Scurvy or scorbutus is a deficiency disease (state of malnutrition) resulting from a lack of vitamin C (ascorbic acid). 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 such as ARFID, alcoholism, and older people who live alone. Other risk factors include intestinal malabsorption and dialysis.
While almost all animals, plants, and other life forms 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; 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 (which may appear before any physical 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.
Signs of scurvy also include hypotension, pulmonary hypertension, and an enlarged heart.
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 (GULO) enzyme has no significance. In modern Western societies, scurvy is seldom present in average adults, although underfed people (drug users, the homeless, neglected children and geriatrics) 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 (other such micronutrient deficiencies are beriberi and pellagra) 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. Vitamin C is needed for a variety of biosynthetic pathways, by accelerating hydroxylation and amidation reactions. It is involved in a wide range of biochemical and physiological processes, including the amidation of several peptide hormones and the synthesis of nitric oxide, norepinephrine, carnitine and collagen. In addition, vitamin C contributes to the modulation of gene expression through epigenetic mechanisms affecting more than a thousand genes.
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 (energy) production. ATP is needed for cellular functions, including muscle contraction. (For low ATP within the muscle cell, see also Purine nucleotide cycle.)
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. The ascorbate anion functions as an essential electron donor to keep iron in its active Fe²⁺ (Ferrous iron) state, preventing the inactivation of lysyl hydroxylase.
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.
Vitamin C deficiency may cause pulmonary hypertension by several mechanisms. It participates in the synthesis of type IV collagen, which is required for basement membrane formation and endothelial cell adhesion. It also participates in the synthesis of NO and carnitine, and may increase prostacyclin levels. Vitamin C also participates in the hydroxylation of specific proline residues of HIF-1α and thereby increases its rate of degradation, leading to decreased HIF-1α levels.
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: Rickets Osteochondrodysplasias especially osteogenesis imperfecta Blount's disease Osteomyelitis
Prevention by food
Scurvy can be prevented by a diet that includes uncooked vitamin C-rich foods providing as little as 10 mg of vitamin C per day. Common examples in typical serving amounts include kiwifruit, grapefruit, strawberries, bell peppers, and citrus fruits. About five servings per day of fresh fruits and vegetables supply enough vitamin C to exceed the scurvy threshold by 10-fold. 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 such as liver, 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. [26 September 1902] [The expedition members] Heald, Mr. Ferrar, and Cross have very badly swollen legs, whilst Heald's are discoloured as well. The remainder of the party seem fairly well, but not above suspicion; Walker's ankles are slightly swollen. [15 October 1902] [After a fresh seal meat diet at base camp] within a fortnight of the outbreak there is scarcely a sign of it remaining [...] Heald's is the only case that hung at all [...] and now he is able to get about once more. Cross's recovery was so rapid that he was able to join the seal-killing party last week.
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 (460–370 BC) described symptoms of scurvy, specifically a "swelling and obstruction of the spleen."Hippocrates described symptoms of scurvy in book 2 of his Prorrheticorum and in his Liber de internis affectionibus. (Cited by James Lind, A Treatise on the Scurvy, 3rd ed. (London, England: G. Pearch and W. Woodfall, 1772), page 285 ) Symptoms of scurvy were also described by: (i) Pliny, in Naturalis historiae, book 3, chapter 49; and (ii) Strabo, in Geographicorum, book 16. (Cited by John Ashhurst, ed., The International Encyclopedia of Surgery, vol. 1 (New York, New York: William Wood and Co., 1881), page 278 ) Pliny the Elder described sailors consuming sea kale to prevent scurvy in his Naturalis historia (77–79 AD). In 406 AD, the Chinese monk Faxian wrote that ginger was carried on Chinese ships to prevent scurvy.Compare:
The knowledge that consuming certain foods is a cure for scurvy has been repeatedly forgotten and rediscovered into the early 20th century.Maciej Cegłowski, 2010-03-06, "Scott and Scurvy" . Retrieved 2016-05-31. 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 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.On returning, Lopes' ship had left him on St Helena, where with admirable sagacity and industry he planted vegetables and nurseries with which passing ships were marvellously sustained. [...] There were 'wild groves' of oranges, lemons, and other fruits that ripened all the year round, large pomegranates and figs. Santa Helena, A Forgotten Portuguese Discovery , Harold Livermore – Estudos em Homenagem a Luis Antonio de Oliveira Ramos, Faculdade de Letras da Universidade do Porto, 2004, p. 630-631
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.Contudo, tais narrativas não impediram que novas tragédias causadas pelo escorbuto assolassem os navegantes, seja pela falta de comunicação entre os viajantes e responsáveis pela sua saúde, ou pela impossibilidade de se disponibilizar de frutas frescas durante as travessias marítimas. A medicina nas caravelas - Século XV , Cristina B. F. M. Gurgel I; Rachel Lewinsohn II, Marujos, Alimentação e Higiene a Bordo
In the 1519-1521 circumnavigation, Magellan's crew suffered from scurvy: "above all other calamities this was the worst: in some men the gums grew over the teeth, both lowers and uppers, so that they could not eat in any way and thus they died of this sickness. Nineteen men died."