5 - Envenomation - Marine.pdf

21/09/2022 Envenomation ‐ Marine •1 Locate & Review • The lymphatic system & its function • Review the nervous system, especially the neuromuscular junction • Describe the mechanism of action of neurotoxins at the NMJ • Review relevant articles •2 Blue‐ringed Octopus • Can ‘attack’ prey (e.g. c...

21/09/2022 Envenomation ‐ Marine •1 Locate & Review • The lymphatic system & its function • Review the nervous system, especially the neuromuscular junction • Describe the mechanism of action of neurotoxins at the NMJ • Review relevant articles •2 Blue‐ringed Octopus • Can ‘attack’ prey (e.g. crab), hold with tentacles, pierce shell with beak and then envenomate • Alternatively, hover over prey, squirt venom into water, waits for paralysis •3 1 21/09/2022 Blue‐ringed Octopus Venom • Tetrodotoxin (TTX) • Neuromuscular blockade, respiratory failure – Blockade of voltage gated Na+ channels stopping action potentials •4 Blue‐ringed Octopus Management • Pressure immobilisation bandage (PIB), if on limb • Assisted ventilation may be required • Closely monitor cardiovascular system • No antivenom available •5 Cone Shells • Classification: according to their prey: – Molluscivorous ‐ mollusk eaters – Vermivorous ‐ worm eaters – Piscivorous ‐ fish eaters (associate with human fatalities) •6 2 21/09/2022 C. marmoreus (marbled cone) • Venoms contain: – Conotoxins (also referred to as conopeptides) – (a, m and w‐conotoxins etc.) – Na+ ion channel toxins which cause paralysis DO NOT: • pick up cones • put cones in your pocket! C. textile (cloth of gold) Clinical Features • Local pain • Neurologic impairment • Progressive paralysis • Respiratory failure •7 Cone Shells ‐ II Conotoxin type Mechanism α‐conotoxin Inhibits nACh receptors at muscle and nerves δ‐conotoxin Inhibits inactivation of voltage gated Na+ channels κ‐conotoxin Inhibits K+ channels μ‐conotoxin Inhibits voltage gated Na+ channels in muscle ω‐conotoxin Inhibits N‐Type voltage gated Ca2+ channels Management • Apply pressure immobilisation bandage • Main treatment is supportive care, particularly respiration • No antivenom available •8 Stonefish •9 3 21/09/2022 Stonefish ‐ II • Clinical Features – Immediate severe pain – Swelling and erythema – At risk of shock • Management – Wash site and clear away any debris – Immerse in hot water (at least 45oC) for approx 20 min and repeat as needed (for up to 2 hr) – Pain relief and supportive care – If analgesics and hot water do not reduce the effects, stonefish antivenom should be considered – Ultrasound or radiograph to make sure no spine material remain in wounds •10 Lion Fish (Zebra Fish) • Often faces its attacker in an upside down posture which brings its spines to bear • The lionfish sting is usually not fatal to humans • If a person is stung, that person will experience: – – – – intense throbbing sharp pain tingling sensations sweatiness and blistering • In worst case scenarios the symptoms may include: – – – – – – – headache nausea, abdominal pain delirium, seizures paralysis of limbs changes in blood pressure breathing difficulties, heart failure and tremors pulmonary oedema, and loss of consciousness •11 Lion Fish (Zebra Fish) ‐ II Management • Immerse in hot water (at least 45oC) for approx 20 min and repeat as needed (for up to 2 hr) • Antivenom (stonefish) • Analgesia ‐ narcotic • Regional nerve block? •12 4 21/09/2022 Scorpion fish • Similar effects to stonefish of the northern waters, painful but not as severe • No deaths associated with envenoming Little scorpionfish Management • Same method as stonefish: • Wash site and clear away any debris • Immerse in hot water (at least 45oC, as with stonefish) • Pain relief and supportive care • If analgesics and hot water do not reduce the effects => stonefish antivenom an option. Southern red scorpionfish •13 Other Fish with Venomous Spines Flathead Red rock cod Catfish Cobbler •14 Toad Fish • • Very similar to the famous puffer fish that is eaten as a delicacy Organs contain tetrodotoxin (same toxin as blue‐ringed octopus) Clinical Features – – – – – Parathesia of lips and tongue Muscle weakness Cyanosis Hypotension Coma Common toadfish Management • Immediate supportive care • Respiratory support • Decontamination – activated charcoal Smooth toadfish •15 5 21/09/2022 Sea Urchins • Most sea urchin injuries are from non‐venomous species, pain from mechanical injury • Venomous species cause more severe pain • Some cases have been linked to paralysis and possible respiratory failure (not in Australia) •16 Sea Urchins ‐ II Pedicellaria Spines •17 Sea Urchins ‐ III Management • Main issue is removal of spines • Venomous injuries may be more painful and hot water immersion is appropriate. • Pedicellaria may have to be carefully scraped off • Further x‐rays or ultrasound scans maybe required to detect debris. • Surgical removal maybe required. • Risk of infection. •18 6 21/09/2022 Stingrays • Common all around Australia • Tail contains a sharp barb • Used in defence Stings: • Usually painful, due to unknown venom components and mechanical damage done by barb • Local pain may spread • Nausea, vomiting, sweating, cramps. •19 Stingray ‐ II Management • Bath wound in seawater and clean as much as possible • If safe, remove any barbs. If unsure, wait for hospital assistance. • Immerse in hot water (approx. 45oC) • If bleeding, try to apply pressure. • Apply heat pack rather than hot water. • Pain relief •20 Jellyfish •21 7 21/09/2022 Australian Box Jellyfish Cnidaria Chirodropid Carybdeid Class: Cubozoa Chiropsalmus sp. Chironex fleckeri Carukia barnesi •22 Jellyfish Envenomation Process • Tentacles and bells (bodies) covered with stinging cells (nematocysts) – different types of nematocysts – nematocysts deliver venom and/or adhere to prey •23 Chironex fleckeri Chiropsalmus • can grow up to 60 tentacles and a bell size of ~325mm • closely related, but smaller with fewer tentacles, bell size of ~105mm • “the most venomous creature in the world”? • >65 documented deaths Australian waters (5-20 min of sting) • due to cardiac or respiratory failure (or both) • Chiropsalmus quadrigatus (fatalities in the Philippines & Japan) • no recorded deaths following envenoming (in Australian waters) •24 8 21/09/2022 Chironex Fleckeri Jellyfish Management • Box Jellyfish (Chironex fleckeri) – Severe local pain – Erythematous wheal (looks like you’ve been whipped) – Rapid cardiovascular collapse • Management – Immediate removal of any tentacles – Wash with vinegar – Local pain initially treated with ice packs – Early resuscitation maybe required – Antivenom available but efficacy is unclear •25 Carukia barnesi • • • • • • Small jellyfish (bell diameter 1.5-2.5 cm) Tentacles up to 1 m large distribution in northern waters of Australia Irukandji syndrome 2 reported deaths since 2002 symptoms thought to be due to excess catecholamines •26 Irunkandji Syndrome • The Irukandji's sting causes symptoms which are collectively known as "Irukandji syndrome". • The initial sting is typically mild and is followed, minutes to hours later, by: – – – – – vomiting, profuse sweating, headache, agitation, rapid heart rate and very high blood pressure. • The increase in blood pressure may be life‐threatening and can be associated with arrhythmias and heart failure • The symptoms may last from hours to several days, and victims usually require hospitalisation. • In rare cases, the victim suffers pulmonary oedema which could be fatal if not treated. •27 9 21/09/2022 Irukandji Jellyfish Management • Box Jellyfish (Carukia barnesi) “Irukandji jellyfish” – – – – “Irukandji” syndrome Minor local effects Severe generalised pain Tachycardia, hypertension, nausea • Management – Wash with vinegar (Controversial) – Pain relief and supportive care – Close monitoring for cardiovascular complications •28 Other Jellyfish Bluebottle Jellyfish • Immediate intense pain • Rash or localised redness at sting site • Management – Wash site with seawater – Immerse in hot water (at least 45oC) for approx 20 min – If immersion is not possible => a flow of hot water over the sting site or hot shower is recommended – Vinegar is not recommended •29 Sea Snakes • Approximately 31 species of sea snake in Northern Australia • Venom components of importance: – Post‐synaptic neurotoxins – Myotoxins • Local effects are rare, usually only systemic effects: – Ptosis, limb weakness, myolysis (CK increase, muscle pain, myoglobinuria) Beaked sea snake Banded sea krait Elegant sea snake •30 10 21/09/2022 Sea snakes + Beaked sea snake Tiger snake Sea snake antivenom is produced from a mixture of antibodies raised against the Beaked sea snake and the land based Tiger snake •31 Sea Snakes Management • Same treatment method as for land based snake bites – Pressure bandage immobilisation • Keep patient calm • Move patient as little as possible • Closely monitor for signs of paralysis – Antivenom if indicated by systemic effects or other diagnostic indications (CK level increase etc.) •32 Any Questions •33 11