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"[[File:Chocolate.jpg|thumb|Chocolate]]"

[[File:Chocolate.jpg|thumb|Chocolate]]

==Introduction==

==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>.  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">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>, is considered the cut-off point in deciding whether or not to treat <ref name="multiples"> Warman, SM (2007)Dietary intoxications'''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme''' ''BSAVA'' </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"> Warman, SM (2007)Dietary intoxications'''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme''' ''BSAVA''</ref>

Toxicity is due to the presence of methylxanthines such as theobromine and caffeine in chocolate <ref name="multiple"> 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="multiple"> 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">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>, is considered the cut-off point in deciding whether or not to treat <ref name="multiples"> Warman, SM (2007)Dietary intoxications'''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme''' ''BSAVA'' </ref>. The concentration of methylxanthines differs between products <ref name="multiples"> Tilley, LP, Smith, FWK'''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"> Warman, SM (2007)Dietary intoxications'''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme''' ''BSAVA''</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>.

Methylxanthines are also present in beverages and foods other than chocolates <ref name="multiple"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.

==Signalment==

==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 <ref name="multiples">Tilley Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Second Edition), ''Lippincott, Williams and Wilkins''</ref>.

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 <ref name="multiple"> Tilley, LP, Smith, FWK ()'''The 5-Minute Veterinary Consult Canine and Feline(Second Edition)''' ''Lippencott, Williams and Wilkins''</ref>.

==Diagnosis==

==Diagnosis==

===Clinical Signs===

===Clinical Signs===

Chocolate poisoning results in CNS, gastrointestinal, cardiovascular, respiratory and urological signs.<ref name="multiples">Tilley Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Second Edition), ''Lippincott, Williams and Wilkins''</ref>, <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref> which are evident soon after ingestion of a toxic amount of chocolate <ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

Chocolate poisoning results in CNS, gastrointestinal, cardiovascular, respiratory and urological signs <ref name="multiple"> Tilley, LP, Smith, FWK ()'''The 5-Minute Veterinary Consult Canine and Feline(Second Edition)''' ''Lippencott, Williams and Wilkins''</ref>, <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref> which are evident soon after ingestion of a toxic amount of chocolate <ref name="multiple"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

*'''CNS:''' hyperactivity, behavioural changes, ataxia, muscle tremors, clonic seizures and hyperthermia <ref name="multiples">Tilley Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Second Edition), ''Lippincott, Williams and Wilkins''</ref>, <ref name="multiples"> Warman, SM (2007)Dietary intoxications'''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme''' ''BSAVA'' </ref>, <ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

*'''CNS:''' hyperactivity, behavioural changes, ataxia, muscle tremors, clonic seizures and hyperthermia <ref name="multiple"> Tilley, LP, Smith, FWK '''The 5-Minute Veterinary Consult Canine and Feline(Second Edition)''' ''Lippencott, Williams and Wilkins''</ref>, <ref name="multiples"> Warman, SM (2007)Dietary intoxications'''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme''' ''BSAVA'' </ref>, <ref name="multiple"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

*'''Gastrointestinal:''' diarrhoea, emesis, haematemesis <ref name="multiples">Tilley Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Third Edition), ''Lippincott, Williams and Wilkins''</ref>, <ref name="multiples"> Warman, SM (2007)Dietary intoxications'''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme''' ''BSAVA'' </ref>.

*'''Gastrointestinal:''' diarrhoea, emesis, haematemesis <ref name="multiples"> Tilley, LP, Smith, FWK'''The 5-Minute Veterinary Consult Canine and Feline(Second Edition)''' ''Lippencott, Williams and Wilkins''</ref>, <ref name="multiples"> Warman, SM (2007)Dietary intoxications'''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme''' ''BSAVA'' </ref>.

*'''Cardiovascular:''' arrhythmias,tachycardia, bradycardia sometimes, hypotension <ref name="multiples">Tilley Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Second Edition), ''Lippincott, Williams and Wilkins''</ref>, <ref name="multiples"> Warman, SM (2007)Dietary intoxications'''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme''' ''BSAVA'' </ref>.

*'''Cardiovascular:''' arrhythmias,tachycardia, bradycardia sometimes, hypotension <ref name="multiple"> Tilley, LP, Smith, FWK ()'''The 5-Minute Veterinary Consult Canine and Feline(Second Edition)''' ''Lippencott, Williams and Wilkins''</ref>, <ref name="multiples"> Warman, SM (2007)Dietary intoxications'''BSAVA Congress 2007 Scientific Proceedings, Veterinary Programme''' ''BSAVA'' </ref>.

*'''Respiratory:''' tachypnoea <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>.

*'''Respiratory:''' tachypnoea <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>.

*'''Urological:''' polydypsia and polyuria may also be present <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>.

*'''Urological:''' polydypsia and polyuria may also be present <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>.

Diagnosis is usually on the basis of clinical signs and a known history of chocolate ingestion <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>. The following laboratory tests are possible but not commonly used;

Diagnosis is usually on the basis of clinical signs and a known history of chocolate ingestion <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>. 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 <ref name="multiples">Tilley Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Third Edition), ''Lippincott, Williams and Wilkins''</ref>.

* Assays for detection of methylxanthines in bodily fluids such as plasma, urine and stomach contents <ref name="multiple"> Tilley, LP, Smith, FWK ()'''The 5-Minute Veterinary Consult Canine and Feline(Second Edition)''' ''Lippencott, Williams and Wilkins''</ref>.

* Blood Glucose: Hypoglycaemia as a sequela to hyperactivity. not seen consistently with chocolate poisoning <ref name="multiples">Tilley Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Third Edition), ''Lippincott, Williams and Wilkins''</ref>.  

* Blood Glucose: Hypoglycaemia as a sequela to hyperactivity. not seen consistently with chocolate poisoning <ref name="multiple"> Tilley, LP, Smith, FWK ()'''The 5-Minute Veterinary Consult Canine and Feline(Second Edition)''' ''Lippencott, Williams and Wilkins''</ref>.  

* Urinalysis: Proteinuria, low specific gravity; not seen consistently with chocolate poisoning <ref name="multiples">Tilley Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Third Edition), ''Lippincott, Williams and Wilkins'' </ref>.

* Urinalysis: Proteinuria, low specific gravity; not seen consistently with chocolate poisoning <ref name="multiple"> Tilley, LP, Smith, FWK ()'''The 5-Minute Veterinary Consult Canine and Feline(Second Edition)''' ''Lippencott, Williams and Wilkins''</ref>.

===Other===

===Other===

*ECG: rate and rhythm abnormalities <ref name="multiples">Tilley Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Third Edition), ''Lippincott, Williams and Wilkins''</ref>.

*ECG: rate and rhythm abnormalities <ref name="multiple"> Tilley, LP, Smith, FWK ()'''The 5-Minute Veterinary Consult Canine and Feline(Second Edition)''' ''Lippencott, Williams and Wilkins''</ref>.

===Pathology===

===Pathology===

Methylxanthines have the following modes of action.

Methylxanthines have the following modes of action.

*'''Antagonism of Adenosine Receptors:'''<ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref> this antagonism results in stimulation of the central nervous system and an increase in heart rate <ref name="multiples">Tilley Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Third Edition), ''Lippincott, Williams and Wilkins'' </ref> and also diureses <ref name="multiples"> '''http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm''', accessed on 04.10.2010 </ref>

*'''Antagonism of Adenosine Receptors:'''<ref name="multiple"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref> this antagonism results in stimulation of the central nervous system and an increase in heart rate <ref name="multiple"> Tilley, LP, Smith, FWK ()'''The 5-Minute Veterinary Consult Canine and Feline(Second Edition)''' ''Lippencott, Williams and Wilkins''</ref> and also diureses <ref name="multiples"> '''http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm''', accessed on 04.10.2010 </ref>

*'''Inhibition of Cyclic Nucleotide Phosphodiesterase:'''<ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref> consequently there is an increase in cyclic AMP, which in turn leads to greater catecholamine release and their effects <ref name="multiples">Tilley Smith'''The 5-Minute Veterinary Consult Canine and Feline''' (Third Edition), ''Lippincott, Williams and Wilkins'' </ref>.

*'''Inhibition of Cyclic Nucleotide Phosphodiesterase:'''<ref name="multiple"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref> consequently there is an increase in cyclic AMP, which in turn leads to greater catecholamine release and their effects <ref name="multiple"> Tilley, LP, Smith, FWK ()'''The 5-Minute Veterinary Consult Canine and Feline(Second Edition)''' ''Lippencott, Williams and Wilkins''</ref>.

*'''Modulation of Intracellular Calcium Concentrations:''' <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>.

*'''Modulation of Intracellular Calcium Concentrations:''' <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>.

Ventricular fibrillation, and other cardiac dysrhythmias are most frequently the ultimate cause of death.<ref> 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 </ref>, <ref> 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 </ref>.

Ventricular fibrillation, and other cardiac dysrhythmias are most frequently the ultimate cause of death.<ref> 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 </ref>, <ref> 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 </ref>.

'''Of dogs presenting with clinical signs'''

'''Of dogs presenting with clinical signs'''

*'''Inital stabilisation of Cardiorespiratory System:'''

*'''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 <ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

**Tachycardia: beta-blockers, eg orally administered metoprolol at a dose of 0.5mg to 1mg per kg every 8 hours <ref name="multiple"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

**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 <ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

**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 <ref name="multiple"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

**Bradycardia: Atropine at a dose of 0.01mg to 0.02mg per kg <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>.

**Bradycardia: Atropine at a dose of 0.01mg to 0.02mg per kg <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>.

*'''Treatment of seizures and hyperactivity'''

*'''Treatment of seizures and hyperactivity'''

**IV Diazepam at a dose of 0.5 to 2 mg/kg <ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

**IV Diazepam at a dose of 0.5 to 2 mg/kg <ref name="multiple"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

**Alternative to diazepam is barbiturates <ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

**Alternative to diazepam is barbiturates <ref name="multiple"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

**Treating the seizures and hyperactivity should help restore normal body temperature. If animal still hyperthermic then this should be treated directly <ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

**Treating the seizures and hyperactivity should help restore normal body temperature. If animal still hyperthermic then this should be treated directly <ref name="multiple"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

*'''Correction of acid/base and electrolyte inbalances''' <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>,

*'''Correction of acid/base and electrolyte inbalances''' <ref name="multiples">Merck & Co (2008) The Merck Veterinary Manual (Eight Edition), Merial found at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/211104.htm&word=chocolate%2cpoisoning accessed January 2011</ref>,

*'''Insertion of urinary catheter'''

*'''Insertion of urinary catheter'''

**Helps prevent further absorption of theobromine and caffeine across bladder wall <ref name="multiples"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

**Helps prevent further absorption of theobromine and caffeine across bladder wall <ref name="multiple"> King, LG, Boag, A (2007) '''BSAVA Manual of Canine and Feline Emergency and Critical Care(2nd Edition)''' ''BSAVA''</ref>.  

==References==

==References==

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