Nutritional eye diseases -Vitamin A deficiency and other deficiencies

Question 1

What are the ocular manifestations of vitamin A deficiency (Xerophthalmia classification)

Answer 1

Night blindness
Conjunctival xerosis
Bitot spots
Corneal xerosis
Corneal ulcer
Keratomalacia
Corneal scarring
Xerophthalmic fundus
Corneal scars presumed 2° to xerophthalmia

Question 2

What is the commonest cause of vitamin A deficiency

Answer 2

Inadequate intake of vitamin A

Question 3

List other causes of vitamin A deficiency

Answer 3

• Lack of dietary lipid
• Impaired secretion of digestive enzymes (as in cystic fibrosis)
• Gastroenteritis
• Celiac sprue
• Heavy worm loads
• Severe protein deficiency (interferes with protein synthesis)

Serum vitamin A levels is between 30 and 40 μg/dL

Question 4

What investigations will you do to confirm vitamin A deficiency and how will you manage?

Answer 4

INVESTIGATION
- Serum vitamin A level
- Total Retinol binding protein

TREATMENT
- children < 1 year:- 200,000IU oral Vit A at day 1, 2 & 14

• children > 2 years:- 100,00IU oral Vit A at day 1, 2 & 14
• pregnant women with night blindness, corneal xerosis, bitot spots are treated with 10,000IU of oral vit A for 2 weeks.

OCULAR THERAPY
- Artificial tears
- Topical antibiotics
- 0.1% retinoic acid

TREAT UNDERLYING CONDITIONS
- Protein energy malnutrition
- Diarrhea
- Electrolyte imbalance & dehydration
- Infections
- Parasitic conditions

Question 5

How do you prevent vitamin A deficiency?

Answer 5

Short term
•Infants less than 6 months old not being breastfed - 50,000 IU orally should be given before they attain the age of 6 months
•Infants 6-12 month old and any older children who weigh less than 8 kg. - 100,000 IU orally every 3-6 months.
•Children over 1 year and under 6 years of age - 200,000 IU orally every 6 months.
•Lactating mothers - 20,000 IU orally once at delivery or during the next 2 months

Medium term
•Food fortification with vitamin A e.g. Sugar, Vegetable Oil fortified with vit A

Long term
•Promotion of adequate intake of vitamin A rich foods such as green leafy vegetables, papaya and carrot
•Nutrition and health education
•Immunization against measles

Question 6

List the causes of vitamin B12 deficiency

Answer 6

•Malabsorbtion
•Inability to split cobalamin from food
•Gastric atrophy (chronic helicobacter pylori)
•Small bowel inflammatory disease

Question 7

What are the ocular manifestations of vitamin B12 deficiency?

Answer 7

Ocular features
•Reduced visual acuity (gradual and symmetric)
•Optic neuropathy* -colour vision
•Optic atrophy – long term
•Visual field defects – central, caecocentral
•Neurological symptoms – spastic paraparesis, ataxia, loss of vibratory and positional sensation.

Question 8

How would you manage a patient that has vitamin B12 deficiency?

Answer 8

Treatment
•IM 1000mcg of vitamin B12 – initially daily for 3 days and monthly thereafter for life

Question 9

List the causes of folate deficiency

Answer 9

•Inadequate intake
•Impaired absorption
•Increase in demand

Question 10

What is the outcome of folate deficiency?

Answer 10

Megaloblastic anemia

Question 11

What are the ocular manifestations of folate deficiency and how would you treat?

Answer 11

Ocular features
•Reduced visual acuity (gradual and symmetric)
•Optic neuropathy* -colour vision
•Optic atrophy – long term
•Visual field defects – central, caecocentral

Treatment
•Oral folate 400-1000μg daily

Question 12

What is the deficiency of vitamin C, its ocular manifestations and how you’ll manage it?

Answer 12

DEFICIENCY
Scurvy

OCULAR MANIFESTATIONS
•Haemorrhages due to increase capillary fragility. It can be Conjunctiva, eyelids, orbit, anterior chamber, vitreous

TREATMENT
100mg qds for 10 to 14 days followed by maintenance dose 60mg daily until recommended dietary allowance of 120mg/day