Scorpion

Aka: Scorpion, Centruroides sculpturatus, Arizona Bark Scorpion

1. See Also
   1. Neurotoxin
2. Mechanism
   1. Arizona Bark Scorpion (Centruroides sculpturatus) venom is a Neurotoxin
   2. Striped Bark Scorpion (Centruroides vittatus) is also a Neurotoxin, but less harmful than sculpturatus
   3. Other Scorpions cause only local reactions
   4. Envenomation is via the tip of the Scorpion tail
3. Types
   1. Arizona Bark Scorpion (Centruroides sculpturatus)
      1. Yellow to brown Scorpions
      2. Subnuclear tooth at the base of the Stinger
      3. Much more potentially dangerous than the Striped Bark Scorpion
   2. Striped Bark Scorpion (Centruroides vittatus)
      1. Black stripes on thorax
4. Symptoms
   1. Immediate burning pain at site of sting
   2. Local or regional hyperesthesia for varying period
5. Signs
   1. Local reaction (Scorpion other than C. sculpturatus)
      1. Erythema
      2. Edema
      3. Ecchymosis
   2. Tap test (Suggests C. sculpturatus sting)
      1. Administer sharp tap at wound site
      2. Positive
         1. Patient experiences significant pain
         2. Abruptly withdraws wound site
   3. Centruroides sculpturatus reaction
      1. Muscle spasm
      2. Excessive Salivation
      3. Fever
      4. Tachycardia
      5. Nystagmus
      6. Blurred Vision
      7. Slurred speech
      8. Respiratory distress or Wheezing
      9. CNS hyperstimulation
      10. Seizures
6. Exam
   1. Sting site evaluation
   2. Thorough Neurologic Exam including Cranial Nerve exam
7. Grading: Envenomation
   1. Grade 1
      1. Pain and Paresthesias at localized site of sting
   2. Grade 2
      1. Pain and Paresthesias at remote site from bite (as well as meeting Grade 1 Criteria)
   3. Grade 3
      1. Meets criteria for Grade 2 sting AND
      2. ONE of the following neurologic criteria
         1. Cranial Nerve Involvement (e.g. Nystagmus, Dysarthria, Dysphagia, Drooling)
         2. Skeletal neuromuscular involvement (e.g. writhing, fasciculations, jerking, Tetany)
         3. Autonomic signs (Salivation, Vomiting, bronchospasm, diaphoresis, Tachycardia)
   4. Grade 4
      1. All findings of Grade 3 Envenomation are present
8. Labs: Grade III and IV Envenomations
   1. Complete Blood Count
   2. Comprehensive Metabolic Panel
   3. Creatine Kinase
   4. Urinalysis
9. Course: Centruroides sculpturatus
   1. Infants <1 years: Fatal reactions are not uncommon
   2. Child <5 years: Potentially life threatening reactions
   3. Adults: Variable reactions but rarely fatal
10. Management
    1. Immediate medical attention for children
    2. Try to identify the Scorpion type that caused the bite
    3. Consult poison control
    4. Tetanus Vaccine as needed
    5. Arizona Bark Scorpion (Centruroides sculpturatus) Antivenom
       1. Indicated for Grade III or Grade 4 Envenomations
       2. Reduces length of severity of symptoms
       3. Antivenom is a risk for Anaphylaxis
    6. Observe closely
       1. ABC Management
          1. Respiratory depression
          2. Adequate ventilation
       2. CNS Hyperstimulation
       3. Seizures
    7. First aid measures
       1. Ice or cool compress to wound site
       2. Elevation of affected part
       3. Tourniquets are not recommended for the affected, stung limb
    8. Symptomatic therapy
       1. Antihistamines
       2. Corticosteroids
       3. Analgesics (Opioids are often needed)
          1. Avoid Morphine if antivenom planned (increases histamine release with risk of Anaphylaxis)
11. References
    1. Cowling and Ferreri (2019) Crit Dec Emerg Med 33(2): 17-25