Cicuta is a small
genusIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
of four species of highly poisonous plants in the family
ApiaceaeThe Apiaceae or Umbelliferae is a family of usually aromatic plants with hollow stems, commonly known as umbellifers. It includes cumin, parsley, carrot, coriander/cilantro, dill, caraway, fennel, parsnip, celery, Queen Anne's Lace and other relatives. It is a large family with about 300 genera...
. They are
perennialA perennial plant or perennial is a plant that lives for more than two years. When used by gardeners or horticulturalists, this term applies specifically to perennial herbaceous plants...
herbaceousA herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
plants which grow up to tall, having distinctive small green or white flowers arranged in an umbrella shape (
umbelAn umbel is an inflorescence which consists of a number of short flower stalks which are equal in length and spread from a common point, somewhat like umbrella ribs....
). Commonly known as
water hemlock, plants in this genus may also be referred to as
cowbane or
poison parsnip.
Cicuta is native to
temperateIn geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally mild, rather than extreme hot or cold. But in continental areas, such as central North America the variations between summer...
regions of the
Northern HemisphereThe Northern Hemisphere is the half of a planet that is north of the equator—the word hemisphere literally means 'half sphere'. It is also that half of the celestial sphere north of the celestial equator...
, mainly
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
and
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
, typically growing in wet meadows, along streambanks and other wet and marshy areas. These plants bear a close resemblance to other members in the family Apiaceae and may be confused with a number of other edible and poisonous plants. The common name hemlock may also be confused with poison hemlock (
Conium maculatum).
Water hemlock is considered one of North America's most toxic plants being highly poisonous to humans. Three members of the genus contain a
toxinA toxin is a poisonous substance produced by living cells or organisms ....
named
cicutoxinCicutoxin is a poisonous polyyne and alcohol found in various plants, most notably water hemlock . It is structurally related to the oenanthotoxin of hemlock water dropwort....
which causes
central nervous systemThe central nervous system is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of bilaterian animals—that is, all animals more advanced than sponges or jellyfish. In vertebrates, the central nervous system is enclosed in the meninges. It contains...
stimulatory effects including
seizureAn epileptic seizure is a transient symptom of excessive or synchronous neuronal activity in the brain. It can manifest as an alteration in mental state, tonic or clonic movements, convulsions, and various other psychic symptoms...
s following ingestion. Medical treatment of poisoning may include the use of activated charcoal to decrease gastrointestinal absorption of the toxic principle along with supportive care including
anticonvulsantThe anticonvulsants are a diverse group of pharmaceuticals used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of bipolar disorder, since many seem to act as mood stabilizers. The goal of an anticonvulsant is to suppress the rapid and...
drugs such as a
benzodiazepineA benzodiazepine is a psychoactive drug whose core chemical structure is the fusion of a benzene ring and a diazepine ring...
. High doses of anticonvulsant medicine are often required to halt seizure activity and further medical care including
intubationIn medicine, intubation refers to the placement of a tube into an external or internal orifice of the body. Although the term can refer to endoscopic procedures, it is most often used to denote tracheal intubation. Tracheal intubation is the placement of a flexible plastic tube into the trachea to...
and
mechanical ventilationIn medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing.This may involve a machine called a ventilator or the breathing may be assisted by a physician or other suitable person compressing a bag or set of bellows...
may be required.
Description
Cicuta spp. are perennial plants that are all similar in
morphologyIn biology morphology is the form, structure and configuration of an organism.This includes aspects of the outward appearance as well as the form and structure of the internal parts like bones and organs...
, growing up to a maximum of in height. The stem of the plant is branching, erect, smooth and hollow (except for partitions at the junction of the leaves and stem), sometimes being purple-striped, or mottled (typically only
C. maculata has the purple stripes or spots). Attached to the base of the stem is a tuberous root with thickened
rootstockA rootstock is a plant, and sometimes just the stump, which already has an established, healthy root system, used for grafting a cutting or budding from another plant. The tree part being grafted onto the rootstock is usually called the scion...
s. The rootstocks are multichambered and contain a yellowish oily liquid which turns reddish brown on exposure to air and emits a characteristic smell of raw parsnip. The
alternateIn botany, phyllotaxis or phyllotaxy is the arrangement of the leaves on the stem of a plant .- Pattern structure :...
leavesLeaves are an Icelandic five-piece alternative rock band who formed in 2001. Late in 2001 they played with Emiliana Torrini and drew early praise from the New York Times. They came to prominence in 2002 with their debut album, Breathe, drawing comparisons to groups such as The Verve and Doves...
are 2 or 3
pinnatePinnate is a term used to describe feather-like or multi-divided features arising from both sides of a common axis in plant or animal structures, and comes from the Latin word pinna meaning "feather", "wing", or "fin". A similar term is pectinate, which refers to a comb-like arrangement of parts...
ly compound and may reach to in length. The leaflets are lanceolate, serrate, to in length, and sharply toothed. The plant flowers in spring or early summer; the flowers are small with green or white petals clustered in an umbrella shape (
umbelAn umbel is an inflorescence which consists of a number of short flower stalks which are equal in length and spread from a common point, somewhat like umbrella ribs....
) characteristic to this family; the umbel measures to across. The plants produce a cylindrical fruit which is to in length. The plant is spread primarily by seeds which are produced in large numbers.
Taxonomy
The
Cicuta genus is one of many genera in the
ApiaceaeThe Apiaceae or Umbelliferae is a family of usually aromatic plants with hollow stems, commonly known as umbellifers. It includes cumin, parsley, carrot, coriander/cilantro, dill, caraway, fennel, parsnip, celery, Queen Anne's Lace and other relatives. It is a large family with about 300 genera...
familyIn biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus...
which is in the order
ApialesThe Apiales are an order of flowering plants. The families given at right are typical of newer classifications, though there is some slight variation, and in particular the Torriceliaceae may be divided. These families are placed within the asterid group of eudicots as circumscribed by the APG II...
. The Apiaceae family is also known as Umbelliferae and both of these family names are permitted to be used by the
International Code of Botanical NomenclatureThe International Code of Botanical Nomenclature is the set of rules and recommendations dealing with the formal botanical names that are given to plants. Its intent is that each taxonomic group of plants has only one correct name that is accepted worldwide...
. In Europe,
Cicuta was not distinguished from the similar genus
ConiumConium is a genus of two species of highly poisonous perennial herbaceous flowering plants in the family Apiaceae, native to Europe and the Mediterranean region , and to southern Africa ....
before the year 1500. The first mention of the genus in the
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
was in the eighteenth century. Carl Linnaeus formally described three species in 1753. The
type speciesIn taxonomy, a type species is a technical phrase, involved in the application of formal names...
is
C. virosa. The genus is now recognized to comprise four species:
| Species Name |
Common Name |
Cicuta bulbifera L.Carl Linnaeus was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature...
|
bulblet-bearing water hemlock, bulbous water hemlock |
| Cicuta douglasii (DC.) Coult. Thomas Coulter , of Dundalk, was an Irish physician, botanist, and explorer. He was a member of the Royal Irish Academy, and a fellow of Trinity College, Dublin, where he founded the college's herbarium....
& RoseJoseph Nelson Rose was an American botanist. He was born in Union County, Indiana. His father died serving during the Civil War when Joseph Rose was a young boy. He later graduated from high school in Liberty, Indiana....
|
Douglas water hemlock, western water hemlock |
Cicuta maculataCicuta maculata is a species of flowering plant in the carrot family known by several common names, including spotted water hemlock, spotted parsley, and spotted cowbane. It is native to nearly all of North America, from northern Canada to southern Mexico. This is a rhizomatous perennial herb...
L.Carl Linnaeus was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature...
|
spotted cowbane, spotted parsley, spotted water hemlock |
Cicuta virosaCicuta virosa is a species of Cicuta, native to northern and central Europe, northern Asia and northwestern North America. It is a perennial herbaceous plant which grows up to 1–2 m tall. The stems are smooth, branching, swollen at the base, purple-striped, and hollow except for partitions at the...
L.Carl Linnaeus was a Swedish botanist, physician, and zoologist, who laid the foundations for the modern scheme of binomial nomenclature...
|
cowbane, Mackenzie’s water hemlock, northern water hemlock |
Other species names such as
Cicuta bolanderi,
Cicuta californica, and
Cicuta curtissii are older names now recognized to be varieties of the widespread,
morphologicallyIn biology morphology is the form, structure and configuration of an organism.This includes aspects of the outward appearance as well as the form and structure of the internal parts like bones and organs...
variable
Cicuta maculata.
Cicuta maculata is now recognized to have four varieties: var.
maculata, var.
augustifolia, var.
victorinii, and var.
bolanderi.
PhylogeneticIn biology, phylogenetics is the study of evolutionary relatedness among various groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
analysis using the
sequencesIn biochemistry, the primary structure of a biological molecule is the exact specification of its atomic composition and the chemical bonds connecting those atoms...
of nuclear
ribosomal DNARibosomal DNA are sequences encoding ribosomal RNA. These sequences regulate amplification and transcription initiation and contain transcribed and nontranscribed spacer segments. The nucleolus consists of expanded chromosomal loops that carry transcriptional units encoding ribosomal RNA. These...
internal transcribed spacerITS refers to a piece of non-functional RNA situated between structural ribosomal RNAs on a common precursor transcript. Read from 5' to 3', this polycistronic rRNA precursor transcript contains the 5' external transcribed sequence , 18S rRNA, ITS1, 5.8S rRNA, ITS2, 26S rRNA and finally the 3'ETS...
(ITS) loci was not conclusive but seems to show that
C. bulbifera and
C. virosa are monophyletic, while
C. douglasii may not be. It was also suggested a specimen from California may warrant recognition as a distinct species. Other common names for the genus in general include poison parsnip, beaver poison, wild carrot, wild parsnip, and false parsley.
Similar species
Members of the family Apiaceae bear close resemblance to each other, and have many characteristics in common.
Cicuta spp. are often mistaken for edible plants such as sweet flag (
Acorus calamus), kvanne (
Angelica archangelica), wild celery (
Apium graveolens), pignut (
Conopodium majusConopodium majus is a small perennial herb, whose underground part resembles a chestnut and is sometimes eaten as a wild or cultivated root vegetable....
), wild carrot (
Daucus carota), watercress (
NasturtiumNasturtium literally "nose-twister" or "nose-tweaker"), as a common name, refers to a genus of roughly 80 species of annual and perennial herbaceous flowering plants in the genus Tropaeolum , one of three genera in the family Tropaeolaceae...
spp.), wild ginseng (
Panax quinquefolius), wild parsnip (
Pastinaca sativa), and water parsnip (
BerulaBerula is a cosmopolitan monotypic genus of flowering plant in the Apiaceae, containing the single species Berula erecta, which is known by the common name cutleaf water parsnip, or also simply water parsnip as are some other plants in Apiaceae such as Sium latifolium and Sium suave...
spp.). One of the more common misidentifications is between water hemlock and water parsnip; both have clusters of small white flowers shaped like umbrellas, and both have the same habitat near the shore line of lakes and rivers. Differences between water parsnip and water hemlock include the water parsnip having leaves only once compound while the water hemlock has leaves which are two or three times compound. Water hemlock also has a large swelling at the stem base which water parsnip lacks. Additionally, water hemlock has
bractIn botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis, or cone scale...
s at the base of each small flower cluster, not at the base of the main flower head, while water parsnip has both bracts at the base of flowers and also at the main flower head.
Other plants that look similar to
Cicuta spp. but are not edible are the yarrow, (
Achillea millefolium, also commonly known as common yarrow, gordaldo, nosebleed plant, old man's pepper, sanguinary, milfoil, soldier's woundwort, thousand-leaf, and thousand-seal), cow Parsnip (
Heracleum lanatum, also known as
Heracleum maxinium, Indian celery or pushki) or hogweed (
Heracleum sphondylium). Features which differentiate them include the yarrow having feathery looking leaves which are
pinnatelyIn botany, a leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat and thin. There is continued debate about whether the flatness of leaves evolved to expose the chloroplasts to more light or to increase the absorption of carbon dioxide. In...
separated into small narrow segments, while cow parsnip and hogweed have large, broad leaves, and an unpleasant odor.
Additionally, there can be confusion between the various water hemlock species and poison hemlock (
Conium maculatum) as the common name hemlock is applied to both
Cicuta and
Conium maculatum. Both are poisonous and can be differentiated by differences in their root structure. Water hemlock has a branched root systems with tubules, while poison hemlock has a single tap root. Another reliable method to identify water hemlock is to examine the leaf veins. Water Hemlock is unique in the Apiaceae family in that it has leaf veins which terminate in the notches between the leaf tips, rather than extend to the tip of the leaf, as is found in the leaf structure of other members of this family.
Distribution and habitat
Cicuta spp. are found growing across North America and Europe. Typically, they grow in wet habitats usually alongside ponds and streams, in marshes or swamps, or areas that are swampy at least part of the year. Plants can also be found growing in water. Of the four species,
Cicuta maculataCicuta maculata is a species of flowering plant in the carrot family known by several common names, including spotted water hemlock, spotted parsley, and spotted cowbane. It is native to nearly all of North America, from northern Canada to southern Mexico. This is a rhizomatous perennial herb...
has the most widespread distribution occurring across the majority of North America.
Cicuta bulbifera also has a relatively large distribution, found throughout Northern North America.
Cicuta douglasii is found in the northwest corner of North America, while
Cicuta virosaCicuta virosa is a species of Cicuta, native to northern and central Europe, northern Asia and northwestern North America. It is a perennial herbaceous plant which grows up to 1–2 m tall. The stems are smooth, branching, swollen at the base, purple-striped, and hollow except for partitions at the...
is only found in central
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
and in the far north of North America.
Toxicity
All members of
Cicuta except
C. bulbifera contain high levels of the poisonous principle
cicutoxinCicutoxin is a poisonous polyyne and alcohol found in various plants, most notably water hemlock . It is structurally related to the oenanthotoxin of hemlock water dropwort....
, an
unsaturatedIn chemistry, saturation has five different meanings:#In physical chemistry, saturation is the point at which a solution of a substance can dissolve no more of that substance and additional amounts of it will appear as a precipitate...
aliphaticIn organic chemistry, compounds composed of carbon and hydrogen are divided into two classes: aromatic compounds, which contain benzene rings or similar rings of atoms, and aliphatic compounds , which do not contain aromatic rings.
Aliphatic compounds can be cyclic, like cyclohexane, or...
alcoholIn chemistry, an alcohol is any organic compound in which a hydroxyl group is bound to a carbon atom of an alkyl or substituted alkyl group. An important group of acohols is formed by the simple acyclic alcohols, the general formula for which is C
nH
2n+1OH...
that is
structurallyA chemical structure includes molecular geometry, electronic structure and crystal structure of a chemical compound. Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together...
closely related to the toxin
oenanthotoxinOenanthotoxin is a toxin extracted from hemlock water dropwort and other plants of the genus Oenanthe. It is a central nervous system poison, and acts as a noncompetitive gamma-aminobutyric acid antagonist. This toxin played some role in euthanasia in ancient Sardinia, for inducing risus...
found in the plant
hemlock water dropwortThe water dropworts, Oenanthe , are a genus of plants in the family Apiaceae. Most of the species grow in damp ground, in marshes or in water....
. Cicutoxin is present at all stages of growth and in all parts of the plant, but is most concentrated in the roots which appear to be the most toxic in the early spring. Its primary toxic effect is to act as a stimulant in the
central nervous systemThe central nervous system is the part of the nervous system that functions to coordinate the activity of all parts of the bodies of bilaterian animals—that is, all animals more advanced than sponges or jellyfish. In vertebrates, the central nervous system is enclosed in the meninges. It contains...
. It is a non-competitive
gamma-aminobutyric acidγ-Aminobutyric acid is the chief inhibitory neurotransmitter in the mammalian central nervous system. It plays an important role in regulating neuronal excitability throughout the nervous system. In humans, GABA is also directly responsible for the regulation of muscle tone...
(GABA)
receptor antagonistA receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...
. Cicutoxin acts on the GABA
A receptor causing a block of the
chloride channelChloride channels are a superfamily of poorly understood ion channels consisting of approximately 13 members.Chloride channels display a variety of important physiological and cellular roles that include regulation of pH, volume homeostasis, organic solute transport, cell migration, cell...
which results in neuronal depolarization. In the presence of cicutoxin this depolarization continues unabated causing cell overactivity. The hyperactivity in brain cells results in seizures. Cicutoxin is highly poisonous and water hemlock is considered one of North America's most toxic plants. Ingestion of
Cicuta can be fatal in humans and there are reports in the medical literature of severe poisoning and death as early as 1670. A number of people have also died following ingestion of the plant in the 20th and 21st century.
The
LD50In toxicology, the median lethal dose, LD50 , LC50 or LCt50 of a toxic substance or radiation is the dose required to kill half the members of a tested population...
in mice administered cicutoxin by
intraperitoneal injectionIntraperitoneal injection or IP injection is the injection of a substance into the peritoneum . IP injection is more often applied to animals than humans...
is 48.3 mg per kg
body weightAlthough some people prefer the less-ambiguous term body mass, the term body weight is overwhelmingly used in daily English speech and in biological and medical science contexts to describe the mass of an organism's body. Body weight is measured in kilograms throughout the world, although in some...
(mg/kg); this compares with 5.9 mg/kg for mice given
potassium cyanidePotassium cyanide is an inorganic compound with the formula KCN. This colorless crystalline compound, similar in appearance to sugar, is highly soluble in water. The vast majority of KCN is used in gold mining followed by use in organic synthesis, and electroplating. Smaller applications include...
by
intraperitoneal injectionIntraperitoneal injection or IP injection is the injection of a substance into the peritoneum . IP injection is more often applied to animals than humans...
, while the LD
50 for
arsenicArsenic is the chemical element that has the symbol As, atomic number 33 and atomic mass 74.92. Arsenic was first documented by Albertus Magnus in 1250. Arsenic is a notoriously poisonous metalloid with many allotropic forms, including a yellow and several black and grey forms...
via intraperitoneal injection in mice is 46.2 mg/kg. The exact toxic dose of plant material in humans is unknown; it is thought ingestion of water hemlock in any quantity can result in poisoning and very small amounts may lead to death. Poisoning has been reported following children blowing whistles made from the hollow stem of water hemlock plants. Intoxication has also been reported following skin contact with the plant; a case was reported where a family of five people rubbed the plant onto the skin and were poisoned, with two children dying.
LivestockLivestock are one or more domesticated animals raised in an agricultural setting to produce commodities such as food or fiber, or labor...
have long been the worst affected, leading to the common name "cowbane". Poisoning in livestock is common and typically occurs following ingestion of roots of the plant. In the spring when the ground is soft, grazing animals tend to pull the entire plant out of the ground ingesting both the foiliage and the roots. Roots exposed by ploughing can also be the source of livestock poisonings. Ingestion of plant material may cause death in the animal in as little as 15 minutes.
Symptoms
Upon consumption, both in humans and other species, the symptoms of poisoning are mainly characterized by generalized seizures. The onset of symptoms following ingestion may be as soon as 15 minutes post ingestion. Initial symptoms reported may include
nauseaNausea is the sensation of unease and discomfort in the stomach with an urge to vomit.-Causes:...
,
vomitingVomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose. Undesired vomiting may result from many causes, ranging from gastritis or poisoning to brain tumors, or elevated intracranial pressure...
,
abdominal painAbdominal pain can be one of the symptoms associated with transient disorders or serious disease. Making a definitive diagnosis of the cause of abdominal pain can be difficult, because many diseases can result in this symptom. Abdominal pain is a common problem...
,
tremorA tremor is an unintentional, somewhat rhythmic, muscle movement involving to-and-fro movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, head, face, vocal cords, trunk, and legs. Most tremors occur in the hands. In some people,...
s,
confusionConFusion is an annual science fiction convention organized by the Stilyagi Air Corps and its parent organization, the Ann Arbor Science Fiction Association. Commonly, it is held the third weekend of January. It is the oldest science fiction convention in Michigan, a regional, general SF con...
, weakness,
dizzinessDizziness refers to an impairment in spatial perception and stability. It is considered imprecise. It can be used to mean vertigo, presyncope, disequilibrium, or for a non-specific feeling such as giddiness or foolishness....
, and drowsiness; although the rapid onset of seizure activity may be the first sign presenting following poisoning. Seizures are usually described as clonic or tonic–clonic. Complications of ongoing seizure activity include
increased body temperatureHyperthermia is an elevated body temperature due to failed thermoregulation. Hyperthermia occurs when the body produces or absorbs more heat than it can dissipate...
,
decreases in the pH of the bloodIn medicine, metabolic acidosis is a process which if unchecked leads to acidemia, i.e. blood pH is low due to increased production of H+ by the body or the inability of the body to form bicarbonate in the kidney. Its causes are diverse, and its consequences can be serious, including...
(metabolic acidosis),
sweliing in the brainCerebral edema is an excess accumulation of water in the intracellular and/or extracellular spaces of the brain.- Vasogenic cerebral edema:...
,
blood coagulation disordersCoagulopathy is a defect in the body's mechanism for blood clotting, causing bleeding diathesis.-Causes:...
,
muscle breakdownRhabdomyolysis is the rapid breakdown of skeletal muscle due to injury to muscle tissue. The muscle damage may be caused by physical , chemical, or biological factors...
(rhabdomyolysis), and kidney failure. Additional neurological symptoms may include hallucinations,
deliriumDelirium is an acute and debilitating decline in attention-focus, perception, and cognition that produces an altered form of semi-consciousness. It is a systemic syndrome caused by a chemical or disease-process which is disrupting the neurons of the cerebral cortex...
,
tingling, pricking, or numbness of a person's skinParesthesia is a sensation of tingling, pricking, or numbness of a person's skin with no apparent long-term physical effect. It is more generally known as the feeling of "pins and needles" or of a limb "falling asleep"...
,
dilated pupilsMydriasis is an excessive dilation of the pupil due to disease, trauma or the use of drugs. Normally, the pupil dilates in the dark and constricts in the light to improve vividity at night and to protect the retina from sunlight damage during the day, respectively...
, and
comaIn medicine, a coma is a profound state of unconsciousness. A comatose person cannot be awakened, fails to respond normally to pain or light, does not have sleep-wake cycles, and does not take voluntary actions....
. Cardiovascular symptoms include alternating
slowBradycardia , as applied to adult medicine, is defined as a resting heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min....
or
fast heart rateTachycardia comes from the Greek words tachys and kardia . Tachycardia typically refers to a heart rate that exceeds the normal range for a resting heartrate...
and alternating
lowIn physiology and medicine, hypotension refers to an abnormally low blood pressure. This 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 opposite of hypertension, which is high blood...
and
high blood pressureHypertension is a chronic medical condition in which the blood pressure is elevated. It is also referred to as high blood pressure or shortened to HT, HTN or HPN. The word "hypertension", by itself, normally refers to systemic, arterial hypertension.Hypertension can be classified as either...
. Other cardiac effects may include ECG abnormalities such as widening of the
PR intervalThe PR interval is measured from the beginning of the P wave to the beginning of the QRS complex. It is usually 120 to 200 ms long. On an ECG tracing, this corresponds to 3 to 5 small boxes. The PR interval reflects the time the electrical impulse takes to travel from the sinus node through the AV...
,
supraventricular tachycardiaSupraventricular tachycardia is any tachycardic rhythm originating above the ventricular tissue. Paroxysmal supraventricular tachycardia ' is a rapid rhythm of the heart which involves an accessory pathway...
, and
ventricular fibrillationVentricular fibrillation is a condition in which there is uncoordinated contraction of the cardiac muscle of the ventricles in the heart, making them tremble rather than contract properly...
. Symptoms of excess salivation, wheezing, respiratory distress, and
absence of breathingApnea, apnoea, or apnœa is a term for suspension of external breathing. During apnea there is no movement of the muscles of respiration and the volume of the lungs initially remains unchanged...
have also been reported.
Deaths usually occur from
respiratory failureThe term respiratory failure, in medicine, is used to describe inadequate gas exchange by the respiratory system, with the result that arterial oxygen and/or carbon dioxide levels cannot be maintained within their normal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial...
or
ventricular fibrillationVentricular fibrillation is a condition in which there is uncoordinated contraction of the cardiac muscle of the ventricles in the heart, making them tremble rather than contract properly...
secondary to ongoing seizure activity; fatalities have occurred within a few hours of ingestion. Poisoned people who recover usually regain consciousness and seizures cease within 24 to 48 hours of poisoning, although seizures may persist for up to 96 hours. There are occasional long-term effects such as
retrograde amnesiaRetrograde amnesia is a form of amnesia where someone will be unable to recall events that occurred before the development of amnesia. The term is used to categorise patterns of symptoms, rather than to indicate a particular cause or etiology....
of the events leading to intoxication and the intoxication itself. Other ongoing mild effects may include restlessness,
muscle weaknessMuscle weakness, also known as muscle fatigue, is a direct term for the inability to exert force with one's muscles to the degree that would be expected given the individual's general physical fitness. A test of strength is often used during a diagnosis of a muscular disorder before the etiology...
, twitching, and
anxietyAnxiety is a psychological and physiological state characterized by cognitive, somatic, emotional, and behavioral components. These components combine to create an unpleasant feeling that is typically associated with uneasiness, fear, or worry....
. Complete resolution of symptoms may take a number of days or, in some cases, these ongoing symptoms may persist for months after poisoning.
Diagnosis and treatment
Water hemlock poisoning is usually diagnosed following a history of plant ingestion and symptoms of abrupt onset of seizures. Laboratory tests to determine the presence of cicutoxin in the blood such as spectrofluorimetry, high pressure liquid chromatography,
thin layer chromatographyThin layer chromatography is a chromatography technique used to separate mixtures. Thin layer chromatography is performed on a sheet of glass, plastic, or aluminum foil, which is coated with a thin layer of adsorbent material, usually silica gel, aluminium oxide, or cellulose...
, and
mass spectrometryMass spectrometry is an analytical technique for the determination of the elemental composition of a sample or molecule. It is also used for elucidating the chemical structures of molecules, such as peptides and other chemical compounds...
have been used to detect cicutoxin but these tests are not performed routinely in
hospital laboratoriesA medical laboratory or clinical laboratory is a laboratory where tests are done on clinical specimens in order to get information about the health of a patient as pertaining to the diagnosis, treatment, and prevention of disease.-Departments:...
. If a sample of the plant ingested has been retained, diagnosis can be confirmed by having the plant identified by a botanist.
Initial treatment of poisoning may include gastrointestinal decontamination with activated charcoal. Decontamination is typically only performed if a potentially toxic amount of plant matter has been ingested up to one hour previously and the patient has an normal intact
airwayFor the Australian television series Airways, see Airways .The airways are those parts of the respiratory system through which air flows, to get from the external environment to the alveoli....
or has been
intubatedIn medicine, intubation refers to the placement of a tube into an external or internal orifice of the body. Although the term can refer to endoscopic procedures, it is most often used to denote tracheal intubation. Tracheal intubation is the placement of a flexible plastic tube into the trachea to...
. There is no specific antidote for water hemlock poisoning and treatment mainly consists of supportive care. Treatment may include control of
seizureAn epileptic seizure is a transient symptom of excessive or synchronous neuronal activity in the brain. It can manifest as an alteration in mental state, tonic or clonic movements, convulsions, and various other psychic symptoms...
s with the administration of a
benzodiazepineA benzodiazepine is a psychoactive drug whose core chemical structure is the fusion of a benzene ring and a diazepine ring...
s such as
lorazepamLorazepam, initially marketed under the brand names Ativan and Temesta, is a benzodiazepine drug with short to medium duration of action. It has all five intrinsic benzodiazepine effects: anxiolytic, amnesic, sedative/hypnotic, anticonvulsant and muscle relaxant...
or
diazepamDiazepam , first marketed as Valium by Hoffmann-La Roche, is a benzodiazepine derivative drug. It possesses anxiolytic, anticonvulsant, hypnotic, sedative, skeletal muscle relaxant, and amnestic properties. It is commonly used for treating anxiety, insomnia, seizures, muscle spasms, restless legs...
, or if seizures are refractory to this treatment, a
barbiturateBarbiturates are drugs that act as central nervous system depressants, and, by virtue of this, they produce a wide spectrum of effects, from mild sedation to total anesthesia. They are also effective as anxiolytics, hypnotics and as anticonvulsants. They have addiction potential, both physical and...
such as
phenobarbitalPhenobarbital or phenobarbitone is a barbiturate, first marketed as Luminal by Friedr. Bayer et comp. It is the most widely used anticonvulsant worldwide...
is administered. The
anticonvulsantThe anticonvulsants are a diverse group of pharmaceuticals used in the treatment of epileptic seizures. Anticonvulsants are also increasingly being used in the treatment of bipolar disorder, since many seem to act as mood stabilizers. The goal of an anticonvulsant is to suppress the rapid and...
phenytoinPhenytoin sodium is a commonly used antiepileptic. Phenytoin acts to dampen the unwanted, runaway brain activity seen in seizure by reducing electrical conductance among brain cells by stabilizing the inactive state of voltage gated sodium channels...
is not recommended as it has not been shown to be effective for seizure control following water hemlock poisoning. Treatment with high doses of benzodiazepines or barbiturates may cause respiratory depression and respiratory support including
intubationIn medicine, intubation refers to the placement of a tube into an external or internal orifice of the body. Although the term can refer to endoscopic procedures, it is most often used to denote tracheal intubation. Tracheal intubation is the placement of a flexible plastic tube into the trachea to...
and
mechanical ventilationIn medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing.This may involve a machine called a ventilator or the breathing may be assisted by a physician or other suitable person compressing a bag or set of bellows...
is required in these patients. Continuous
electroencephalographyElectroencephalography is the recording of electrical activity along the scalp produced by the firing of neurons within the brain . In clinical contexts, EEG refers to the recording of the brain's spontaneous electrical activity over a short period of time, usually 20–40 minutes, as recorded from...
monitoring is recommended in symptomatic patients.
Further treatment for complications of
metabolic acidosisIn medicine, metabolic acidosis is a process which if unchecked leads to acidemia, i.e. blood pH is low due to increased production of H+ by the body or the inability of the body to form bicarbonate in the kidney. Its causes are diverse, and its consequences can be serious, including...
,
rhabdomyolysisRhabdomyolysis is the rapid breakdown of skeletal muscle due to injury to muscle tissue. The muscle damage may be caused by physical , chemical, or biological factors...
,
hyperthermiaHyperthermia is an elevated body temperature due to failed thermoregulation. Hyperthermia occurs when the body produces or absorbs more heat than it can dissipate...
, or low blood pressure may be required. Metabolic acidosis is treated by administering
sodium bicarbonateSodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula NaHCO3. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slight alkaline taste resembling that of washing soda . It is a component of the...
. Low blood pressure is usually treated with intravenous
fluid replacementFluid replacement or fluid resuscitation is the medical practice of replenishing bodily fluid lost through sweating, bleeding, fluid shifts or other pathologic processes. Fluids can be replaced via oral administration , intravenous administration, rectally, or hypodermoclysis, the direct injection...
, but the administration of
dopamineDopamine is a neurotransmitter occurring in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this phenethylamine functions as a neurotransmitter, activating the five types of dopamine receptors — D
1, D
2, D
3, D
4, and...
or
norepinephrineNoradrenaline or norepinephrine is a catecholamine with dual roles as a hormone and a neurotransmitter....
may be required to restore blood pressure. The management of rhabdomyolysis includes ensuring adequate hydration and urinary alkalinization; a complication of rhabdomyolysis is acute renal failure which may require management with
hemodialysisIn medicine, hemodialysis is a method for removing waste products such as potassium and urea, as well as free water from the blood when the kidneys are in renal failure. Hemodialysis is one of three renal replacement therapies .Hemodialysis can be an outpatient or inpatient therapy...
. However, hemodialysis,
hemoperfusionHemoperfusion is a medical process used to remove toxic substances from a patients blood. The technique involves passing large volumes of blood over an adsorbent substance. The adsorbent substance most commonly used in hemoperfusion are resins and activated carbon...
or other
extracorporealAn extracorporeal medical procedure is a medical procedure which is performed outside the body.-Circulatory procedures:A procedure in which blood is taken from a patient's circulation to have a process applied to it before it is returned to the circulation...
techniques do remove cicutoxin from the blood and are therefore not useful in enhancing elimination.