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$Unique_ID{BRK03899}
$Pretitle{}
$Title{Keratomalacia}
$Subject{Keratomalacia Xerotic Keratitis Xerophthalmia Night Blindness Vitamin
A Deficiency Retinol Deficiency Sjogren's Syndrome Keratoconus Interstitial
Keratitis Bullous Keratopathy}
$Volume{}
$Log{}
Copyright (C) 1990 National Organization for Rare Disorders, Inc.
762:
Keratomalacia
** IMPORTANT **
It is possible that the main title of the article (Keratomalacia) is not
the name you expected. Please check the SYNONYM listing to find the
alternate names and disorder subdivisions covered by this article.
Synonyms
Xerotic Keratitis
Xerophthalmia
Night Blindness
Vitamin A Deficiency
Retinol Deficiency
Information on the following diseases can be found in the Related
Disorders section of this report:
Sjogren's Syndrome
Keratoconus
Interstitial Keratitis
Bullous Keratopathy
General Discussion
** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only. It should not be used for diagnostic or treatment
purposes. If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section of this report.
Keratomalacia is an eye disease caused by a deficiency of vitamin A.
Vitamin A (retinol) is found mainly in fish liver oils, liver, egg yolk,
cream and butter. The human body stores vitamin A mainly in the liver. Once
it is released by the liver, vitamin A is converted to light sensitive
pigments in the retina that are involved in night, day and color vision.
Vitamin A also helps maintain healthy body tissue.
Keratomalacia is very rare in North America and Western Europe, but is a
leading cause of blindness in Southeast Asia, parts of Africa and Central and
South America. In these areas vitamin A deficiency is usually caused by
general malnutrition in infants and young children.
Symptoms
A deficiency of Vitamin A may interfere with the eye's ability to adapt to
the dark, resulting in night blindness. It may also cause a lack of tears
leading to abnormal dryness (xerosis) of the inner surface of the eyelid
(conjunctiva) and the transparent covering (cornea) of the eyes. This
dryness may result in a sensation of grittiness in the eyes and a painful
sensitivity to light (photophobia). Shiny, pearled spots of triangular
shaped tissue may occur on the inner surface of the eyelids (Bitot's spots).
The cornea may become hazy and gradually dissolve, leading to rupture of the
eyeball with extrusion of the eye's contents.
In vitamin A deficiency, cells in the lung, gastrointestinal tract and
urinary tract may be keratonized. The senses of taste and smell may be
defective, and there may be a thickening of the skin. Individuals with
Keratomalacia may develop anemia and an increased susceptibility to
infection. Growth retardation is a common symptom in children.
Causes
Keratomalacia is most commonly caused by prolonged dietary deprivation of
sources of vitamin A. It occurs most frequently in areas such as southern
and eastern Asia where rice is the staple (rice does not contain the
necessary dietary pigment, carotene, which the body converts to vitamin A).
A secondary cause of Keratomalacia may be due to the body's inadequate
conversion of carotene to vitamin A. Keratomalacia may also be caused by an
interference with absorption, storage or transport of vitamin A.
Interference with absorption or storage of vitamin A may be associated with
digestive diseases (sprue), cystic fibrosis, surgery of the pancreas or the
small intestine (duodenal bypass), obstruction of the small intestine,
obstruction of the bile ducts, chronic diarrhea due to giardiasis and
cirrhosis of the liver.
In the United States vitamin A deficiency in adults is most likely to be
secondary to severe malabsorption of the vitamin, or to eating disorders such
as Anorexia Nervosa.
Affected Population
Keratomalacia affects males and females in equal numbers. It occurs most
commonly in developing countries in the Far East and India, affecting poorly
nourished infants and adults.
Related Disorders
Symptoms of the following disorders can be similar to those of Keratomalacia.
A comparison may be useful for a differential diagnosis:
Sjogren's Syndrome is an autoimmune disorder characterized by abnormally
dry eyes and mouth. Membrane dryness may be widespread involving the nose,
esophagus, trachea, upper gastrointestinal tract and the vagina. (For more
information on this disorder, choose "Sjogren's Syndrome" as your search term
in the Rare Disease Database).
Keratoconus is a disorder characterized by slow and progressive expansion
of the cornea of the eye. The abnormal cone shape that the cornea develops
causes major changes in vision, and may require frequent changes in
eyeglasses or contact lenses. It may progress to blindness. However, a
cornea transplant can cure this eye disease. (For more information on this
disorder, choose "Keratoconus" as your search term in the Rare Disease
Database).
Interstitial Keratitis is a disorder characterized by a chronic
inflammation of the deep layers of the cornea. It rarely occurs in the
United States. Symptoms may include painful sensitivity to light
(photophobia), pain in the eyes, an excess secretion of tears (lacrimation)
and a gradual loss of vision. Interstitial Keratitis most commonly affects
children and is a late complication of congenital syphilis.
Bullous Keratopathy is a disorder characterized by excessive fluid
accumulation in the cornea. Symptoms may include pain in the eyes and
decreased vision. Bullous Keratopathy most frequently affects the elderly
and occasionally occurs after surgery for some other eye problem such as
cataracts.
Therapies: Standard
In treating individuals with Keratomalacia, the cause must be corrected. When
dietary deficiency of vitamin A is the cause, Vitamin A supplements must be
administered. However, vitamin A can cause birth defects if given in high
doses to pregnant women, so care must be taken in treating women of child
bearing years. In general, individuals with Keratomalacia respond rapidly to
vitamin A replacement therapy if the case is treated early. Dry eyes may be
treated with artificial tears. If the eye complications have progressed to
the most severe stage (blindness), little can be done to restore vision.
Antibiotic sulfonamide ointments may be used for secondary infections. In
mild cases of night blindness improvement is often shown following the
administration of vitamin A or as a fish liver oil. More advanced cases may
require higher doses daily for several months. Large doses of vitamin A
should be monitored by a physician to avoid possible overdose.
If Keratomalacia is caused by an interference of absorption, storage or
transport of vitamin A, the underlying disorder must be treated.
Therapies: Investigational
This disease entry is based upon medical information available through July
1990. Since NORD's resources are limited, it is not possible to keep every
entry in the Rare Disease Database completely current and accurate. Please
check with the agencies listed in the Resources section for the most current
information about this disorder.
Resources
For more information on Keratomalacia, please contact:
National Organization for Rare Disorders (NORD)
P.O. Box 8923
New Fairfield, CT 06812-1783
(203) 746-6518
NIH/National Eye Institute
9000 Rockville Pike
Bethesda, MD 20892
(301) 496-5248
Eye Research Institute of Retina Foundation
20 Staniford St.
Boston, MA 02114
(617) 742-3140
National Society to Prevent Blindness
79 Madison Avenue
New York, NY 10016
(212) 684-3505
Vision Foundation, Inc.
818 Mt. Auburn Street
Watertown, MA 02172
(617) 926-4232
1-800-852-3029
References
INTERNAL MEDICINE, 2nd Ed.: Jay H. Stein, ed.-in-chief; Little, Brown and
Co., 1987. Pp. 282, 1264.
THE MERCK MANUAL, Volume 1, 14th Ed.: Robert Berkow, M.D., ed.-in-chief;
Merck Sharp & Dohme Laboratories, 1982. Pp. 922-923.
IMPRESSION CYTOLOGY: A PRACTICAL INDEX OF VITAMIN A STATUS. G.
Natadisastra et al.; AM J CLIN NUTR (September, 1988: issue 48(5)). Pp. 426-
429.
VITAMIN A FORTIFIED MONOSODIUM GLUTAMATE AND HEALTH, GROWTH, AND SURVIVAL
OF CHILDREN: A CONTROLLED FIELD TRIAL. Muhilal et al.; AM J CLIN NUTR
(November, 1988: issue 48(5)). Pp. 1271-1276.