METABOLIC
DISEASES OF
BONE
By Syeda Batul Fatima
Outline
RICKETS
SCURVY
HYPERPARATHYROIDISM
GIGANTISM & ACROMEGALY
FLUOROSIS
Metabolic bone diseases describes a
group of disorders due to abnormalities
of formation (bone morphology) and
metabolism of bone (functions) .
INTRODUCTION
OR
Any systemic condition that results in
reduced bone strength, altered
mineralization or composition.
Rickets
Rickets is the softening and weakening
of bones in children, usually because of
an extreme and prolonged vitamin D
deficiency.
Rickets
Causes defective calcification & development of the skeleton
Onset usually in infancy
Its adult counterpart is osteomalacia
The main defects are broadening of the growing ends of bones &
prominent costochondral junctions due to the epiphyseal defects.
Overgrowth of cartilage (as shown) causes the
epiphyseal plate to be broad, thick and irregular, and
the ends of the bone become splayed. The growing
end of the bone is ill-defined and calcification
defective.
Rickets
Typical changes in the skull are
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wide fontanelles
bossing of the frontal and parietal eminences
thinning of the back of the skull
Dental effects/Oral manifestations
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Occur in the most severe cases
Hypocalcification of dentine, with a wide band
of predentine & excessive interglobular
spaces
Enamel hypoplasia
Eruption of teeth may also be delayed in such
cases
Rickets
Causes
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In developing countries is usually due to
deficiency of dietary calcium
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Cereal & wholemeal grains containing phytates
which impairs calcium absorption
Rare in developed countries; caused by
deficiency of vitamin D, either in the diet or
through lack of exposure to sunlight
Renal rickets; excess mineral excretion in
chronic renal diseases; include renal
tubular acidosis, hypophosphatemic rickets
& defects in vitamin D metabolism in the
kidney
Rickets
Treatment
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Vitamin D.
Adequate dietary Calcium & phosphorus
provided by milk, formula & other dairy
products; or added to vitamin D
prescriptions
Symptomatic hypocalcemia need IV
CaCl as 20mg/kg or Ca gluconate as 100
mg/kg as a bolus, followed by oral
calcium tapered over 2-6 weeks.
Health education
Treatment of the cause if possible
Rickets
Vitamin D resistant rickets
This condition caused by genetic failure of reabsorption of
phosphate in the kidney is associated with characteristic dental
defects
Scurvy
Prolonged deficiency of vitamin C may
result in scurvy.
Scurvy
It is characterized by:
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Weakened blood vessels particularly microvessels
having least muscular supports.
Defective synthesis of osteoid which is derivative of
collagen.
Impaired wound healing.
Pathogenesis of Scurvy
There is defective formation of collagen in connective tissues
because of failure of hydroxylation of proline to
hydroxyproline which is a characteristic amino acid of
collagen.
There is also:
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Increase permeability of capillary (hemorrhage).
Anemia due to erythropoiesis and defective collagen
formation.
Oral manifestations of
scurvy & Management
It occurs chiefly in gingival and periodontal region.
Interdental and marginal gingiva is bright red, swollen, smooth,
shiny surface producing an appearance known as scurvy bud.
In fully developed scurvy, the gingiva becomes boggy, ulcerated and
bleeds easily. These types of gingival lesion are termed as scorbutic
gingivitis.
Color changes to violaceous red.
Typical fetid breath of the patient with fusospirochetal stomatitis.
In severe cases, hemorrhage and swelling of periodontal ligament
membrane occurs followed by loss of bone and loosening of teeth
which are exfoliated.
Management; Vitamin C 250 mg 3 times daily can be given.
Hyperparathyroidism
It is an endocrine disorder in which there
is an excess of circulating parathyroid
hormone. Excess PTH stimulates
osteoclast to mobilize calcium from
skeleton leading to hypercalcemia in
addition to PTH increased renal tubular
reabsorption of calcium.
Clinical features of
hyperparathyroidism
Age and sex distribution: Female to male ratio is
3:1.
Mainly in 30 to 60 years of age.
Classic triad: It has classic triad of stones, bones and
abdominal organs.
1)
2)
3)
Stones: Renal calculi are common due to
elevated level of serum calcium. Metastatic
calcification is seen.
Bones: There are variety of osseous changes
seen in bones. There is also bone and joint
pain.
Abdominal organs: There is tendency for the
development of duodenal ulcers.
There is gradual loosening drifting and loss of
teeth, malocclusion.
There is pathological fracture of bone.
Cystic lesion involving jaws are seen over 10
percent of cases.
Oral manifestations of
Hyperparathyroidism
Brown tumor is present intraorally.
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Dental Radiograph in
hyperparathyroidism
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Reduced bone density,
Loss of trabecular pattern and lamina dura
around the teeth.
In severe disease there is development of
one or
More brown tumours in the jaws which
appear as unilocular or multilocular cysts
There is diffuse mandibular enlargement in
hyperparathyroidism secondary to renal
disease
Pathological fractures
There is loss of lamina dura around the roots, loss of
trabeculae centrally and coarsening of the
trabecular pattern elsewhere.
Serum alkaline phosphatase and serum calcium
level is increased. Decreased blood phosphorus
level. Increase in circulating hormone demonstrated
by radioisotope studies.
Diagnosis &
Treatment
Cinacalcet is now a day use in management of
overproduction of parathormone associated with
secondary hyperparathyroidism. This is
calcimimetic agent that sensitize the calcium
receptor of the parathyroid cells to extracellular
calcium causing the cell to reduce output of
parathormone.
Gigantism: If the increase occurs before
the epiphysis of the long bone are closed.
Acromegaly: If the increase occurs later in
life after epiphysis closure.
Gigantism &
Acromegaly
Gigantism
Generalized overgrowth of most tissue in childhood occurs. Most of the
soft tissue and bones respond to the excess hormone by enlarging.
Symptoms:
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Height 7 to 8 feet
Later in life, may show genital underdevelopment
Excessive perspiration & complain of headache, lassitude, fatigue,
muscle & joints pain and hot flashes
Increase in size of calvarium
Gigantism
Signs:
Pituitary tumors may also induce deficiency of other
pituitary hormones causing signs of hypogonadism
including decreased libido and menstrual problems in
women.
This disease is caused by prolonged and excessive
secretion of growth hormone, usually due to a secreting
adenoma of the anterior lobe of the pituitary developing
after the epiphyses have closed.
Acromegaly
Bone overgrowth and thickening of the soft tissue cause a
characteristic coarsening of facial features termed
acromegaly.
It is more common in males and occurs most frequently in
3rd decade.
Acromegaly
Symptoms
Hand and feet become large, with clubbing of the toes and
fingers due to enlargement of the tufts of the terminal
phalanges.
There is temporal headache, photophobia & reduction in
vision.
Ribs also increase in size.
Hypertrophy of soft palatal tissue may cause or
accentuate sleep apnea.
Acromegaly
Oral Manifestations
The palatal vault is usually flattened and the tongue
increase in size and may cause crenation on its lateral
border.
Teeth are proportional to the size of jaw & the rest of the
body and root may be longer than normal
The teeth become spaced
Class III malocclusion
Acromegaly
Diagnosis
Laboratory Findings
It can be made from the characteristic clinical and
radiographic findings. Growth hormone
concentration can be measured by
radioimmunoassay technique.
Measurement of serum growth hormone level
should be done. This should be done after giving
patient a measured quantity of glucose. Normally,
this glucose challenge will reduce the production
of growth hormone.
Radiological Features
It shows enlarge sella as a results presence of
pituitary adenoma. MRI will diagnose pituitary
adenoma.
Management
Trans-sphenoidal surgery may result in cure of
GH excess
Octreotide, pegvisomant & dopamine
antagonists.
Fluorosis
It is a cosmetic condition that occurs
during first eight years of life.
Also termed as mottled enamel is an
extremely common disorder, characterized
by hypomineralization of tooth enamel
caused by ingestion of excessive fluoride
during enamel formation.
Causes of fluorosis
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Excess fluoridation of drinking water
Ingestion of fluoride toothpaste
Overuse of Fluoride tablets
Consumption of processed food made
with fluoridated water
Mechanism of action in fluorosis
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Structurally, an increase in fluoride intake results in an
increase in degree & extent of porosity of enamel.
Enamel changes described may be a result of fluoride
damage of secretory ameloblast.
There can either be due to fluoride induce change in
compositon of enamel matrix or be a result of
disturbance of the cellular processes during enamel
maturation.
Signs & Symptoms of fluorosis
● Chalk like discoloration of teeth with
white spot or lines on tooth enamel
● In more severe cases, the affected area
have yellow or brown discoloration.
● In extreme forms, fluorosis may result in
pitted tooth surface
Classification of
fluorosis
1.
2.
3.
4.
5.
6.
Normal
Questionable
Very mild
Mild
Moderate
Severe
1.
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Normal
Smooth
Glossy
Pale
Creamy white
translucent surface
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Questionable
Ranging from few white
flecks to occassional
white spot
Very mild
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Small opaque paper
white area scattered
over the tooth but not
involving as much as 25
% of tooth surface
Mild
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The white opaque
areas in the enamel of
the tooth are more
extensive but do not
involve as much as
50% of the tooth
Moderate
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All enamel surface of
teeth are affected
and the surface
subject to attrition
show wear.
Brown stain is
frequently a
disfiguring feature
Severe
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All enamel surfaces are affected
discrete or confluent pitting .
Brown stains are widespread
and teeth often present a
corroded like appearance.
Prevention
of fluorosis
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To prevent fluorosis , fluoridation of drinking
water should not exceed normal range (Normal
range : 0.7 to 1.2 ppm)
Fluoride supplement should only be prescribed
for children living in non fluoridated water
supply areas
Use only acceptable amount of toothpaste for
children under 6 year (pea size)
It is important to teach the child to spit out the
toothpaste after brushing instead of swallowing
Treatment of fluorosis
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Microabrasion : (Conservative removal of outer layer of enamel)
Followed by tooth whitening can make the brown discoloration
less apparent
Bonding: coats the teeth with hard resin that bonds to the
enamel.
Veneers: These are the customized shells that cover the front of
teeth to improve the appearance.
References
1. Textbook of Oral
Pathology
2. Soames’ Southam’s Oral
Pathology