What are the effects of theobromine toxicity in dogs if they ingest chocolate?

Chocolate Toxicity in Dogs from Cadbury Mini Eggs

If a dog eats a Cadbury Mini Egg, the risk depends critically on the dog's size and the type of chocolate, but immediate veterinary assessment is warranted because theobromine toxicity can be fatal, with symptoms potentially appearing within 2-24 hours and requiring prompt decontamination and supportive care. 1

Understanding the Toxic Mechanism

Theobromine is the primary toxic component in chocolate that dogs cannot efficiently metabolize. 1 Key pharmacokinetic differences include:

• Dogs have a theobromine half-life of approximately 18 hours compared to 2-3 hours in humans 1
• Absorption is slow with hepatic metabolism and extrahepatic recirculation before urinary excretion 1
• This prolonged exposure allows toxic accumulation affecting multiple organ systems 1

Risk Assessment Based on Chocolate Type

Cadbury Mini Eggs are milk chocolate, which contains approximately 2 mg/g of theobromine - significantly less than dark chocolate (15 mg/g) or cocoa powder (20 mg/g), but still potentially dangerous. 1

The lethal dose of theobromine is 100-500 mg/kg body weight in dogs. 1 This means:

• A 10 kg (22 lb) dog could potentially die from consuming less than 100 g of plain chocolate 1
• For milk chocolate at 2 mg/g, a 10 kg dog would need approximately 500-2500 g to reach lethal doses 1
• However, clinical toxicity occurs at much lower doses than lethal doses 2

Clinical Presentation Timeline

Symptoms typically begin within 2 hours but can take up to 24 hours to appear, with recovery potentially requiring up to 3 days. 1

Early Signs (First 2-6 Hours):

• Vomiting and hematemesis 1
• Polydipsia (excessive thirst) 1
• Agitation and hyperexcitability 1, 2

Progressive Signs:

• Sinus tachycardia (most common finding in 64% of symptomatic dogs) 2
• Tremors (50% of symptomatic cases) 2
• Tachypnea and excessive panting 1, 2
• Hyperirritability and ataxia 1
• Hyperthermia 2

Severe Complications:

• Cardiac arrhythmias 1
• Seizures 1
• Death 1

Laboratory Abnormalities to Expect

In symptomatic dogs, expect: 2

• Hyperlactatemia (68% of cases)
• Hypokalemia (47% of cases)
• Mild hyperglycemia (47% of cases)
• Mild ALT and AST elevation (41% of cases)

Immediate Management Protocol

There is no specific antidote for theobromine toxicity; treatment is entirely supportive and focused on decontamination. 1

Decontamination (Time-Sensitive):

• Induce vomiting with apomorphine if ingestion occurred within 2 hours 1, 2
• Administer activated charcoal to prevent further absorption 1, 2

Supportive Care:

• Intravenous fluid therapy 1, 2
• Forced diuresis to enhance theobromine excretion 2
• Esmolol for tachycardia management 2
• Sedatives for agitation and tremors 2
• Oxygen supplementation as needed 1

Prognosis

With appropriate decontamination and supportive therapy, prognosis is excellent with mortality rates less than 3%. 2 In a recent case series of 156 dogs with chocolate ingestion, 43 of 44 symptomatic dogs survived with treatment. 2

Critical Pitfalls to Avoid

• Do not wait for symptoms to appear before seeking veterinary care - the 18-hour half-life means toxicity can worsen over time 1
• Do not underestimate milk chocolate - while less concentrated than dark chocolate, sufficient quantities still cause severe toxicity 2
• Dark and bitter chocolate ingestion requires more aggressive management - 64% of symptomatic dogs in one series had ingested dark chocolate 2
• Monitor for at least 24 hours as delayed symptom onset is possible 1