Amanita ocreata
Encyclopedia
Amanita ocreata, commonly known as the death angel, destroying angel, angel of death or more precisely Western North American destroying angel, is a deadly poison
ous basidiomycete fungus
, one of many in the genus Amanita
. Occurring in the Pacific Northwest
and California floristic province
s of North America, A. ocreata associates
with oak trees. The large fruiting bodies (the mushrooms) generally appear in spring; the cap
may be white or ochre and often develops a brownish centre, while the stipe
, ring
, gill and volva
are all white.
Amanita ocreata resemble several edible species commonly consumed by humans, increasing the risk of accidental poisoning. Mature fruiting bodies can be confused with the edible A. velosa
, A. lanei
or Volvariella speciosa, while immature specimens may be difficult to distinguish from edible Agaricus
mushrooms or puffballs. Similar in toxicity to the death cap (A. phalloides) and destroying angels of Europe (A. virosa
) and eastern North America (A. bisporigera
), it is a potentially deadly fungus responsible for a number of poisonings in California. Its principal toxic constituent, α-amanitin, damages the liver and kidneys, often fatally, and has no known antidote. The initial symptoms are gastrointestinal and include colicky
abdominal pain, diarrhea
and vomiting
. These subside temporarily after 2–3 days, though ongoing damage to internal organs during this time is common; symptoms of jaundice
, diarrhea, delirium
, seizures, and coma
may follow with death from liver failure 6–16 days post ingestion.
Charles Horton Peck
in 1909 from material collected by Charles Fuller Baker
in Claremont, California
. The specific epithet is derived from the Latin
ocrěātus 'wearing greaves' from ocrea 'greave
', referring to its loose, baggy volva
. Amanita bivolvata is a botanical synonym. The mushroom belongs to the same section
(Phalloideae) and genus (Amanita) as several deadly poisonous fungi including the death cap (A. phalloides) and several all-white species of Amanita known as "destroying angels": A. bisporigera
of eastern North America, and the European A. virosa
. "Death angel" is used as an alternate common name.
. As it grows, the mushroom breaks free, though there may rarely be ragged patches of veil left at the cap edges. The cap
is initially hemispherical, before becoming more convex and flattening, sometimes irregularly. This may result in undulations in the cap, which may reach up to 12 cm (5 in) in diameter. The colour varies from white, through yellowish-white to shades of ochre, sometimes with a brownish centre. Occasionally parts of the fruiting bodies may have pinkish tones. The rest of the fungus below the cap is white. The crowded gills are free to narrowly adnate. The stipe
is 8–20 cm (3–8 in) high and 1.5–2 cm (½–⅔ in) thick at the apex, and bears a thin white membranous ring
. The volva
is thin, smooth and sac-like, although may be quite extensive and contain almost half the stipe. The spore print
is white, and the subglobose to ovoid to subellipsoid, amyloid
spores are 9–14 x 7–10 μm viewed under a microscope. There is typically no smell, though some fruiting bodies may have a slight odour, described as that of bleach or chlorine
, dead fish or iodine
. Like other destroying angels, the flesh stains yellow when treated with potassium hydroxide
(KOH).
This fungus resembles the edible mushrooms Agaricus arvensis
and A. campestris
, and the puffballs (Lycoperdon
spp.) before the caps have opened and the gills have become visible, so those collecting immature fungi run the risk of confusing the varieties. It also resembles and grows in the same areas as the edible and prized Amanita velosa
, which can be distinguished from A. ocreata by its lack of ring, striate cap
margin and thick universal veil
remnants comprising the veil. The edible Amanita lanei
lacks a ring and is more likely to have veil patches remaining on its cap, which is generally darker. Volvariella speciosa has pink spores and no ring or volva.
of North America, from Washington south through California to Baja California
in Mexico
. It may feasibly occur on Vancouver Island
in British Columbia
though this has never been confirmed. It forms ectomycorrhizal
relationships and is found in association with coast live oak
(Quercus agrifolia), as well as hazel
(Corylus spp.). In Oregon and Washington, it may also be associated with the Garry oak
(Quercus garryana).
Amanita ocreata is highly toxic, and has been responsible for a number of mushroom poisoning
s in western North America, particularly in the spring. It contains highly toxic amatoxin
s, as well as phallotoxin
s, a feature shared with the closely related death cap (A. phalloides), half a cap of which can be enough to kill a human, and other species known as destroying angels. There is some evidence it may be the most toxic of all the North American phalloideae, as a higher proportion of people consuming it had organ damage and 40% perished. Dogs, too, have been known to consume this fungus in California with fatal results.
Amatoxins consist of at least eight compounds with a similar structure, that of eight amino-acid rings; of those found in A. ocreata, α-amanitin is the most prevalent and along with β-amanitin is likely to be responsible for the toxic effects. The major toxic mechanism is the inhibition of RNA polymerase II
, a vital enzyme in the synthesis of messenger RNA
(mRNA), microRNA, and small nuclear RNA (snRNA). Without mRNA, essential protein synthesis
and hence cell metabolism stop and the cell dies. The liver
is the principal organ affected, as it is the first organ encountered after absorption by the gastrointestinal tract, though other organs, especially the kidney
s, are susceptible to the toxins.
The phallotoxins consist of at least seven compounds, all of which have seven similar peptide rings. Although they are highly toxic to liver cells, phallotoxins have since been found to have little input into the destroying angel's toxicity as they are not absorbed through the gut. Furthermore, one phallotoxin, phalloidin
, is also found in the edible (and sought-after) blusher (Amanita rubescens).
abdominal pain, with watery diarrhea
and vomiting
which may lead to dehydration
, and, in severe cases, hypotension
, tachycardia
, hypoglycemia
, and acid-base disturbances. The initial symptoms resolve two to three days after ingestion of the fungus. A more serious deterioration signifying liver involvement may then occur—jaundice
, diarrhea, delirium
, seizures, and coma
due to fulminant hepatic failure and attendant hepatic encephalopathy
caused by the accumulation of normally liver-removed substances in the blood. Renal failure
(either secondary to severe hepatitis
or caused by direct toxic renal damage) and coagulopathy
may appear during this stage. Life-threatening complications include increased intracranial pressure
, intracranial hemorrhage, sepsis
, pancreatitis
, acute renal failure
, and cardiac arrest
. Death generally occurs six to sixteen days after the poisoning.
that requires hospitalization. There are four main categories of therapy for poisoning: preliminary medical care, supportive measures, specific treatments, and liver transplantation
.
Preliminary care consists of gastric decontamination with either activated carbon
or gastric lavage
. However, due to the delay between ingestion and the first symptoms of poisoning, it is commonplace for patients to arrive for treatment long after ingestion, potentially reducing the efficacy of these interventions. Supportive measures are directed towards treating the dehydration which results from fluid loss during the gastrointestinal phase of intoxication and correction of metabolic acidosis
, hypoglycemia, electrolyte
imbalances, and impaired coagulation.
No definitive antidote for amatoxin poisoning is available, but some specific treatments such as intravenous penicillin G
have been shown to improve survivability. There is some evidence that intravenous silibinin
, an extract from the blessed milk thistle (Silybum marianum), may be beneficial in reducing the effects of amatoxins, preventing their uptake by hepatocyte
s, thereby protecting undamaged hepatic tissue. In patients developing liver failure, a liver transplant is often the only option to prevent death. Liver transplants have become a well-established option in amatoxin poisoning. This is a complicated issue, however, as transplants themselves may have significant complications
and mortality; patients require long-term immunosuppression
to maintain the transplant. Evidence suggests that, although survival rates have improved with modern medical treatment, in patients with moderate to severe poisoning up to half of those who did recover suffered permanent liver damage. However, a follow-up study has shown that most survivors recover completely without any sequelae if treated within 36 hours of mushroom ingestion.
Poison
In the context of biology, poisons are substances that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....
ous basidiomycete fungus
Fungus
A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...
, one of many in the genus Amanita
Amanita
The genus Amanita contains about 600 species of agarics including some of the most toxic known mushrooms found worldwide. This genus is responsible for approximately 95% of the fatalities resulting from mushroom poisoning, with the death cap accounting for about 50% on its own...
. Occurring in the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
and California floristic province
California Floristic Province
The California Floristic Province is a floristic province with a Mediterranean climate located on the Pacific Coast of North America with a distinctive flora that bears similarities to floras found in other regions experiencing a winter rainfall, summer drought climate like the Mediterranean...
s of North America, A. ocreata associates
Mycorrhiza
A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....
with oak trees. The large fruiting bodies (the mushrooms) generally appear in spring; the cap
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
may be white or ochre and often develops a brownish centre, while the stipe
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
, ring
Annulus (mycology)
An annulus is the ring like structure sometimes found on the stipe of some species of mushrooms. The annulus represents the remaining part of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. An annulus may be thick and membranous, or it may be cobweb-like...
, gill and volva
Volva (mycology)
The volva is a mycological term to describe a cup-like structure at the base of a mushroom that is a remnant of the universal veil. This macrofeature is important in wild mushroom identification due to it being an easily observed, taxonomically significant feature which frequently signifies a...
are all white.
Amanita ocreata resemble several edible species commonly consumed by humans, increasing the risk of accidental poisoning. Mature fruiting bodies can be confused with the edible A. velosa
Amanita velosa
Amanita velosa is an edible species of agaric found in California, as well as Oregon and Baja California.-Description and classification:...
, A. lanei
Amanita lanei
Amanita lanei , also known as coccora or coccoli, is a white-spored mushroom that fruits naturally in the coastal forests of the western United States during the fall and winter...
or Volvariella speciosa, while immature specimens may be difficult to distinguish from edible Agaricus
Agaricus
Agaricus is a large and important genus of mushrooms containing both edible and poisonous species, with possibly over 300 members worldwide...
mushrooms or puffballs. Similar in toxicity to the death cap (A. phalloides) and destroying angels of Europe (A. virosa
Amanita virosa
Amanita virosa, commonly known as the European destroying angel, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Occurring in Europe, A. virosa associates with various deciduous and coniferous trees...
) and eastern North America (A. bisporigera
Amanita bisporigera
Amanita bisporigera is a deadly poisonous species of fungus in the Amanitaceae family. It is commonly known as the eastern North American destroying angel or the destroying angel, although it shares this latter name with three other lethal white Amanita species, A. ocreata, A. verna and...
), it is a potentially deadly fungus responsible for a number of poisonings in California. Its principal toxic constituent, α-amanitin, damages the liver and kidneys, often fatally, and has no known antidote. The initial symptoms are gastrointestinal and include colicky
Biliary colic
Biliary colic is pain associated with irritation of the viscera secondary to cholecystitis and gallstones. Unlike renal colic, the phrase 'biliary colic' refers to the actual cholelithiasis....
abdominal pain, diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
and vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
. These subside temporarily after 2–3 days, though ongoing damage to internal organs during this time is common; symptoms of jaundice
Jaundice
Jaundice is a yellowish pigmentation of the skin, the conjunctival membranes over the sclerae , and other mucous membranes caused by hyperbilirubinemia . This hyperbilirubinemia subsequently causes increased levels of bilirubin in the extracellular fluid...
, diarrhea, delirium
Delirium
Delirium or acute confusional state is a common and severe neuropsychiatric syndrome with core features of acute onset and fluctuating course, attentional deficits and generalized severe disorganization of behavior...
, seizures, and coma
Coma
In medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
may follow with death from liver failure 6–16 days post ingestion.
Taxonomy and naming
Amanita ocreata was first described by American mycologistMycology
Mycology is the branch of biology concerned with the study of fungi, including their genetic and biochemical properties, their taxonomy and their use to humans as a source for tinder, medicinals , food and entheogens, as well as their dangers, such as poisoning or...
Charles Horton Peck
Charles Horton Peck
Charles Horton Peck, born March 30, 1833 in Sand Lake, New York, died 1917 in Albany, New York, was an American mycologist of the 19th and early 20th centuries...
in 1909 from material collected by Charles Fuller Baker
Charles Fuller Baker
Charles Fuller Baker was an American entomologist, botanist, agronomist and collector.-References:...
in Claremont, California
Claremont, California
Claremont is a small affluent college town in eastern Los Angeles County, California, United States, about east of downtown Los Angeles at the base of the San Gabriel Mountains. The population as of the 2010 census is 34,926. Claremont is known for its seven higher-education institutions, its...
. The specific epithet is derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
ocrěātus 'wearing greaves' from ocrea 'greave
Greave
A greave is a piece of armour that protects the leg.-Description:...
', referring to its loose, baggy volva
Volva (mycology)
The volva is a mycological term to describe a cup-like structure at the base of a mushroom that is a remnant of the universal veil. This macrofeature is important in wild mushroom identification due to it being an easily observed, taxonomically significant feature which frequently signifies a...
. Amanita bivolvata is a botanical synonym. The mushroom belongs to the same section
Section (botany)
In botany, a section is a taxonomic rank below the genus, but above the species. The subgenus, if present, is higher than the section, and the rank of series, if present, is below the section. Sections are typically used to help organise very large genera, which may have hundreds of species...
(Phalloideae) and genus (Amanita) as several deadly poisonous fungi including the death cap (A. phalloides) and several all-white species of Amanita known as "destroying angels": A. bisporigera
Amanita bisporigera
Amanita bisporigera is a deadly poisonous species of fungus in the Amanitaceae family. It is commonly known as the eastern North American destroying angel or the destroying angel, although it shares this latter name with three other lethal white Amanita species, A. ocreata, A. verna and...
of eastern North America, and the European A. virosa
Amanita virosa
Amanita virosa, commonly known as the European destroying angel, is a deadly poisonous basidiomycete fungus, one of many in the genus Amanita. Occurring in Europe, A. virosa associates with various deciduous and coniferous trees...
. "Death angel" is used as an alternate common name.
Description
A. ocreata is generally stouter than the other fungi termed destroying angels. It first appears as a white egg-shaped object covered with a universal veilVeil (botany)
A veil, in mycology, is one of several structures in fungi, especially the thin membrane that covers the cap and stalk of an immature mushroom.Veils may be regarded as falling into two categories:*Partial veil*Universal veil...
. As it grows, the mushroom breaks free, though there may rarely be ragged patches of veil left at the cap edges. The cap
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
is initially hemispherical, before becoming more convex and flattening, sometimes irregularly. This may result in undulations in the cap, which may reach up to 12 cm (5 in) in diameter. The colour varies from white, through yellowish-white to shades of ochre, sometimes with a brownish centre. Occasionally parts of the fruiting bodies may have pinkish tones. The rest of the fungus below the cap is white. The crowded gills are free to narrowly adnate. The stipe
Stipe (mycology)
thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...
is 8–20 cm (3–8 in) high and 1.5–2 cm (½–⅔ in) thick at the apex, and bears a thin white membranous ring
Annulus (mycology)
An annulus is the ring like structure sometimes found on the stipe of some species of mushrooms. The annulus represents the remaining part of the partial veil, after it has ruptured to expose the gills or other spore-producing surface. An annulus may be thick and membranous, or it may be cobweb-like...
. The volva
Volva (mycology)
The volva is a mycological term to describe a cup-like structure at the base of a mushroom that is a remnant of the universal veil. This macrofeature is important in wild mushroom identification due to it being an easily observed, taxonomically significant feature which frequently signifies a...
is thin, smooth and sac-like, although may be quite extensive and contain almost half the stipe. The spore print
Spore print
thumb|300px|right|Making a spore print of the mushroom Volvariella volvacea shown in composite: mushroom cap laid on white and dark paper; cap removed after 24 hours showing pinkish-tan spore print...
is white, and the subglobose to ovoid to subellipsoid, amyloid
Amyloid (mycology)
In mycology the term amyloid refers to a crude chemical test using iodine in either Melzer's reagent or Lugol's solution, to produce a black to blue-black positive reaction. It is called amyloid because starch gives a similar reaction, and that reaction for starch is also called an amyloid reaction...
spores are 9–14 x 7–10 μm viewed under a microscope. There is typically no smell, though some fruiting bodies may have a slight odour, described as that of bleach or chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
, dead fish or iodine
Iodine
Iodine is a chemical element with the symbol I and atomic number 53. The name is pronounced , , or . The name is from the , meaning violet or purple, due to the color of elemental iodine vapor....
. Like other destroying angels, the flesh stains yellow when treated with potassium hydroxide
Potassium hydroxide
Potassium hydroxide is an inorganic compound with the formula KOH, commonly called caustic potash.Along with sodium hydroxide , this colorless solid is a prototypical strong base. It has many industrial and niche applications. Most applications exploit its reactivity toward acids and its corrosive...
(KOH).
This fungus resembles the edible mushrooms Agaricus arvensis
Agaricus arvensis
Agaricus arvensis, commonly known as the Horse Mushroom, is a mushroom of the genus Agaricus.-Taxonomy:Described as Agaricus arvensis by Jacob Christian Schaeffer in 1762, and given numerous binomial descriptions since. Its present name arvensis means 'of the field'.-Description:The cap is similar...
and A. campestris
Agaricus campestris
Agaricus campestris is commonly known as the field mushroom or, in North America, meadow mushroom. It is a widely eaten gilled mushroom closely related to the cultivated button mushroom Agaricus bisporus.-Taxonomy:...
, and the puffballs (Lycoperdon
Lycoperdon
Lycoperdon is a genus of puffball mushrooms. The genus has a widespread distribution and contains about 50 species. In general, it contains the smaller species such as the pear shaped puffball and the gem studded puffball. Most of the time they grow from dead wood and if they grow through the...
spp.) before the caps have opened and the gills have become visible, so those collecting immature fungi run the risk of confusing the varieties. It also resembles and grows in the same areas as the edible and prized Amanita velosa
Amanita velosa
Amanita velosa is an edible species of agaric found in California, as well as Oregon and Baja California.-Description and classification:...
, which can be distinguished from A. ocreata by its lack of ring, striate cap
Pileus (mycology)
The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...
margin and thick universal veil
Universal veil
In mycology, a universal veil is a temporary membranous tissue that fully envelops immature fruiting bodies of certain gilled mushrooms. The developing Caesar's mushroom , for example, which may resemble a small white sphere at this point, is protected by this structure...
remnants comprising the veil. The edible Amanita lanei
Amanita lanei
Amanita lanei , also known as coccora or coccoli, is a white-spored mushroom that fruits naturally in the coastal forests of the western United States during the fall and winter...
lacks a ring and is more likely to have veil patches remaining on its cap, which is generally darker. Volvariella speciosa has pink spores and no ring or volva.
Distribution and habitat
Appearing from January to April, A. ocreata occurs later in the year than other amanitas except A. calyptroderma. It is found in mixed woodland on the Pacific coastPacific Coast
A country's Pacific coast is the part of its coast bordering the Pacific Ocean.-The Americas:Countries on the western side of the Americas have a Pacific coast as their western border.* Geography of Canada* Geography of Chile* Geography of Colombia...
of North America, from Washington south through California to Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. It may feasibly occur on Vancouver Island
Vancouver Island
Vancouver Island is a large island in British Columbia, Canada. It is one of several North American locations named after George Vancouver, the British Royal Navy officer who explored the Pacific Northwest coast of North America between 1791 and 1794...
in British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
though this has never been confirmed. It forms ectomycorrhizal
Mycorrhiza
A mycorrhiza is a symbiotic association between a fungus and the roots of a vascular plant....
relationships and is found in association with coast live oak
Coast Live Oak
Quercus agrifolia, the Coast Live Oak, is an evergreen oak , native to the California Floristic Province. It grows west of the Sierra Nevada from Mendocino County, California, south to northern Baja California in Mexico. It is classified in the red oak section Quercus agrifolia, the Coast Live Oak,...
(Quercus agrifolia), as well as hazel
Hazel
The hazels are a genus of deciduous trees and large shrubs native to the temperate northern hemisphere. The genus is usually placed in the birch family Betulaceae, though some botanists split the hazels into a separate family Corylaceae.They have simple, rounded leaves with double-serrate margins...
(Corylus spp.). In Oregon and Washington, it may also be associated with the Garry oak
Garry Oak
Quercus garryana, the Garry Oak, Oregon White Oak or Oregon Oak, has a range from southern California to extreme southwestern British Columbia, particularly southeastern Vancouver Island and the adjacent Gulf Islands. It grows from sea level to 210 m altitude in the northern part of its range, and...
(Quercus garryana).
Toxicity
Mushroom poisoning
Mushroom poisoning refers to harmful effects from ingestion of toxic substances present in a mushroom. These symptoms can vary from slight gastrointestinal discomfort to death. The toxins present are secondary metabolites produced in specific biochemical pathways in the fungal cells...
s in western North America, particularly in the spring. It contains highly toxic amatoxin
Amatoxin
Amatoxins are a subgroup of at least eight toxic compounds found in several genera of poisonous mushrooms, most notably Amanita phalloides and several other members of the genus Amanita, as well as some Conocybe, Galerina and Lepiota mushroom species.-Structure:The compounds have a similar...
s, as well as phallotoxin
Phallotoxin
The phallotoxins consist of at least seven compounds, all of which are bicyclic heptapeptides , isolated from the death cap . Phalloidin had been isolated in 1937 by Feodor Lynen, Heinrich Wieland's student and son-in-law, and Ulrich Wieland of the University of Munich...
s, a feature shared with the closely related death cap (A. phalloides), half a cap of which can be enough to kill a human, and other species known as destroying angels. There is some evidence it may be the most toxic of all the North American phalloideae, as a higher proportion of people consuming it had organ damage and 40% perished. Dogs, too, have been known to consume this fungus in California with fatal results.
Amatoxins consist of at least eight compounds with a similar structure, that of eight amino-acid rings; of those found in A. ocreata, α-amanitin is the most prevalent and along with β-amanitin is likely to be responsible for the toxic effects. The major toxic mechanism is the inhibition of RNA polymerase II
RNA polymerase II
RNA polymerase II is an enzyme found in eukaryotic cells. It catalyzes the transcription of DNA to synthesize precursors of mRNA and most snRNA and microRNA. A 550 kDa complex of 12 subunits, RNAP II is the most studied type of RNA polymerase...
, a vital enzyme in the synthesis of messenger RNA
Messenger RNA
Messenger RNA is a molecule of RNA encoding a chemical "blueprint" for a protein product. mRNA is transcribed from a DNA template, and carries coding information to the sites of protein synthesis: the ribosomes. Here, the nucleic acid polymer is translated into a polymer of amino acids: a protein...
(mRNA), microRNA, and small nuclear RNA (snRNA). Without mRNA, essential protein synthesis
Protein biosynthesis
Protein biosynthesis is the process in which cells build or manufacture proteins. The term is sometimes used to refer only to protein translation but more often it refers to a multi-step process, beginning with amino acid synthesis and transcription of nuclear DNA into messenger RNA, which is then...
and hence cell metabolism stop and the cell dies. The liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
is the principal organ affected, as it is the first organ encountered after absorption by the gastrointestinal tract, though other organs, especially the kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s, are susceptible to the toxins.
The phallotoxins consist of at least seven compounds, all of which have seven similar peptide rings. Although they are highly toxic to liver cells, phallotoxins have since been found to have little input into the destroying angel's toxicity as they are not absorbed through the gut. Furthermore, one phallotoxin, phalloidin
Phalloidin
Phalloidin is one of a group of toxins from the death cap known as phallotoxins.-Background:Pioneering work on this toxin was done by the Nobel laureate Heinrich Wieland in the 1930s...
, is also found in the edible (and sought-after) blusher (Amanita rubescens).
Symptoms
Symptoms of poisoning by A. ocreata are initially gastrointestinal in nature and include colickyBiliary colic
Biliary colic is pain associated with irritation of the viscera secondary to cholecystitis and gallstones. Unlike renal colic, the phrase 'biliary colic' refers to the actual cholelithiasis....
abdominal pain, with watery diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
and vomiting
Vomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
which may lead to dehydration
Dehydration
In physiology and medicine, dehydration is defined as the excessive loss of body fluid. It is literally the removal of water from an object; however, in physiological terms, it entails a deficiency of fluid within an organism...
, and, in severe cases, hypotension
Hypotension
In physiology and medicine, hypotension is abnormally low blood pressure, especially in the arteries of the systemic circulation. It is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the...
, tachycardia
Tachycardia
Tachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heart rate...
, hypoglycemia
Hypoglycemia
Hypoglycemia or hypoglycæmia is the medical term for a state produced by a lower than normal level of blood glucose. The term literally means "under-sweet blood"...
, and acid-base disturbances. The initial symptoms resolve two to three days after ingestion of the fungus. A more serious deterioration signifying liver involvement may then occur—jaundice
Jaundice
Jaundice is a yellowish pigmentation of the skin, the conjunctival membranes over the sclerae , and other mucous membranes caused by hyperbilirubinemia . This hyperbilirubinemia subsequently causes increased levels of bilirubin in the extracellular fluid...
, diarrhea, delirium
Delirium
Delirium or acute confusional state is a common and severe neuropsychiatric syndrome with core features of acute onset and fluctuating course, attentional deficits and generalized severe disorganization of behavior...
, seizures, and coma
Coma
In medicine, a coma is a state of unconsciousness, lasting more than 6 hours in which a person cannot be awakened, fails to respond normally to painful stimuli, light or sound, lacks a normal sleep-wake cycle and does not initiate voluntary actions. A person in a state of coma is described as...
due to fulminant hepatic failure and attendant hepatic encephalopathy
Hepatic encephalopathy
Hepatic encephalopathy is the occurrence of confusion, altered level of consciousness and coma as a result of liver failure. In the advanced stages it is called hepatic coma or coma hepaticum...
caused by the accumulation of normally liver-removed substances in the blood. Renal failure
Renal failure
Renal failure or kidney failure describes a medical condition in which the kidneys fail to adequately filter toxins and waste products from the blood...
(either secondary to severe hepatitis
Hepatitis
Hepatitis is a medical condition defined by the inflammation of the liver and characterized by the presence of inflammatory cells in the tissue of the organ. The name is from the Greek hepar , the root being hepat- , meaning liver, and suffix -itis, meaning "inflammation"...
or caused by direct toxic renal damage) and coagulopathy
Coagulopathy
Coagulopathy is a condition in which the blood’s ability to clot is impaired. This condition can cause prolonged or excessive bleeding, which may occur spontaneously or following an injury or medical and dental procedures.The normal clotting process depends on the interplay of various proteins in...
may appear during this stage. Life-threatening complications include increased intracranial pressure
Intracranial pressure
Intracranial pressure is the pressure inside the skull and thus in the brain tissue and cerebrospinal fluid . The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF...
, intracranial hemorrhage, sepsis
Sepsis
Sepsis is a potentially deadly medical condition that is characterized by a whole-body inflammatory state and the presence of a known or suspected infection. The body may develop this inflammatory response by the immune system to microbes in the blood, urine, lungs, skin, or other tissues...
, pancreatitis
Pancreatitis
Pancreatitis is inflammation of the pancreas. It occurs when pancreatic enzymes that digest food are activated in the pancreas instead of the small intestine. It may be acute – beginning suddenly and lasting a few days, or chronic – occurring over many years...
, acute renal failure
Acute renal failure
Acute kidney injury , previously called acute renal failure , is a rapid loss of kidney function. Its causes are numerous and include low blood volume from any cause, exposure to substances harmful to the kidney, and obstruction of the urinary tract...
, and cardiac arrest
Cardiac arrest
Cardiac arrest, is the cessation of normal circulation of the blood due to failure of the heart to contract effectively...
. Death generally occurs six to sixteen days after the poisoning.
Treatment
Consumption of A. ocreata is a medical emergencyMedical emergency
A medical emergency is an injury or illness that is acute and poses an immediate risk to a person's life or long term health. These emergencies may require assistance from another person, who should ideally be suitably qualified to do so, although some of these emergencies can be dealt with by the...
that requires hospitalization. There are four main categories of therapy for poisoning: preliminary medical care, supportive measures, specific treatments, and liver transplantation
Liver transplantation
Liver transplantation or hepatic transplantation is the replacement of a diseased liver with a healthy liver allograft. The most commonly used technique is orthotopic transplantation, in which the native liver is removed and replaced by the donor organ in the same anatomic location as the original...
.
Preliminary care consists of gastric decontamination with either activated carbon
Activated carbon
Activated carbon, also called activated charcoal, activated coal or carbo activatus, is a form of carbon that has been processed to make it extremely porous and thus to have a very large surface area available for adsorption or chemical reactions.The word activated in the name is sometimes replaced...
or gastric lavage
Gastric lavage
Gastric lavage, also commonly called stomach pumping or Gastric irrigation, is the process of cleaning out the contents of the stomach. It has been used for over 200 years as a means of eliminating poisons from the stomach. Such devices are normally used on a person who has ingested a poison or...
. However, due to the delay between ingestion and the first symptoms of poisoning, it is commonplace for patients to arrive for treatment long after ingestion, potentially reducing the efficacy of these interventions. Supportive measures are directed towards treating the dehydration which results from fluid loss during the gastrointestinal phase of intoxication and correction of metabolic acidosis
Metabolic acidosis
In medicine, metabolic acidosis is a condition that occurs when the body produces too much acid or when the kidneys are not removing enough acid from the body. If unchecked, metabolic acidosis leads to acidemia, i.e., blood pH is low due to increased production of hydrogen by the body or the...
, hypoglycemia, electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
imbalances, and impaired coagulation.
No definitive antidote for amatoxin poisoning is available, but some specific treatments such as intravenous penicillin G
Benzylpenicillin
Benzylpenicillin, commonly known as penicillin G, is the gold standard type of penicillin. 'G' in the name 'Penicillin G' refers to 'Gold Standard'. Penicillin G is typically given by a parenteral route of administration because it is unstable in the hydrochloric acid of the stomach...
have been shown to improve survivability. There is some evidence that intravenous silibinin
Silibinin
Silibinin , also known as silybin, is the major active constituent of silymarin, standardized extract of the milk thistle seeds, containing mixture of flavonolignans consisting of among others of silibinin, isosilibinin, silicristin and silidianin. Silibinin itself is mixture of two diastereomers...
, an extract from the blessed milk thistle (Silybum marianum), may be beneficial in reducing the effects of amatoxins, preventing their uptake by hepatocyte
Hepatocyte
A hepatocyte is a cell of the main tissue of the liver. Hepatocytes make up 70-80% of the liver's cytoplasmic mass.These cells are involved in:* Protein synthesis* Protein storage* Transformation of carbohydrates...
s, thereby protecting undamaged hepatic tissue. In patients developing liver failure, a liver transplant is often the only option to prevent death. Liver transplants have become a well-established option in amatoxin poisoning. This is a complicated issue, however, as transplants themselves may have significant complications
Complication (medicine)
Complication, in medicine, is an unfavorable evolution of a disease, a health condition or a medical treatment. The disease can become worse in its severity or show a higher number of signs, symptoms or new pathological changes, become widespread throughout the body or affect other organ systems. A...
and mortality; patients require long-term immunosuppression
Immunosuppression
Immunosuppression involves an act that reduces the activation or efficacy of the immune system. Some portions of the immune system itself have immuno-suppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reaction to treatment of other...
to maintain the transplant. Evidence suggests that, although survival rates have improved with modern medical treatment, in patients with moderate to severe poisoning up to half of those who did recover suffered permanent liver damage. However, a follow-up study has shown that most survivors recover completely without any sequelae if treated within 36 hours of mushroom ingestion.