II. Background

  1. Scorpions are Arachnids with venomous Stingers in their tails
  2. Scorpions tend to hide in crevices, shoes

III. Mechanism: Toxicity

  1. Envenomation is via the tip of the Scorpion tail
  2. Most Scorpions cause only self-limited, local reactions
  3. Centruroides Scorpion Stings may result in severe Envenomation (5% of cases)
    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

IV. Types: Centruroides

  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

V. Symptoms

  1. Immediate burning pain at site of sting (typically on an extremity)
  2. Local or regional hyperesthesia for varying period

VI. 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. Cranial Nerve dysfunction (e.g. roving eye movement)
    10. CNS hyperstimulation
    11. Seizures
    12. Cardiogenic Shock
    13. Pulmonary Edema

VII. Exam

  1. Sting site evaluation
  2. Thorough Neurologic Exam including Cranial Nerve exam

VIII. 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

IX. Labs: Grade 3 and 4 Envenomations

  1. Complete Blood Count
  2. Comprehensive Metabolic Panel
  3. Creatine Kinase
  4. Urinalysis

X. 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 (elderly may be at higher risk)

XI. Management: General

  1. First aid and general measures
    1. Clean bite site with soap and water
    2. Ice or cool compress to wound site
    3. Elevation of affected part
    4. Tourniquets are not recommended for the affected, stung limb
    5. Avoid home remedies (e.g. Garlic)
  2. General Medical Approach
    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
  3. Symptomatic therapy
    1. Antihistamines
    2. Corticosteroids
    3. Consider Regoinal Anesthesia
    4. Analgesics
      1. NSAIDs
      2. Acetaminophen
      3. Opioids are often needed
        1. Avoid Morphine if antivenom planned (increases histamine release with risk of Anaphylaxis)
  4. Disposition
    1. Observe Grade 1 cases for at least 4 hours
    2. Observe Grade 2 cases at least 4 hours and until symptoms are controlled or improving
    3. Admit Grade 3 and 4 Envenomations to ICU (see below)

XII. Management: Severe Envenomation (Grade 3 and 4 Envenomation)

  1. Admit to Intensive Care Unit
  2. Arizona Bark Scorpion (Centruroides sculpturatus) Antivenom
    1. Indicated for Grade 3 or Grade 4 Envenomations
    2. Reduces length of severity of symptoms
    3. Antivenom is a risk for Anaphylaxis
  3. Observe closely
    1. ABC Management
      1. Respiratory depression
      2. Adequate ventilation
    2. CNS Hyperstimulation
    3. Seizures
    4. Severe Hypertension
      1. Consider Prazosin or vasodilator
    5. Manage Cardiogenic Shock
    6. Parenteral Analgesics
    7. Parenteral Benzodiazepines

XIII. Complications: Severe Envenomation

XIV. References

  1. (2021) Presc Lett 28(7): 40
  2. Cowling and Ferreri (2019) Crit Dec Emerg Med 33(2): 17-25
  3. Herness (2022) Am Fam Physician 106(2): 137-47 [PubMed]

Images: Related links to external sites (from Bing)

Related Studies

Ontology: Scorpions (C0036451)

Definition (MSH) Arthropods of the order Scorpiones, of which 1500 to 2000 species have been described. The most common live in tropical or subtropical areas. They are nocturnal and feed principally on insects and other arthropods. They are large arachnids but do not attack man spontaneously. They have a venomous sting. Their medical significance varies considerably and is dependent on their habits and venom potency rather than on their size. At most, the sting is equivalent to that of a hornet but certain species possess a highly toxic venom potentially fatal to humans. (From Dorland, 27th ed; Smith, Insects and Other Arthropods of Medical Importance, 1973, p417; Barnes, Invertebrate Zoology, 5th ed, p503)
Concepts Eukaryote (T204)
MSH D012605
SnomedCT 106864000, 68483004
English Scorpions, Scorpion, Order Scorpionida, Scorpionida, Order scorpionida (organism), Order scorpionida, Order Scorpiones (organism), Order Scorpiones, Order Scorpionida (organism), scorpion, scorpions, Scorpiones, Scorpion (organism), Subclass: Scorpiones, True scorpion, Scorpion, NOS
French Scorpions, Scorpio
Swedish Skorpioner
Czech štíři
Finnish Skorpionit
Spanish orden scorpionida (organismo), orden Scorpionida, Scorpionida, orden scorpionida, orden Scorpiones, orden Scorpiones (organismo), orden Scorpionida (organismo), escorpión (organismo), escorpión, Scorpiones, escorpión verdadero, subclase: Scorpiones, Escorpiones
Polish Skorpiony
Norwegian Skorpioner
Portuguese Scorpiones, Escorpiões
German Skorpione
Italian Scorpioni
Dutch Schorpioen, Schorpioenen

Ontology: Centruroides sculpturatus (C0323793)

Concepts Eukaryote (T204)
SnomedCT 52244005
English Centruroides sculpturatus, Centruroides sculptuatus, Centruroides sculpturatus Ewing, 1928, Centruroides sculpturatus (organism)
Spanish Centruroides sculpturatus, Centruroides sculpturatus (organismo)