Rickets is defined as the failure of
calcification of osteoid in the growing
it is a general disorder of metabolism affecting chiefly the
growing bones due to deficiency of the active form of
vit.D “1,25 dihydroxy vit.D” .
The essential changes of the bones are :
1. Decalcification of the normal bones.
2. Formation of imperfectly calcified bone
1. widening & enlargement of the epiphyseal end of the long
THE SKELETAL MUSCLES &THE NERVOUS
SYSTEM ARE SOMETIMETIMES AFFECTED.
THERE ARE 2 TYPES OF VIT. D:
1.D3 "CHOLICALCIFEROLE" which is of animal origin and
produced by action of the U/V on 7-dehydochlesterol in
2. D2 "ERGOSTEROLE" which is of plant origin and
produced by action of U/V on ergosterol in the plants.
The both types are biologically inactive, so they
HYDROXYLATED in the LIVER -->25 HYDROXY vit.d
then HYDROXYLATED in the KIDNEYS ---> the final active
form of vit.D 1,25 HYDROXY VIT.D which called
Vit D actions
1. Promotes ca & p absorption in small gut .
2. Increase ca & p reabsorption in the kidneys.
3. Direct effect of menirals metabolism of bones
"depositioin & resorption "
a. early symptoms "appear b/w 3-6 months " :
2.irrit. by day & sleepnessness by night.
b. advanced rickets :
delayed motor development "sitting,
standing & walking "
Normal bone growth
THERE ARE 4 ZONES :
1.ZONE OF RESTING CARTILAGE : 1 layer
2.ZONE OF PROLIFERATING CART. : 6 layers
3.zone OF PROVISSIONAL CALCIFICATION "epiphyseal line " :
the cart. cells in this layer bere mature, they containe alkaline phosphatase
release the phosphate in the matrix which already contains ca. & po4 in
solution increase production of ca. & po4 once the production
exceeds 40 precipitation of ca.phosphate in the matrix around the
cartilage cells death of the cells.
4.ZONE OF BONE FORMATION :
The layer of prov. calc. is invaded by capillaries and osteoblast which deposit a
layer of organic bone matrix "osteoid tis.“ rapidly meniralized and the
calcified cartilage ultimitly replaced by bone.
THE CHANGES IN INFANTILE RICKETS:
VIT.D DEFICIENCY decrease absorption of ca. & p from the gut
decrease ca. level in blood
mobilization of ca. & po4 from bones and decrease tubular
reabsorption of p in kidneys
normal serum ca. & low serum po4
decrease ca. available for bones
ca. & po4 will be far below 40
failure of calcification around the mature cart. cells
and osteoblasts in the ostoeid tis.
1. the mature cartilage cells will not die and the
proliferating zone will be formed of many layers and
invades the adjacent zone of of provis. calc. and hence
the irregularity of epiphseal line in the X-RAY.
2. the prov. calc. zone and newly formed ost. tis. will
failed to calcified or will calcified irregularly...
wide irregular frayed zone of non rigid tis. "
RACHITIC METAPHSIS " is produced
flaring of bone & rachitic rosary.
3. in the shaft the preformed bone is replaced by
uncalcified ost. tis. from the periosteom ...
formation of shell surrounding the shaft
soft rarified cortical bone
bone deformities & green stick fractures.
Craniotabes, Frontal and parietal bossing, flat
Rosary, Harrison’s sulcus, Pigeon chest
Widening of wrist, Marphan’s sign at ankle,
Bowing of legs, Knock knee
Hypotonia and laxity of joints
Delayed motor milestones as sitting & walking.
Flaccidity of the whole body hyperextinsibility
of joints. Smooth kyphosis in the dorso-lumber
region while sitting
it is correctable if the pt. suspended from the
The abdomen is distended “POT BELLY “ due to
hypotonia of abd. Muscles & intistine .
downward displacement of the liver & spleen due to :
1. laxity of their lig. & deformity of chest wall .
2.hypotonia of the abd. Muscles.
The X-RAYS of the wrists is best for early diagnosis an
1.The classic triad of rickets :
broadening + cupping (concave) + fraying ( irregular) of
lower ends of radius & ulna .
2.Increase distance between the distal ends of radius &
ulna and the metacarpal bones .
3.Demeniralization of the shaft “ hypodensity”
4.Fractures & deformities may be present
LOOSER’S ZONE linear partial fractures of
long bones which failed to calcify.
THE EVIDENCE OF HEALING WILL
APPEAR IN X-RAY BTWEEN THE 2ND &
3rd weeks the line preparatory
calcification indicate start of healing
Complications of rickets
TETANY : it is usually precipitated by inf. Due to
failure of compensatory mechanism.
RECURR. CHEST INF. : due to
a. chest wall deformity .
b. ass. Vit.A deficiency which is essential for integrity of epith.
Surface of the resp. mucosa.
c. defective function of immunity system “esp. T-lymph “
FRACTURES OF BONES.
DEFORMITIES OF BONES : the most
important is RACHITIC PELVIS .
Treatment of rickets
Daily administration of 1000 – 4000 units : produce
healing in 2 – 4 weeks & the healing complete in 6 – 8
alternative method of treatment :oral or IM administration
of massive dose of vit.D 600.000 IU that should not
repeated except if there is no evidence of healing in X-
the prematures in addition to vit.D also ca. & p( 60mg
elemental ca/day & 30 mg elemental p / day ).
Calcium: Early calcium (ionized fraction) will be
low; however, more often, normal at diagnosis.
Phosphorus: low for age unless recent partial
treatment or recent exposure to sunlight has
Alkaline phosphatase: Elevated
Calcidiol levels are low, and parathyroid
hormone levels are elevated.
Aminoaciduria: Occurs from the parathyroid
activity; aminoaciduria does not occur in familial
hypophosphatemia rickets (FHR).
Calcium: Increased in Jansen type
Increased in renal osteodystrophy
Normal in metaphyseal dysostosis
Low in hypophospatasia
Normal in metaphyseal dysostosis
Aminoaciduria: no in phosphate deficiency
rickets except fanconi syndrome. No in
1: Calcium deficient 2: Phosphate deficient
Lack of vit D
Lack of sunlight
Dietary deficiency Fanconi syndrome
Malabsorp of vit D Oncogenic
Hepatic disease hypophosphetemia
Vit D dependent type 1 4: Conditions mimicking rickets
3: End organ resistance to vit D Metaphyseal dysostosis
VDDR type 2 Jansen
Vitamin D dependent-caused by reduced
activity of 25 hydroxy alpha-
hydroxylase(enzyme that activates vitamin
Vitamin D deficiency- “classical rickets”
caused by low endogenous vitamin D
Vitamin D resistant- defect in tubular
reabsorption of phosphate
VITAMIN-D–DEPENDENT RICKETS, TYPE 1
Genetic deficiency (variable) in the enzyme to
convert calcidiol to calcitriol in the kidney.
Autosomal recessive, chromosome 12.
Presentation as nutritional rickets with a more
variable phosphate concentration.
Medical therapy: Treatment is calcitriol 0.5-1.5
Also respond to pharmacologic doses of vitamin
D (5000-10,000 u/d).
RECEPTOR DEFECT RICKETS
(FORMERLY VITAMIN-D–DEPENDENT RICKETS, TYPE II).
Recessively inherited lack of calcitriol receptor
Properly called vitamin-D–resistant.
50% have alopecia, which sometimes is
Hypocalcemic and usually normophosphatemic.
Several mutant forms and a wide range of
severity and of response to calcitriol therapy
including some totally resistant to therapy.
May respond to high oral calcium intake plus
Two cases (a single family in the US and
possibly 1 in Germany) have been reported
having deficiency of 25 hydroxylase.
Inheritance probably is autosomal recessive.
The clinical picture resembles nutritional rickets
with a later age of onset.
Treatment with calcidiol in physiologic amounts
is sufficient. Calcidiol is a natural metabolite of
vitamin D. It is hydroxylated once at the 25
position and is the circulating form for vitamin D
FANCONI SYNDROME AND
E.g. cystinosis and tyrosinemia,
Renal phosphate wasting along with aminoaciduria
Responsive to a combination of managing the
underlying cause when possible and to either vitamin
D or calcitriol therapy.
Several mesenchymal tumors of bone or connective
tissue (including those called nonossifying fibromas,
fibroangioma, and giant cell tumors) secrete a
phosphaturic substance (parathyroidlike protein) that
results in rickets.
Osteodystrophy (renal rickets)
In end-stage renal disease, renal 1-hydroxylase
is diminished or lost, and there is defective
excretion of phosphate.
This leads to hypocalcemia and to failure of
Only variety of rickets with a high serum
Management of these patients includes a low
phosphate intake, calcitriol
This autosomal recessive
Absence of alkaline phosphatase
Causes rickets without disturbance of
calcium and phosphate metabolism.
There is a range of clinical expression
from a severe, even lethal, form to mild
disturbance. There is currently no useful
METAPHYSEAL DYSPLASIA (SCHMID VARIETY)
genetic disorder of collagen with the gene
locus on chromosome 6.
The appearance of the metaphyses on
radiographs cannot be distinguished from
changes seen in rickets
Osteotomies, if needed, should be
deferred until growth is complete.
The AAP Committee on Environmental
Health recommends that infants less than
6 months of age avoid all sunshine
exposure (Pediatrics, 104:328- 333.1999)
AAP: Vit D Supplementation
2003 AAP Recommendation: 200 IU/day
of Vitamin D for all infants and children
beginning in the first two months of life
Knock Knees / Genu Valgum
Legs are bowed
inwards in the
Bowing occurs at or
around the knee. On
standing with knees
together, the feet are