Difference between revisions of "Sea urchins"

(Differential Diagnosis)
 
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==Background==
 
==Background==
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*Sea urchins are marine invertebrate echinoderms
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*Anatomy consists of soft viscera surrounded by a hard plated body with protruding spines and pedicellariae
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*Around 950 known species and some are venomous<ref>Auerbach P. Chapter 73. Envenomation by aquatic invertebrates. In: Auerbach P. Wilderness Medicine.</ref>
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**Nonvenomous species have blunt, rounded spines
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**Venomous species have sharp, hollow, thin spines
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**Some have pedicellariae with sharp jaws and venom glands
  
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===Mechanism===
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*Nonvenomous spines cause direct trauma
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*Venoms are known to contain proteases, hemolysins, steroid glycosides, serotonin, cholinergic substances, and rarely neurotoxins
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*Pedicellariae attach to the victim and break off from the urchin, releasing venom for several hours
  
 
==Clinical Features==
 
==Clinical Features==
 
[[File:PMC3760923 abd-88-0496-g09.png|thumb|Black sea urchins (''Echinometra lucunter''). Below: spinesin the feet of bathers. Right: hyperkeratotic noduleson the hands of a diver who suffered several injuries caused by black sea urchins (foreign body granuloma).]]
 
[[File:PMC3760923 abd-88-0496-g09.png|thumb|Black sea urchins (''Echinometra lucunter''). Below: spinesin the feet of bathers. Right: hyperkeratotic noduleson the hands of a diver who suffered several injuries caused by black sea urchins (foreign body granuloma).]]
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 +
*Minor to severe pain the the site of the embedded spine
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*Venomous spines and pedicellariae generally cause much more severe pain and may be accompanied by systemic signs and symptoms with a significant envenomation including [[pruritus]], [[nausea]], vomiting, [[abdominal pain]], [[respiratory distress]], [[paresthesias]], muscle [[weakness]], and [[hypotension]]
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*Rarely severe envenomations can lead to death
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==Differential Diagnosis==
 
==Differential Diagnosis==
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==Evaluation==
 
==Evaluation==
  
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*Clinical diagnosis
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*Plain films of the injured areas to locate embedded spines
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**Evaluate for intraarticular spines
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**Ultrasound may be useful if none are seen but radiolucent FB is suspected
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**MRI can also locate spines not seen on plain film
  
 
==Management==
 
==Management==
  
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*Emersion in non-scalding water up to 45°C
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*Prompt removal of pedicellariae
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*Remove spines/foreign bodies
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**If spines are intraarticular or near neurovascular structures they need to be carefully removed in the OR
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*Thorough irrigation
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*Update [[tetanus vaccination]] if needed
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*Prophylactic [[antibiotics]] for deep puncture wounds
  
 
==Disposition==
 
==Disposition==
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*Depends on the extent and location of injury and degree of envenomation
  
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==Complications==
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*Retained spines
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*Infection ('''[[Vibrio]]''' species)
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*Granuloma and cyst formation
  
 
==See Also==
 
==See Also==
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==References==
 
==References==
 
<references/>
 
<references/>
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[[Category:Environmental]]

Latest revision as of 17:49, 25 October 2020

Background

  • Sea urchins are marine invertebrate echinoderms
  • Anatomy consists of soft viscera surrounded by a hard plated body with protruding spines and pedicellariae
  • Around 950 known species and some are venomous[1]
    • Nonvenomous species have blunt, rounded spines
    • Venomous species have sharp, hollow, thin spines
    • Some have pedicellariae with sharp jaws and venom glands

Mechanism

  • Nonvenomous spines cause direct trauma
  • Venoms are known to contain proteases, hemolysins, steroid glycosides, serotonin, cholinergic substances, and rarely neurotoxins
  • Pedicellariae attach to the victim and break off from the urchin, releasing venom for several hours

Clinical Features

Black sea urchins (Echinometra lucunter). Below: spinesin the feet of bathers. Right: hyperkeratotic noduleson the hands of a diver who suffered several injuries caused by black sea urchins (foreign body granuloma).


Differential Diagnosis

Marine toxins, envenomations, and bites

Evaluation

  • Clinical diagnosis
  • Plain films of the injured areas to locate embedded spines
    • Evaluate for intraarticular spines
    • Ultrasound may be useful if none are seen but radiolucent FB is suspected
    • MRI can also locate spines not seen on plain film

Management

  • Emersion in non-scalding water up to 45°C
  • Prompt removal of pedicellariae
  • Remove spines/foreign bodies
    • If spines are intraarticular or near neurovascular structures they need to be carefully removed in the OR
  • Thorough irrigation
  • Update tetanus vaccination if needed
  • Prophylactic antibiotics for deep puncture wounds

Disposition

  • Depends on the extent and location of injury and degree of envenomation

Complications

  • Retained spines
  • Infection (Vibrio species)
  • Granuloma and cyst formation

See Also

External Links

References

  1. Auerbach P. Chapter 73. Envenomation by aquatic invertebrates. In: Auerbach P. Wilderness Medicine.