Diagnosis
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| Jamaican vomiting sickness | |
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| Specialty | Toxicology |
Jamaican vomiting sickness, also known as toxic hypoglycemic syndrome (THS), [1] acute ackee fruit intoxication, [2] or ackee poisoning, [1] is an acute illness caused by the toxins hypoglycin A and hypoglycin B, which are present in fruit of the ackee tree. Unripe arils contain concentrations of hypoglycin A that are 20-fold higher than those of ripe arils, [3] and can cause vomiting and even death. Some countries in the Caribbean and Western Africa experience frequent cases. [4]
Abdominal discomfort begins two to six hours after eating unripe ackee fruit, followed by sudden onset vomiting. In severe cases, profound dehydration, seizures, coma, and death may ensue. Children and those who are malnourished are more susceptible to the disease. [3]
When ingested, hypoglycin A is metabolized to produce methylenecyclopropylacetic acid (MCPA). MCPA acts to inhibit the beta-oxidation of fatty acids in two ways. First, it interferes with the transport of long-chain fatty acids into the mitochondria by forming ester linkages with carnitine and coenzyme A (CoA). [3] Also, it inhibits acyl-CoA dehydrogenases, [3] so that only unsaturated fatty acids can be fully oxidized.[ citation needed ] Fatty acids accumulate in the liver in a microvesicular pattern that can be seen on biopsy. In the absence of fatty acid metabolism, the body becomes dependent on glucose and glycogen for energy. Octreotide can be used to reduce the secretion of insulin by the pancreas, thereby preventing severe hypoglycemia. [3]
Inhibition of beta-oxidation of fatty acids, however, also depletes nicotinamide adenine dinucleotide (NADH) and acetyl CoA—the latter an activator of pyruvate carboxylase—inhibiting gluconeogenesis. Once the liver glycogen stores are depleted, the body cannot synthesize glucose, and severe hypoglycemia results. [3]
Initial symptoms appear after about four hours, and deaths have been reported from 12 to 48 hours following consumption. Supportive care involves carefully metered IV glucose infusion and fluid/electrolyte replacement; mortality was 80% before glucose infusion was introduced in 1954. [5] [6]
A similar outbreak of lethal hypoglycemic encephalopathy has been linked to the consumption of lychee fruit in Muzaffarpur, India. Urinalysis of children affected by the disease has shown all affected have elevated levels of hypoglycin suggesting the same underlying pathophysiology as Jamaican vomiting sickness. [7]
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The disease appears in the ER episode "Great Expectations", where the symptoms are recognised by Dr. Mallucci who, it is later revealed, attended medical school in Grenada.[ citation needed ]
Hypoglycemia, also called low blood sugar, is a fall in blood sugar to levels below normal, typically below 70 mg/dL (3.9 mmol/L). Whipple's triad is used to properly identify hypoglycemic episodes. It is defined as blood glucose below 70 mg/dL (3.9 mmol/L), symptoms associated with hypoglycemia, and resolution of symptoms when blood sugar returns to normal. Hypoglycemia may result in headache, tiredness, clumsiness, trouble talking, confusion, fast heart rate, sweating, shakiness, nervousness, hunger, loss of consciousness, seizures, or death. Symptoms typically come on quickly.
Ketogenesis is the biochemical process through which organisms produce ketone bodies by breaking down fatty acids and ketogenic amino acids. The process supplies energy to certain organs, particularly the brain, heart and skeletal muscle, under specific scenarios including fasting, caloric restriction, sleep, or others.
The ackee, also known as acki, akee, or ackee apple, is a fruit of the Sapindaceae (soapberry) family, as are the lychee and the longan. It is native to tropical West Africa. The scientific name honours Captain William Bligh who took the fruit from Jamaica to the Royal Botanic Gardens in Kew, England, in 1793. The English common name is derived from the West African Akan akye fufo.
Carbohydrate metabolism is the whole of the biochemical processes responsible for the metabolic formation, breakdown, and interconversion of carbohydrates in living organisms.
Ketoacidosis is a metabolic state caused by uncontrolled production of ketone bodies that cause a metabolic acidosis. While ketosis refers to any elevation of blood ketones, ketoacidosis is a specific pathologic condition that results in changes in blood pH and requires medical attention. The most common cause of ketoacidosis is diabetic ketoacidosis but can also be caused by alcohol, medications, toxins, and rarely, starvation.
Medium-chain acyl-CoA dehydrogenase deficiency is a disorder of fatty acid oxidation that impairs the body's ability to break down medium-chain fatty acids into acetyl-CoA. The disorder is characterized by hypoglycemia and sudden death without timely intervention, most often brought on by periods of fasting or vomiting.
Hyperinsulinemic hypoglycemia describes the condition and effects of low blood glucose caused by excessive insulin. Hypoglycemia due to excess insulin is the most common type of serious hypoglycemia. It can be due to endogenous or injected insulin.
Ketotic hypoglycemia refers to any circumstance in which low blood glucose is accompanied by ketosis, the presence of ketone bodies in the blood or urine. This state can be either physiologic or pathologic; physiologic ketotic hypoglycemia is a common cause of hypoglycemia in children, often in response to stressors such as infection or fasting. Pathologic ketotic hypoglycemia is typically caused by metabolic defects, such as glycogen storage disorders.
Glycogen storage disease type I is an inherited disease that prevents the liver from properly breaking down stored glycogen, which is necessary to maintain adequate blood sugar levels. GSD I is divided into two main types, GSD Ia and GSD Ib, which differ in cause, presentation, and treatment. There are also possibly rarer subtypes, the translocases for inorganic phosphate or glucose ; however, a recent study suggests that the biochemical assays used to differentiate GSD Ic and GSD Id from GSD Ib are not reliable, and are therefore GSD Ib.
Diabetic hypoglycemia is a low blood glucose level occurring in a person with diabetes mellitus. It is one of the most common types of hypoglycemia seen in emergency departments and hospitals. According to the National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP), and based on a sample examined between 2004 and 2005, an estimated 55,819 cases involved insulin, and severe hypoglycemia is likely the single most common event.
Glycogen storage disease type 0 is a disease characterized by a deficiency in the glycogen synthase enzyme (GSY). Although glycogen synthase deficiency does not result in storage of extra glycogen in the liver, it is often classified as a glycogen storage disease because it is another defect of glycogen storage and can cause similar problems. There are two isoforms (types) of glycogen synthase enzyme; GSY1 in muscle and GSY2 in liver, each with a corresponding form of the disease. Mutations in the liver isoform (GSY2), causes fasting hypoglycemia, high blood ketones, increased free fatty acids and low levels of alanine and lactate. Conversely, feeding in these patients results in hyperglycemia and hyperlactatemia.
Hypoglycin A is a naturally occurring amino acid derivative found in the unripened fruit of the Ackee tree and in the seeds of the box elder tree. It is toxic if ingested, and is the causative agent of Jamaican vomiting sickness. A 2017 Lancet report established a link between the consumption of unripened lychees resulting in hypoglycaemia and death from acute toxic encephalopathy.
Hypoglycin B is a naturally occurring organic compound in the species Blighia sapida. It is particularly concentrated in the fruit of the plant especially in the seeds. Hypoglycin B is toxic if ingested and is one of the causative agents of Jamaican vomiting sickness. It is a dipeptide of glutamic acid and hypoglycin A.
Acute fatty liver of pregnancy is a rare life-threatening complication of pregnancy that occurs in the third trimester or the immediate period after delivery. It is thought to be caused by a disordered metabolism of fatty acids by mitochondria in the fetus, caused by long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency. This leads to decreased metabolism of long chain fatty acids by the feto-placental unit, causing subsequent rise in hepatotoxic fatty acids in maternal plasma. The condition was previously thought to be universally fatal, but aggressive treatment by stabilizing the mother with intravenous fluids and blood products in anticipation of early delivery has improved prognosis.
The Randle cycle, also known as the glucose fatty-acid cycle, is a metabolic process involving the competition of glucose and fatty acids for substrates. It is theorized to play a role in explaining type 2 diabetes and insulin resistance.
Fructolysis refers to the metabolism of fructose from dietary sources. Though the metabolism of glucose through glycolysis uses many of the same enzymes and intermediate structures as those in fructolysis, the two sugars have very different metabolic fates in human metabolism. Under one percent of ingested fructose is directly converted to plasma triglyceride. 29% - 54% of fructose is converted in liver to glucose, and about a quarter of fructose is converted to lactate. 15% - 18% is converted to glycogen. Glucose and lactate are then used normally as energy to fuel cells all over the body.
Amanita sphaerobulbosa, commonly known as the Asian abrupt-bulbed Lepidella, is a species of agaric fungus in the family Amanitaceae. First described by mycologist Tsuguo Hongo in 1969, it is found in Southern Asia.
Neonatal hypoglycemia, also called low blood sugar in newborn babies, occurs when an infant's blood glucose level is less than what is considered normal. There is inconsistency internationally for diagnostic thresholds. In the US, hypoglycemia is when the blood glucose level is below 30 mg/dL within the first 24 hours of life and below 45 mg/dL after, but international standards differ. Age, birth weight, metabolic needs, and wellness state of the newborn has a substantial impact on their blood glucose level. This is a treatable condition, but its treatment depends on the cause of the hypoglycemia. Though it is treatable, it can be fatal if gone undetected. Hypoglycemia is the most common metabolic problem in newborns.
Methylene cyclopropyl acetic acid (MCPA) is found in lychee seeds and also a toxic metabolite in mammalian digestion after eating hypoglycin, present in the unripe ackee fruit, grown in Jamaica and in Africa. By blocking coenzyme A and carnitine, MPCA causes a decrease in β-oxidation of fatty acids, and hence gluconeogenesis.
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