Nematocysts: Difference between revisions

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==Mechanism==
==Background==
*Jellyfish; Box Jelly is most deadly
*Jellyfish; Box Jelly is most deadly
*Most toxic: Australia and other Indo-Pacific waters
*Most toxic: Australia and other Indo-Pacific waters
===Mechanism===
[[File:Nematocyst discharge.png|thumb|Nematocyst stages of discharge]]
[[File:Nematocyst discharge.png|thumb|Nematocyst stages of discharge]]
*Physical contact or osmotic gradient  causes discharge of neamtocysts
*Physical contact or osmotic gradient  causes discharge of neamtocysts
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*Severe
*Severe
**Respiratory paralysis, cardiovascular collapse, limb paralysis and death
**Respiratory paralysis, cardiovascular collapse, limb paralysis and death
**Irukandji syndrome - myalgias, back, chest, abdominal pain, nausea, vomiting, diaphoresis, hypertension, tachycardia, hypertension, myocardial injury, pulmonary edema
 
===Irukandji syndrome===
*Myalgias, back, chest,  
*[[Abdominal pain]]
*[[Nausea and vomiting]]
*Diaphoresis
*[[Hypertension]]
*[[Tachycardia]]
*Myocardial injury
*[[Pulmonary edema]]


==Differential Diagnosis==
==Differential Diagnosis==

Revision as of 02:24, 20 August 2016

Background

  • Jellyfish; Box Jelly is most deadly
  • Most toxic: Australia and other Indo-Pacific waters

Mechanism

Nematocyst stages of discharge
  • Physical contact or osmotic gradient causes discharge of neamtocysts
  • A spring loaded venom delivery system

Clinical Features

  • Isolated stinging
  • Severe
    • Respiratory paralysis, cardiovascular collapse, limb paralysis and death

Irukandji syndrome

Differential Diagnosis

Marine toxins, envenomations, and bites

Management

  • Remove tentacles and nematocysts
  • Hot water immersion
  • Consider topical lidocaine
  • Consider oral or parenteral analgesia for severe pain
  • Acetic Acid may inhibit or trigger nematocyst discharge and thereby increase or decrease pain depending on species
  • Avoid urine, ethanol, ammonia
  • Avoid fresh or tap water since it causes nematocyst discharge via the osmotic gradient
  • Symptomatic treatment for Irukandji syndrome
  • Antivenom is available for severe box-jellyfish sting

See Also

References

  1. Ward NT, Darracq MA, Tomaszewski C, et al. Evidence based treatment of jellyfish stings in North America and Hawaii. Ann Emerg Med. 2012;60(4):339-414.
  2. Cegolon L, Heymann WC, Lange JH, et al. Jellyfish stings and their management: a review. Mar Drugs. 2013;11(2): 523-50