Case Definition: Long-Acting Anticoagulant (Super Warfarin)
After an acute unintentional ingestion of a long-acting anticoagulant, the majority of patients are entirely asymptomatic. After a substantial ingestion of a long-acting anticoagulant, clinical signs of coagulopathy typically occur within 24-72 hours. Coagulopathy might manifest as epistaxis, gingival bleeding, hematemesis, hematuria, hematochezia, menometrorrhagia, ecchymosis, petechial hemorrhages, intracranial hemorrhages, or bleeding that is disproportionate to the level of the injury (1-3).
Laboratory criteria for diagnosis
Biologic: The criteria for diagnosis of a long-acting anticoagulant is the presence of one of the following factors:
- Prolonged prothrombin time (PT) and international normalized ratio (INR) (24 to 72 hours after exposure) persisting for weeks to months, as determined by hospital laboratory tests.
- Abnormal assays for factors II and VII in patients with unexplained bleeding and a normal PT, partial thromboplastin time, or INR, as determined by hospital or commercial laboratory tests.
- Detection of a long-acting anticoagulant (e.g., brodifacoum) in serum, plasma, or urine, as determined by commercial laboratory tests.
– OR –
- Environmental: Detection of a long-acting anticoagulant in environmental samples.Case classification
Suspected: A case in which a potentially exposed person is being evaluated by health-care workers or public health officials for poisoning by a particular chemical agent, but no specific credible threat exists.
Probable: A clinically compatible case in which a high index of suspicion (credible threat or patient history regarding location and time) exists for a long-acting anticoagulant exposure, or an epidemiologic link exists between this case and a laboratory-confirmed case.
Confirmed: A clinically compatible case in which laboratory tests have confirmed exposure.
- Caravati EM, Erdman AR, Scharman EJ, et al. Long-acting anticoagulant rodenticide poisoning: an evidence-based consensus guideline for out-of-hospital management. Clin Toxicology 2007;45(1):1-22.
- 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.
- NIOSH. NIOSH manual of analytical methods [online]. 2003. [cited 2013 Apr 5]. Available from URL: https://www.cdc.gov/niosh/docs/2003-154/.
- OSHA. Sampling and analytical methods [online]. 2010. [cited 2013 Apr 5]. Available from URL: http://www.osha.gov/dts/sltc/methods/index.html.
- FDA. Food: Laboratory methods [online]. 2013. [cited 2013 Apr 5]. Available from URL: http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/default.htm.
- EPA. Selected analytical methods: chemical methods query [online]. 2013. [cited 2013 Apr 5]. Available from URL: http://www.epa.gov/sam/searchchem.htm.
- Page last reviewed: April 4, 2018
- Page last updated: April 10, 2013
- Content source: National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)
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