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Poison Ivy
Although poison is in its name, the rash that results from contact with poison ivy (Toxicodendron radicans) is, in fact, an allergic reaction to the sap generated by the plant. The other plants in the same family are poison oak (T. toxicarium, T. diversilobum) and poison sumac (T. vernix). They are recognizable because their leaves grow in groups on three. Avoidance is the most important way to deal with poison ivy. Remember: "Leaves of three, let it be!" Poison ivy is a Type IV (delayed-onset) hypersensitivity. Your body must have had exposure to the sap at least one time before a rash will develop. The first time you touch poison ivy, you may be perfectly fine and think you are not allergic to it. However, the second contact might prove you wrong! Most people are sensitized to it because poison ivy is so widespread, while some lucky people were never allergic to the sap. Direct contact with leaves, roots, or branches of the plant is not necessary. The sap can still reach skin through clothing, transfer from pets, and even fumes from burning. Washing the skin thoroughly with soap and water within 15 minutes of exposure may prevent or reduce the severity of the allergic reaction. Poison ivy is not contagious. The goal of treatment is to prevent scratching, which can lead to other skin infections. An itchy rash presents between 4 hours to 10 days post-exposure. The rash is often accompanied with pus-filled blisters. The fluid in the blisters will not spread the rash. The symptoms typically last 5 to 21 days. Mild cases clear on their own within 7-14 days. Cool compresses and wet dressings may help reduce the urge to scratch the rash. Creams that contain benzocaine, pramoxine, or benzyl alcohol are also effective for symptom relief. Severe cases of poison ivy may require prescription corticosteroids.
Belladonna
In Italian, "bella donna" means beautiful woman. The belladonna plant was used as an ingredient in eye drops to dilate the pupils and make women appear more seductive. Belladonna (Atropa belladonna) is also known as Deadly Nightshade. All parts of the plant contain toxic tropane alkaloids. Belladonna is very attractive with bell-shaped purple flowers with green tinges. Its berries are shiny and black when ripe, but extremely deadly. Eating 2 to 5 berries is fatal to an adult. (Nightlock, anyone? Sorry... not from Harry Potter.)
Jimsonweed (Datura stramonium) is a plant that contains a belladonna alkaloid. In 1676, British troops started behaving bizarrely after consuming jimsonweed. It has a spiny fruit that contains 50 to 100 seeds. About 100 jimsonweed seeds is equivalent to a 6 mg dose of atropine. The active ingredients in belladonna are atropine, scopolamine, and hyoscyamine. All three are used in medications for their anticholinergic properties. The best way to describe the anticholinergic toxidrome is by using the following mnemonic:
Hemlock
Poison hemlock (Conium maculatum) is native to Europe and the Mediterranean area. It is a rather tall plant, reaching heights of 2.5 meters (8 feet). The stem has purple stripes or spots, especially near the bottom. There are triangular or umbrella-shaped clusters of small, white flowers. All parts of poison hemlock are poisonous. It can even remain poisonous up to 3 years after the plant is dead. Eating the plant causes the most toxicity, but it can also go through the skin and the lungs. The toxin in poison hemlock is coniine, which is similar to nicotine. Coniine affects the central nervous system. It paralyzes the muscles used in breathing, so victims die due to lack of oxygen. Birds are not affected by coniine and may carry it in their muscles. It is possible to get poisoned by eating certain bird meat. A water-loving relative of the poison hemlock is the aptly named water hemlock (Cicuta maculata). It is found in aqueous environments including wet meadows, stream banks, and marshes. The poison in water hemlock is cicutoxin, which stimulates GABA receptors in the brain leading to seizures.
Curare
Originating in South America, curare is used as an arrow poison. There are three types of curare, but only tubocurare is found in nature. Strychnos toxifera is a flowering plant that was found to cause muscle spasms and rigidity. The other natural source of curare is a tree native to Central and South America, Chondrodendron tomentosum. Its bark extract is used to produce medication, like rocuronium. The most important toxin is d-tubocurarine, a muscle relaxant. Similar to hemlock, it blocks nicotinic acetylcholine receptors. This shuts down the victim's ability to breathe. Curare does not affect the heart, which is what made it attractive to use in medicine in the operating room. (As long as the anesthesia team keeps the patient breathing properly!)
To manage curare poisoning, make sure the victim is breathing. This may require mouth to mouth resuscitation. The oxygen level should be kept above 85%. Antidotes are physostigmine and neostigmine.
Oleander
Although oleander (Nerium oleander) is commonly used as an ornamental plant, it is also one of the most poisonous plants found in the garden. It thrives in subtropical and tropical areas around the world. Oleander grows to a height of 2 to 6 meters (6 to 20 feet). The beautiful flowers are white, pink, or red. Oleander belongs to a group of plants that contain cardiac glycosides. They were first discovered in the common foxglove (Digitalis purpura). The scientific name of the foxglove comes from its finger-like flowers, which are various shades of purple and pink. The cardiac glycoside extract taken from foxglove is the active ingredient in the heart medication digoxin. Digoxin is excellent at regulating heart beat, but it has a very narrow therapeutic window. There is a very limited range of doses for digoxin to be effective. Toxic effects of digoxin include nausea, vomiting, and diarrhea. The potassium concentration increases, which can lead to irregular heartbeats. Digoxin toxicity may cause a decrease in appetite. Victims of digoxin toxicity may start having a yellow tint to their vision or see blue halos around objects. Some historians believe Vincent van Gogh was suffering from digoxin toxicity when painting Starry Night.
The plants that contain cardiac glycosides have a wide range of toxicity. Two seeds of yellow oleander (Thevetia peruviana) is fatal, but death from lily of the valley (Convallaria majalis) is rare. Lily of the valley is a popular wedding flower with its white bell-shaped flowers. It does contain cardiac glycosides and its red berries are especially attractive to children.
Activated charcoal is useful early in intoxication. An antidote, digoxin specific antibody fragment, is also available.
Christmas Spirit
Iconic holiday decorations elicit festive Christmas spirit as well as the possibility of poisoning. The red berries of holly (Ilex species) are accompanied by prickly leaves for good reason. Ingesting six or more of the berries is associated with toxicity, including nausea, vomiting, diarrhea, and cramping.
There are more than nargles in mistletoe! Lectin is a protein that binds molecules in the gut. This leads to severe stomach upset, especially if mistletoe is given as a tea or extract. There are two types of mistletoe. American mistletoe (Phoradendron species) and European mistletoe (Viscum album) both have the same effect. Remember that the funny feeling in your stomach may not solely be the effect of kissing.
On the other hand, poinsettia, widely believed as toxic, is not poisonous at all!
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