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Toxicology – Strychnine Poisoning
Source
Strychnine is a naturally occurring toxin derived from the seeds of the Strychnos nux-vomica tree. It is commonly used in rodenticides and pest control products and may also be found as an adulterant in illicit drugs.
Typical Presentation
Exposure typically follows ingestion or inhalation. Patients often present with sudden onset of severe muscle spasms and convulsions, sometimes after accidental or intentional ingestion of poison products.
Clinical Features
Early signs include anxiety, increased salivation, and dilated pupils. Rapidly, painful muscle spasms begin in the face and neck—manifesting as grimacing (risus sardonicus) and jaw stiffness (trismus)—then spread to the entire body.
Patients develop intense, prolonged muscle contractions (tetany), often with a characteristic arching posture (opisthotonus). Unlike typical seizures, patients may remain conscious and aware during these episodes. Severe complications include:
Strychnine blocks the inhibitory neurotransmitter glycine in the central nervous system, particularly at the spinal cord level. Without glycine’s inhibitory effect, motor neurons become overactive, leading to uncontrolled muscle contractions and spasms.
Management
Treatment is supportive and focused on controlling muscle activity and protecting the airway:
Source
Strychnine is a naturally occurring toxin derived from the seeds of the Strychnos nux-vomica tree. It is commonly used in rodenticides and pest control products and may also be found as an adulterant in illicit drugs.
Typical Presentation
Exposure typically follows ingestion or inhalation. Patients often present with sudden onset of severe muscle spasms and convulsions, sometimes after accidental or intentional ingestion of poison products.
Clinical Features
Early signs include anxiety, increased salivation, and dilated pupils. Rapidly, painful muscle spasms begin in the face and neck—manifesting as grimacing (risus sardonicus) and jaw stiffness (trismus)—then spread to the entire body.
Patients develop intense, prolonged muscle contractions (tetany), often with a characteristic arching posture (opisthotonus). Unlike typical seizures, patients may remain conscious and aware during these episodes. Severe complications include:
- Rhabdomyolysis
- Hyperthermia
- Metabolic (lactic) acidosis
- Respiratory failure due to sustained muscle contraction
Strychnine blocks the inhibitory neurotransmitter glycine in the central nervous system, particularly at the spinal cord level. Without glycine’s inhibitory effect, motor neurons become overactive, leading to uncontrolled muscle contractions and spasms.
Management
Treatment is supportive and focused on controlling muscle activity and protecting the airway:
- Benzodiazepines and barbiturates for seizure and spasm control
- Early intubation with sedation and use of nondepolarizing paralytics (e.g., rocuronium, vecuronium)
- IV fluids for rhabdomyolysis
- Active cooling for hyperthermia
- Patients may remain conscious during severe spasms (“conscious seizures”).
- Avoid succinylcholine, as it can worsen muscle contractions.
- Respiratory failure is a major cause of death.
- Rapid, aggressive supportive care is critical.
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