Page 630 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

Anticoagulant Chapter | 46 595

VetBooks.ir hemorrhage after accidental brodifacoum exposure in a susceptibility of individuals to anticoagulant rodenticide
poisoning) (Beasley and Buck, 1983; Mount et al., 1985).
child is rarely known to occur (Travis et al., 1993; Watts
A point-of-care test kit was evaluated and found to be
et al., 1990; Beriain Rodrı ´guez et al., 2008); however, it
may occur after intentional dosing (Babcock et al., 1993). able to detect warfarin at concentrations below the manu-
Adult: Iatrogenic toxicosis cases in adults occur with facturer’s recommended limit of detection, but was unable
more frequency (Walker and Beach, 2002; Waien et al., to detect pindone, chlorphacinone, brodifacoum, bro-
2001; Weitzel et al., 1990; Hong et al., 2010; Moery methalin, or its metabolite desmethylbromethalin (Istvan
and Pontious, 2009), and combinations of anticoagulant et al., 2014).
rodenticides and glass (Tsutaoka et al., 2003), ethylene Identification of dye in fecal material may be used to
glycol (Seidelmann et al., 1995), and drugs of abuse raise a question about potential ingestion of a pesticide.
(Spahr et al., 2007) have been reported. As many as For example, a 57-year-old woman ingested red-dyed pel-
three different compounds have been detected in one lets of anticoagulant rodenticide containing difethialone
woman (Zolcinski et al., 2008). Human bromadiolone tox- and warfarin, as well as tablets of nitrazepam. Although
icosis has recently been reported in China (Shi et al., she presented to the hospital in a comatose state,
2005), and is known elsewhere (Shanberge, 1988). Cases notable pink-colored excreta hinted at the consumption of
of intentional exposures in adults with major depressive anticoagulant rodenticide.
disorders (Yu et al., 2013), attempts at potentiating self-
mutilation (Centorino et al., 2012), and suicide have
recently been reported (Altay et al., 2012). Clinical Signs
Toxicosis should be considered in any adult who pre- A history of exposure to anticoagulant rodenticides is not
sents with an unexplained coagulopathy with extreme always available, or reliable, so toxicosis is occasionally
elevation of PT and partial thromboplastin time with inferred from symptoms in humans and clinical signs in
associated depletion of vitamin K dependent factors. If animals. Clinical symptoms and signs have been reported
toxicosis is confirmed, intentional ingestion should be in a number of human and animal cases.
considered (Watson et al., 2012). Most clinical observations are interpreted as an
acquired coagulopathy (Huic et al., 2002; Humphry, 1989).
The onset of the coagulopathy is, however, delayed. Dogs
DIAGNOSIS exposed to toxic doses of anticoagulant rodenticides remain
asymptomatic until depletion of the active clotting factors
History occurs, so clinical signs are not generally observed until
A clinical diagnosis of anticoagulant rodenticide poison- 1 2 days (Dorman, 1990)or3 5 days (Murphy and
ing is most often dependent on a history of exposure, Gerken, 1989) postexposure.
clinical signs, evidence of a coagulopathy, and response Symptoms in humans: Epistaxis, gingival bleeding,
to vitamin K 1 therapy. The most pragmatic approach widespread bruising, hematomas, hematuria, menorrhea,
for determining the specific anticoagulant rodenticide GI bleeding, rectal bleeding, hemorrhage into any body
involved is to read the product package. This approach organ, and anemia have been reported (Watt et al., 2005).
alone is not definitive, because as much as 25% of antico- Cases of abdominal pain, hematuria, red blood in feces,
agulant rodenticide-intoxicated dogs do not have the diffuse cutaneous hematomas, hemoperitoneum, urethral
anticoagulant in serum the owners suspect. hematoma on tomography (Terneu et al., 2003; Barlow
A 25-year-old man attempted suicide by eating four et al., 1982; Berry et al., 2000), and diffuse alveolar
42-g boxes of 0.005% brodifacoum bait, and succeeded in hemorrhage (Barnett et al., 1992) may be observed.
developing a coagulopathy (Kruse and Carlson, 1992). Hemoperitoneum after fluconazole administration (Kim
A 33-year-old man ate 1875 mg of chlorophacinone et al., 2010), hematuria in 8 of 9 patients (Wu et al.,
(Lagrange et al., 1999) and an 18-year-old female deliber- 2009; Nelson et al., 2006), hemarthrosis (Kotsaftis et al.,
ately ingested 100 mg chlorophacinone (Vogel et al., 2007), and red sputum (Grobosch et al., 2006) have been
1988), and both became anticoagulated. reported.
Rodenticides may be more toxic when repeatedly Symptoms do not normally help identify the anticoag-
ingested over several days than when an equal amount ulant rodenticide involved. For example, hemoperitoneum
is consumed in a single feeding (Dorman, 1990). and intramural hematoma of the small intestine (Soubiron
Susceptibility may be greater in hypoprothrombinemic et al., 2000), epistaxis, hematoma, purpuria, and bruising
juveniles or animals with malabsorption syndromes. Also, (McCarthy et al., 1997; Laposata et al., 2007), hematuria
the concurrent administration of highly protein-bound (Butcher et al., 1992; Fang et al., 2012), neck pain, and
drugs (e.g., phenylbutazone, aspirin, or disease states, cervical hematoma have also been observed in humans
such as chronic renal disease, may increase the with diphenacoum exposure (Nighoghossian et al., 1990).