Pediatrics Dr. Nawal
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Rickets
disease of growing bone( fusion of the epiphyses) due to unmineralized matrix
at the growth plates. Because growth plate cartilage and osteoid continue to
expand, but mineralization is inadequate, the growth plate thickens, increase in
the circumference of the growth plate and the metaphysis.
Rickets, principally due to vitamin D deficiency
Causes of Rickets
VITAMIN D DISORDERS
Nutritional vitamin D deficiency
Congenital vitamin D deficiency
Secondary vitamin D deficiency
Malabsorption
Increased degradation
Decreased liver 25-hydroxylase
Vitamin D–dependent rickets type 1
Vitamin D–dependent rickets type 2
Chronic renal failure
CALCIUM DEFICIENCY
Premature infants (rickets of prematurity
Low Diet intake
Malabsorption
Primary disease
Dietary inhibitors of calcium absorption
PHOSPHORUS DEFICIENCY
Inadequate intake
Premature infants (rickets of prematurity).
Aluminum-containing antacids
RENAL LOSSES
Fanconi syndrome
RTA
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Clinical Features
GENERAL
Failure to thrive
Listlessness
Protuding abdomen
Fractures
Muscle weakness (especially proximal)
HEAD
Craniotabes
Frontal bossing
Delayed fontanelle closure
Delayed dentition; caries
Craniosynostosis
CHEST
Rachitic rosary
Harrison groove
Respiratory
infections and
atelectasis
BACK
Scoliosis
Kyphosis
Lordosis
HYPOCALCEMIC
SYMPTOMS
Tetany
Seizures
Stridor due to
laryngeal spasm
EXTREMITIES
Enlargement of wrists and ankles
Valgus or varus deformities
Anterior bowing of the tibia and femur
Coxa vara
Leg pain
Radiology
radiographs of the wrist: thickening of the growth plate. The edge of the
metaphysis loses its sharp border ( fraying).
the edge of the metaphysis changes to concave surface ( cupping) which is seen
at the distal ends of the radius, ulna and fibula.
widening of the distal end of the metaphysis.
coarse trabeculation of the diaphysis and generalized rarefaction
Pediatrics Dr. Nawal
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laboratory tests
-serum calcium N, low.
-phosphorus low.
-alkaline phosphatase high
-parathyroid hormone (PTH) high
-25-hydroxyvitamin D , low
-1,25-dihydroxyvitamin D3 low, N, H.
-creatinine; and electrolytes.
-Urinalysis:glycosuria and aminoaciduria(Fanconi syndrome).
-Evaluation of urinary excretion of calcium (24 hr collection for calcium or
calcium-creatinine ratio) is helpful if hereditary hypophosphatemic rickets with
hypercalciuria or Fanconi syndrome .
-
Direct measurement of other fat-soluble vitamins if malabsorption is a consideration
NUTRITIONAL VITAMIN D DEFICIENCY
Etiology
poor intake and inadequate cutaneous synthesis.
-Transplacental transport of vitamin D, mostly 25-D(1st 2 mo of life)
-feeding:- formula-fed ( adequate vitamin D).
Breast-fed infants,(low vitamin D),
rely on cutaneous synthesis or vitamin supplements.
Cutaneous synthesis can be limited due to:-
1. ineffectiveness of the winter sun in stimulating vitamin D synthesis.
2. avoidance of sunlight(cancer, neighborhood safety,cultural practices.
3. decreased cutaneous synthesis(dark skin)
Treatment
1-stoss therapy, 300,000–600,000 IU of vitamin D orally or intramuscularly
as 2–4 doses over 1day
2-The alternative is daily, high-dose vitamin D, from 2,000–5,000 IU/day
over 4–6 wk.
-followed by daily vitamin D intake of 400 IU/day, given as a multivitamin.
-adequate dietary calcium and phosphorus(milk, formula, and other dairy
products
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symptomatic hypocalcemia
intravenous calcium followed by oral calcium supplements, tapered over 2–6 wk
in children who receive adequate dietary calcium.
Transient use of intravenous or oral 1,25-D (calcitriol) is often helpful in
reversing hypocalcemia in doses 0.05 μmg/kg/day.
Prognosis
Most children have an excellent response to treat. radiologic healing occurring
within a few months. Laboratory test results should normalize rapidly. Many
bone malformations improve dramatically. severe disease may cause
permanent deformities & functional problems. Short stature does not resolve in
some children. Rarely, orthopedic intervention
Prevention
breast-fed child : by universal administration of a daily multivitamin containing
200–400 IU of vitamin D .
For other children, the diet should be reviewed to ensure that there is a source
of vitamin D.