Vitamin D Deficiency - Rickets Rickets in wrist

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Vitamin D Deficiency Rickets

• Fan Yang
• Associated Professor
• Pediatric Department

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Vitamin D

• Vitamin D comprises a group of sterols
• Vitamin D2 ergocalciferol
• Completely synthetic form produced by the
  irradiation of the plant steroid ergosterol
• Vitamin D3 cholecalciferol
• Produced photochemically by the action of
  sunlight or ultraviolet light from the precursor
  sterol 7-dehydrocholesterol
• Vitamin D calciferol

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VITAMIN D

• Humans animal utilize only vitamin D3 they
  can produce it inside their bodies from
  cholesterol.
• Cholesterol is converted to 7-dehydro-cholesterol
  (7DC), which is a precursor of vitamin D3.

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VITAMIN D

• Exposure to the ultraviolet rays in the sunlight
  convert 7DC to cholecalciferol.
• Vitamin D3 is metabolically inactive until it is
  hydroxylated in the kidney the liver to the
  active form 1,25 Dihydroxycholecalciferol.
• 1,25 DHC acts as a hormone rather than a
  vitamin, endocrine paracrine properties.

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Vitamin D The Sunshine Vitamin

• Not always essential
• Body can make it if exposed to enough sunlight
• Made from cholesterol in the skin

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Formation of Vitamin D

• Skin (UV light)
• 7-dehydro cholesterol ? Vitamin D3
• Ergosterol ? Vitamin D2
• Liver
• OH-group added
• 25-Hydroxy vitamin D3
• Storage form of vitamin (3 months storage in
  liver)
• Kidney
• OH-group added by 1-hydroxylase
• 1,25-dihydroxy vitamin D3
• Active form of vitamin D, a steroid hormone
• OH-group added by 24-hydroxylase
• 24,25-dihydroxy vitamin D3
• Inactive form of vitamin D, ready for excretion

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FUNCTIONS

• Calcium metabolism vitamin D enhances ca
  absorption in the gut renal tubules.

• Cell differentiation particularly of collagen
  skin epithelium

• Immunity important for Cell Mediated Immunity
  coordination of the immune response.

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Vitamin D - Functions

• Bone development
• Calcium absorption (small intestine)
• Calcium resorption (bone and kidney)
• Maintain blood calcium levels
• Phosphorus absorption (small intestine)
• Hormone
• Regulation of gene expression
• Cell growth

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Vitamin D Functions
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Vitamin D Affects Absorption of Dietary Ca

• 1,25-(OH)2 D binds to vitamin D receptor (VDR) in
  nucleus
• Increase in calbindin (Ca-binding protein)

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Vitamin D Affects Absorption of Dietary Phosphorus

• 1,25-(OH)2 D3 increases activity of alkaline
  phosphatase
• Hydrolyses phosphate ester bonds
• Releases phosphorus
• Increase in phosphate carriers

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Vitamin D deficiency
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Etiology

• 1. Lack of sunshine due to
• 1) Lack of outdoor activities
• 2) Lack of ultraviolet light in fall and
  winter
• 3) Too much cloud, dust vapour and smoke

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Etiology

• 2. Improper feeding
• 1) Inadequate intake of Vitamin D
• Breast milk 0-10IU/100ml
• Cows milk 0.3-4IU/100ml
• Egg yolk 25IU/average yolk
• Herring 1500IU/100g
• 2) Improper Ca and P ratio

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Etiology

• 3. Fast growth, increased requirement
• Relative deficiency
• 4. Diseases and drug
• Liver diseases, renal diseases
• Gastrointestinal diseases
• Antiepileptic
• Glucocorticosteroid

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GROUPS AT RISK

• Infants
• Elderly
• Dark skinned
• Covered women
• Kidney failure patients
• Patients with chronic liver disease
• Fat malabsorption disorders
• Genetic types of rickets
• Patients on anticonvulsant drugs

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Vitamin D deficiency

• Deficiency of vitamin D leads to
• Rickets in small children.
• Osteomalacia
• Osteoporosis

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Parathyroid Hormone (PTH)

• Calcium-sensor protein in the thyroid gland
• Detects low plasma calcium concentrations
• Effects of parathyroid hormone
• Urine / kidneys
• Increases calcium reabsorption
• Increases phosphorus excretion
• Stimulates 1-hydroxylase activity in the kidneys
• 25-OH D ? 1,25-(OH)2 D
• PTH required for resorption of Ca from bone
• Activates a calcium pump on the osteocytic
  membrane
• Activates osteoclasts

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Pathogenesis

• Vitamin D deficiency
• Absorption of Ca, P
• Serum Ca
• Function of Parathyroid
  

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Pathogenesis

• PTH
• High
  secretion
• P in urine
  Decalcification of old bone
• P in blood
  Ca in blood normal or low slightly
• Ca, P
  product
• 
  Rickets

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Pathogenesis

• Low secretion of PTH
• Failure of decalcification of bone
• Low serum Ca level
• Rachitic tetany

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Clinical manifestation

• Rickets is a systematic disease with skeletons
  involved most, but the nervous system, muscular
  system and other system are also involved.

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Clinical manifestation

• Early stage
• Usually begin at 3 months old
• Symptoms mental psychiatric symptoms
• Irritability, sleepless, hidrosis
• Signs occipital bald
• Laboratory findings Serum Ca, P normal or
• decreased slightly, AKP normal or elevated
  slightly,25(OH)D3 decreased
• Roentgenographic changes normal or change
  slightly

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Clinical manifestation

• Advanced stage
• On the base of early rickets, osseous changes
  become marked and motor development becomes
  delayed.
• 1. Osseous changes
• 1) Head craniotables, frontal bossing, boxlike
  appearance of skull, delayed closure of anterior
  fontanelle
• 2) Teeth delayed eruption, with abnormal
  order, defects
• 3) Chest rachitic rosary, Harrisons groove,
  pigeon chest, funnel-shaped chest, flaring of ribs

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Clinical manifestation

• 4) Spinal column scoliosis,kyphosis, and
• lordosis
• 5) Extremities bowlegs,or knock knee,
• greenstick fracture
• 6) Rachitic dwarfism
• 2. Muscular system potbelly, late in standing
  and walking
• 3. Motor development delayed
• 4. Other nervous and mental symptoms
  

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Clinical manifestation

• Laboratory findings Serum Ca and P decreased
• Ca and P
  product decreased
• AKP elevated
• Roentgenographic changes Wrist is the best site
  for
• watching the
  changes.
• Late appearance of ossification
  center
• Widening of the epiphyseal
  cartilage
• Blurring of the preparatory
  calcification line
• metaphyses like a cup
• rarefaction of the bone
• thinned cortex of the shaft of long
  bone

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Clinical manifestation

• Healing stage
• Symptoms and signs of Rickets alleviate or
  disappear by use of appropriate treatment. The
  blood chemistries become normal, except AKP may
  be slightly elevated.
• Sequelae stage
• All the clinical symptoms and signs disappear.
  Blood Chemistries and X-ray changes are
  recovered, but osseous deformities may be left.
  Usually seen in Children after 3 years old.

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Rachitic vs. normal chick
Rickets due to deficiency of vitamin D, Ca, or P
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Vitamin D Deficiency - Rickets
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Rickets in wrist - uncalcified lower ends of
bones are porous, ragged, and saucer-shaped
(A) Rickets in 3 month old infant
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(B) Healing after 28 days of treatment
(C) After 41 days of treatment
B
C
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Diagnosis

• Assessed according to the followings
• 1. History
• 2. Physical examination
• 3. Laboratory findings
• 4. Roentgenographic changes

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Differential diagnosis

• 1. Hypophosphatemic Vitamin D resistant rickets
• 2. Rickets of Vitamin D dependency
• 3. Distal renal tubular acidosis
• 4. Cretinism
• 5. Chondrodystrophy

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Treatment

• 1. Food and nursing care
• 2. Prevention of complications
• 3. Special therapy
• 1) Vitamin D therapy
• A. General method
• Vitamin D 2000-4000IU/day for 2-4
  weeks, then change to preventive dosage (400IU).
• B. A single large dose
• For severe case, or Rickets with
  complication, or those who cant bear oral
  therapy. Vitamin D3 200000-300000IU, im,
  preventive dosage will be used after 2-3 months.

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Treatment

• 2) Calcium supplementation
• only used for special cases, such as baby fed
  mainly with cereal, or infants under 3 months of
  age, and those who have already developed tetany.
  Dosage1-3 g/day.
• 3) Plastic therapy
• In children with bone deformities after 4
  years old plastic surgery may be useful.

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Prevention

• 1. Pay much attention to the health care of
  pregnant and lactating women, instruct them to
  take adequate amount of vitamin D.
• 2. Advocate sunbathing
• 3.Advocate breast feeding, give supplementary
  food on time

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Prevention

• 4. Vitamin D supplementation
• In prematures, twins and weak babies, give
  Vitamin D 800IU per day,
• For term babies and infants the demand of
  Vitamin D is 400IU per day,
• For those babies who cant maintain a daily
  supplementation, inject muscularly Vitamin D3
  10000-200000 IU.

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Prevention

• 5. Calcium supplementation
• 0.5-1gm/day, for premature, weak babies and
  babies fed mainly with cereal

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Sources of Vitamin D

• Sunlight is the most important source
• Fish liver oil
• Fish sea food (herring salmon)
• Eggs
• Plants do not contain vitamin D3

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Vitamin D - Sources

• Not found naturally in many foods
• Synthesized in body
• Plants (ergosterol)
• Sun-cured forages
• Fluid milk products are fortified with vitamin D
• Oily fish
• Egg yolk
• Butter
• Liver
• Difficult for vegetarians

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TOXICITY

• Hypervitaminosis D
• causes hypercalcemia, which manifest as
• Nausea vomiting
• Excessive thirst polyuria
• Severe itching
• Joint muscle pains
• Disorientation coma.

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Vitamin D Toxicity

• Calcification of soft tissue
• Lungs, heart, blood vessels
• Hardening of arteries (calcification)
• Hypercalcemia
• Normal is 10 mg/dl
• Excess blood calcium leads to stone formation in
  kidneys
• Lack of appetite
• Excessive thirst and urination
• Infants

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Thank You!