Nematocysts: Difference between revisions

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==Mechanism==
==Background==
*Jellyfish; [[box jellyfish|box jellyfish]] is most deadly
*Most toxic: Australia and other Indo-Pacific waters
 
<gallery mode="packed">
File:Avispa marina cropped.png|[[Box jellyfish]]
File:Lithothamnion sp..jpg|Coral reef
File:Portuguese Man-O-War (Physalia physalis).jpg|Portuguese Man-O-War {Physalia physalis)
File:Actiniaria.jpg|A selection of various sea anemones
</gallery>
 
 
===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 nematocysts
*A spring loaded venom delivery system
*A spring loaded venom delivery system
*Once opened, a nematocyst releases all of its contained venom
==Clinical Features==
[[File:PMC3760923 abd-88-0496-g04.png|thumb|Skin lesion after contact with the cubomedusa Chiropsalmus quadrumanus jellyfish]]
*Isolated stinging, pain
*Severe
**Limb [[weakness|paralysis]]
**[[Respiratory arrest|Respiratory paralysis]]
**[[Shock|Cardiovascular collapse]]
**[[cardiac arrest|Death]]
===Irukandji syndrome===
*[[Myalgia]]s, [[back pain|back]], [[chest pain]],
*[[Abdominal pain]]
*[[Nausea and vomiting]]
*Diaphoresis
*[[Hypertension]]
*[[Tachycardia]]
*[[Myocardial ischemia|Myocardial injury]]
*[[Pulmonary edema]]
==Differential Diagnosis==
{{Marine envenomation DDX}}
==Evaluation==
*Generally a clinical diagnosis
==Management==
*Remove tentacles and nematocysts
*Hot salt water immersion (inactivates heat labile toxins), submerging the area in 45 ℃ water for 20 minutes has been shown to provide significant pain relief<ref>#Isbister GK, Currie BJ. Hot water immersion v icepacks for treating pain of Chironex fleckeri stings: a randomised controlled trial. Med J Aust. 2017 Oct 16;207(8):362. PubMed PMID: 29020913.</ref>
*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 (can use fruit juice or other flavored sodas if vinegar not available)
**It does inhibit nematocyst discharge in the Box Jellyfish species <ref>Yanagihara AA, Wilcox CL. Cubozoan Sting-Site Seawater Rinse, Scraping, and Ice Can Increase Venom Load: Upending Current First Aid Recommendations. Toxins (Basel). 2017;9(3):105. Published 2017 Mar 15. doi:10.3390/toxins9030105</ref>
*'''Symptomatic treatment for Irukandji syndrome'''
*'''Antivenom is available for severe [[box jellyfish]] sting'''
===Avoid===
*Urine, ethanol, ammonia
*Fresh or tap water (causes nematocyst discharge via the osmotic gradient)
==Disposition==
==See Also==
*[[Marine toxins and envenomations]]
*[[Sea wasp]]
==References==
#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.
#Cegolon L, Heymann WC, Lange JH, et al. Jellyfish stings and their management: a review. Mar Drugs. 2013;11(2): 523-50


==Treatment==
[[Category:Environmental]][[Category:Toxicology]]
* Immerse in 5% acetic acid to inactivate nematocysts
*Alternatives
** Immersion in rubbing alcohol (isopropyl 40%)
**Baking soda
*'''Avoid  fresh or tap water since it causes nematocyst discharge via the osmotic gradient'''
*'''Antivenom is available for severe box-jellyfish sting'''
[[Category:Environ]][[Category:Tox]]

Revision as of 15:30, 4 January 2021

Background

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


Mechanism

Nematocyst stages of discharge
  • Physical contact or osmotic gradient causes discharge of nematocysts
  • A spring loaded venom delivery system
  • Once opened, a nematocyst releases all of its contained venom

Clinical Features

Skin lesion after contact with the cubomedusa Chiropsalmus quadrumanus jellyfish

Irukandji syndrome

Differential Diagnosis

Marine toxins, envenomations, and bites

Evaluation

  • Generally a clinical diagnosis

Management

  • Remove tentacles and nematocysts
  • Hot salt water immersion (inactivates heat labile toxins), submerging the area in 45 ℃ water for 20 minutes has been shown to provide significant pain relief[1]
  • 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 (can use fruit juice or other flavored sodas if vinegar not available)
    • It does inhibit nematocyst discharge in the Box Jellyfish species [2]
  • Symptomatic treatment for Irukandji syndrome
  • Antivenom is available for severe box jellyfish sting

Avoid

  • Urine, ethanol, ammonia
  • Fresh or tap water (causes nematocyst discharge via the osmotic gradient)

Disposition

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
  1. #Isbister GK, Currie BJ. Hot water immersion v icepacks for treating pain of Chironex fleckeri stings: a randomised controlled trial. Med J Aust. 2017 Oct 16;207(8):362. PubMed PMID: 29020913.
  2. Yanagihara AA, Wilcox CL. Cubozoan Sting-Site Seawater Rinse, Scraping, and Ice Can Increase Venom Load: Upending Current First Aid Recommendations. Toxins (Basel). 2017;9(3):105. Published 2017 Mar 15. doi:10.3390/toxins9030105