Vitamin A Deficiency

ETIOLOGY:
  • Primary vitamin A deficiency
  1. Prolonged dietary deprivation
  2. Vegetarians,
  3. Refugees, and
  4. Chronic alcoholics,
  5. Toddlers and
  6. Preschool children
  • Secondary  vitamin A deficiency
  1. Sprue,
  2. Cystic fibrosis,
  3. Pancreatic insufficiency,
  4. Duodenal bypass,
  5. Chronic diarrhea,
  6. Bile duct obstruction,
  7. Giardiasis, and cirrhosis.
CLINICAL MANIFESTATION:
  • Bitot spots - Areas of abnormal squamous cell proliferation and keratinization of the conjunctiva can be seen in young children with VAD.
  • Blindness due to retinal injury -Vitamin A has a major role in photo transduction. VAD leads to a lack of visual pigments; this reduces the absorption of various wavelengths of light, resulting in blindness. Most common cause of blindness in children in India is Vitamin A deficiency
  • Poor adaptation to darkness (nyctalopia), which can lead to night blindness, is an early symptom.
  • Hydrocephalus is infrequent in vit. A deficiency
  • Xerophthalmia results from keratinization of the conjunctiva.
  • 1st symptom of vitamin A deficiency is Night blindness
  • Extra ocular manifestations of vitamin A deficiency include anorexia, growth retardation and follicular hyperkeratosis.
  • Keratomalacia- In advanced deficiency; the cornea becomes hazy and can develop erosions, which can lead to its destruction (Keratomalacia).
  • Increased susceptibility to infections - Keratinization of the mucous membranes of respiratory tracts and urinary tract takes place, increasing the susceptibility to infections.
  • During infection the synthesis of retinol binding protein is reduced in response to infection since it is a negative ‘Acute phase protein’, that results in decreased circulatory concentration of the vitamin with further deterioration of the immune system. 
TREATMENT:
  • Any stage of xerophthalmia should be treated with 60 mg of vitamin A in oily solution, usually contained in a soft-gel capsule.
  • Mothers with night blindness or Bitot's spots should be given vitamin A orally.
  • 3 doses of vitamin A are required to treat deficiency
  • A common approach to prevention is to supplement young children living in high-risk areas with 60 mg every 4–6 months, with a half-dose given to infants 6–11 months of age.
  • Extremely low-birth-weight infants 
  • Children hospitalized with measles should receive two 60-mg doses of vitamin A on two consecutive days.
  • The patients with malabsorption syndrome require vitamin A supplements.
  • Bitot spots in 10 month children should be given 1 lakh units IM on day 0, 1 and 14
PREVENTION:
  • Vitamin A prophylaxis to a child is Specific protection
  • The diet should include dark green leafy vegetables, deep- or bright-colored fruits (e.g., papayas, oranges), carrots, and yellow vegetables (e.g., squash, pumpkin).
  • Vitamin A–fortified milk and cereals, liver, egg yolks, and fish liver oils are helpful.
  • Carotenoids are absorbed better when consumed with some dietary fat. 
  • Under national programme for prevention of nutritional blindness, a child in the age group of 6-11 months is given a mega dose of vitamin A equal to 1,00,000 IU
VITAMIN A TOXICITY:
  • Vitamin A toxicity can be acute (usually due to accidental ingestion by children) or chronic.
  • Both types usually cause headache and increased intracranial pressure.
  • Acute toxicity also causes nausea and vomiting
  • Vitamin A is teratogenic
  • Excess of vitamin A can lead to rupture of Lysosomal membranes
  • Abnormalities of bone metabolism is associated with excess of Vitamin A deficiency
  • Chronic toxicity also causes changes in skin, hair, and nails; abnormal liver test results; and, in a fetus, birth defects.
  • Diagnosis is usually clinical. Unless birth defects are present, adjusting the dose almost always leads to complete recovery.
Exam Question of : -

  • Vitamin A prophylaxis to a child is Specific protection
  • Vitamin A intoxication causes injury to Lysosomes
  • Bitot spots in 10 month children should be given 3 dose of  1 lakh units IM on day 0, 1 and 14
  • Under national programme for prevention of nutritional blindness, a child in the age group of 6-11 months is given a mega dose of vitamin A equal to 1,00,000 IU
  • Extra ocular manifestations of vitamin A deficiency include anorexia, growth retardation and follicular hyperkeratosis.
  • Vitamin A deficiency is characterized by Bitot's spot,Xerophthalmia , Night blindness, Corneal xerosis, Keratomalacia and corneal ulcers.
  • A child with dry skin and scaling is suspected of having vitamin A deficiency shows early features Nyctalopia
  • Growth retardation is common in vit. A deficiency
  • Frequent infections can occur in vit. A deficiency
  • Hydrocephalus is infrequent in vit. A deficiency
  • The earliest clinical sign of Vitamin A deficiency is Conjunctival xerosis
  • Most common cause of blindness in children in India is Vitamin A deficiency
  • Abnormalities of bone metabolism is associated with excess of Vitamin A deficiency
  • Vitamin A is teratogenic
  • 1st symptom of vitamin A deficiency is Night blindness
  • Xerosis/ Xerophthalmia is due to deficiency of Vitamin A
  • 3 doses of vitamin A are required to treat deficiency
  • Follicular hyperkeratosis is related to deficiency of vitamin A

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