Rickets is a childhood disorder
involving softening and
weakening of the bones.
It is primarily caused by lack of
vitamin D, calcium, or
Vitamin D is a fat-soluble vitamin that may be absorbed
from the intestines or may be produced by the skin when
the skin is exposed to sunlight (ultraviolet light of sunlight
helps the body to form vitamin D).
The absorbed vitamin D is converted into its active form to
act as a hormone to regulate calcium absorption from the
intestine and to regulate levels of calcium and phosphate in
If there is a deficiency of Vitamin D, the body is unable to
properly regulate calcium and phosphate levels. When the
blood levels of these minerals become too low, it results in
destruction of the support matrix of the bones.
In rickets, another mechanism in the body works to increase
the blood calcium level. The parathyroid gland may increase
its functioning rate to compensate for decreased levels of
calcium in the bloodstream.
To increase the level of calcium in the blood the hormone
destroys the calcium present in the bones of the body and
this results in further loss of calcium and phosphorous from
the bones. In severe cases, cysts may develop in the bones.
Environmental conditions where sunlight exposure
is limited like indoor confinement or working
indoors during daylight hours may reduce source
of vitamin D;
Inadequate daily consumption - a lack of vitamin D
in the diet, a dietary lack of calcium and
phosphorous may also play a part in nutritional
causes of rickets, have trouble digesting milk
products, people who are lactose intolerant;
Cholecalciferol (vitamin D-3) is formed in the skin from
7-dehydrotachysterol. This steroid undergoes hydroxylation in 2 steps.
Pathophysiology - Metabolism of vitamin D
• The first hydroxylation occurs at position 25 in the liver,
producing calcidiol (25-hydroxycholecalciferol), which
circulates in the plasma as the most abundant of the vitamin D
metabolites and is thought to be a good indicator of overall
vitamin D status.
Cholecalciferol (vitamin D-3) is formed in the skin from
7-dihydrotachysterol. This steroid undergoes hydroxylation in 2 steps.
• The second hydroxylation step occurs in the kidney at the 1 position,
where it undergoes hydroxylation to the active metabolite calcitriol
(1,25-dihydroxycholecalciferol - DHC). This cholecalciferol is not a
vitamin, but a hormone.
Calcitriol acts on regulation of
Calcitriol promotes absorption of calcium and
phosphorus from the intestine,
increases reabsorption of phosphate in the kidney,
acts on bone to release calcium and phosphate;
Calcitriol may also directly facilitate calcification.
Calcitriol (1,25-DHC) – acts as a hormone rather than a
vitamin, endocrine and paracrine properties
•These actions increase the concentrations of calcium
and phosphorus in extracellular fluid.
• The increase of Ca and
P in extracellular fluid,
in turn, leads to the
calcification of osteoid,
primarily at the
ends of bones but also
throughout all osteoid
in the skeleton.
• Parathyroid hormone
facilitates the 1-hydro-
xylation step in
vitamin D metabolism
In the vitamin D deficiency state,
hypocalciemia develops, which
stimulates excess parathyroid
hormone, which stimulates renal
phosphorus loss, further
reducing deposition of calcium
in the bone.
Excess parathyroid hormone
also produces changes in the
bone similar to those occurring
Early in the course of rickets, the
calcium concentration in the
After the parathyroid response, the
calcium concentration usually
returns to the reference range,
though phosphorus levels remain
Alkaline phosphatase, which is
produced by overactive osteoblast
cells, leaks to the extracellular fluids
so that its concentration rises to
anywhere from moderate elevation
to very high levels.
The history in patients with rickets may include the
The infant's gestational age, diet and degree of
sunlight exposure should be noted.
A detailed dietary history should include specifics of
vitamin D and calcium intake.
A family history of short stature, orthopedic
abnormalities, poor dentition, alopecia, parental
consanguinity may signify inherited rickets.
Rickets is a systemic disease with skeletons
involved most, but the nervous system,
muscular system and other system are also
Generalized muscular hypotonia is observed in the most
patients with clinical signs of rickets.
Craniotabes manifests early in infants, although this
feature may be normal in infants, especially for those
• If rickets occurs at a later age,
thickening of the skull
develops. This produces
frontal bossing and delays
the closure of the anterior
including Bow legs,
Forward projection of
the breastbone -
pigeon chest or pectus
"Bumps" in the rib
cage (rachitic rosary)
and asymmetrical or
In the chest, knobby
deformities results in the
rachitic rosary along the
The weakened ribs
pulled by muscles also
produce flaring over the
diaphragm, which is
known as Harrison sulcus.
The sternum may be
pulled into a pigeon-chest
The ends of the long bones demonstrate that same
knobby thickening. At the ankle, palpation of the tibial
of a double
Increased tendency toward
bone fractures. Because the
softened long bones may
bend, they may fracture
one side of the cortex
In the long bones, laying
down of uncalcified osteoid
at the metaphyses leads to
spreading of those areas,
deformity (cupping and
fraying of the metaphyses).
(spine curves abnormally,
including scoliosis or
In more severe instances
in children older than 2
years, vertebral softening
Pain in the bones of Arms, Legs, Spine, Pelvis.
Delayed formation of teeth
Defects in the structure of teeth
Holes in the enamel
Increased incidence of cavities in the teeth (dental caries)
Decreased muscle tone (loss of muscle
Short stature (adults less than 5 feet tall)
In children with rickets,
complete physical and
dental examinations should
be performed. The entire
skeletal system must be
palpated to search for
tenderness and bony
Rickets should be
suspected in older
bowlegged children and in
cases associated with
asymmetry, pain, or
progression in severity. a
.Gait disturbances and neurologic abnormalities (such as
hyperreflexia) in all children should be
. The review of systems should focus on growth and
orthopedic concerns and signs and symptoms of
hypocalcemia, such as muscle cramps, numbness,
paresthesias, tetany and seizures.
Laboratory investigation may include:
serum levels of calcium (total and ionized with
alkaline phosphatase (ALP)
urine studies include urinalysis and levels of
urinary calcium and phosphorus.
in serum calcium,
The most common laboratory findings in
nutritional rickets are:
levels are elevated.
Early on in the course of rickets, the calcium (ionized fraction)
is low; however it is often within the reference range at the
time of diagnosis as parathyroid hormone levels increase.
Calcidiol (25-hydroxy vitamin D) levels are low, and
parathyroid hormone levels are elevated; however,
determining calcidiol and parathyroid hormone levels is
typically not necessary.
Calcitriol levels may be normal or elevated because of
increased parathyroid activity.
The phosphorus level is invariably low for age.
Alkaline phospohatase levels are elevated.
A generalized aminoaciduria occurs from the parathyroid
activity; aminoaciduria does not occur in familial
hypophosphatemia rickets (FHR).
Classic radiographic findings
widening of the distal epiphysis,
fraying and cupping of the
metaphysis, and angular
deformities of the arm and leg
Classic radiographic findings include
Anteroposterior and lateral radiographs of the wrist of an 8-year-
old boy with rickets demonstrates cupping and fraying of the
Rickets in wrist - uncalcified lower ends of bones
are porous, ragged, and saucer-shaped
(A) Rickets in 3 month old infant
(B) Healing after 28 days of
(C) After 41 days of
Radiographic image of wrist and
forearm showing pathologic
fractures of radius and ulna with
rachitic changes of distal end of
radius and ulna.
Usually begin at 3 months old
Symptoms: mental psychiatric symptoms
Signs: occipital bald
Laboratory findings: Serum Ca, P normal or
decreased slightly, ALP normal or elevated
slightly, 25(OH)D3 decreased
X-ray changes: normal or slightly changed
On the basis of early rickets, osseous changes
become marked and motor development becomes
1. Osseous changes:
1) Head: craniotabes, frontal bossing, boxlike
appearance of skull, delayed closure of anterior
2) Teeth: delayed dentition with abnormal order,
3) Chest: rachitic rosary, Harrison’s groove, pigeon
chest, funnel-shaped chest, flaring of ribs
4) Spinal column: scoliosis, kyphosis, lordosis
5) Extremities: bowlegs, knock knee,
6) Rachitic dwarfism
2. Muscular system: potbelly, late in standing and
3. Motor development: delayed
4. Other nervous and mental symptoms
Serum Ca and P decreased
Wrist is the best site for watching the changes
Widening of the epiphyseal cartilage
Blurring of the cup-shape metaphyses of long bone
Symptoms and signs of Rickets alleviate or
disappear by use of appropriate treatment.
The blood investigations become normal, except
ALP, that may be slightly elevated.
All the clinical symptoms and signs disappear.
Blood investigations and X-ray changes are
recovered, but osseous deformities may be left.
Usually seen in children after 3 years old.
I Mild form: small changes of nervous system,
changes of one part of the skeleton;
II Moderate form: changes of all organs and
systems, changes of two parts of the skeleton;
III Severe form: damaging function of all
organs and systems, changes of three parts of
Types of Rickets
Nutritional rickets results from inadequate
sunlight exposure or inadequate intake of
dietary vitamin D, calcium, or phosphorus.
Vitamin D dependent
Vitamin D-dependent rickets, type I is secondary to a
defect in the gene that codes for the production of renal
Vitamin D-dependent rickets, type II is a rare autosomal
disorder caused by mutations in the vitamin D receptor.
Type II does not respond to vitamin D treatment;
elevated levels of circulating calcitriol differentiate this
type from type I.
Vitamin D resistant
Rickets refractory to vitamin D treatment may be caused
by the most common heritable form, known as vitamin
D-resistant rickets or familial hypophosphatemic rickets.
Because of mutations of the phosphate-regulating gene
on the X chromosome, renal wasting of phosphorus at
the proximal tubule level results in hypophosphatemia.
Normal levels of calcitriol are found in this disorder.
Other Conditions That Can Cause Rickets
Diseases of organs associated with vitamin D and calcium
Liver and biliary tract disease
Cystic fibrosis (rare)
Assessed according to the followings:
2. Physical examination
3. Laboratory findings
4. X-ray changes
The replacement of Vitamin D may correct rickets using
these methods of ultraviolet light and medicine. Rickets
heals promptly with 4000 IU of oral vitamin D per day
administered for approximately one month.
Parents are instructed to take their infants outdoors for
approximately 20 minutes per day with their faces
exposed. Children should also be encouraged to play
Foods that are good sources of vitamin D include cod
liver oil, egg yolks, butter and oily fish. Some foods,
including milk and breakfast cereals, are also fortified
with synthetic vitamin D.
1. Special therapy: Vitamin D therapy
A. General method: Vitamin D 2000-4000 IU/day
for 2-4 weeks, then change to
preventive dosage – 400 IU.
B. A single large dose: For severe case, or Rickets with
complication, or those who can’t bear oral therapy.
Vitamin D3 200000 – 300000 IU, im,
preventive dosage will be used after 2-3 months.
4. Calcium supplementation: Dosage: 1-3 g/day
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
5. Plastic surgery:
In children with bone deformities after 4 years
old plastic surgery may be useful.
Splints-for correction of deformities
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
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 can’t maintain a daily
supplementation, inject muscularly
Vitamin D3 100000-200000 IU.
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