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Chemical food poisoning
CHAPTER
Chemical food poisoning CHAPTER OUTLINE 29.1 29.2 29.3 29.4
29
Introduction ...................................................................................................327 Mushrooms....................................................................................................327 Poisonous Plant Toxins ..................................................................................328 Poisonous Marine Bites and Stings .................................................................329 29.4.1 Poisonous Fishes........................................................................329 29.4.2 Shellfish....................................................................................330
29.1 INTRODUCTION Chemical food poisoning is caused by eating plants or animals that contain a naturally occurring toxin containing chemicals such as acetylcholine, alkaloids, serotonin, histamines, sulfur, lipids, phenols, and glycocides. Chemical food poisoning often involves mushrooms, poisonous plants, or marine animals. The toxicity of some of plants has already been discussed in other chapters in this book. The reader may refer to chapters dealing with toxic agents.
29.2 MUSHROOMS Mushrooms are fungi with umbrella-shaped tops and stems. Stropheria semeglobata, Hypholoma froomasciculare, and Lactarius vellereus are among the poisonous varieties of mushrooms. Symptoms of poisoning All toxic mushrooms cause vomiting and abdominal pain; other manifestations vary significantly depending on the type of mushroom ingested. Mushroom poisoning causes nausea, vomiting, diarrhea, bloody vomit and stools, enlarged tender liver and jaundice, oliguria, pulmonary edema, mental confusion, convulsions, and coma. Generally, mushrooms that cause early symptoms (within 2 h) are less dangerous than those that cause later symptoms (usually after 6 h). Certain mushrooms act by parasympathomimetic action or may be due to hypersensitivity. The little brown mushrooms that grow in lawns cause gastroenteritis, sometimes with headache or myalgias. Diarrhea is occasionally bloody. Usually, symptoms vary with the type of mushroom ingested. Some mushrooms contain psilocybin, which may Fundamentals of Toxicology. DOI: http://dx.doi.org/10.1016/B978-0-12-805426-0.00029-9 © 2016 BSP Books Pvt. Ltd. Published by Elsevier Inc. All rights reserved.
327
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CHAPTER 29 Chemical food poisoning
cause hallucinations, tachycardia, and hypertension. Some mushrooms cause muscrinic symptoms such as miosis, diarrhea, and bradycardia. Members of Amanita genera cause hypoglycemia and hepatic and renal failure. Treatment Supportive and symptom-based treatment such as gastric lavage, atropine, exchange transfusion in children, charcoal, and hemoperfusion in adults are used. In the case of central nervous system toxicity resulting in neurological symptoms, pyridoxine 25 mg/kg (maximum daily dose, 25 g) is recommended.
29.3 POISONOUS PLANT TOXINS The many toxic chemicals produced by plants, usually referred to as secondary plant compounds, often have chemicals that are used as defense mechanisms against herbivorous animals, particularly insects and mammals. This chapter focuses only on the human toxicity of some of the more well-known plants. These compounds may be repellent but not particularly toxic, or they may be acutely toxic to a wide range of organisms. They include sulfur compounds, lipids, phenols, alkaloids, glycosides, and many other types of chemicals. Many of the common drugs of abuse such as cocaine, caffeine, nicotine, morphine, and the cannabinoids are plant toxins (for details, see the other chapters). Many chemicals that have been shown to be toxic are constituents of plants that form part of the human diet. For example, the carcinogen safrole and related compounds are found in black pepper. Solanine and chaconine, which are cholinesterase inhibitors and possible teratogens, are found in potatoes, and quinines and phenols are widespread in food. Livestock poisoning by plants is still an important veterinary problem in some areas. Some plants are known to cause damage to various organs of the body. For example, there are a several plants that affect the skin and make contact painful. This occurs either through an allergic antibody-mediated response or through direct action by chemicals. For an allergic type of response, it is not the first contact that produces the reaction, but rather the next contact. For example, poison ivy produces a class of chemicals called urushiol, which causes a widely variable allergic response in approximately 70% of people exposed. Similarly, pollen of ragweed, mugwort, or grasses causes an allergic response in many people. Dieffenbachia or dumb cane, a common houseplant, produces a juice that is released when a stem is broken or chewed and causes painful, rapid swelling and inflammation of the tongue and mouth. The symptoms can take several days to resolve and are caused by oxalate crystals coated with an irritating protein. Stinging nettle (Urtica) releases histamine, acetylcholine, and serotonin from fine tubes with bulbs at the end that break off onto the skin, causing an intense burning or stinging sensation. Some plants cause direct irritation of the stomach lining. For example, the chemical colchicine stops cell division (an antimitotic), producing severe nausea,
29.4 Poisonous Marine Bites and Stings
vomiting, and dehydration, which can lead to delirium, neuropathy, and kidney failure. However, colchicine is used in the treatment of gout and as an anticancer agent because it stops cell division. Most toxic of all plants are the ones that produce lectins, and the most toxic of these is the chemical ricin, which is produced by castor beans. Only five to six seeds are necessary to kill a small child. Ricin is extremely toxic and 0.1 µg/kg of body weight can be fatal. Another example is the medically important drug digitalis, which is derived from foxglove (Digitalis purpurea). Digitalis slows and stabilizes the heart rate, but at high dose it produces an irregular heart rate and decreased blood pressure. Likewise, there are several other poisons such as “mad honey poisoning,” which is caused by bees. The cardiovascular effects are caused by grayanotoxin, which is produced in the leaves and nectar of rhododendrons and are concentrated in the honey by the bees. Hepatitis and cirrhosis of the liver from contaminated grain caused by ragwort or pyrrolizidine alkaloids are well known. Children are often the most susceptible to many of the naturally occurring toxins, just as they are to other toxicants. The caffeine from a can of cola will have a much larger effect on a small child than it will on an adult. Health status and age, both young and old, also influence the response. Aflatoxin from contaminated nuts has a greater likelihood of causing cancer in some with a liver disease such as hepatitis. It is important to develop a knowledge of which plants and animals can be dangerous and to learn how to avoid dangerous contact with them.
29.4 POISONOUS MARINE BITES AND STINGS Some marine bites and stings are toxic, and all create wounds at risk for infection with marine organisms. Shark bites result in jagged lacerations with near-total or total amputations and should be treated as traumas.
29.4.1 POISONOUS FISHES There are several species of venomous fish that are capable of producing poisoning. Fish poisoning may occur due to attacks and bites (eg, sharks and barracudas), by injecting toxic venom through their venomous spines or tentacles (eg, stingrays), and through eating fish whose flesh is toxic. There are three common types of fish whose flesh is toxic and cause poisoning. They are described here. Ciguatera poisoning may result from eating any of the more than 400 species of fish in which a dinoflagellate produces a toxin that accumulates in the flesh of the body. Symptoms may begin 2 8 h after eating; intravenous (IV) mannitol has been suggested as a treatment. Scombroid poisoning is caused by high histamine levels in fish flesh due to bacterial decomposition after the fish is caught. Commonly affected species include tuna, mackerel, bonito, skipjack, and mahi mahi. Symptoms include facial
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CHAPTER 29 Chemical food poisoning
flushing, nausea, vomiting, and urticaria. Treatment may include administration of antihistamines. Tetrodotoxin poisoning is most common due to eating puffer fish, but more than 100 fresh water and salt water species contain tetrodotoxin. Symptoms are similar to ciguatera and may produce fatal respiratory paralysis. Tetrodotoxin is found in all organs of the fish but is highest in the liver, skin, and intestine. The origins of the toxin are not clear, but one possibility is that the fish has come in contact with bacteria that produce tetrodotoxin. Puffer fish may also have elevated levels of saxitoxin, a neurotoxin responsible for paralytic shellfish poisoning. Saxitoxin is produced by dinoflagellates (algae) and most often contaminates mussels, clams, and scallops. Both saxitoxin and tetrodotoxin are heat-stable, so cooking does not reduce toxicity. Mode of action Tetrodotoxin causes paralysis by affecting the sodium ion transport in both the central and peripheral nervous systems. A low dose of tetrodotoxin produces tingling sensations and numbness around the mouth, fingers, and toes. Higher doses produce nausea, vomiting, respiratory failure, difficulty walking, extensive paralysis, and death. As little as 1 4 mg of the toxin can kill an adult. Saxitoxin has a very different chemical structure than tetrodotoxin, but it has similar effects on transport of cellular sodium and produces similar neurological effects. Saxitoxin is less toxic than tetrodotoxin. Some people, particularly in Asia, consider the puffer fish a fine delicacy if it is carefully prepared by experienced chefs. The trick is to get just a small dose to feel mild tingling effects, but not the more serious symptoms of tetrodotoxin poisoning. In the United States tetrodotoxin poisoning is rare, but a recent US report indicated several cases of people catching and consuming puffer fish containing elevated levels of these toxins and suffering the ill effects. Treatment Treatment is supportive and symptom-based. Activated charcoal may be helpful.
29.4.2 SHELLFISH Shellfish such as mussels, clams, oysters, and scallops are not naturally toxic, but they can become so after feeding on plankton contaminated with a toxin. When visible, the blooming of the plankton (dinoflagellate) is called red tide and can cause significant death among marine animals. There are several types of toxins, mostly affecting the nervous system. The newest, domoic acid, first appeared in 1987 off Prince Edward Island in Canada. This neurotoxin caused confusion and memory loss, particularly in the elderly. Several elderly people died after seizures and coma. Domoic acid is heat-stable, so cooking does not affect the toxin. Government agencies now monitor for contaminants of shellfish and move quickly to restrict harvesting. The puffer fish is probably the best known neurotoxic fish. Several related species of fish as well as other marine life, such as some frogs, starfish, octopus, and others, contain tetrodotoxin. Many people consider these fish a delicacy despite the occasional reported death from poor
29.4 Poisonous Marine Bites and Stings
preparation. Tetrodotoxin is heat-stable but water-soluble, so careful preparation is necessary to limit neurological effects. Symptoms of poisoning include rapid onset of numbness in the lips and mouth that then extends to the fingers and toes, followed by general weakness, dizziness, respiratory failure, and death. The mechanism of action is similar to that of saxitoxin and affects sodium channel permeability. It should also be remembered that fish high in the food chain such as tuna, swordfish, and shark accumulate toxic substances like mercury or PCBs. Mercury affects the nervous system and is a proven reproductive hazard. Treatment Supportive and symptom-based treatment such as gastric lavage, IV mannitol, atropine, exchange transfusion in children, charcoal, and hemoperfusion in adults are administered. In some cases, treatment may include H1 and H2 blockers.
331
Chemical food poisoning CHAPTER OUTLINE 29.1 29.2 29.3 29.4
29
Introduction ...................................................................................................327 Mushrooms....................................................................................................327 Poisonous Plant Toxins ..................................................................................328 Poisonous Marine Bites and Stings .................................................................329 29.4.1 Poisonous Fishes........................................................................329 29.4.2 Shellfish....................................................................................330
29.1 INTRODUCTION Chemical food poisoning is caused by eating plants or animals that contain a naturally occurring toxin containing chemicals such as acetylcholine, alkaloids, serotonin, histamines, sulfur, lipids, phenols, and glycocides. Chemical food poisoning often involves mushrooms, poisonous plants, or marine animals. The toxicity of some of plants has already been discussed in other chapters in this book. The reader may refer to chapters dealing with toxic agents.
29.2 MUSHROOMS Mushrooms are fungi with umbrella-shaped tops and stems. Stropheria semeglobata, Hypholoma froomasciculare, and Lactarius vellereus are among the poisonous varieties of mushrooms. Symptoms of poisoning All toxic mushrooms cause vomiting and abdominal pain; other manifestations vary significantly depending on the type of mushroom ingested. Mushroom poisoning causes nausea, vomiting, diarrhea, bloody vomit and stools, enlarged tender liver and jaundice, oliguria, pulmonary edema, mental confusion, convulsions, and coma. Generally, mushrooms that cause early symptoms (within 2 h) are less dangerous than those that cause later symptoms (usually after 6 h). Certain mushrooms act by parasympathomimetic action or may be due to hypersensitivity. The little brown mushrooms that grow in lawns cause gastroenteritis, sometimes with headache or myalgias. Diarrhea is occasionally bloody. Usually, symptoms vary with the type of mushroom ingested. Some mushrooms contain psilocybin, which may Fundamentals of Toxicology. DOI: http://dx.doi.org/10.1016/B978-0-12-805426-0.00029-9 © 2016 BSP Books Pvt. Ltd. Published by Elsevier Inc. All rights reserved.
327
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CHAPTER 29 Chemical food poisoning
cause hallucinations, tachycardia, and hypertension. Some mushrooms cause muscrinic symptoms such as miosis, diarrhea, and bradycardia. Members of Amanita genera cause hypoglycemia and hepatic and renal failure. Treatment Supportive and symptom-based treatment such as gastric lavage, atropine, exchange transfusion in children, charcoal, and hemoperfusion in adults are used. In the case of central nervous system toxicity resulting in neurological symptoms, pyridoxine 25 mg/kg (maximum daily dose, 25 g) is recommended.
29.3 POISONOUS PLANT TOXINS The many toxic chemicals produced by plants, usually referred to as secondary plant compounds, often have chemicals that are used as defense mechanisms against herbivorous animals, particularly insects and mammals. This chapter focuses only on the human toxicity of some of the more well-known plants. These compounds may be repellent but not particularly toxic, or they may be acutely toxic to a wide range of organisms. They include sulfur compounds, lipids, phenols, alkaloids, glycosides, and many other types of chemicals. Many of the common drugs of abuse such as cocaine, caffeine, nicotine, morphine, and the cannabinoids are plant toxins (for details, see the other chapters). Many chemicals that have been shown to be toxic are constituents of plants that form part of the human diet. For example, the carcinogen safrole and related compounds are found in black pepper. Solanine and chaconine, which are cholinesterase inhibitors and possible teratogens, are found in potatoes, and quinines and phenols are widespread in food. Livestock poisoning by plants is still an important veterinary problem in some areas. Some plants are known to cause damage to various organs of the body. For example, there are a several plants that affect the skin and make contact painful. This occurs either through an allergic antibody-mediated response or through direct action by chemicals. For an allergic type of response, it is not the first contact that produces the reaction, but rather the next contact. For example, poison ivy produces a class of chemicals called urushiol, which causes a widely variable allergic response in approximately 70% of people exposed. Similarly, pollen of ragweed, mugwort, or grasses causes an allergic response in many people. Dieffenbachia or dumb cane, a common houseplant, produces a juice that is released when a stem is broken or chewed and causes painful, rapid swelling and inflammation of the tongue and mouth. The symptoms can take several days to resolve and are caused by oxalate crystals coated with an irritating protein. Stinging nettle (Urtica) releases histamine, acetylcholine, and serotonin from fine tubes with bulbs at the end that break off onto the skin, causing an intense burning or stinging sensation. Some plants cause direct irritation of the stomach lining. For example, the chemical colchicine stops cell division (an antimitotic), producing severe nausea,
29.4 Poisonous Marine Bites and Stings
vomiting, and dehydration, which can lead to delirium, neuropathy, and kidney failure. However, colchicine is used in the treatment of gout and as an anticancer agent because it stops cell division. Most toxic of all plants are the ones that produce lectins, and the most toxic of these is the chemical ricin, which is produced by castor beans. Only five to six seeds are necessary to kill a small child. Ricin is extremely toxic and 0.1 µg/kg of body weight can be fatal. Another example is the medically important drug digitalis, which is derived from foxglove (Digitalis purpurea). Digitalis slows and stabilizes the heart rate, but at high dose it produces an irregular heart rate and decreased blood pressure. Likewise, there are several other poisons such as “mad honey poisoning,” which is caused by bees. The cardiovascular effects are caused by grayanotoxin, which is produced in the leaves and nectar of rhododendrons and are concentrated in the honey by the bees. Hepatitis and cirrhosis of the liver from contaminated grain caused by ragwort or pyrrolizidine alkaloids are well known. Children are often the most susceptible to many of the naturally occurring toxins, just as they are to other toxicants. The caffeine from a can of cola will have a much larger effect on a small child than it will on an adult. Health status and age, both young and old, also influence the response. Aflatoxin from contaminated nuts has a greater likelihood of causing cancer in some with a liver disease such as hepatitis. It is important to develop a knowledge of which plants and animals can be dangerous and to learn how to avoid dangerous contact with them.
29.4 POISONOUS MARINE BITES AND STINGS Some marine bites and stings are toxic, and all create wounds at risk for infection with marine organisms. Shark bites result in jagged lacerations with near-total or total amputations and should be treated as traumas.
29.4.1 POISONOUS FISHES There are several species of venomous fish that are capable of producing poisoning. Fish poisoning may occur due to attacks and bites (eg, sharks and barracudas), by injecting toxic venom through their venomous spines or tentacles (eg, stingrays), and through eating fish whose flesh is toxic. There are three common types of fish whose flesh is toxic and cause poisoning. They are described here. Ciguatera poisoning may result from eating any of the more than 400 species of fish in which a dinoflagellate produces a toxin that accumulates in the flesh of the body. Symptoms may begin 2 8 h after eating; intravenous (IV) mannitol has been suggested as a treatment. Scombroid poisoning is caused by high histamine levels in fish flesh due to bacterial decomposition after the fish is caught. Commonly affected species include tuna, mackerel, bonito, skipjack, and mahi mahi. Symptoms include facial
329
330
CHAPTER 29 Chemical food poisoning
flushing, nausea, vomiting, and urticaria. Treatment may include administration of antihistamines. Tetrodotoxin poisoning is most common due to eating puffer fish, but more than 100 fresh water and salt water species contain tetrodotoxin. Symptoms are similar to ciguatera and may produce fatal respiratory paralysis. Tetrodotoxin is found in all organs of the fish but is highest in the liver, skin, and intestine. The origins of the toxin are not clear, but one possibility is that the fish has come in contact with bacteria that produce tetrodotoxin. Puffer fish may also have elevated levels of saxitoxin, a neurotoxin responsible for paralytic shellfish poisoning. Saxitoxin is produced by dinoflagellates (algae) and most often contaminates mussels, clams, and scallops. Both saxitoxin and tetrodotoxin are heat-stable, so cooking does not reduce toxicity. Mode of action Tetrodotoxin causes paralysis by affecting the sodium ion transport in both the central and peripheral nervous systems. A low dose of tetrodotoxin produces tingling sensations and numbness around the mouth, fingers, and toes. Higher doses produce nausea, vomiting, respiratory failure, difficulty walking, extensive paralysis, and death. As little as 1 4 mg of the toxin can kill an adult. Saxitoxin has a very different chemical structure than tetrodotoxin, but it has similar effects on transport of cellular sodium and produces similar neurological effects. Saxitoxin is less toxic than tetrodotoxin. Some people, particularly in Asia, consider the puffer fish a fine delicacy if it is carefully prepared by experienced chefs. The trick is to get just a small dose to feel mild tingling effects, but not the more serious symptoms of tetrodotoxin poisoning. In the United States tetrodotoxin poisoning is rare, but a recent US report indicated several cases of people catching and consuming puffer fish containing elevated levels of these toxins and suffering the ill effects. Treatment Treatment is supportive and symptom-based. Activated charcoal may be helpful.
29.4.2 SHELLFISH Shellfish such as mussels, clams, oysters, and scallops are not naturally toxic, but they can become so after feeding on plankton contaminated with a toxin. When visible, the blooming of the plankton (dinoflagellate) is called red tide and can cause significant death among marine animals. There are several types of toxins, mostly affecting the nervous system. The newest, domoic acid, first appeared in 1987 off Prince Edward Island in Canada. This neurotoxin caused confusion and memory loss, particularly in the elderly. Several elderly people died after seizures and coma. Domoic acid is heat-stable, so cooking does not affect the toxin. Government agencies now monitor for contaminants of shellfish and move quickly to restrict harvesting. The puffer fish is probably the best known neurotoxic fish. Several related species of fish as well as other marine life, such as some frogs, starfish, octopus, and others, contain tetrodotoxin. Many people consider these fish a delicacy despite the occasional reported death from poor
29.4 Poisonous Marine Bites and Stings
preparation. Tetrodotoxin is heat-stable but water-soluble, so careful preparation is necessary to limit neurological effects. Symptoms of poisoning include rapid onset of numbness in the lips and mouth that then extends to the fingers and toes, followed by general weakness, dizziness, respiratory failure, and death. The mechanism of action is similar to that of saxitoxin and affects sodium channel permeability. It should also be remembered that fish high in the food chain such as tuna, swordfish, and shark accumulate toxic substances like mercury or PCBs. Mercury affects the nervous system and is a proven reproductive hazard. Treatment Supportive and symptom-based treatment such as gastric lavage, IV mannitol, atropine, exchange transfusion in children, charcoal, and hemoperfusion in adults are administered. In some cases, treatment may include H1 and H2 blockers.
331