Rosen & Barkin's 5-Minute Emergency Medicine Consult (678 page)

TREATMENT

Most deaths occur within 1st hour owing to either respiratory obstruction or anaphylaxis causing cardiovascular and respiratory collapse.

• ABCs:
  
  • Intubation/ventilation with rapidly increasing signs of laryngeal compromise
    
  • Oxygen
    
  • 0.9% normal saline (NS) IV access
    
• Epinephrine SC/IV
  
• Antihistamines IV
  
• Corticosteroids
  
• When signs of systemic reactions:
  
  • Assess for patent airway
    
  • Establish IV access
    

• Systemic reactions:
  
  • Epinephrine for respiratory symptoms/hypotension
    
  • Antihistamines—H
    ₁
    (diphenhydramine) and H
    ₂
    (cimetidine, ranitidine, or famotidine) blockers
    
  • Steroids (prednisone, methylprednisolone, or dexamethasone)
    
  • Inhaled β-agonist for wheezing/shortness of breath
    
  • For persistent hypotension:
    
    • 0.9% NS IV fluid resuscitation
      
    • Vasopressor (epinephrine/α-adrenergic) for hypotension resistant to IV fluids
      
• Removal of remnants of stinger at site of envenomation (bees may leave stingers with venom sacs) by scraping, not squeezing
  
• Local reactions:
  
  • Cool compress
    
  • Elevation
    
  • Remove constrictive clothing or jewelry
    
  • Topical antihistamine/topical steroidal cream as needed
    
  • Oral antihistamine or steroids as needed
    

• Albuterol, β-agonist (inhaled): 3 mg in 5 mL NS (peds: 0.1 mg/kg of 5 mg/mL concentration) via nebulization
  
• Cimetidine: 300 mg (peds: 5 mg/kg) IV/IM/PO
  
• Diphenhydramine:
  
  • 50–100 mg (peds: 1 mg/kg) IV for severe reactions
    
  • 25–50 mg (peds: 1 mg/kg) PO QID for severe local reactions
    
• Epinephrine:
  
  • 0.1 mg: 1 mL of 1:10,000 dilution (peds: 0.01 mg/kg 0.1 mL/kg of 1:10,000 dilution up to 1 mL) IV over 5 min for shock
    
  • 0.3 mg (0.3 mL of 1:1,000 dilution); (peds: 0.01 mg/kg up to 0.5 mg) SC for severe reactions but not in shock
    
• Famotidine: 40 mg IV (peds: 1 mg/kg/d div. BID IV)
  
• Methylprednisolone: 125 mg (peds: 1–2 mg/kg) IV
  
• Norepinephrine: 2–4 μg/kg/min (peds: 0.1 μg/kg/min) titrated continuous infusion
  
• Prednisone: 60 mg (peds: 1–2 mg/kg) PO
  
• Ranitidine: 50 mg IV/IM (peds: 2–4 mg/kg/d div. q6–8h IV/IM)
  

FOLLOW-UP

• Worsening symptoms, airway compromise
  
• Persistent unstable vital signs require ICU admission.
  
• Life-threatening reaction requires 24-hr observation.
  
• Systemic reaction requires minimum of 6 hr of observation.
  

• Minimal isolated local reaction
  
• Systemic reactions that resolve and do not recur during 6-hr observation period
  

Follow-up:

• Provide patients with life-threatening reactions, emergency anaphylaxis kits (EpiPen; peds: EpiPen Jr if <15 kg), and medical identification bracelets (Medi-Alert).
  
• Systemic reaction requires follow-up for possible immunotherapy.
  

Allergist follow-up for patients with systemic reactions.

• Treat patients who present with systemic reactions to bee stings aggressively.
  
• Provide prescriptions for EpiPen to patients discharged after presenting with life-threatening reactions to bee stings.
  

• Bahna SL. Insect sting allergy: A matter of life and death.
  Pediatr Ann
  . 2000;29:753–758.
  
• Freeman T. Stings of hymenoptera insects: Reaction types and acute management. UpToDate. Accessed on Sept 25, 2009.
  
• McDougle L, Klein GL, Hoehler FK. Management of hymenoptera sting anaphylaxis: A preventive medicine survey.
  J Emerg Med
  . 1995;13:9–13.
  
• Moffitt JE, Golden DB, Reisman RE. Stinging insect hypersensitivity: A practice parameter update.
  J Allergy Clin Immunol
  . 2004;114:869–886.
  
• Reisman RE. Insect stings.
  N Engl J Med
  . 1994;331:523–527.
  

See Also (Topic, Algorithm, Electronic Media Element)

Anaphylaxis

CODES

989.5 Toxic effect of venom

BASICS

• Scorpion venom is neurotoxic:
  
  • Sodium channels opening
    
  • Prolonged firing of neurons
    
• Autonomic, somatic, and cranial nerve excitation occurs.
  
• Symptoms begin within minutes of bite.
  
• Symptoms persist 1–72 hr.
  

• Centruroides
  species found in Southern US, Mexico, Central America, and Caribbean
  
• Many other species in Asia, Africa, Israel, South America, and Middle East
  

• Can be misdiagnosed as seizures, amphetamine poisoning, or meningitis
  
• Higher mortality and severity of illness
  

DIAGNOSIS

• Onset within minutes, progressing to maximum severity in ∼1–2 hr but may persist ≤48–72 hr.
  
• Scorpion species determines symptomatology (
  Centruroides sculpturatus
  , aka
  Centruroides exilicauda
  or bark scorpion, is the only species in US causing symptoms).
  
• Local tissue effects:
  
  • No erythema
    
  • Pain
    
  • Hyperesthesia
    
• Autonomic effects:
  
  • Sympathetic symptoms:
    
    • Tachycardia
      
    • Hypertension
      
    • Hyperthermia
      
    • Pulmonary edema
      
    • Agitation
      
    • Perspiration
      
  • Parasympathetic effects:
    
    • Hypotension
      
    • Bradycardia
      
    • Hypersalivation
      
• Somatic effects:
  
  • Involuntary muscle contractions
    
  • Restlessness
    
• Cranial nerve effects:
  
  • Roving eye movements
    
  • Blurred vision
    
  • Nystagmus
    
  • Tongue fasciculations
    
  • Loss of pharyngeal muscle control
    

• Identification of scorpion species not needed if scorpion is native to US (see above).
  
• Maintain high clinical suspicion in endemic areas
  
• Assess envenomation grade severity:
  
  • Grade I: Local pain and/or paresthesias at site
    
  • Grade II: Local pain and/or paresthesias at a remote site
    
  • Grade III: Either cranial/autonomic
    or
    somatic skeletal neuromuscular dysfunction
    
  • Grade IV: Both cranial/autonomic
    and
    somatic skeletal muscle dysfunction