Rosen & Barkin's 5-Minute Emergency Medicine Consult (679 page)

• Grades I and II envenomations:
  
  • None
    
• Grades III and IV envenomations:
  
  • BUN, creatinine
    
  • Electrolytes
    
  • UA
    
  • CBC
    
• Severely agitated patients:
  
  • Creatine kinase
    
  • Urine myoglobin
    
• Severe respiratory distress:
  
• ABGs
  

• Chest radiograph for respiratory symptoms
  
• ECG for tachycardia
  

• Snake, spider, insect envenomation
  
• Tetanus
  
• Diphtheria
  
• Botulism
  
• Overdose/dystonic reaction
  
• Seizures
  
• Infections
  

TREATMENT

• Evaluate ABCs
  
• IV access
  

• ABCs
  
• Endotracheal intubation if necessary
  
• IV
  
• O
  ₂
  
• Monitor
  

• Mild envenomations—grades I and II:
  
  • Oral analgesics
    
  • Tetanus prophylaxis
    
• Severe envenomations—grades III and IV:
  
  • Antivenom (Anascorp), expensive therapy
    
  • Tetanus prophylaxis
    
  • Hypertensive urgencies/emergencies (rare):
    
    • Standard therapy such as labetalol
      
  • Hypotension:
    
    • IV fluid resuscitation and pressor therapy with dopamine
      
  • Severe agitation:
    
    • Midazolam
      
  • Treatment for rhabdomyolysis if present
    

• Antivenom: Centruroides (scorpion) (Rx: Anascorp infuse 3 vials IV over 10 min); monitor for up to 60 min after completing infusion to determine if symptoms are resolved. Additional doses may be used if needed; infuse 1 vial at a time at 30–60 min intervals.
  
• Dopamine: 2–5 μg/kg/min IV; increase in 5–10 μg/kg/min as needed
  
• Midazolam: 1–2 mg (peds: 0.01–0.05 mg/kg) IV
  
• Labetalol: 20 mg (peds: 0.3–1 mg/kg/dose) q10min
  
• Fentanyl: 50–150 μg (peds: 1–3 μg/kg) IV
  
• Tetanus toxoid: 0.5 mL IM (peds: Same dose)
  

Antivenom doses are the same in children because dosage is based on venom burden.

FOLLOW-UP

• Grades III and IV envenomations require admission to ICU.
  
• If antivenom is given with resolution of symptoms, observe for 1–2 hr if asymptomatic.
  

• Grades I and II envenomations after a short observation period (3–4 hr after sting occurred) for progression of symptoms
  
• Grades III and IV envenomations given antivenom with resolution of symptoms can be discharged.
  
• If patient received antivenom, discuss signs and symptoms of delayed serum sickness.
  
• Discuss possibility of persistence of pain and paresthesias at site.
  
• Encourage patient to return for progression of symptoms.
  

Toddlers are more likely to have early airway involvement.

Primary care follow-up if antivenin given.

• Maintain high index of suspicion for scorpion stings in endemic areas when patients present with typical symptoms.
  

• Boyer LV, Theodorou AA, Berg RA, et al. Antivenom for critically ill children with neurotoxicity from scorpion stings.
  N Engl J Med
  . 2009;360(20):2090–2098.
  
• LoVecchio F, McBride C. Scorpion envenomations in young children in central Arizona.
  J Toxicol Clin Toxicol
  . 2003;41(7):937–940.
  
• O’Connor A, Ruha AM. Clinical course of bark scorpion envenomation managed without antivenom.
  J Med Toxicol.
  2012;8(3):258–262.
  
• Quan D. North American poisonous bites and stings
  Crit Care Clin
  . 2012;28(4):633–659.
  

See Also (Topic, Algorithm, Electronic Media Element)

• Botulism
  
• Rhabdomyolysis
  
• Seizures
  
• Spider Bite, Black Widow
  
• Tetanus
  

CODES

989.5 Toxic effect of venom

BASICS

• Increase in frequency of aggressive streptococcal necrotizing skin infection noted in 1980s and dubbed “flesh-eating bacteria.”
  
• Affects otherwise healthy patients aged 20–50 yr who did not have underlying predisposing diseases.
  
• Rapid progression of shock and multiorgan dysfunction, with death occurring within 1–2 days.
  
• Incidence is 3–4 per 100,000 in industrialized countries
  
• Invasive infections caused by group A
  Streptococcus
  (GAS) include:
  
  • Necrotizing fasciitis (NF):
    
    • Progressive, rapidly spreading soft tissue infection located within the deep fascia and subcutaneous fat
      
  • Streptococcal toxic shock syndrome (STSS):
    
    • May occur in patients with GAS associated NF.
      
    • Portals of entry for streptococci include vagina, pharynx, mucosa, and skin.
      
    • Unknown cause in 50% of cases.
      
  • “Other” invasive disease defined as isolation of GAS from a normally sterile body site (i.e., sepsis, bacteremic pneumonia, septic arthritis, etc.)
    
• Occurs sporadically, with occasional outbreaks in long-term care facilities and hospitals.
  
• Rate of invasive GAS disease 6 times the annual incidence of meningococcal disease.
  

• Isolation of GAS from sterile or nonsterile body site
  
• Hypotension
  
• 2 or more of the following:
  
  • Renal impairment
    
  • Coagulopathy
    
  • Liver abnormalities
    
  • Acute respiratory distress
    
  • Extensive tissue necrosis (NF)
    
  • Erythematous rash
    

• NF:
  
  • GAS is causative in 10% of cases. Blunt trauma is risk factor.
    
  • Mixed anaerobic and aerobic organisms are found in 70% of cases.
    
  • Staphylococcus aureus
    ,
    Clostridium
    species, and other enteric organisms
    
• Streptococcal toxic shock syndrome:
  
  • Occurs when susceptible host is infected with virulent strain
    
  • M protein types 1, 3, and 28 are most common.
    
  • Pyrogenic exotoxins (e.g., A, B, and C) produce fever and shock via activation of tumor necrosis factor and interleukins.
    
  • Nonsteroidal anti-inflammatory drugs appear to mask or predispose patients.
    
  • Risk factors:
    
    • Age <10 or >60 yr
      
    • Cancer
      
    • Renal failure
      
    • Leukemia
      
    • Severe burns
      
    • Corticosteroids
      

DIAGNOSIS