Internal Medicine

Jamaican vomiting sickness

Acute illness caused by the toxins hypoglycin A & B, which are present in fruit of the ackee tree.

  • While in the fully ripened arils, hypoglycin A is at levels of less than 0.1 ppm, in unripe arils it can be over 1000 ppm and cause vomiting and even death


Hypoglycin A

Methylenecyclopropylacetic acid (MCPA)
Inhibits the beta-oxidation of fatty acids

Fatty acids accumulation in liver
(microvesicular pattern on biopsy)

Body dependent on glucose and glycogen for energy (in absence of fatty acid metabolism)

Inhibition of beta-oxidation of fatty acids also depletes a necessary cofactor for gluconeogenesis.
Once the liver glycogen stores are depleted, the body cannot synthesize glucose, and severe hypoglycemia results

Jamaican vomiting sickness

  • Hypoglycin A is found in both the seeds and the arils
  • Hypoglycin B is found only in the seeds

Clinical features

  • Abdominal discomfort (2-6 hours after eating unripe ackee fruit), followed by sudden onset vomiting
  • Severe cases:
    • Profound dehydration, seizures, coma, and death
    • Children, esp. malnourished are more susceptible to the disease

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