Vitamin A deficiency

What is Vitamin A deficiency?

What are the causes of this deficiency?

What are the signs and symptoms?

How is it diagnosed?

How is it treated?

Are there any precautionary measures?

What is Vitamin A deficiency?

Vitamin A deficiency is one of the leading causes of preventable blindness in developing countries. Vitamin A is a fat-soluble vitamin and is found mainly in fish liver oils, liver, egg yolks, butter and cream, green leafy and yellow vegetables.

What are the causes of this deficiency?

Primary vitamin A deficiency is caused by malnutrition.

Secondary vitamin A deficiency is caused by:

Celiac disease, inability to tolerate wheat protein (gluten); often accompanied by lactose intolerance. 
Sprue, where nutrients are not absorbed. 
Cystic fibrosis, the most common congenital disease in the west; the child's lungs and intestines and pancreas become clogged with thick mucus; characterised by frequent respiratory tract infections, mal-absorption etc. 
Pancreatic disease. 
Duodenal bypass. 
Congenital partial obstruction of the jejunum. 
Obstruction of the bile ducts. 
Giardiasis, which is the infection of the intestines with protozoa found in contaminated food and water, causing malabsorption. 
Cirrhosis, destruction of the liver parenchyma, the major cause being chronic alcohol intake. 
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What are the signs and symptoms?

World Health Organisation has proposed an ocular symptom classification of vitamin A deficiency, which is as follows.

XN: Night Blindness is the earliest symptom of vitamin A deficiency, which is often reported by the mother as reduced visual acuity of the child in the evening and the night-time. 
X1A: Conjunctival xerosis or drying of the conjunctiva. 
X1B: Bitot’s spots on the conjunctiva. 
X2: Corneal xerosis or dryness of the cornea with a granular looking surface. 
X3A: Keratomalacia involving less than a third of the cornea. Cornea becomes dry, thin and soft, and then ulcerates. Usually presents with indolent corneal ulcers surrounded by dull lack-luster hazy cornea, ±intolerance to light. The cornea then becomes soft and necrotic with perforation being common. 
X3B: Keratomalacia involving greater than one third of cornea. 
XF: Fundoscopic changes visible on ophthalmoscopy. 
XS: Corneal Scarring compromising severely on visual acuity. 
Other signs of vitamin A deficiency are:

Frequent infections like measles, diarrhea, and malaria. 
Stunted growth. 
Anemia. 
Malnutrition. 
Thickened toad like skin. 
How is it diagnosed?

Diagnosis is essentially clinical. Investigations that may help in diagnosis are:·

Fundoscopic examination. 
Serum retinol and retinol binding protein level. 
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How is it treated?

The cause should be corrected.

Administration of oral vitamin A palmitate for two days regularly and once before discharge from the hospital after 14 days is usually effective. 
In the presence of vomiting or malabsorption, water-miscible vitamin A must be given IM. 
During pregnancy and lactation, prophylactic or therapeutic doses should not exceed two times the RDA to avoid possible damage to the fetus. 
Surgical treatment (keratoplasty) is needed in case of Keratomalacia. 
Are there any precautionary measures?

Vitamin A deficiency is an easily preventable disorder. Some of the precautionary measures are:

Use of oral vitamin A. 
Treatment of malnutrition. 
Usage of vitamin A rich foods. 
Usage of vitamin A fortified foods. 
Treatment of associated disorders. 
Screening of siblings of children with manifest vitamin A deficiency. 
Administration of vitamin A to lactating women. 
** - RDA: Recommended Dietary Allowance, IM: Intramuscular.