Vitamins and Minerals Flashcards
What type of foods are Vitamin A found?
Brightly colored vegetables, especially carrots, peppers and tomatoes, Also found in dairy, eggs, and fish. Many foods are fortified with this.
When might Vitamin A deficiency be seen?
Rare in the U.S but may be seen in patients with malabsorption, on fad diets, and the malnourished.
Key roles of Vitamin A.
Maintains healthy epithelial structure and function; operates in the visual conductive system as part of the rods and cones.
How does Vitamin A work intracellularly?
It binds to the RXR/RAR complex, which allows it to bind to nuclear targets.
This regulates cell activity and promotes various activities that help normal function of the skin, hematopoiesis, GI tract, GU system, eyes, etc.
How is Vitamin A involved in vision?
Vitamin A derivatives make up the photosensitive chemicals of the rods and cones (rods/rhodopsin, cones/iodopsin).
Upon exposure to light, these chemicals photoisomerize and send a signal down the optic nerve.
What is the most obvious symptom of Vitamin A deficiency?
Reduced integrity of epithelial tissues throughout the body. (keratosis pilaris, bronchial obstruction, Bitot spot, diarrhea, pyuria, hematuria, xerophthalmia).
Also leads to night blindness due to loss of pigment in the rods that slows adaptation to the dark. Eventually total blindness with destruction to the RPE.
What is generally the chief complaint of a patient with Vitamin A deficiency?
Typically Bitot spot, skin changes, or reduced adaptation to dark. Others may be present as well such as chronic infections.
What is the management of Vitamin D deficiency?
Vitamin D replacement
Patient/parent education.
What are the steps for management of Vitamin A deficiency?
Vitamin A supplementation and/or increased dietary intake.
Address malabsorption in present (may need higher dose of Vitamin A).
Refer to a nutritionist; other referrals may be necessary depending on symptoms.
Follow-up to check progress.
What causes hypervitaminosis A?
Excess Vitamin A ingestion for several weeks or months.
Can also be caused by certain medications (isotretinoin).
What are the signs of hypervitaminosis A?
Non-specific: headache, irritability, vomiting, diplopia, hepatomegaly, splenomegaly.
More-specific: Increased ICP, bulging fontanelles, desquamating rash (palm/soles), cheilitis, hyperostosis.
Describe the manifestation of Vitamin D dependent Rickets, Type 1 and why.
Same symptoms of Vitamin D deficiency despite the fact that the child is getting sufficient dietary Vitamin D.
Major differential diagnosis is malabsorption (calcitriol doesn’t work to convert Vitamin D).
What is the management for hypervitaminosis A?
Withdraw source of Vitamin A.
Manage hypercalcemia w/fluids, diuretics, bisphosphonates if necessary.
If inter cranial pressure is a problem, therapeutic lumbar puncture is an option.
Patient/parent education.
Follow-up to document progress.
What is Rickets?
Impairment of bone mineralization prior to epiphyseal closure which may be due to any of a host of factors. The most common being Vitamin D deficiency or receptor mutation.
Can also be calcium and phosphate deficiency.
How is Rickets manifested?
Skeletal malformations which appear as genu varum (bowleggedness) in younger children, and genu valgum (knock-knees) in older children.
Can also be manifested as skeletal (kyphoscoliosis, lumbar lordosis, rachitic rosary, greenstick fx, metaphysical cupping, craniotabes) or dental problems, muscle weakness, and Harrison’s groove.
