Saidala 24: Jellyfish and other sea creature stings

Introduction

Marine envenomations from jellyfish and other sea creatures are a significant cause of injury in coastal regions worldwide. They can range from mild local irritation to life-threatening systemic reactions, depending on the species involved and the amount of venom delivered. Immediate recognition and appropriate first aid are essential to prevent complications.

Causative Marine Organisms

1. Jellyfish (Cnidarians)

Box jellyfish (Chironex fleckeri) – Found in Australian and Indo-Pacific waters; venom can cause cardiovascular collapse and death within minutes.
Irukandji jellyfish (Carukia barnesi) – Causes severe systemic syndrome (“Irukandji syndrome”) with delayed onset pain, hypertension, and organ dysfunction.
Portuguese man o’ war (Physalia physalis) – Not a true jellyfish; venom causes painful skin welts and systemic symptoms.
Common coastal jellyfish species – Cause mild to moderate pain, redness, and swelling.

2. Other Marine Creatures

Sea urchins – Spine punctures can lead to pain, swelling, infection, and rarely systemic symptoms.
Stonefish and scorpionfish – Highly venomous spines; can cause intense pain, tissue necrosis, and cardiovascular collapse.
Stingrays – Venomous tail spines; can cause deep lacerations, bleeding, and systemic symptoms.
Cone snails – Neurotoxic venom; potentially fatal paralysis.
Fire coral and anemones – Mild to moderate skin irritation and dermatitis.

Pathophysiology

Marine venoms are complex mixtures containing:

Neurotoxins – Affect nerve conduction and muscle contraction.
Cardiotoxins – Disrupt cardiac rhythm and contractility.
Hemotoxins – Damage blood vessels, causing bleeding or clotting disorders.
Cytotoxins – Destroy local tissues and cells.

Delivery mechanisms include nematocysts (stinging cells), spines, or barbs.

Clinical Features

Local Symptoms

Immediate burning or stinging pain.
Redness, swelling, wheals, or linear whip-like lesions.
Vesicles or blisters in severe cases.
Retained spines or tentacles in the wound.

Systemic Symptoms (species-dependent)

Nausea, vomiting, abdominal cramps.
Headache, dizziness, sweating.
Muscle cramps, spasms, or paralysis.
Hypotension or hypertension.
Respiratory distress or cardiovascular collapse (e.g., box jellyfish, cone snail).
Delayed hypersensitivity rash (may appear days later).

Diagnosis

Clinical evaluation based on exposure history, geographic location, and lesion appearance.
Identification of the species helps guide treatment (especially for antivenom use).
Laboratory tests may be needed for systemic cases (ECG, cardiac enzymes, blood gases).

Management

First Aid – General Principles

Ensure scene safety – Avoid further exposure to tentacles or venomous spines.
Remove victim from the water – Prevent drowning if systemic symptoms are present.
Avoid rubbing the affected area – This can trigger more nematocyst discharge.

Species-Specific First Aid

Jellyfish Stings

Immediate action: Rinse with vinegar (4–6% acetic acid) for 30 seconds to inactivate nematocysts (effective for box jellyfish, Irukandji, and many tropical species).
- For Portuguese man o’ war: Avoid vinegar (may worsen nematocyst discharge); rinse with seawater instead.
Remove visible tentacles using tweezers or gloves.
Hot water immersion (40–45°C) for 20–45 minutes to reduce pain.
Apply ice packs if hot water is unavailable.

Stonefish, Scorpionfish, Stingray Injuries

Immediate hot water immersion (40–45°C) for 30–90 minutes to denature venom proteins.
Control bleeding and clean wound thoroughly.
Remove visible spines carefully; surgical removal may be required.

Sea Urchin Injuries

Remove superficial spines with tweezers.
Soak in hot water (40–45°C) for 30–90 minutes.
For deeply embedded spines, seek surgical evaluation.

Cone Snail and Highly Venomous Species

Apply a pressure immobilization bandage (as used for snakebites) to slow venom spread.
Immobilize the affected limb and seek emergency care immediately.

Medical Treatment

Pain Management

Paracetamol (acetaminophen) 500–1000 mg orally every 4–6 hours (max 4 g/day).
Ibuprofen 400–600 mg orally every 6–8 hours (max 2400 mg/day).
Opioids (e.g., morphine) for severe pain under medical supervision.

Antivenom Therapy

Box jellyfish antivenom (Chironex fleckeri) – Indicated for severe envenomation with cardiovascular compromise; given IV or IM under emergency settings.
Stonefish antivenom – Used for severe stonefish stings with systemic toxicity or intractable pain; IM injection.

Wound Care and Infection Prevention

Cleanse with antiseptic solution (povidone-iodine or chlorhexidine).
Consider tetanus booster if indicated.
Prophylactic antibiotics for puncture wounds at high risk of infection (e.g., ciprofloxacin 500 mg orally twice daily for 5–7 days).

Management of Systemic Reactions

Anaphylaxis: Administer adrenaline (epinephrine) 0.5 mg IM (1:1000 solution) every 5–15 minutes as needed, plus oxygen, IV fluids, and antihistamines.
Cardiac arrest: Advanced cardiac life support (ACLS) protocols.
Hypertension in Irukandji syndrome: May require IV magnesium sulfate or antihypertensive infusion in a monitored setting.

Complications

Persistent pain and hypersensitivity reactions.
Skin necrosis and scarring.
Secondary bacterial infection.
Long-term neurological symptoms (rare, species-dependent).

Prevention

Avoid swimming in known high-risk jellyfish seasons or areas.
Wear protective clothing such as stinger suits, wetsuits, or gloves.
Follow local safety warnings and lifeguard advice.
Carry a marine first aid kit with vinegar, tweezers, and protective gloves when in high-risk waters.

Saidala 24

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Tuesday, August 12, 2025

Jellyfish and other sea creature stings