Scurvy


Scurvy or scorbutus is a deficiency disease resulting from a lack of vitamin C. Early symptoms of deficiency include weakness, fatigue, and sore arms and legs. Without treatment, decreased red blood cells, gum disease, changes to hair, and bleeding from the skin may occur. As scurvy worsens, there can be poor wound healing, personality changes, and finally death from infection or bleeding.
It takes at least a month of little to no vitamin C in the diet before symptoms occur. In modern times, scurvy occurs most commonly in neglected children, people with mental disorders, unusual eating habits, alcoholism, and older people who live alone. Other risk factors include intestinal malabsorption and dialysis.
While many animals produce their vitamin C, humans and a few others do not. Vitamin C, an antioxidant, is required to make the building blocks for collagen, carnitine, and catecholamines, and assists the intestines in the absorption of iron from foods. Diagnosis is typically based on outward appearance, X-rays, and improvement after treatment.
Treatment is with vitamin C supplements taken by mouth, or intravenously for optimal resolution. Improvement often begins in a few days with complete recovery in a few weeks. Sources of vitamin C in the diet include raw citrus fruit and several raw vegetables, including red peppers, broccoli, and tomatoes. Cooking often decreases the residual amount of vitamin C in foods.
Scurvy is rare compared to other nutritional deficiencies. It occurs more often in the developing world in association with malnutrition. Rates among refugees are reported at 5 to 45 percent. Scurvy was described as early as the time of ancient Egypt, and historically it was a limiting factor in long-distance sea travel, often killing large numbers of people. During the later Age of Sail, it was assumed that 50 percent of the sailors would die of scurvy on a major voyage of exploration. In long sea voyages, crews were isolated from land for extended periods and these voyages relied on large staples of a limited variety of foods and the lack of fruit, vegetables, and other foods containing vitamin C in diets of sailors resulted in scurvy.

Signs and symptoms

Early symptoms are malaise and lethargy. After one to three months, patients develop shortness of breath and bone pain. Myalgias may occur because of reduced carnitine production. Other symptoms include skin changes with roughness, easy bruising, and petechiae, gum disease, loosening of teeth, poor wound healing, and emotional changes. Dry mouth and dry eyes similar to Sjögren's syndrome may occur. In the late stages, jaundice, generalised edema, oliguria, neuropathy, fever, convulsions, and eventual death are frequently seen.

Cause

Scurvy, including subclinical scurvy, is caused by a deficiency of dietary vitamin C since the human liver is unable to synthesize vitamin C. Provided the diet contains sufficient vitamin C, the lack of working L-gulonolactone oxidase enzyme has no significance. In modern Western societies, scurvy is seldom present in average adults, although underfed people are affected. Virtually all commercially available baby formulas contain added vitamin C, preventing infantile scurvy. Human breast milk contains sufficient vitamin C if the mother has an adequate intake. Commercial milk is pasteurized, a heating process that destroys the natural vitamin C content of the milk.
Scurvy is one of the accompanying diseases of malnutrition and thus is still widespread in areas of the world dependent on external food aid. Although rare, there are also documented cases of scurvy due to poor dietary choices by people living in industrialized nations.

Pathogenesis

Vitamins are essential to the production and use of enzymes in ongoing processes throughout the human body. Ascorbic acid is needed for a variety of biosynthetic pathways, by accelerating hydroxylation and amidation reactions.
The early symptoms of malaise and lethargy may be due to either impaired fatty acid metabolism from a lack of carnitine and/or from a lack of catecholamines, which are needed for the cAMP-dependent pathway in both glycogen metabolism and fatty acid metabolism. Impairment of either fatty acid metabolism or glycogen metabolism leads to decreased ATP production. ATP is needed for cellular functions, including muscle contraction.
In the synthesis of collagen, ascorbic acid is required as a cofactor for prolyl hydroxylase and lysyl hydroxylase. These two enzymes are responsible for the hydroxylation of the proline and lysine amino acids in collagen. Hydroxyproline and hydroxylysine are important for stabilizing collagen by cross-linking the propeptides in collagen.
Collagen is a primary structural protein in the human body, necessary for healthy blood vessels, muscle, skin, bone, cartilage, and other connective tissues. Defective connective tissue leads to fragile capillaries, resulting in abnormal bleeding, bruising, and internal hemorrhaging. Collagen is an important part of bone, so bone formation is also affected. Teeth loosen, bones break more easily, and once-healed breaks may recur. Defective collagen fibrillogenesis impairs wound healing. Untreated scurvy is invariably fatal.

Diagnosis

Diagnosis is typically based on physical signs, X-rays, and improvement after treatment.

Differential diagnosis

Various childhood-onset disorders can mimic the clinical and X-ray picture of scurvy such as:
Scurvy can be prevented by a diet that includes uncooked vitamin C-rich foods such as amla, bell peppers, blackcurrants, broccoli, chili peppers, citrus fruits, kiwifruit, and parsley. Other sources rich in vitamin C are dandelion, raw liver, sauerkraut, and many fruits such as guava, papaya, strawberries, and tomato. It is also found in vegetables, such as brussels sprouts, cabbage, potatoes, and spinach. Some fruits and vegetables not high in vitamin C may be pickled in lemon juice, which is high in vitamin C. Nutritional supplements that provide ascorbic acid well above what is required to prevent scurvy may cause adverse health effects.
Uncooked fresh meat from animals, notably internal organs, contains enough vitamin C to prevent scurvy, and even partly treat it.
Scott's 1902 Antarctic expedition used fresh seal meat and increased allowance of bottled fruits which reportedly led to complete recovery from incipient scurvy in less than two weeks.

Treatment

Scurvy will improve with doses of vitamin C as low as 10 mg per day, though doses of around 100 mg per day are typically recommended. Most people make a full recovery within 2 weeks.

History

Symptoms of scurvy have been recorded in Ancient Egypt as early as 1550 BC. It was first reported amongst soldiers and sailors having inadequate access to fruits and vegetables which resulted in vitamin C deficiency. In Ancient Greece, the physician Hippocrates described symptoms of scurvy, specifically a "swelling and obstruction of the spleen." In 406 AD, the Chinese monk Faxian wrote that ginger was carried on Chinese ships to prevent scurvy.
The knowledge that consuming certain foods is a cure for scurvy has been repeatedly forgotten and rediscovered into the early 20th century. Scurvy occurred during the Great famine of Ireland in 1845 and also the American Civil War. In 2002, scurvy outbreaks were recorded in Afghanistan following the most intense phase of the war.

Early modern era

In the 13th century Crusaders developed scurvy. In the 1497 expedition of Vasco da Gama, the curative effects of citrus fruit were already observed and were confirmed by Pedro Álvares Cabral and his crew in 1507.
The Portuguese planted fruit trees and vegetables on Saint Helena, a stopping point for homebound voyages from Asia, and left their sick who had scurvy and other ailments to be taken home by the next ship if they recovered. In 1500, one of the pilots of Cabral's fleet bound for India noted that in Malindi, its king offered the expedition fresh supplies such as lamb, chicken, and duck, along with lemons and oranges, due to which "some of our ill were cured of scurvy".
These travel accounts did not prevent further maritime tragedies caused by scurvy, partly because of the lack of communication between travelers and those responsible for their health, and because fruits and vegetables could not be kept for long on ships.
In 1536, the French explorer Jacques Cartier, while exploring the St. Lawrence River, used the local St. Lawrence Iroquoians' knowledge to save his men dying of scurvy. He boiled the needles of the aneda tree 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. Later, possibly inspired by this incident, several European countries experimented with preparations of various conifers, such as spruce beer, as cures for scurvy.
In 1579, the Spanish friar and physician Agustin Farfán published a book in which he recommended oranges and lemons for treating scurvy, a remedy that was already known in the Spanish navy.
In February 1601, Captain James Lancaster, while commanding the first English East India Company fleet en route to Sumatra, landed on the northern coast of Madagascar specifically to obtain lemons and oranges for his crew to stop scurvy. Captain Lancaster conducted an experiment using four ships under his command. One ship's crew received routine doses of lemon juice while the other three did not receive such treatment. As a result, members of the non-treated ships started to contract scurvy, with many dying as a result.
Researchers have estimated that during the Age of Exploration, scurvy killed at least two million sailors. Jonathan Lamb wrote: "In 1499, Vasco da Gama lost 116 of his crew of 170; In 1520, Magellan lost 208 out of 230; ... all mainly to scurvy."
In 1593, Admiral Sir Richard Hawkins advocated drinking orange and lemon juice to prevent scurvy.
A 1609 book by Bartolomé Leonardo de Argensola recorded several different remedies for scurvy known at this time in the Moluccas, including a kind of wine mixed with cloves and ginger, and "certain herbs". The Dutch sailors in the area were said to cure the same disease by drinking lime juice.
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. He repeated the experience of mariners that the cure for scurvy was fresh food or, if not available, oranges, lemons, limes, and tamarinds. He was, however, unable to explain the reason why, and his assertion had no impact on the prevailing opinion of the influential physicians of the age, that scurvy was a digestive complaint.
Besides afflicting ocean travelers, until the late Middle Ages scurvy was common in Europe in late winter, when few green vegetables, fruits, and root vegetables were available. This gradually improved with the introduction of potatoes from the Americas; by 1800, scurvy was virtually unheard of in Scotland, where it had previously been endemic.