Scurvy
2008/9 Schools Wikipedia Selection. Related subjects: Health and medicine
| Scurvy Classification and external resources |
|
 |
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|---|---|
| Scorbutic gums, a symptom of scurvy | |
| ICD- 10 | E 54. |
| ICD- 9 | 267 |
| OMIM | 240400 |
| DiseasesDB | 13930 |
| MedlinePlus | 000355 |
| eMedicine | med/2086 derm/521 ped/2073 radio/628 |
| MeSH | D012614 |
Scurvy (N.Lat. scorbutus) is a deficiency disease resulting from insufficient intake of vitamin C, which is required for correct collagen synthesis in humans. The scientific name of vitamin C, ascorbic acid, is derived from the Latin name of scurvy, scorbutus. Scurvy leads to the formation of spots on the skin, spongy gums, and bleeding from all mucous membranes. The spots are most abundant on the thighs and legs, and a person with the ailment looks pale, feels depressed, and is partially immobilized. In advanced scurvy there are open, suppurating wounds and loss of teeth.
Scurvy was at one time common among sailors, pirates and others aboard ships at sea longer than perishable fruits and vegetables could be stored, and by soldiers similarly separated from these foods for extended periods. It was described by Hippocrates (c. 460 BC–c. 380 BC). Herbal cures for scurvy have been known in many native cultures since prehistory. In 1536, the French explorer Jacques Cartier, exploring the St. Lawrence River, used the local natives' knowledge to save his men who were dying of scurvy. He boiled the needles of the arbor vitae tree (Eastern White Cedar) to make a tea that was later shown to contain 50 mg of vitamin C per 100 grams. Such treatments were not available aboard ship, where the disease was most common. It was a Scottish surgeon in the British Royal Navy, James Lind who first proved it could be treated with citrus fruit in experiments he described in his 1753 book, A Treatise of the Scurvy.
In infants, scurvy is sometimes referred to as Barlow's disease, named after Sir Thomas Barlow, a British physician who described it. (N.B. Barlow's disease may also refer to mitral valve prolapse.) Other eponyms include Moeller's disease and Cheadle's disease.
Symptoms
- Dark purplish spots on skin, especially legs.
- Spongy gums, often leading to tooth loss.
- Bleeding from all mucous membranes.
- Pallor
- Bleeding gums.
- Sunken eyes
- Opening of healed scars and separation of knitted bone fractures.
- Nosebleeds
- non-stopping diarrhea
- nail loss
Prognosis
Untreated scurvy is invariably fatal. Since all that is required for a full recovery is the resumption of normal vitamin C intake, death from scurvy is rare in modern times.
Pathophysiology
Normal collagen synthesis depends upon the hydroxylation of proline and lysine residues in the endoplasmic reticulum, to form hydroxyproline and hydroxylysine, respectively. Prolyl and lysyl hydroxylase, the enzymes that catalyze the hydroxylation, require ascorbic acid (vitamin C) to function correctly. With no ascorbic acid, the enzymes cannot hydroxylate proline and lysine, and so normal collagen synthesis cannot be performed.
History
Scurvy was probably first observed as a disease by Hippocrates. In the 13th century the Crusaders suffered from scurvy frequently. Scurvy was one of the limiting factors of marine travel, often killing large numbers of the passengers and crew on long-distance voyages. It even played a significant role in World War I.
The British civilian medical profession of 1614 knew that it was the acidic principle of citrus fruit which was lacking, although they considered any acid acceptable when ascorbic acid (Vitamin C) was unavailable. In 1614 John Woodall (Surgeon General of the East India Company) published "The Surgion's Mate" as a handbook for apprentice surgeons aboard the company's ships. In it he described scurvy as resulting from a dietary deficiency. His recommendation for its cure was fresh food or, if not available, oranges, lemons, limes and tamarinds, or as a last resort, Oil of Vitriol (sulfuric acid).
In 1734, the Leiden-based physician Johann Bachstrom published a book on scurvy in which he stated that "scurvy is solely owing to a total abstinence from fresh vegetable food, and greens; which is alone the primary cause of the disease." and urged the use of fresh fruit and vegetables as a cure. It was not until 1747 that James Lind formally proved that scurvy could be treated and prevented by supplementing the diet with citrus fruit such as lemons and lime. James Cook succeeded in circumnavigating the world (1768-71) in HM Bark Endeavour without losing a single man to scurvy, but his suggested methods, including a diet of sauerkraut and wort of malt, were of limited value. Sauerkraut was the only vegetable food that retained a reasonable amount of ascorbic acid in a pickled state, but it was boiled to reduce it for preservation and much of the Vitamin C content was lost. In Cook's time it was impractical to preserve citrus fruit for long sea voyages. More important was Cook's regime of shipboard cleanliness, enforced by strict discipline, as well as frequent replenishing of fresh food. The most effective regime implemented by Cook was his prohibition against the consumption of fat scrubbed from the ship's copper pans, then a common practice in the Navy. In contact with the hot copper, this fat acquired substances which possibly irritated the gut and prevented proper absorption of vitamins. The first major long distance expedition that experienced virtually no scurvy was that of Alessandro Malaspina, 1789-1794. Malaspina's medical officer, Pedro González, was convinced that fresh oranges and lemons were essential for preventing scurvy. Only one outbreak occurred, during a 56-day trip across the open sea. Five sailors came down with symptoms, one seriously. After three days at Guam all five were healthy again. Spain's large empire and many ports of call made it easier to acquire fresh fruit. Despite advances, British sailors throughout the American Revolutionary period continued to suffer from scurvy, particularly in the Channel Fleet. The eradication of scurvy from the Royal Navy was finally due to the chairman of the Navy's Sick and Hurt Board, Gilbert Blane, who finally put Bachstrom and Lind's long-ignored prescription of fresh lemons to use during the Napoleonic Wars. Other navies soon adopted this successful solution.
The plant known as " scurvy grass" acquired its name from the observation that it cured scurvy, but this was of no great help to those who spent months at sea. During sea voyages, it was discovered that sauerkraut was of limited use in preventing scurvy. In the Royal Navy's Arctic expeditions in the 19th century it was widely believed that scurvy was prevented by good hygiene on board ship, regular exercise, and maintaining the morale of the crew, rather than by a diet of fresh food, so that Navy expeditions continued to be plagued by scurvy even while fresh meat was well-known as a practical antiscorbutic among civilian whalers and explorers in the Arctic. At the time Robert Falcon Scott made his two expeditions to the Antarctic in the early 20th century, the prevailing theory was that scurvy was caused by "tainted" canned food.
The use of limes by the British Royal Navy to prevent scurvy gave rise to the name "limey" for an English immigrant in the former British colonies (particularly America, New Zealand and South Africa). The use of this word has been extended to include all British people in American slang.
In 1927, Hungarian biochemist Szent-Györgyi (who won the 1937 Nobel Prize for Medicine) isolated the compound "hexuronic acid" while working with antioxidant compounds in the adrenal cortex. It was not until 1932 that the connection between vitamin C and scurvy was established by American researcher Charles Glen King of the University of Pittsburgh.
Modern incidence
Scurvy or subclinical scurvy is caused by the lack of vitamin C. In modern western society, scurvy is rarely present in adults, although infants and elderly people are affected. Vitamin C is destroyed by the process of pasteurization, so babies fed with ordinary bottled milk sometimes suffer from scurvy if they are not provided with adequate vitamin supplements. Virtually all commercially available baby formulas contain added vitamin C for this reason, but heat and storage destroy vitamin C. Human breast milk contains sufficient vitamin C, if the mother has an adequate intake.
Scurvy is one of the accompanying diseases of malnutrition (other such micronutrient deficiencies are beriberi or pellagra) and thus is still widespread in areas of the world depending on external food aid. Though rare, there are also documented cases of scurvy due to poor dietary choices by people living in industrialized nations.
Prevention
Scurvy can be prevented by a diet that includes certain citrus fruits such as oranges or lemons. Other sources rich in vitamin C are fruits such as blackcurrants, guava, kiwifruit, papaya, tomatoes and strawberries. It can also be found in some vegetables, such as carrots, bell peppers, broccoli, potatoes, cabbage, spinach and paprika, as well as some pickled vegetables. Many animal products, including calf liver and oysters, contain vitamin C. Though redundant in the presence of a balanced diet, various nutritional supplements are available that provide ascorbic acid well in excess of that required to prevent scurvy, and even some candies and most Soft drinks contain vitamin C as a preservative.
Scurvy in animals
Like humans, other primates and guinea pigs lack the gene that makes vitamin C and thus require vitamin C in the diet to prevent the development of scurvy. Scurvy is sometimes seen in pet guinea pigs that are fed an inadequate diet. To prevent scurvy in guinea pigs, they should be fed guinea pig food such as guinea pig pellets, which must be supplemented with fresh fruit and vegetables or vitamin C drops as the vitamin C in the pellets degrades very quickly (50% within six weeks of manufacture). It is not recommended that any supplement or medication be given to a guinea pig via a water bottle as it may impact their water consumption.