Treatment of Rodenticide Poisoning with Dilated Pupils
Rodenticide poisoning presenting with dilated pupils requires immediate high-dose intravenous vitamin K1 therapy combined with urgent management of potential intracranial hemorrhage, as dilated pupils in this context likely indicate life-threatening cerebral bleeding with rising intracranial pressure. 1, 2, 3
Immediate Emergency Management
Neurological Assessment and Stabilization
- Perform rapid neurological assessment focusing on pupil size, symmetry, reactivity to light, level of consciousness, and motor responses, as dilated pupils may indicate impending brain herniation 1
- Elevate head of bed to 30 degrees immediately to improve venous drainage and reduce intracranial pressure 1, 4
- Administer osmotic therapy with mannitol or hypertonic saline as first-line intervention for suspected rising intracranial pressure 1, 4
- Obtain urgent neuroimaging (CT or MRI of the head) to identify intracranial hemorrhage, as rodenticide poisoning can cause subarachnoid hemorrhage, intracerebral hematoma, and brain edema 1, 2, 3
Coagulation Management
- Immediately check coagulation parameters including PT, APTT, and INR, which are typically markedly prolonged beyond measurable limits in long-acting anticoagulant rodenticide (LAAR) poisoning 5, 2, 3
- Administer high-dose intravenous vitamin K1 at 50-100 mg IV initially for acute hemorrhagic symptoms 5
- Transfuse fresh frozen plasma to rapidly correct coagulopathy in the setting of active bleeding 2, 3
- Consider prothrombin complex concentrate or recombinant factor VIIa as adjunctive hemostatic therapy for life-threatening hemorrhage 5
Definitive Treatment Protocol
Vitamin K1 Dosing Strategy
- Initial phase: Continue IV vitamin K1 at 50-100 mg daily until bleeding stabilizes and coagulation parameters improve 5
- Maintenance phase: Transition to oral vitamin K1 at 100 mg daily (most frequently used maintenance dose) once stable 5
- Gradually taper the maintenance dose over time as coagulation function normalizes 6
- Expect prolonged treatment duration averaging 168 days due to the extremely high affinity of LAARs for vitamin K epoxide reductase 5
Monitoring Requirements
- Continuously monitor pupillary size and reactivity, level of consciousness, vital signs, and neurological status 1, 4
- Watch for signs of brainstem compression including bradycardia, irregular breathing patterns, and sudden apnea 1, 4
- Serial coagulation testing to guide vitamin K1 dosing adjustments and detect rebound coagulopathy 5, 3
- Reassess neurological status frequently as symptoms may progress despite initial stabilization 2, 3
Critical Clinical Considerations
Specific Rodenticide Characteristics
- Long-acting anticoagulant rodenticides (bromadiolone, brodifacoum, difenacoum) have extremely long half-lives and cause rebound coagulopathy after initial treatment 5, 2
- These "super-warfarins" have much higher affinity for vitamin K epoxide reductase compared to warfarin, requiring prolonged high-dose therapy 5
Common Pitfalls to Avoid
- Do not underestimate treatment duration: Premature discontinuation of vitamin K1 leads to rebound bleeding 5
- Do not delay neuroimaging: CNS hemorrhage is rare but potentially lethal in rodenticide poisoning 2, 3
- Avoid hyperventilation except in cases of imminent cerebral herniation, and only for short periods 1, 4
- Monitor for paradoxical thrombosis: LAAR poisoning can rarely cause thrombotic complications 5
Surgical Intervention
- Neurosurgical consultation is indicated for significant intracranial hematoma with mass effect or midline shift 2, 3
- Decompressive surgery may be necessary in addition to medical management with mannitol and vitamin K1 2, 3