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Atypical bromethalin intoxication in a dog: pathologic features and identification of an isomeric breakdown product.

Bates MC, Roady P, Lehner AF, Buchweitz JP, Heggem-Perry B, Lezmi S - BMC Vet. Res. (2015)

Bottom Line: Bromethalin exposure and tissue absorption was confirmed by identification of one of two isomeric 543.7 molecular weight (MW) breakdown products in the patient's adipose and kidney samples using gas chromatography (GC) combined with tandem quadrupole mass spectrometry (MS/MS).Meningeal hemorrhages are atypical of bromethalin intoxication, and might have been caused by hyperthermia, secondary to tremors or hypernatremia.Identification of one of two isomeric breakdown products in the adipose tissue and kidney provides an additional molecule to the toxicologic testing regime for bromethalin intoxication.

View Article: PubMed Central - PubMed

Affiliation: College of Veterinary Medicine, Department of Pathobiology & Veterinary Diagnostic Laboratory, University of Illinois, 2001 S. Lincoln Ave, Urbana, IL, 61802, USA. mbates@illinois.edu.

ABSTRACT

Background: Definitive post mortem confirmation of intoxication by the neurotoxic rodenticide bromethalin can be challenging. Brain lesions are not specific and detection of bromethalin and its metabolites are unpredictable due to rapid photodegradation and inconsistent behavior in tissues.

Case presentation: A 2-year-old dog presented with rapid onset of severe muscle tremors and death within hours after a known ingestion of a reportedly low dosage of bromethalin and subsequent decontamination using activated charcoal. Marked meningeal hemorrhages and multifocal myelin sheath vacuolation were observed in the brain. A marked reactive astrocytosis and neuronal hypoxia/necrosis were identified using immunohistochemistry (IHC) for glial fibrillary acidic protein (GFAP) and for neuron specific protein (NeuN). Bromethalin exposure and tissue absorption was confirmed by identification of one of two isomeric 543.7 molecular weight (MW) breakdown products in the patient's adipose and kidney samples using gas chromatography (GC) combined with tandem quadrupole mass spectrometry (MS/MS).

Conclusions: The severity of clinical signs and subsequent death of this dog was not expected with the low dosage of bromethalin reportedly ingested, and the use of activated charcoal possibly precipitated a hypernatremic status. Meningeal hemorrhages are atypical of bromethalin intoxication, and might have been caused by hyperthermia, secondary to tremors or hypernatremia. Identification of one of two isomeric breakdown products in the adipose tissue and kidney provides an additional molecule to the toxicologic testing regime for bromethalin intoxication.

No MeSH data available.


Related in: MedlinePlus

Application of GC-MS/MS bromethalin MRM method. a Bromethalin spiked at 100 ppm into control liver sample. Note bromethalin peak at 17.95-min RT, and principal 543.7 MW breakdown peaks (detected with sensitive m/z 543-derived MRMs) at 16.3-min and 18.6-min retention times, respectively. b Fat sample collected from our dog. Note that only the 16.3-min bromethalin breakdown compound was present. c Kidney from the same dog shows the 16.3-min peak and a trace of the 18.6-min peak
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Fig3: Application of GC-MS/MS bromethalin MRM method. a Bromethalin spiked at 100 ppm into control liver sample. Note bromethalin peak at 17.95-min RT, and principal 543.7 MW breakdown peaks (detected with sensitive m/z 543-derived MRMs) at 16.3-min and 18.6-min retention times, respectively. b Fat sample collected from our dog. Note that only the 16.3-min bromethalin breakdown compound was present. c Kidney from the same dog shows the 16.3-min peak and a trace of the 18.6-min peak

Mentions: Bromethalin analytical standard was generously supplied by the US Environmental Protection Agency (US EPA) National Pesticide Standard Repository. Desmethylbromethalin standard was from Toronto Research Chemicals (Toronto, Ontario, Canada). IUPAC chemical names were obtained by use of ChemDraw Professional software version 15.0.0.106 (Perkin Elmer, Waltham, MA). Analytical screening of bromethalin, desmethylbromethalin, and physicochemical breakdown products in adipose fat, brain, kidney, liver, and stomach content was performed by GC-MS/MS using two 15 m × 0.250 mm × 0.25 um DB5-MS capillary columnsi joined with a “T” configuration to enable post-run backflushing. The GC oven temperature was held at 15 °C for 3 minutes and then ramped to 260 °C at a rate of 20 °C/minute The oven temperature was maintained for 10 minutes then increased at 60 °C/minute to 320 °C (held 8-minutes) for a total run time of 27.5 minutes. Helium was used as the carrier gas with an inlet pressure of 18.1 psi. The inlet configuration was set to pulsed splitless mode and 5 uL of sample was injected for analysis. The inlet temperature was held at 130 °C for 1 min. and then ramped to 325 °C at a rate of 600 °C/min for 5 min. The transfer line temperature was set to 280 °C. The collision cell used helium as the quench gas at 2.25 mL/min, nitrogen as the collision gas at 1.5 mL/min, and a collision energy ranging from 5 to 35 volts depending on analyte. Results for kidney and adipose samples as well as a spiked liver control are shown in Fig. 3a. The positive control for this study consisted of unexposed bovine liver spiked with bromethalin in methanolic solution to 100 ppm. The negative control was the same liver matrix treated with solvent only, and its examination produced a flat baseline in comparison to the chromatographic peaks seen in the spike or samples (result not shown).Fig. 3


Atypical bromethalin intoxication in a dog: pathologic features and identification of an isomeric breakdown product.

Bates MC, Roady P, Lehner AF, Buchweitz JP, Heggem-Perry B, Lezmi S - BMC Vet. Res. (2015)

Application of GC-MS/MS bromethalin MRM method. a Bromethalin spiked at 100 ppm into control liver sample. Note bromethalin peak at 17.95-min RT, and principal 543.7 MW breakdown peaks (detected with sensitive m/z 543-derived MRMs) at 16.3-min and 18.6-min retention times, respectively. b Fat sample collected from our dog. Note that only the 16.3-min bromethalin breakdown compound was present. c Kidney from the same dog shows the 16.3-min peak and a trace of the 18.6-min peak
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4584469&req=5

Fig3: Application of GC-MS/MS bromethalin MRM method. a Bromethalin spiked at 100 ppm into control liver sample. Note bromethalin peak at 17.95-min RT, and principal 543.7 MW breakdown peaks (detected with sensitive m/z 543-derived MRMs) at 16.3-min and 18.6-min retention times, respectively. b Fat sample collected from our dog. Note that only the 16.3-min bromethalin breakdown compound was present. c Kidney from the same dog shows the 16.3-min peak and a trace of the 18.6-min peak
Mentions: Bromethalin analytical standard was generously supplied by the US Environmental Protection Agency (US EPA) National Pesticide Standard Repository. Desmethylbromethalin standard was from Toronto Research Chemicals (Toronto, Ontario, Canada). IUPAC chemical names were obtained by use of ChemDraw Professional software version 15.0.0.106 (Perkin Elmer, Waltham, MA). Analytical screening of bromethalin, desmethylbromethalin, and physicochemical breakdown products in adipose fat, brain, kidney, liver, and stomach content was performed by GC-MS/MS using two 15 m × 0.250 mm × 0.25 um DB5-MS capillary columnsi joined with a “T” configuration to enable post-run backflushing. The GC oven temperature was held at 15 °C for 3 minutes and then ramped to 260 °C at a rate of 20 °C/minute The oven temperature was maintained for 10 minutes then increased at 60 °C/minute to 320 °C (held 8-minutes) for a total run time of 27.5 minutes. Helium was used as the carrier gas with an inlet pressure of 18.1 psi. The inlet configuration was set to pulsed splitless mode and 5 uL of sample was injected for analysis. The inlet temperature was held at 130 °C for 1 min. and then ramped to 325 °C at a rate of 600 °C/min for 5 min. The transfer line temperature was set to 280 °C. The collision cell used helium as the quench gas at 2.25 mL/min, nitrogen as the collision gas at 1.5 mL/min, and a collision energy ranging from 5 to 35 volts depending on analyte. Results for kidney and adipose samples as well as a spiked liver control are shown in Fig. 3a. The positive control for this study consisted of unexposed bovine liver spiked with bromethalin in methanolic solution to 100 ppm. The negative control was the same liver matrix treated with solvent only, and its examination produced a flat baseline in comparison to the chromatographic peaks seen in the spike or samples (result not shown).Fig. 3

Bottom Line: Bromethalin exposure and tissue absorption was confirmed by identification of one of two isomeric 543.7 molecular weight (MW) breakdown products in the patient's adipose and kidney samples using gas chromatography (GC) combined with tandem quadrupole mass spectrometry (MS/MS).Meningeal hemorrhages are atypical of bromethalin intoxication, and might have been caused by hyperthermia, secondary to tremors or hypernatremia.Identification of one of two isomeric breakdown products in the adipose tissue and kidney provides an additional molecule to the toxicologic testing regime for bromethalin intoxication.

View Article: PubMed Central - PubMed

Affiliation: College of Veterinary Medicine, Department of Pathobiology & Veterinary Diagnostic Laboratory, University of Illinois, 2001 S. Lincoln Ave, Urbana, IL, 61802, USA. mbates@illinois.edu.

ABSTRACT

Background: Definitive post mortem confirmation of intoxication by the neurotoxic rodenticide bromethalin can be challenging. Brain lesions are not specific and detection of bromethalin and its metabolites are unpredictable due to rapid photodegradation and inconsistent behavior in tissues.

Case presentation: A 2-year-old dog presented with rapid onset of severe muscle tremors and death within hours after a known ingestion of a reportedly low dosage of bromethalin and subsequent decontamination using activated charcoal. Marked meningeal hemorrhages and multifocal myelin sheath vacuolation were observed in the brain. A marked reactive astrocytosis and neuronal hypoxia/necrosis were identified using immunohistochemistry (IHC) for glial fibrillary acidic protein (GFAP) and for neuron specific protein (NeuN). Bromethalin exposure and tissue absorption was confirmed by identification of one of two isomeric 543.7 molecular weight (MW) breakdown products in the patient's adipose and kidney samples using gas chromatography (GC) combined with tandem quadrupole mass spectrometry (MS/MS).

Conclusions: The severity of clinical signs and subsequent death of this dog was not expected with the low dosage of bromethalin reportedly ingested, and the use of activated charcoal possibly precipitated a hypernatremic status. Meningeal hemorrhages are atypical of bromethalin intoxication, and might have been caused by hyperthermia, secondary to tremors or hypernatremia. Identification of one of two isomeric breakdown products in the adipose tissue and kidney provides an additional molecule to the toxicologic testing regime for bromethalin intoxication.

No MeSH data available.


Related in: MedlinePlus