Difference between revisions of "Chocolate Poisoning-Dog"

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Chocolate

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Introduction

Toxicity is due to the presence of methylxanthines such as theobromine and caffeine in chocolate ^[1]. Concentrations ranging from of 100-250mg/kg of theobromine and 110-200mg/kg of caffeine have been reported to cause fatalities ^[1]. The consumption of more than 20mg/kg of total methylxanthines, the dose at which mild signs such as vomiting, diarrhoea and polyuria are induced ^[1], is considered the cut-off point in deciding whether or not to treat ^[1]. The concentration of methylxanthines differs between products ^[1] and therefore the number of grammes required to reach this threshold vary according to the product; in a 10kg dog 5000g of white chocolate provides the equivalent 20mg/kg dose of methylxanthines that 12-40g of plain chocolate, 83-117g of milk chocolate or 7-25g of cocoa powder does ^[1]. Methylxanthines are also present in beverages and foods other than chocolates ^[1].

Signalment

Dog that live indoors are more likely to have access to chocolate. Also puppies and dogs that scavenge are at a greater risk of eating food that is not intended for their consumption. Small breeds of dogs may reach the toxic level of methylxanthine concentration per body weight more easily ^[1].

Diagnosis

Clinical Signs

Chocolate poisoning results in CNS, gastrointestinal, cardiovascular, respiratory and urological signs.^[1], ^[2] which are evident soon after ingestion of a toxic amount of chocolate ^[1]

CNS: hyperactivity, behavioural changes, ataxia, muscle tremors, clonic seizures and hyperthermia ^[1], ^[2], ^[1]
Gastrointestinal: diarrhoea, emesis, haematemesis ^[1], ^[2]
Cardiovascular: arrhythmias,tachycardia, bradycardia sometimes, hypotension ^[1], ^[2]
Respiratory: tachypnoea ^[1].
Urological: polydypsia and polyuria may also be present ^[1]

Laboratory Tests

Diagnosis is usually on the basis of clinical signs and a known history of chocolate ingestion ^[3]. The following laboratory tests are possible but not commonly used;

Assays for detection of methylxanthines in bodily fluids such as plasma, urine and stomach contents ^[1].
Blood Glucose: Hypoglycaemia as a sequela to hyperactivity. not seen consistently with chocolate poisoning ^[1].
Urinalysis: Proteinuria, low specific gravity; not seen consistently with chocolate poisoning ^[1].

Other

ECG: rate and rhythm abnormalities ^[1].

Pathology

Following absorption from the gastrointestinal tract caffeine and theobromine are metabolised in the liver ^[1]. Caffeine has a half life of 4.5 hours in dogs while theobromine has a half life of 17.5 hours ^[1]. In humans the half life of theobromine ranges from 6 to 10 hours, significantly shorter than that in dogs which may explain the susceptibility of dogs to chocolate poisoning REF. Methylxanthines have the following modes of action.

Antagonism of Adenosine Receptors:^[1] this antagonism results in stimulation of the central nervous system and an increase in heart rate ^[1] and also diureses ^[1]
Inhibition of Cyclic Nucleotide Phosphodiesterase:^[2] consequently there is an increase in cyclic AMP, which in turn leads to greater catecholamine release and their effects ^[1].
Modulation of Intracellular Calcium Concentrations: ^[1].

Ventricular fibrillation, and other cardiac dysrhythmias are most frequently the ultimate cause of death.^[4], ^[5].

Treatment

Of dogs presenting with clinical signs
- Inital stabilisation of Cardiorespiratory System:
  - Tachycardia: beta-blockers, eg orally administered metoprolol at a dose of 0.5mg to 1mg per kg every 8 hours ^[1].
  - Premature Ventricluar Contractions: lidocaine; iv bolus of 2mg to 6mg per kg administered slowly, after which a constant rate infusion of 20ug to 70ug per kg per minute should be given ^[1].
  - Bradycardia: Atropine at a dose of 0.01mg to 0.02mg per kg ^[1]

- Treatment of seizures and hyperactivity
  - IV Diazepam at a dose of 0.5 to 2 mg/kg ^[1].
  - Alternative to diazepam is barbiturates ^[1].
  - Treating the seizures and hyperactivity should help restore normal body temperature. If animal still hyperthermic then this should be treated directly ^[1]

- Correction of acid/base and electrolyte inbalances ref merck

- Insertion of urinary catheter
  - Helps prevent further absorption of theobromine and caffeine across bladder wall ref bsava

Of dogs with a known history of recent chocolate ingestion but who have not yet developed clinical signs
- Administration of apomorphine (0.03mg/kg IV) or hydrogen peroxide (1-5 ml/kg PO) ref 5 min vet consult in order to induce emesis and/or of activated charcoal in order to minimise further absorption of methylxanthines re 5 min vet consult

Prognosis

If treated correctly and early enough ref 5min consult the prognosis is good and a complete recovery can be expected ref bsava proceedings. For animals presenting with seizures and arrhythmias the prognosis is mor cautious.

References

↑ ^1.00 ^1.01 ^1.02 ^1.03 ^1.04 ^1.05 ^1.06 ^1.07 ^1.08 ^1.09 ^1.10 ^1.11 ^1.12 ^1.13 ^1.14 ^1.15 ^1.16 ^1.17 ^1.18 ^1.19 ^1.20 ^1.21 ^1.22 ^1.23 ^1.24 ^1.25 ^1.26 ^1.27 ^1.28 ^1.29 ^1.30 ^1.31 ^1.32 King, LG, Boag, A (2007) BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition) BSAVA Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content Cite error: Invalid <ref> tag; name "multiples" defined multiple times with different content
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↑ Carson TL (2006) Methylxanthines. In: Small Animal Toxicology, ed. ME Peterson, PA Talcott, pp.845-852. Elsevier Saunders, St. Louis in BSAVA Manual of Canine and Feline Emergency Care Chapter 19, Second Edition,2007
↑ Holmgren P, Norden-Petterson L and Ahlner J (2004)Caffeine fatalaties: four case reports. Forensic Science International 139, 71-73 BSAVA Manual of Canine and Feline Emergency Care Second Edition,2007

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[4] Carson TL (2006) Methylxanthines. In: Small Animal Toxicology, ed. ME Peterson, PA Talcott, pp.845-852. Elsevier Saunders, St. Louis in BSAVA Manual of Canine and Feline Emergency Care Chapter 19, Second Edition,2007

[5] Holmgren P, Norden-Petterson L and Ahlner J (2004)Caffeine fatalaties: four case reports. Forensic Science International 139, 71-73 BSAVA Manual of Canine and Feline Emergency Care Second Edition,2007

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 "[[File:Chocolate.jpg|thumb|Chocolate]]"
 ==Introduction==
-Toxicity is due to the presence of methylxanthines such as theobromine and caffeine in chocolate <ref name="multiples"> King,LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>. Concentrations ranging from of 100-250mg/kg of theobromine and 110-200mg/kg of caffeine have been reported to cause fatalities <ref name="multiples"> King,LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>. <ref name="multiples"> '''BSAVA Manual of Canine and Feline Emergency and Critical Care'''Chapter 19, Second Edition,2007 </ref>.  The consumption of more than 20mg/kg of total methylxanthines, the dose at which mild signs such as vomiting, diarrhoea and polyuria are induced <ref name="multiples"> http://www.merckvetmanual.com/mvm/index </ref>, is considered the cut-off point in deciding whether or not to treat <ref name="multiples"> '''Dietary intoxications, Chocolate (Theobromine and Caffeine)''', Warman SM, p253,''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme'' </ref>. The concentration of methylxanthines differs between products <ref name=multiples> Tilley, Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Second Edition), ''Lippencott, Williams and Wilkins''</ref> and therefore the number of grammes required to reach this threshold vary according to the product; in a 10kg dog 5000g of white chocolate provides the equivalent 20mg/kg dose of methylxanthines that 12-40g of plain chocolate, 83-117g of milk chocolate or 7-25g of cocoa powder does <ref name="multiples"> '''Dietary intoxications, Chocolate (Theobromine and Caffeine)''', Warman SM, p253,''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme'' </ref>.
+Toxicity is due to the presence of methylxanthines such as theobromine and caffeine in chocolate <ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>. Concentrations ranging from of 100-250mg/kg of theobromine and 110-200mg/kg of caffeine have been reported to cause fatalities <ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  The consumption of more than 20mg/kg of total methylxanthines, the dose at which mild signs such as vomiting, diarrhoea and polyuria are induced <ref name="multiples"> http://www.merckvetmanual.com/mvm/index </ref>, is considered the cut-off point in deciding whether or not to treat <ref name="multiples"> '''Dietary intoxications, Chocolate (Theobromine and Caffeine)''', Warman SM, p253,''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme'' </ref>. The concentration of methylxanthines differs between products <ref name=multiples> Tilley, Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Second Edition), ''Lippencott, Williams and Wilkins''</ref> and therefore the number of grammes required to reach this threshold vary according to the product; in a 10kg dog 5000g of white chocolate provides the equivalent 20mg/kg dose of methylxanthines that 12-40g of plain chocolate, 83-117g of milk chocolate or 7-25g of cocoa powder does <ref name="multiples"> '''Dietary intoxications, Chocolate (Theobromine and Caffeine)''', Warman SM, p253,''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme'' </ref>.
-Methylxanthines are also present in beverages and foods other than chocolates <ref name="multiples"> '''BSAVA Manual of Canine and Feline Emergency and Critical Care'''Chapter 19, Second Edition,2007 </ref>.
+Methylxanthines are also present in beverages and foods other than chocolates <ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.
 ==Signalment==