Diseases xerophthalmia

Sommer, A., Rarwotjo, 1., and Katz, J. (1986). Increased risk of xerophthalmia following diarrhea and respiratory disease. Am. J. Clin. Nutr. 45,977-980. 

In Southeast Asia, an estimated 5 million children develop an eye disease known as xerophthalmia due to vitamin A dehciency every year. Of these, 0.25-0.5 million will eventually go blind. Vitamin A dehciency is also correlated with a weakened immune system and consequentially an increased susceptibility to potentially fatal afflictions, including diarrhea, respiratory diseases, and childhood diseases such as measles. According to statistics compiled by UNICEF, improved vitamin A nutrition could be expected to prevent approximately 1-2 million deaths a year among children aged 1-4, and an additional 0.25-0.5 million deaths during later childhood. 

The principal physiological functions of tins vitamin include growth, production of visual purple, maintenance of skin and epithelial cells, resistance to infection, gluconeogenesis. mucopolysaccharide synthesis, bone development, maintenance of myelin and membranes, maintenance of color and peripheral vision, maintenance of adrenal cortex and steroid hormone synthesis, Specific vitamin A deficiency diseases include xerophthalmia, nyctalopia, hemeralopia, keratomalacia, and hyperkeratosis. 

The symptoms of vitamin D deficiency disease has been documented in 16th century literature. A clear picture of the basis for the disease and methods of treatment were unclear until the experiments by Sir Edward Mellanby (3,4). In the early 1920 s, cod liver oil was known to cure rickets and xerophthalmia. The name vitamin D was given to... 

The discovery, isolation and final synthesis of a whole group of new compounds essential to health in a balanced diet was another triumph of the chemist. These compounds called vitamins A, Ba or G, C, D, E, K, and several others closely associated with vitamin Ba, such as niacin, pantothenic acid, inositol, para-amino benzoic acid, choline, pyndoxine (Be), biotin (H), folic acid and Bn, prevent deficiency diseases such as xerophthalmia (an eye disease), beriberi, pellagra, scurvy, rickets, sterility (in rats), excessive bleeding and so forth. Professors Elmer V. McCollum and Herbert M. Evans, and Joseph Goldberger were among the early American pioneers in this field of research. Drugs, anaesthetics, and medicines like procaine, cyclopropane, dramamme, ephedrine, aspirin, phenace-tin, urotropin, veronal, quinine, and strychnine have been synthesized to alleviate the pains of mankind. The essential... 

A mild infection, such as measles, commonly triggers the development of xerophthalmia in children whose vitamin A status is marginal. In addition to functional deficiency as a result of impaired synthesis of RBP (Section 2.2.3) and transthyretin in response to infection, there may be a considerable urinary loss of vitamin A because of increased renal epithelial permeability and proteinuria, permitting loss of retinol bound to RBP-transthyretin. The American Academy of Pediatrics Committee on Infectious Diseases (1993) recommended vitamin A supplements for aU children who have been hospitalized with measles. 

DEFICIENCY Vitamin A deficiency results in night blindness and xerophthalmia (dry cornea and conjunctiva, sometimes with ulceration of the cornea). Nonocular changes may also occur dry skin and mucous membranes. Deficiency may result from poor dietary intake, or poor absorption, as from bowel disease, or a defect in bile flow that causes fet malabsorption. Poor protein intake may result in a reduced level of the transport protein that carries vitamin A in the blood stream. 

Some of the dreaded nutritional diseases of the past — such as scurvy, pellagra, and pernicious anemia — are discussed in this book. Such contemporary problems as infectious diarrhea, xerophthalmia, protein/energy malnutrition, and folate deficiency are discussed, as are diabetes and cardiovascular disease, two of the most sigf cant nutrition-related diseases. The last two conditions can be controlled in part by dietary intervention. 

A Dermatitis, night blindness, keratomalacia, xerophthalmia Serum vitamin A Teratogenic effects, liver toxicity with excessive intake alcohol intake, liver disease, hyperlipidemia, and severe protein malnutrition increase susceptibility to adverse effects of high intake , 6-carotene supplements recommended only for those at risk of deficiency (fat malabsorption)... 

Following the initial light stimulus, retinal returns to the cis isomer and reassociates with opsin. The system is then ready for the next impulse of light. However, some retinal is lost in the process and must be replaced by conversion of dietary vitamin A to retinal. As you might expect, a deficiency of vitamin A can have terrible consequences. In children, lack of vitamin A causes xerophthalmia, an eye disease that results first in night blindness and eventually in total blindness. This can be prevented by an adequate dietary supply of this vitamin. 

Nutritional vitamin A deficiency causes xerophthalmia, a progressive disease characterized by night blindness, xerosis (dryness), and keratomalacia (comeal thinning), which may lead to perforation xerophthalmia may be reversed with vitamin A therapy. However, rapid, irreversible blindness ensues once the cornea perforates. Vitamin A also is involved in epithelial differentiation and may have some role in corneal epithelial wound healing. There is no evidence to support using topical vitamin A for keratoconjunctivitis sicca in the absence of a nutritional deficiency. 

Ans. The disease is called xerophthalmia, or night blindness. It is caused by the insufficient synthesis of the visual pigment rhodopsin. Rhodopsin contains the retinal group, derived from vitamin A. 

Deficiency of vitamin A leads to degenerative lesions in the epithelium, xerophthalmia being the classical vitamin A deficiency disease. The drug-equivalent uses of vitamin A can be seen in Table 1. 

At the end of the last century, a new child s disease was observed for the first time in Japan during a period of depression. It was called Hikan and was characterized by hemeralopia, xerophthalmia, and keratomalacia. Untreated, the victims soon died, but they could be cured almost instantly by the administration of cod liver oil. 

In Japan at the turn of the century, infantile xerophthalmia was widely prevalent but since World War II has virtually disappeared. The disappearance of clinical vitamin A deficiency is consistent with dietary data collected annually or biannually since 1945 that show an increased intake of vitamin A, with a larger portion coming from preformed sources (Fukui, 1978 Abe, 1982). Singapore is another east Asian country now largely technologically developed where xerophthalmia was formerly prevalent and now has disappeared. These latter examples demonstrate how economic and technical development can dramatically influence deficiency disease patterns. 

Xerophthalmia can occur at any age, but its prevalence is much higher among young children than among older children and adults. This is particularly true of the severe blinding, and often fatal, form. When xerophthalmia occurs in adults, it is usually associated with an unusual dietary pattern such as in alcoholism or self-induced dietary deficiency or as a secondary consequence of chronic liver or malabsorptive diseases. 

There is an indisputable relationship between the occurrence of infectious disease and xerophthalmia. This was recognized in the first global survey conducted in 1964 and is illustrated in Table XIV taken from that publication (Oomen et aL, 1964) that shows the prevalence of xerophthalmia in relation to admission diagnosis for nearly 5700 preschool-aged children in one Indonesian hospital in the late 1950s. Clearly gastroenteritis/diarrhea and infectious diseases are a frequent accompaniment of xerophthalmia in this country known to have marginal intakes of vitamin A. 

Table XIV Oomen, 1971 McLaren era/., 1965a Sommer era/., 1975a, 1976). Measles, though prevalent in developed countries, is not reported to be a blinding disease in such countries. There is substantial literature that documents the association shown in Table XIV between malnutrition and xerophthalmia. A controversy has developed in the medical literature, therefore, as to whether vitamin A deficiency is the primary cause of keratomalacia, with intercurrent measles as a precipitating factor (Oomen, 1971 Sauter, 1976 Franken, 1974), or whether measles can cause blinding corneal disease in a malnourished child in the absence of vitamin A deficiency (Frederique et aL, 1969).

Although tradition in some cultures attributes a cause and effect relationship between worms and xerophthalmia, the scientific evidence for more than mere coexistence is somewhat equivocal. Thirty percent of the subjects with Bitot s spots and active comeal disease recmited from a hospital based study in Indonesia, reported a history of passing worms within the past month, but when only comeal cases were compared with a matched control group, the differences in the prevalence of worms (24% and 18%, respectively) were not significantly different. In the countrywide xerophthalmia prevalence survey, significantly different prevalence rates were recorded for children with Bitot s spots (22%), their matched controls (14%), and all others (9%) (Sommer, 1982a). In the Philippines, Solon et aL (1978) did not find a difference in infestation rates between children with mild xerophthalmia and those without, but in Jordan a difference was reported. 

A disease resulting from a deficiency of one or more vitamins is hypovitaminosis (if vitamin is supplied in insufficient quantity) or avitaminosis (complete lack of vitamin manifested by some biochemical processes disorder). Deficiency of vitamins was formerly one of the main causes of many diseases and deaths. Pellagra (deficiency of some B-complex vitamins), scurvy (vitamin C), beriberi (thiamine), rickets (vitamin D), pernicious anaemia associated with reduced ability to absorb vitamin Bj2 (corrinoids) and xerophthalmia (vitamin A) are now well-known diseases caused by vitamin deficiency. Excessive intake of one or more vitamins (especially of lipophilic vitamins A and D) also causes an abnormal state resulting from disturbances of biochemical processes and can lead to severe diseases known as hypervitaminosis. 

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