Difference between revisions of "Sea urchins"

(Differential Diagnosis)
(Management)
Line 1: Line 1:
 
==Background==
 
==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
 +
**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==
 
==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).]]
 +
 +
*Minor to severe pain the the site of the embedded spine
 +
*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, parasthesias, muscle weakness, and hypotension
 +
*Rarely severe envenomations can lead to death
 +
  
 
==Differential Diagnosis==
 
==Differential Diagnosis==
Line 10: Line 27:
 
==Evaluation==
 
==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==
 
==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
 +
 +
===Complications===
 +
*Retained spines
 +
*Infection ('''[[Vibrio]]''' species)
 +
*Granuloma and cyst formation
 +
*
  
 
==Disposition==
 
==Disposition==
 
+
*Depends on the extent and location of injury and degree of envenomation
  
 
==See Also==
 
==See Also==
Line 27: Line 62:
 
==References==
 
==References==
 
<references/>
 
<references/>
 +
1.Auerbach P. Chapter 73. Envenomation by aquatic invertebrates. In: Auerbach P. Wilderness Medicine.

Revision as of 18:14, 29 July 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
    • 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).
  • Minor to severe pain the the site of the embedded spine
  • 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, parasthesias, muscle weakness, and hypotension
  • Rarely severe envenomations can lead to death


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

Complications

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

Disposition

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

See Also

External Links

References

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