Encephalopathy after chocolate consumption

Clinical record

Three hospitality workers presented to a Sydney tertiary hospital emergency department within a 24-hour period with vague neurological symptoms, including sudden onset unsteadiness, vertigo, nausea, presyncope, mutism and drowsiness. These symptoms occurred 1–2 hours after eating chocolate that had been left behind in a hotel guest’s room after checkout. Two patients (patients 1 and 2) were admitted for observation. Patient 3 was discharged from the emergency department after 5 hours of observation.

Patient 1

A woman in her 40s, with a history of diet-controlled type 2 diabetes, presented with a sudden onset of vertigo and vomiting at work which came on a few hours after eating one square of chocolate. In the emergency department, her heart rate was 104 beats per minute and her blood pressure was 152/92 mmHg. She was reported to have bilateral gaze-evoked nystagmus. She was assessed by the emergency department to possibly have a posterior circulation stroke, and brain computed tomography perfusion and angiogram scans were performed, both of which were normal. Routine blood tests and electrocardiogram were normal. She was given intravenous fluids and prochlorperazine. She had persistent vertigo, unsteady gait and nausea and was observed overnight. Her symptoms had resolved by the morning and she was discharged home. A urine drug screen was retrospectively performed on the urine sample and tested positive for cannabinoids.

Patient 2

A woman in her 20s presented in a drowsy state. She was mute but able to follow simple commands. She subsequently reported symptoms of vertigo, nausea and unsteady gait one hour after consuming four square pieces of chocolate. She had brain computed tomography perfusion and angiogram scans, both normal. She was admitted and remained in a mildly drowsy, non-verbal state, with psychomotor slowing for 24 hours before complete neurological recovery. Routine blood tests were normal. An awake electroencephalogram showed intermittent short runs of generalised as well as variably asymmetrical temporal delta slow waves, consistent with a mild encephalopathy. Cannabinoids were detected in her urine.

Patient 3

A woman in her 30s presented with mild unsteadiness of gait and nausea after eating one piece of chocolate. She was observed in the emergency department for 5 hours and discharged after resolution of symptoms, with normal blood tests and septic screen. A urine drug screen was not performed.

These three patients presented within 24 hours of each other. The chocolate that had been eaten by all three was brought to the emergency department and visually identified as a commercially available cannabis-infused chocolate, with 100 mg tetrahydrocannabinol per ten-piece block, made in the United States.

Lessons from practice

• Cannabis chocolate is available for sale in some states in the United States and is available online. Doctors in Australia need to be aware of the clinical presentations and side effects of edible cannabis.

• The effects of edible cannabis can be difficult to predict and patients may intentionally or inadvertently consume large amounts.

• Cannabis intoxication may include a variety of neurological clinical features, such as an encephalopathic state, with large consumption.

• A urine drug screen is a useful non-invasive test in the setting of acute neurological and psychiatric presentations.

• An electroencephalogram may be useful in differentiating a toxic encephalopathic state from a primary psychiatric presentation.