corneal dry spot
Introduction
Introduction Corneal dry spots are corneal dry spots formed by the accumulation of corneal epithelium, mainly found in vitamin A deficiency. This disease is a systemic nutritional disorder, the appearance of vitamin A deficiency in the eye. Prevention of vitamin A deficiency not only prevents night blindness, dry eye disease, avoids blindness, but also allows children to develop normally, and the chance of infection in various epithelial tissues can be reduced. Such as chronic respiratory infections, persistent pneumonia, measles, etc., on the basis of insufficient intake of vitamin A, symptoms appear due to increased consumption of vitamin A.
Cause
Cause
1. Improper diet: When the baby is born, his liver stores little vitamin A and is quickly consumed. However, the content of colostrum is extremely high. Human milk and milk are the main sources of vitamin A needed by the baby. Other foods such as vegetables, Fruits, eggs and liver can supply enough vitamin A. Therefore, proper diet can provide enough vitamin A to cause deficiency. However, foods in infants are simple, such as insufficient milk, and do not replenish food supplements, which may cause subclinical vitamin A deficiency. After weaning, if the baby is fed with food such as rice cake, batter, porridge, and skim milk, and without supplements rich in protein and fat, it can cause deficiency.
2, digestive system diseases: chronic diseases of the digestive system such as long-term diarrhea, chronic dysentery, intestinal tuberculosis, pancreatic diseases, etc. can affect the absorption of vitamin A. The liver is the main organ for the metabolism and storage of vitamin A. The bile salts in bile can emulsify lipids, promote the absorption of vitamin A, and enhance the activity of -carotene-15,15 -oxygenase to promote its transformation. It is retinol, so it is easy to cause vitamin A deficiency when suffering from hepatobiliary diseases such as congenital biliary atresia and chronic hepatitis. Hepatitis A caused by various viruses or toxic hepatitis complicated by infectious diseases can also cause vitamin A deficiency.
3, consumptive diseases: such as chronic respiratory infections, persistent pneumonia, measles, etc., on the basis of insufficient intake of vitamin A, due to increased consumption of vitamin A and symptoms. In addition, long-term intake of mineral oil (such as liquid paraffin, etc.), neomycin and methotrexate can also affect the absorption of vitamin A. Malignant tumors and urinary system diseases can increase the excretion of vitamin A. Protein deficiency affects the synthesis of retinol transporters, causing vitamin A to try to decrease in plasma, resulting in a lack of symptoms.
4, hypothyroidism and diabetes: can make beta carotene into a process of retinol disorders, resulting in vitamin A deficiency, and blood and skin accumulate a larger amount of carotene, much like jaundice, but the bulbar conjunctiva is not obvious yellow.
5, zinc deficiency: pre-albumin and vitamin A reductase combined with vitamin A are reduced, so that vitamin A can not be used and excreted, vitamin A deficiency can also occur. In recent years, changes in nutritional status have been reported, which have an impact on the utilization of vitamin A.
Examine
an examination
Related inspection
Corneal examination
1. Eye symptoms: The earliest symptoms are unclear vision in the dark environment, difficulty in orientation, and night blindness. If not carefully examined, it is easy to ignore. After several weeks to several months, the conjunctiva and cornea gradually lose their luster, and when exposed slightly in the air, they dry abnormally. In particular, the conjunctiva on both sides of the cornea appears to be the earliest change, dry and wrinkled, and the keratinous epithelium gradually regulates to form a white spot shaped like a foam, which is called a conjunctival dry spot, also known as a Bidelet spot. At this time, the lacrimal gland epithelial cells are degenerated, the secretion of tears is reduced, and the epithelial cells of the lacrimal duct are occluded, and the tears are less. Children with photophobia, conscious dry eyes, eye pain, feeling of rolling, often blinking, or rubbing with hands, easy to cause secondary infection. The cornea is gradually dry, turbid, and it becomes white and softens. The disease progresses, the cornea can ulcer, and within a few days to several weeks, necrosis, perforation, extra-irisal dislocation and corneal scar formation, eventually to blindness, retinal lesions, dry fundus, both eyes are generally sick at the same time, sometimes two eyes Has been onset, unilateral onset only occasionally. Although the eye symptoms appear earlier in most cases, the eye symptoms of older children often appear after other symptoms.
2, skin performance: dry skin, keratinized hyperplasia, desquamation. The keratin is filled in the hair follicle cavity and protrudes from the epidermis, so there is a goose bump or a coarse sand-like feeling when touching. It is most prominent on the extremities and shoulders of the extremities. This symptom is rare in infants under 4 years of age. In addition, there are still many lines of nails, tarnishing, creases, and easy to fall off hair.
3, other performance: due to vitamin A deficiency, respiratory and urinary tract epithelial proliferation and keratinization, as well as decreased immune function, easy to cause secondary respiratory infection and pyuria. Tongue taste buds are lost due to epithelial keratosis, affecting appetite, and some children may have vomiting. Physical development retardation can be seen in infants and young children. In severe cases of vitamin A deficiency, poor blood cell formation can form anemia, and treatment with sufficient iron can not correct anemia. It has been reported that small babies can develop licking milk and add symptomatic control after taking vitamin A.
diagnosis
Diagnosis of the eye with obvious symptoms, combined with feeding history, chronic digestive system or history of wasting disease, is not difficult. Because of vitamin A deficiency, there are often comorbidities. Therefore, if you have malnutrition, chronic diarrhea, chronic diarrhea, or measles, you should have a long-term avoidance. If you have photophobia or blink, you should check your eyes carefully. Older children should pay attention to changes in the skin. In early and atypical cases, changes in the eye are mild, especially in infants and young children. The following checks can be performed on suspicious cases to help diagnose:
1 Using a small cotton swab to lick normal saline, gently scrape off a small amount of material from the conjunctival surface, and visible keratinocytes under the microscope;
2 serum vitamin A determination is the most reliable indicator, normal children's serum vitamin A value is generally 300 ~ 500g / L, when the deficiency is reduced to 200g / L or even 100g / L;
3 Take a few drops of fresh mid-stage urine about 10mg plus 1% gentian violet solution, shake well, and do epithelial cell counting. Normal urine per cubic millimeter contains up to 3 skin cells; more than 3 patients may have vitamin A deficiency in addition to urinary inflammation. The urine sediment was examined by a high power microscope, and the degree of keratinosis of the epithelial cells was measured.
If the food is deficient in vitamin A or has a malabsorption, symptoms may appear within a few weeks. Small infants suffer from congenital biliary obstruction and infantile hepatitis syndrome. If pneumonia is complicated, eye dryness may occur in a short period of time. Early attention should be paid.
Diagnosis
Differential diagnosis
1. Identification with keratoconjunctivitis.
(1) The surface of the conjunctiva is dry, dull and dull, easy to wrinkle, even as thick as the skin, the conjunctival blood vessels are blue, the cornea is dry and turbid, and the perception is slow.
(2) Consciously dry eyes, burning, severe vision loss.
(3) Adults are more common.
2. Other causes of night blindness, such as retinitis pigmentation, must be ruled out, secondary infection can make corneal changes worse, the therapeutic dose of vitamin A can help diagnose.
