Calcium oxalate
Overview
 
Calcium oxalate is a chemical compound that forms needle-shaped crystals, known in plants as raphides
Raphides
Raphides are needle-shaped crystals of calcium oxalate as the monohydrate or calcium carbonate as aragonite, found in more than 200 families of plants.Both ends are needle-like, but raphides tend to be more blunt at one end and more tapering at the other....

. A major constituent of human kidney stones, the chemical is also found in beerstone, a scale that forms on containers used in breweries. Its chemical formula is CaC2O4 or Ca (COO)2.
Quantities of calcium oxalate are found in many tropical house plants. Calcium oxalate is a poisonous substance that can produce sores and numbing on ingestion and could even be fatal.
The poison
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 plant dumb cane (Dieffenbachia
Dieffenbachia
Dieffenbachia is a genus of tropical plants in the Family Araceae noted for their patterned leaves. Members of this genus are popular as houseplants because of their tolerance for shade. The common name is "dumb cane" due to its poisoning effect on the throat due to raphides...

) contains the substance and on ingestion can prevent speech and be suffocating.
Encyclopedia
Calcium oxalate is a chemical compound that forms needle-shaped crystals, known in plants as raphides
Raphides
Raphides are needle-shaped crystals of calcium oxalate as the monohydrate or calcium carbonate as aragonite, found in more than 200 families of plants.Both ends are needle-like, but raphides tend to be more blunt at one end and more tapering at the other....

. A major constituent of human kidney stones, the chemical is also found in beerstone, a scale that forms on containers used in breweries. Its chemical formula is CaC2O4 or Ca (COO)2.

Occurrence

Quantities of calcium oxalate are found in many tropical house plants. Calcium oxalate is a poisonous substance that can produce sores and numbing on ingestion and could even be fatal.
The poison
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 plant dumb cane (Dieffenbachia
Dieffenbachia
Dieffenbachia is a genus of tropical plants in the Family Araceae noted for their patterned leaves. Members of this genus are popular as houseplants because of their tolerance for shade. The common name is "dumb cane" due to its poisoning effect on the throat due to raphides...

) contains the substance and on ingestion can prevent speech and be suffocating. It is also found in rhubarb
Rhubarb
Rhubarb is a group of plants that belong to the genus Rheum in the family Polygonaceae. They are herbaceous perennial plants growing from short, thick rhizomes. They have large leaves that are somewhat triangular-shaped with long fleshy petioles...

 (in large quantities in the leaves) and in species of Oxalis
Oxalis
Oxalis is by far the largest genus in the wood-sorrel family Oxalidaceae: of the approximately 900 known species in the Oxalidaceae, 800 belong here...

, Araceae
Araceae
Araceae are a family of monocotyledonous flowering plants in which flowers are borne on a type of inflorescence called a spadix. The spadix is usually accompanied by, and sometimes partially enclosed in, a spathe or leaf-like bract. Also known as the Arum family, members are often colloquially...

, taro
Taro
Taro is a common name for the corms and tubers of several plants in the family Araceae . Of these, Colocasia esculenta is the most widely cultivated, and is the subject of this article. More specifically, this article describes the 'dasheen' form of taro; another variety is called eddoe.Taro is...

, kiwifruit
Kiwifruit
The kiwifruit, often shortened to kiwi in many parts of the world, is the edible berry of a cultivar group of the woody vine Actinidia deliciosa and hybrids between this and other species in the genus Actinidia....

, tea
Tea
Tea is an aromatic beverage prepared by adding cured leaves of the Camellia sinensis plant to hot water. The term also refers to the plant itself. After water, tea is the most widely consumed beverage in the world...

 leaves, agave
Agave
Agave is a genus of monocots. The plants are perennial, but each rosette flowers once and then dies ; they are commonly known as the century plant....

s, and Alocasia
Alocasia
Alocasia is a genus of broad-leaved rhizomatous or tuberous perennials from the Family Araceae. There are 78 species of Alocasia occurring in Tropical & Subtropical Asia to Eastern Australia and widely cultivated in Oceania and South America. The large cordate or sagittate leaves grow to a length...

and in spinach
Spinach
Spinach is an edible flowering plant in the family of Amaranthaceae. It is native to central and southwestern Asia. It is an annual plant , which grows to a height of up to 30 cm. Spinach may survive over winter in temperate regions...

 in varying amounts. Insoluble calcium oxalate crystals are found in plant stems, roots, and leaves and produced in idioblasts. Kidney stone sufferers should not eat plants high in oxalates.
Calcium oxalate, as 'beerstone', is a brownish precipitate that tends to accumulate within vats, barrels and other containers used in the brewing
Brewing
Brewing is the production of beer through steeping a starch source in water and then fermenting with yeast. Brewing has taken place since around the 6th millennium BCE, and archeological evidence suggests that this technique was used in ancient Egypt...

 of beer
Beer
Beer is the world's most widely consumed andprobably oldest alcoholic beverage; it is the third most popular drink overall, after water and tea. It is produced by the brewing and fermentation of sugars, mainly derived from malted cereal grains, most commonly malted barley and malted wheat...

. If not completely removed in a cleaning process, beerstone will leave an unsanitary surface that can harbour microorganisms. Beerstone is composed of calcium and magnesium salts and various organic compounds left over from the brewing process; it promotes the growth of unwanted microorganisms that can adversely affect or even ruin the flavor of a batch of beer.

Calcium oxalate crystals in the urine are the most common constituent of human kidney stones, and calcium oxalate crystal formation is also one of the toxic effects of ethylene glycol poisoning
Ethylene glycol poisoning
Ethylene glycol poisoning is caused by the ingestion of ethylene glycol . It is a toxic, colorless, odorless, almost nonvolatile liquid with a sweet taste and is occasionally consumed by children and dogs for its sweetness...

.

Hydrated forms of the compound occur naturally as three mineral species: whewellite
Whewellite
Whewellite is a mineral, hydrated calcium oxalate, formula CaC2O4·H2O. Because of its organic content it is thought to have an indirect biological origin and this is supported by it being found in coal and sedimentary nodules. However, it has also been found in hydrothermal deposits where a...

 (monohydrate, known from some coal beds), weddellite
Weddellite
Weddellite is a mineral form of calcium oxalate named for occurrences of millimeter-sized crystals found in bottom sediments of the Weddell Sea, off Antarctica...

 (dihydrate) and a very rare trihydrate called caoxite.

Effects of Ingestion

Even a small dose of calcium oxalate is enough to cause intense sensations of burning in the mouth and throat, swelling, and choking that could last for up to two weeks. In greater doses it can cause severe digestive upset, breathing difficulties, coma or even death. Recovery from severe oxalate poisoning is possible, but permanent liver and kidney damage may have occurred.

The stalks of plants in the Dieffenbachia
Dieffenbachia
Dieffenbachia is a genus of tropical plants in the Family Araceae noted for their patterned leaves. Members of this genus are popular as houseplants because of their tolerance for shade. The common name is "dumb cane" due to its poisoning effect on the throat due to raphides...

genus produce the most severe oxalate reactions. The needle-like oxalate crystals produce pain and swelling when they contact lips, tongue, oral mucosa, conjunctiva, or skin. Edema
Edema
Edema or oedema ; both words from the Greek , oídēma "swelling"), formerly known as dropsy or hydropsy, is an abnormal accumulation of fluid beneath the skin or in one or more cavities of the body that produces swelling...

 primarily is due to direct trauma from the needle-like crystals and, to a lesser extent, by other plant toxins (e.g., bradykinin
Bradykinin
Bradykinin is a peptide that causes blood vessels to dilate , and therefore causes blood pressure to lower. A class of drugs called ACE inhibitors, which are used to lower blood pressure, increase bradykinin further lowering blood pressure...

s, enzymes).

Depending on the plant ingested, mild (Elephant Ear Colocasia esculenta
Colocasia esculenta
Colocasia esculenta is a tropical plant grown primarily for its edible corms, the root vegetables whose many names include Taro and Eddoe. It is believed to be one of the earliest cultivated plants.-Description:Rhizomes of different shapes and sizes...

) to more severe (Jack in the Pulpit
Arisaema triphyllum
Arisaema triphyllum is a herbaceous perennial plant growing from a corm. It is a highly variable species typically growing from 30 to 65 cm in height with three parted leaves and flowers contained in a spadix that is covered by a hood...

, Arisaema
Arisaema
Arisaema is a genus of about 150 species in the flowering plant family Araceae, native to eastern and central Africa, Asia and eastern North America. Its species are often called Cobra lilies, particularly the Asiatic species...

) can cause compromised airways. One bite on the Arisaema seed pod will result in immediate swelling and burning. It will take over 12 hours for the swelling to subside.

Treatment

Medication administered at the ER may include diphenhydramine
Diphenhydramine
Diphenhydramine hydrochloride is a first-generation antihistamine possessing anticholinergic, antitussive, antiemetic, and sedative properties which is mainly used to treat allergies. Like most other first-generation antihistamines, the drug also has a powerful hypnotic effect, and for this reason...

, epinephrine
Epinephrine
Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...

, or famotidine
Famotidine
Famotidine is a histamine H2-receptor antagonist that inhibits stomach acid production, and it is commonly used in the treatment of peptic ulcer disease and gastroesophageal reflux disease . It is commonly marketed by Johnson & Johnson/Merck under the trade names Pepcidine and Pepcid and by...

, all intravenously. Although this most likely will be a localized reaction, it will be treated by the ER as an anaphylactic
Anaphylaxis
Anaphylaxis is defined as "a serious allergic reaction that is rapid in onset and may cause death". It typically results in a number of symptoms including throat swelling, an itchy rash, and low blood pressure...

 reaction.

See also

  • Oxalic acid
    Oxalic acid
    Oxalic acid is an organic compound with the formula H2C2O4. This colourless solid is a dicarboxylic acid. In terms of acid strength, it is about 3,000 times stronger than acetic acid. Oxalic acid is a reducing agent and its conjugate base, known as oxalate , is a chelating agent for metal cations...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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