Introduction
- Toxic signs caused by theobromine (methylxanthine).
- Signs : onset of signs often delayed <10 hours.
- Theobromine may persist in blood for up to 20 hours.
- Theobromine stimulates the central nervous system (CNS) and heart, causes diuresis and relaxes smooth muscles.
- Diagnosis : history, clinical signs.
- Treatment : within 2 hours of ingestion, activated charcoal orally, supportive therapy.
- Gastric lavage often beneficial <6 hours after ingestion.
- Prognosis : poor to good depending on quantity ingested and time to treatment.
Diagnosis
Clinical signs
- Tachycardia.
- Cardiac arrhythmias.
- Hyperthermia.
- Muscle tremors.
- Seizures.
- Abdominal pain.
Diagnosis
Differential diagnosis
- Other poisonings:
- Strychnine.
- Nicotine.
- Amphetamines.
- Metaldehyde.
- Organophosphates.
Sequelae
Prognosis
- Consumption of >200 mg/kg bodyweight of theobromine has a grave prognosis.
Expected response to treatment
- Recovery may not be acute.
- Signalled by return of consciousness, regular heart rhythm and diminution of neurological signs.
Reasons for treatment failure
- Failure most likely to be caused by owner delay in seeking help or consumption of more than 200 mg/kg of available theobromine.
- Other factors include concurrent theophylline medication, or pre-existing conditions such as epilepsy or cardiac disease.
Sources
Publications
Refereed papers
- Owens J G & Dorman D C (1997) Drug poisoning in small animals. Vet Med 92 , 144-156.
- Murphy M (1994) Toxin exposure in dogs and cats - drug and household products JAVMA 205 , 557-560.
- Glauberg A & Blumenthal H P (1983) Chocolate poisoning in the dog. JAAHA 19 , 977-980. (This reference was used in Canine Medicine and Therapeutics3rd Edition (1990) to provide a paragraph referencing the sudden deaths of some Dachshunds after consuming 300 g chocolate and a Springer Spaniel that died 12 hours after consuming 250 g of household cocoa.)
- Sutton R H (1981) Cocoa poisoning in the dog. Vet Rec 109 , 563-565. (This paper was referenced in Feline Medicine and Therapeutics2nd Edition (1994) to provide the following information: poisoning from cocoa and related products has been described on a number of occasions in dogs; the toxic principle is the methylxanthine derivative, theobromine. The symptoms are vomiting, diarrhea, sudden collapse and death.)
Other sources of information
- Campbell A (2002) Chocolate intoxication in dogs. UK Vet 6 (6).
- Fraser, Clarence M et al (eds) (1991) The Merck Veterinary Manual. 7th edn. Rahway: Merck & Co. pp 1643-1644.
Organization(s)
- Nearest poisons information center - call your local hospital if unsure of location.
- VPIS (London) , Poisons Unit, Avonley Road, London SE14 5ER, UK; telephone 020 7635 9195.
- National Animal Poisoning Control Center , University of Illinois, College of Veterinary Medicine, USA.
