
  • Delayed Reactions:
    • Serum sickness
    • Vasculitis
    • Nephritis

Diagnostic Approach

Initial Assessment

  • History Taking:
    • Insect identification
    • Number of stings
    • Time course of symptoms
    • Previous reactions
    • Current medications
  • Physical Examination:
    • Vital signs
    • Sting site assessment
    • Systemic involvement
    • Stinger presence

Laboratory Testing

  • Acute Phase:
    • Serum tryptase
    • Complete blood count
    • Basic metabolic panel
    • Coagulation profile
  • Follow-up Testing:
    • Specific IgE testing
    • Skin prick testing
    • Intradermal testing
    • Component resolved diagnostics

Management Protocol

Immediate Management

  • Stinger Removal:
    • Scraping method preferred
    • Avoid squeezing venom sac
    • Timing critical (<30 seconds)
  • Local Care:
    • Cold compress application
    • Wound cleansing
    • Elevation if extremity
    • Remove constrictive items

Pharmacologic Interventions

  • First-Line Medications:
    • H1 Antihistamines:
      • Diphenhydramine: 1-2 mg/kg/dose
      • Cetirizine: 2.5-5 mg daily
    • H2 Antihistamines:
      • Ranitidine: 1-2 mg/kg/dose
      • Maximum: 50 mg/dose
  • Additional Treatments:
    • Oral corticosteroids
      • Prednisolone: 1-2 mg/kg/day
      • 5-7 day course
    • Pain management
      • Acetaminophen
      • Ibuprofen if >6 months

Anaphylaxis Management

Recognition and Assessment

  • Diagnostic Criteria:
    • Acute onset (<2 hours)
    • Multiple system involvement
    • Cardiovascular compromise
    • Respiratory distress
  • Risk Stratification:
    • Previous anaphylaxis
    • Asthma presence
    • Multiple stings
    • Delayed access to care

Emergency Management

  • Immediate Actions:
    • Epinephrine Administration:
      • IM 0.01 mg/kg (1:1000)
      • Maximum: 0.3 mg child, 0.5 mg teen
      • Repeat q5-15min if needed
    • Airway Management:
      • High-flow oxygen
      • Position of comfort
      • Early intubation if needed
  • Secondary Interventions:
    • Fluid Resuscitation:
      • 20 mL/kg boluses
      • Repeat as needed
      • Monitor response
    • Additional Medications:
      • IV antihistamines
      • IV corticosteroids
      • Beta-agonists if wheeze

Monitoring and Observation

  • Initial Period:
    • Continuous vital signs
    • Cardiac monitoring
    • Pulse oximetry
    • Frequent reassessment
  • Observation Duration:
    • Minimum 4-8 hours
    • 24 hours if severe reaction
    • Extended for biphasic reactions
    • Risk factor assessment

Prevention & Education

Risk Reduction Strategies

  • Environmental Measures:
    • Avoid bright clothing
    • Cover food outdoors
    • Proper garbage disposal
    • Regular nest inspection
  • Behavioral Modifications:
    • Avoid perfumes/scents
    • Wear closed shoes
    • Remain calm if approached
    • Avoid swatting insects

Patient Education

  • Emergency Action Plan:
    • Written instructions
    • Auto-injector training
    • Recognition of symptoms
    • Emergency contact numbers
  • Long-term Management:
    • Medical alert identification
    • School/daycare notification
    • Regular follow-up visits
    • Venom immunotherapy discussion

Special Considerations

High-Risk Groups

  • Asthmatic Patients:
    • Increased reaction severity
    • Lower threshold for treatment
    • Optimized asthma control
    • Additional monitoring needed
  • Multiple Allergy Patients:
    • Cross-reactivity risk
    • Complex management plans
    • Increased vigilance needed
    • Specialist consultation

Venom Immunotherapy (VIT)

  • Indications:
    • Systemic reactions
    • Positive venom testing
    • Age >5 years preferred
    • Quality of life impact
  • Protocol:
    • Build-up phase:
      • Weekly injections
      • 12-16 weeks duration
      • Careful dose escalation
    • Maintenance Phase:
      • Monthly injections
      • 3-5 years duration
      • Efficacy monitoring
  • Outcomes:
    • 95% protection rate
    • Long-term immunity
    • Improved quality of life
    • Cost-effective long-term

Follow-up Care

  • Monitoring Schedule:
    • Initial: 1-2 weeks
    • Regular: 3-6 months
    • Annual risk assessment
    • Emergency plan updates
  • Quality of Life Assessment:
    • Activity modifications
    • Psychological impact
    • Family adjustment
    • School/social integration


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