Case on caffeine toxicity and learning points

We write here to highlight our experience in caring for a patient who ultimately died following acute ingestion of 10 g of caffeine in the form of stimulant tablets.

The patient was found collapsed at home and subsequently had a ventricular fibrillation arrest en route to hospital. On arrival, the patient re-arrested prior to transfer to cardiac catheterisation lab and was intubated and ventilated at this point. Cardiac catheterisation and echo showed no abnormalities, and the patient was then transferred to the intensive care unit for thermoregulation, inotropic support and optimisation of the metabolic state. The patient had further refractory ventricular fibrillation treated using the UK advanced life support algorithm plus lignocaine boluses and aggressive electrolyte replacement which resulted in return of spontaneous circulation. Following this, the patient developed acute kidney injury and severe metabolic acidosis requiring haemofiltration. The patient was noted to have a raised creatinine kinase and potassium as well as clinical signs of upper and lower limb compartment syndrome. This was managed by fasciotomy, but the patient subsequently deteriorated with multi-organ failure and died four days after admission to the intensive care unit. It was confirmed by the patient’s next of kin at the time of admission that they had ingested a significant quantity of 200 mg caffeine tablets (amounting to over 10 g of caffeine) several hours prior to hospital admission (a cup of ground coffee typically contains 60–180 mg of caffeine/150 mL cup; an ‘Energy’ soft drink, e.g. Red Bull contains 80 mg/250 mL can). ¹ The caffeine tablets had been bought in bulk from a well-known sports nutrition website.

Learning Points

There are risks associated with consuming non-prescribed ‘over-the-counter’ medications.

The need for an increased awareness and understanding of the many supplements that can be bought by anyone in any quantity via the internet. This is of importance due to the detrimental side effects they may have. We suggest this should be recognised at a higher level and addressed with stricter regulations.

Recognition of the effects of a significant caffeine excess and treating them promptly. Oral bioavailability is nearly 100%, with an average half-life of 5 h. ² In this case, symptoms and signs included: neurological (agitation, tremors and seizures), cardiovascular (arrythmias and infarction) and other (hyperthermia, raised creatinine kinase and rhabdomyolysis). ¹ A fatal dose of about 5–10 g or 150–200 mg/kg body weight is usually quoted in the literature. ¹

Ensure a toxicology screen is carried out in patients presenting with overdose and a detailed patient history is taken where possible, as certain drugs would not routinely be screened. Collateral history from family or friends may provide crucial information.

Diagnosing compartment syndrome in an intubated patient can be challenging, due to the absence of expressed pain. Prompt diagnosis and early management of compartment syndrome is essential, with a low threshold for diagnosis and treatment in unconscious patients. ³

We feel that this is an interesting case, which has highlighted many learning points and improved our knowledge base. We hope that it will raise awareness and understanding of the potential dangers of taking supplements (caffeine, in particular) that have not been prescribed by a healthcare professional and can be readily bought in bulk via the internet.