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Clinical
description
Following
an acute unintentional exposure to “super warfarin” (i.e.,
a long-acting anticoagulant), most patients are initially asymptomatic;
however, vomiting may occur. Clinical signs of coagulopathy may occur
in some patients within 24 to 72 hours (most commonly within 48 hours)
post exposure. Coagulopathy may manifest as epistaxis, gingival bleeding,
hematemesis, hemoptysis, hematuria, hematochezia, melena, menometrorrhagia,
ecchymosis, petechiae, intracranial hemorrhages, or bleeding out of proportion
to an injury. Tachycardia and hypotension may also occur in severely affected
patients due to acute blood loss.
Laboratory
criteria for diagnosis
One of the
following:
- Prolonged
prothrombin time (PT) and international normalized ratio (INR) (24 to
72 hours after exposure) persisting for weeks to months
- Abnormal
assays for coagulation factors II, VII, IX, and X in patients with unexplained
bleeding and normal PT/partial thromboplastin time (PTT) or INR
- Detection
of a long-acting anticoagulant in biological samples
– OR
–
- Detection
of a long-acting anticoagulant in environmental samples
Case
classification
- Probable:
a clinically compatible case with a high index of suspicion (reliable
intelligence or patient history) for a long-acting anticoagulant exposure
- Confirmed:
a clinically compatible case with laboratory confirmation or with an
epidemiological link to a laboratory-confirmed case
Additional
Resources
- Goldfrank LR, Flomenbaum
ME, Lewin NE, et al., editors. Goldfrank’s Toxicologic Emergencies.
7th ed. McGraw-Hill; 2002.
- Corke PJ. Superwarfarin
(brodifacoum) poisoning. Anaesth Intensive Care 1997;25:707–9.
- Barnett VT, Bergmann
F, Humphrey H, Chediak J. Diffuse alveolar hemorrhage secondary to superwarfarin
ingestion. Chest 1992;102:1301–2.
- Kruse JA, Carlson
RW. Fatal rodenticide poisoning with brodifacoum. Ann Emerg Med 1992;21:331–6.
- Chua JD, Friedenberg
WR. Superwarfarin poisoning. Arch Intern Med 1998;158:1929–32.
- Bruno GR, Howland
MA, McMeedking A, Hoffman RS. Long-acting anticoagulant overdose: Brodifacoum
kinetics and optimal vitamin K dosing. Ann Emerg Med 2000;36:262–7.
- Hollinger BR, Pastoor
TP. Case management and plasma half-life in a case of brodifacoum poisoning.
Arch Intern Med 1993;153:1925–8.
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