Venomous Substances: Identification and Management
Venomous substances are those produced by animals that can deliver toxins through specialized injection mechanisms like fangs, stingers, or spines, causing harmful effects in humans. 1
Distinguishing Venoms from Poisons
- Venoms are actively delivered through specialized injection structures (fangs, stingers, spines), while poisons are passively delivered through ingestion, absorption, or inhalation 1, 2
- Venomous animals include snakes, scorpions, spiders, marine creatures like jellyfish, cone snails, and certain fish species 1, 3
- Animal venoms are complex mixtures containing hundreds of different components, primarily proteins and peptides, producing diverse physiological effects 2
Clinical Effects of Venomous Exposures
Local Effects
- Pain, swelling, sweating, blistering, bleeding, and tissue necrosis at the site of envenomation 1
- Local tissue damage can be severe with certain snake species and some spider bites (particularly those causing loxoscelism) 3
Systemic Effects
- Neurological: Paralysis, seizures, sensory disturbances, ataxia, headache, and altered mental status 3
- Cardiovascular: Hypertension, hypotension, cardiac arrhythmias, and cardiac arrest 1, 3
- Hematological: Coagulopathy, hemorrhage, and consumption of clotting factors 3
- Respiratory: Respiratory depression or failure, particularly with neurotoxic venoms 1
- Renal: Acute kidney injury, particularly with certain snake venoms 1, 4
Management of Venomous Exposures
Immediate First Aid
- Contact emergency services or poison control center immediately 5
- Immobilize the affected limb and keep the patient still for snakebites 1
- For painful marine stings, hot water immersion is often recommended 1
- Remove all contaminated clothing and jewelry to prevent continued exposure 5
Medical Treatment
- Antivenom is the principal specific treatment for many venomous bites and stings 1
- Supportive care including airway management, ventilatory support, and correction of hemostatic disorders 3
- For specific venomous exposures, refer to specialized protocols based on the identified animal 6
Specific Antivenoms
- For snake envenomation: Antivenin (Crotalidae) polyvalent or Crotalidae Polyvalent Immune Fab for pit vipers 6
- For black widow spider bites: Antivenin (Latrodectus mactans) 6
- For coral snake bites: Antivenin (Micrurus fulvius) 6
Special Considerations
- Antivenom availability is limited for many species and may be in short supply in areas of highest need 1
- Prompt transport to a medical facility is crucial for severe envenomations 3
- Many inappropriate or dangerous first aid methods are in widespread use and should be avoided (cutting, sucking, tourniquets) 1
- Regional poison centers should be contacted for expert advice on management 5