Calcium metabolism - i.h

2. CALCIUM METABOLISM
Presenter – Dr. Itrat Hussain
Moderator – Dr. Sanjeev Kumar

3. NORMAL VALUES
Total body calcium – 1100 g {27.5 mol / L}
99 % in bones
Plasma calcium : 9 – 11 mg / dL
{5 m Eq / L or 2.5 mmol / L}
Ionized calcium – 50 % {1.2 mmol / L}
Protein bound – 41 % {1.0 mmol / L}
Complexed with anions – 9 % {0.2 mmol / L}

4. Calcium transport in the blood
• 50% as ionised, 41% bound to protein (mainly
albumin, some globulins) and 9% bound to anions in
soluble complexes
• Ionized fraction depends on pH:
• protein binding decreases as pH decreases
pH 7. 45
pH 7.35
Alkalosis: increased calcium binding to protein;
decreased ionised fraction
Acidosis: decreased calcium binding to protein;
increased ionised fraction
Guyton & Hall Textbook of Medical physiology, 11
th
ed.; J.E.Hall; Chapter 79
Each 0.1 decrease in pH increases ionized calcium by 0.05
mmol/L

5. FUNCTIONS OF CALCIUM
Blood coagulation
Muscle contraction
Transmission of nerve impulses
Formation of skeleton ,etc.
FREE IONIZED CALCIUM

6. REQUIREMENTS :
• The Food and Nutrition Board of the National Academy of Sciences,
National Research Council, recommends daily dietary calcium
intake : -
• For newborn infants : 360 mg/day
• For children and adults : 800 mg/day
• Adolescents and pregnant : 1200 mg/day
women and lactating women

7. ABSORPTION :
• Site of Absorption : Absorption of calcium
occurs mainly from upper jejunum and
duodenum.
• The absorption is by : - i) A carrier
mediated mechanism ii) Passive diffusion
• Carrier mediated mechanism: The carrier
molecule resides in the “brush border” of
the jejunal mucosa.
• Form of Absorption : Soluble inorganic
forms are much better absorbed.

8. EFFECTS OF ALTERED CALCIUM
HYPOCALCEMIA
• Nerve and muscle cells becomes hyperexcitable.
• Increased neuronal membrane permeability to Na +
channels
HYPOCALCEMIC TETANY – latent or manifest
Calcium at 6 mg / dL --- TETANY
at 4 mg / dL --- LETHAL
Alkaline pH – tetany at higher values.

9. SIGNS OF MANIFEST TETANY
CARPOPEDAL SPASM
Obstetric hand /
• Laryngeal stridor
• Convulsions
• Visceral features like
intestinal spasm,
bronchospasm and
profuse sweating.

10. LATENT TETANY
• CHVOSTEK’S SIGN
• TROUSSEAU’S SIGN

11. CAUSES OF HYPOCALCEMIA
• HYPOPARATHYROIDISM
– POSTSURGICAL (MOST COMMON)
– AUTOIMMUNE
– PSEUDOHYPOPARATHYROIDISM (PTH RESISTANCE)
– IDIOPATHIC
• HYPOVITAMINOSIS D
– DIETARY DEFICIENCY
– RICKETS, OSTEOMALACIA
• ORGAN DYSFUNCTION
– GI MALABSORPTION, RENAL LOSS
• ENDOCRINE RESPONSE TO NON-
HYPOPARATHYROID HYPOCALCEMIA
– SECONDARY HYPERPARATHYROIDISM (2o
HPT)

12. Treatment :
• 1. Temporary measures : Injections of
soluble calcium salt. 10 ml of 10% calcium
gluconate -slow intravenous.
• 2. Long term measures – Large dose of
Vitamin D (100,000 units /day), along with
1-2 gms of calcium.
• At times it might be necessary to administer
1, 25 DHCC instead of the non-activated
form of Vitamin D because of its much
more potent and much more rapid action.

13. CALCIUM IN BONE
Two types
1. Readily exchangeable reservoir
{500 mmol of Ca2+
is exchanged}
2. Stable calcium
{7.5 mmol of Ca2+
is exchanged}

14. CALCIUM IN KIDNEYS
• 98 % - 99 % is reabsorbed
60 % in PCT
40 % in Ascending limb of LOH
Distal tubule
PARATHYROID HORMONE

15. CALCIUM IN GIT
• 30 – 80 % of ingested calcium is absorbed
• Actively transported out of the intestinal cells with
the help of
Ca 2+
dependent ATPase
• Increased plasma calcium – decreased absorption
from the gut
• Decreased by phosphates and oxalates and alkalis
• Increased by high protein diet
1,25 Vitamin D3

16. GLOMERULAR
FILTRATE
250 mmol
DIET
25mmol (1000 mg)
GIT
FECES
22.5mmol
ABSORPTION
15 mmol
SECRETION
12.5 mmol
REABSORPTION
247.5
mmol
ECF
35 mmol
URINE
2.5 mmol
BONE
EXCHANGEABLE
100 mmol
STABLE
27,200 mmol
RAPID
EXCHANGE
500 mmol
REABSORPTION
7.5 mmol

17. PHOSPHATE METABOLISM

18. NORMAL VALUES
• Total body phosphate – 500 to 800 g.
• 85 – 90 % in skeleton
• Plasma phosphate – 12 mg / dL
2/3rd
– organic
1/3rd
– inorganic {Pi}
ex. PO4
3-
, HPO4
2-
, H2PO4
2-
FUNCTIONS
ATPase , c AMP , 2-3 DPG
Phosphorylation and Dephosphorylation

19. BONE:
3 mg of PO4enters and is again reabsorbed.
KIDNEYS:
85 % - 90 % of filtered Pi is reabsorbed by
Active Transport in PCT
PTH
Overflow mechanism

20. G I T
• Absorbed in duodenum and small intestine
by Active transport and passive diffusion.
• Absorption is linear to dietary intake.
• All PO4 excreted in urine.

21. BONE PHYSIOLOGY

22. Made up of organic matrix and salts
COLLAGEN FIBERS
• 90 – 95 %
• Type 1 collagen made
up of triple helix
GROUND
SUBSTANCES
• Gelatinous substances
(ECF + proteoglycans)
Chondroitin sulphate
Hyaluranic acid
ORGANIC MATRIX

23. BONE SALTS
• Salts of calcium and phosphate.
HYDROXYAPATITE
Ca10(PO4)6. (OH)2
Ca / P ratio – 1.3 to 2.0
Other salts:
Mg2+
, Na+
, K+
ions conjugated to
bone crystals.

24. STRUCTURE OF BONE
2 types of bones
Compact or Cortical bone – 80 %
• surface to volume ratio is low
• receive nutrients by canaliculi
Trabecular or Spongy bone – 20 %
• made up of spicules or plates with high
surface to volume ratio
• receive nutrients from the ECF through
Haversian canal

26. BONE GROWTH
Fetus to adults – ENCHONDRAL BONE
FORMATION
Exception: clavicles, mandibles and certain
skull bones.
INTRAMEMBRANOUS BONE
FORMATION

27. BONE FORMATION &
RESORPTION
• Bone formation by OSTEOBLASTS
• Bone resorption by OSTEOCLASTS

28. CELLS OF BONE
• OSTEOPROGENITOR CELLS
• OSTEOBLASTS
• OSTEOCYTES
• OSTEOCLASTS

29. OSTEOBLASTS
• Modified fibroblasts developed from
mesenchymal cells
• Secrete collagen monomers and ground
substances
• Finally forms an ‘OSTEOID’
• Calcium salts are deposited in the collagen
fibers and forms hydroxyapatite crystals.

30. OSTEOCYTES
• Mature bone cells – imprisoned osteoblasts
in the lacunae of osteon.
• Sends processes throughout bone matrix
• Maintains the metabolic activity of bone
• Opens the channels for distribution of
nutrients
• Exchanges calcium between bone and ECF.

31. OSTEOCLASTS
• MEMBER OF MONOCYTE FAMILY
• Attach its ruffled border to bone via integrins in the
“sealing zone”
• Proton pumps secrete acid and acidify the isolated area
• Proteolytic enzymes breaks down the organic matrix
• Eats away the bone in 3 wks - tunnel
• Osteoblasts are activated - forms a new Haversian
canal.

33. MEASUREMENT OF BONE
TURNOVER
• THE COUPLED PROCESS OF BONE
TURNOVER CAN BE MEASURED BY:
– MARKERS OF OSTEOBLAST METABOLISM
• SERUM BONE-SPECIFIC ALKALINE PHOSPHATASE
• SERUM OSTEOCALCIN
– MARKERS OF OSTEOCLAST METABOLISM
• URINE PRODUCTS OF BONE COLLAGEN
BREAKDOWN
– HYDROXYPROLINE
– N-TELOPEPTIDES
– PYRIDINIUM CROSSLINKS

34. BONE PHYSIOLOGY, cont.
• WHEN THE COUPLED PROCESS OF BONE
TURNOVER (FORMATION AND RESORPTION) IS
SHIFTED IN FAVOR OF RESORPTION, THERE IS
RELATIVE OR NET BONE LOSS. THIS OCCURS IN
A VARIETY OF CONDITIONS:
– age
– menopause in women or hypogonadism in men
– glucocorticoid therapy
– hyperparathyroidism (primary of secondary)
– defects in organ physiology (GI, RENAL, BONE)
– others (medications, genes, comorbid conditions, etc.)

35. HORMONES INVOLVED…
1,25 Dihydrocholecalciferol
Parathyroid hormone
Calcitonoin
Miscellaneous hormones :
Glucocorticoids, Growth hormone,
Estrogen

36. VITAMIN D 3

37. 7 DEHYDROCHOLESTEROL
PREVITAMIN D3 VITAMIN D3
CHOLECACIFEEROL
25- HYDROXY CHOLECALCIFEROL
25 HYDROXYLASE LIVER
24, 25 DIHYDROXY
CHOLECALCIFEROL 1, 25 DIHYDROXY
CHOLECALCIFEROL
KIDNEY
1 α HYDROXYLASE24 α HYDROXYLASE
SUNLIGHT

38. MECHANISM OF ACTION
• 1,25 – dihydroxycholecalciferol is a steroid
compound (secosteroid)
• Acts via the steroid receptor superfamily
• Exposes the DNA – binding domain and
results in increased transcription of some
mRNAs.

39. ACTIONS OF VITAMIN D3
1. Promotes intestinal calcium absorption
BY
1. Formation of calcium binding protein
(calbindin)
2. Formation of calcium stimulated ATPase
3. Formation of alkaline phosphatase

40. 25-HYDROXYLASE

41. 2. Promotes phosphate absorption by the
intestines
• As a direct effect
• Calcium acts as a transport mediator for
phosphate.
3. Decreases renal excretion of calcium &
phosphate
• Increases reabsorption of Ca and PO4by the
renal tubules

42. 4. Increases both bone resorption and bone
mineralization
BONE RESORPTION – by stimulating PTH.
Calcitriol receptors are present in osteobasts
Receptor – calcitriol complex – stimulate osteoblasts
--- activation & differentiation of osteoclasts.
BONE MINERALIZATION – by stimulation
osteoblasts and alkaline phosphatase secretion

43. RICKETS & OSTEOMALACIA
VITAMIN D deficiency in children and adults
- defective bone mineralization and calcification
- failure to deliver adequate Ca and PO4
FEATURES:
Weakness and bowing of weight bearing bones,
dental defects and hypocalcemia.
Responsive to Vitamin D therapy.
VITAMIN D RESISTANT RICKETS:
mutations in the gene coding for the enzyme
1 α HYDROXYLASE

44. Rickety rosary

45. HYPERVITAMINOSIS D
• EXCESSIVE INTAKE OF VITAMIN D
– GENERALLY REQUIRES PRESCRIPTION STRENGTH
VITAMIN D, PARTICULARLY 1,25(OH)2D (CALCITRIOL)
• EXCESSIVE PRODUCTION OF 1,25(OH)2D
– EXTRA-RENAL 1-HYDROXYLATION OF 25(OH)VITAMIN
D BY AN ENZYME WITH 1-HYDROXYLASE ACTIVITY,
BUT WHICH IS DISTINCT FROM THE RENAL ENZYME
• USUALLY ASSOCIATED WITH GRANULOMAS
(MACROPHAGES) OR ABNORMAL LYMPHOID TISSUE (B
CELL LYMPHOMA)
• NOT REGULATED BY PTH OR CALCIUM

46. HYPERVITAMINOSIS D:
CLINICAL CHARACTERISTICS
• HYPERCALCEMIA
• SUPPRESSED PTH
• INCREASED 1,25(OH)2D
• SOURCE
– DIET?
– GRANULOMA?
• SARCOIDOSIS MOST COMMON; ALSO TB, OTHERS
– LYMPHOMA?

48. STRUCTURE
• FOUR parathyroid
glands located behind
the thyroid gland
• 6 x 3 x 2 mm
• Two types of cells
1. Chief cells
2. Oxyphil cells

49. ACTIONS OF PTH
I. Increases calcium and phosphate
absorption from the bones
II. Decreases excretion of calcium by the
kidneys
III. Increases the excretion of phosphate by
the kidneys
IV. Increases intestinal absorption of calcium
and phosphate.
INCREASED PLASMA CALCIUM

50. I. Ca & PO4 absorption from the bone
Two phases
1. Rapid phase – osteolysis by osteocytes
2. Slow phase – by osteoclasts

51. RAPID PHASE - OSTEOLYSIS
BONE
ECF
OSTEOCYTIC MEMBRANE
OCTEOCYTES
BONE FLUID
B.FL BECF O.M

52. Ca
Ca
Ca
Ca
Ca
Ca
Ca
Ca
Ca
BONEBONE FLUID
OSTEOCYTIC
MEMBRANE
ECF
PTH

53. SLOW PHASE
Done by OSTEOCLASTS…
immediate activation of existing cells
formation of new cells
Excess bone resorption
Stimulates osteoblastic activity

54. II. Excretion of calcium and phosphate...
• Decreases excretion of calcium
increases reabsorption in CD, DT
and Ascending limb of LOH
• Increases excretion of phosphate
PHOSPHATURIC ACTION
dimishes absorption in PCT

55. III. Absorption of Ca & PO4 in GIT…
Enhances absorption of both calcium and
phosphate by stimulating
1,25 – dihydroxycholecalciferol.
• cAMP mediated.
• cAMP is in plenty in osteoblasts and
osteocytes

56. Calcium homeostasis
INCREASED Ca++
C
DECREASED Ca++
C
INCREASED PARATHYROID
HORMONE SECRETION
Increased
osteoclast
activity
Sensed by Chief cells in parathyroid
gland
Increased
Vitamin D
activation
Increased bone
resorption
Increased calcium
uptake from
duodenum and
reuptake in the
nephron
Decreased calcium
uptake from
duodenum and
reuptake in the
nephron
Decreased bone
resorption
Sensed by Chief cells in parathyroid
gland
DECREASED PARATHYROID
HORMONE SECRETION
Decreased
osteoclast activity
Decreased
Vitamin D
activation
Guyton & Hall Textbook of Medical physiology, 11
th
ed.; J.E.Hall; Chapter 79

57. • Produced by the parafollicular cells / C cells
of thyroid gland.
STRUCTURE:
Molecular weight – 3500 and has 32
aminoacids.
In brain “Calcitonin gene related
polypeptide ( CGrP)” is formed.

58. • STIMULUS : Increased plasma calcium
Others: β adrenergic agonists, dopamine and
estrogen, GASTRIN, glucagon..
• ACTIONS:
Decreases absorptive action of osteoclasts
Deposits exchangeable Ca in bone salts
Decreases the formation of osteoclasts
• CLINICAL USE:
Used in the treatment of
PAGET’S DISEASE.

59. DISORDERS OF PTH
• HYPOPARATHYROIDISM
• HYPERPARATHYROIDISM
primary and secondary
• PSEUDOHYPOPARATHYROIDISM

60. HYPOPARATHYROIDISM
• Body calcium level decreases
• Osteoclasts are inactive
• Sudden removal – signs of tetany appears
• Responds to treatment with PTH or Vitamin D3
PSEUDOHYPOPARATHYROIDISM
PTH is normal
Defect is in PTH receptors
Not responsive to hormone therapy

61. PRIMARY
HYPERPARATHYROIDISM
• Tumors – adenoma of parathyroid glands
• More common in women.
• Extreme osteolytic resorption - calcium and
phosphate levels.
Bone :
Punched out cystic areas in the bone filled by osteoclasts
– osteoclast tumors
‘ osteitis fibrosa cystica’
Serum Alkaline phosphatase is elevated.

62. Hypercalcemia:
P. Calcium – 12 – 15 mg / dL
CNS depression, muscle weakness, constipation,
abdominal pain, peptic ulcer, lack of appetite etc…
Metastatic calcification:
CaHPO4 crystals are deposited in renal tubules, lung
alveoli, thyroid glands etc…
Renal stones:
Calcium phosphate and also calcium oxalate stones

63. TREATMENT OF PRIMARY
HYPERPARATHYROIDISM
• SURGICAL PARATHYROIDECTOMY IS CURATIVE
• THERE ARE NO MEDICATIONS YET AVAILABLE
TO TREAT THE DISEASE
• SOME PATIENTS CAN BE WATCHED
– NO CLINICAL CONSEQUENCES OF HYPERCALCEMIA
(FRACTURE, STONES, ETC.)
– MILD HYPERCALCEMIA
– OLDER AGE GROUPS
• AVOID DEHYDRATION
• AVOID EXCESSIVE DIETARY CALCUIM

64. SECONDARY
HYPERPARATHYROIDISM
• Increased levels of PTH is the result of
compensatory mechanism to hypocalcemia
• Due to chronic renal disease or deficiency
of Vitamin D 3

65. HYPERPARATHYROIDISM:
PRIMARY vs. SECONDARY
1o
HPT 2o
HPT
BLOOD
CALCIUM
HIGH LOW OR NORMAL
PTH LEVEL HIGH HIGH
URINARY
CALCIUM
HIGH USUALLY LOW
(EXCEPT RENAL
LEAK)
ABNORMALITY/
DYSFUNCTION
PARATHYROID(S) NON-PARATHYROID
(VITAMIN D DEFECT,
ETC.)

66. NON-HORMONAL
HYPERCALCEMIA
• MILK-ALKALI SYNDROME:
– INTAKE OF HIGH DOSES OF CALCIUM AND
ABSORBABLE ANTACID (SUCH AS NaCO3)
– RARE CAUSE OF HYPERCALCEMIA NOW
• MORE COMMONLY DESCRIBED IN EARLIER PART OF
20TH
CENTURY (NO H2 BLOCKERS OR PPI’S!!)
– MECHANISM NOT ABSOLUTELY CLEAR:
• INCREASED INTESTINAL ABSORPTION
• DECREASED RENAL CLEARANCE
– PTH SUPPRESSED, PTHrP NORMAL, 1,25(OH)2D
NORMAL

67. RENAL FAILURE-ASSOCIATED
HYPERCALCEMIA
• RENAL FAILURE MAY CAUSE EITHER HYPERCALCEMIA OR
HYPOCALCEMIA
• HYPERCALCEMIA USUALLY RESULTS FROM A
COMBINATION OF FACTORS INCLUDING DECREASED
CALCIUM CLEARANCE AND INCREASED BONE
RESORPTION, +/- GI UPTAKE
– PTH ELEVATION
– LOW ENDOGENOUS 1,25(OH)2D
• EXOGENOUS 1,25(OH)2D MAY CONTRIBUTE TO
HYPERCALCEMIA
– CALCIUM AND PHOSPHATE RENAL CLEARANCE IS
ABOLISHED, AND DIALYSIS DOES A RELATIVELY POOR JOB
AT CLEARANCE (COMPARED TO, SAY, POTASSIUM)

68. DRUG-INDUCED
HYPERCALCEMIA
• THIAZIDE DIURETIC-INDUCED
HYPERCALCEMIA:
– STIMULATE RENAL TUBULAR CALCIUM
REABSORPTION
• DECREASE URINARY LOSS OF CALCIUM
– UNCOMMON CAUSE OF HYPERCALCEMIA AT
DOSES USED TO TREAT HYPERTENSION
• MORE LIKELY IN COMBINATION WITH RENAL
DISEASE, 1o
HPT, ETC.

69. DRUG-INDUCED
HYPERCALCEMIA, cont.
• LITHIUM-INDUCED HYPERCALCEMIA:
– LITHIUM MAY BE ASSOCIATED WITH
HYPERCALCEMIA AT DOSES ROUTINELY USED
TO TREAT BIPOLAR AFFECTIVE DISORDER
(DURATION OF THERAPY IS A FACTOR)
– SHIFTS “SET POINT” FOR CALCIUM
REGULATION OF PTH SECRETION
– AUGMENTS PTH EFFECT AT TARGET TISSUES
(BONE AND KIDNEY)

70. DRUG-INDUCED
HYPERCALCEMIA, cont.
• HIGH DOSES OF VITAMIN A, OR RETINOIC
ACID-INDUCED HYPERCALCEMIA:
– VARIOUS RETINOIDS ARE USED IN TREATMENT OF
ACNE, AND CERTAIN HEMATOLOGIC MALIGNANCIES
– BIND TO RECEPTORS IN THE SUPERGENE FAMILY OF
NUCLEAR RECEPTORS WHICH INCLUDES STEROID
HORMONE, THYROID, VITAMIN D RECEPTORS, ETC.
– APPEAR TO DIRECTLY ACTIVATE OSTEOCLASTS AND
MEDIATE BONE RESORPTION
– HYPERCALCEMIA IS ASSOCIATED WITH SUPPRESSED
PTH, NORMAL PTHrP, NORMAL 1,25(OH)2D

71. Management of severe
hypercalcemia
• Rehydrate aggressively WHILE giving loop
diuretics
• Aim for a daily urine output of 4-5 litres
• If there are no kidneys to work with, go with
dialysis.
• Infusion of bisphosphonates: pamidronate,
zolendronate, etidronate…
• Takes 1-3 days to reach maximum effect
th

72. Specific strategies
in the management of hypercalcemia
• Chloroquine for sarcoidosis- reduces serum vitamin D levels
• Ketoconazole is also for sarcoidosis-induced hypercalcemia and
vitamin D intoxication
• Hydrocortisone for myeloma, granulomae, Vitamin D intoxication
th

73. OTHER HORMONES
PARATHYROID HORMONE RELATED PROTEIN
( PTHrP)
• Produced by different tissues of our body
• Binds to PTH receptors
• Marked effect on growth and development of cartilage in
utero.
• Cartilage growth is stimulated by a protein called
“Indian hedgehog”
• Other uses :
Brain – prevents excitotoxic damage
Placenta – transports calcium
• Defect in PTHrP – severe skeletal deformities.

74. GLUCOCORTICOIDS
Lowers plasma calcium by inhibiting
osteoclasts.
Over Long periods – osteoporosis
Inhibit protein synthesis in osteoblasts,thereby
synthesis of organic matrix
Inhibit absorption of Ca and Po4from the gut
and facilitate its excretion in the kidneys.

75. GROWTH HORMONE
Increases intestinal absorption of Calcium
“Positive calcium balance”
THYROID HORMONE
Hypercalcemia, Hypercalciuria and
Osteoporosis.
ESTROGENS
Prevents osteoporosis by inhibiting certain
cytokines
INSULIN
Increases bone formation

76. OSTEOPOROSIS
Diminished bone matrix due to poor
oeteoblastic activity
Causes:
1. Lack of physical stress
2. Malnutrition
3. Postmenopausal lack of estrogen
4. Old age
5. Lack of Vitamin C
6. Cushing’s syndrome
7. Reconstruction plates.

77. AKA: Albers-Schönberg Disease = Marble Bone Disease
Osteopetrosis
• Rare hereditary disorder
• There is defective osteoclast function and overgrowth of bone: which become
thick, dense and sclerotic.
• However, their increased size does not improve their strength. Instead, their
disordered architecture, results in weak and brittle bones that results in
multiple fractures with poor healing.

78. Autosomal recessive osteopetrosis
Infantile autosomal recessive osteopetrosis is the more severe form that tends to present earlier. Hence, it is
referred to as "infantile" and "malignant“, compared to the autosomal dominant osteopetrosis.
Epidemiology
The natural history of the condition means that by age 6, 70% of the affected will die.
Most of the remainder have a very poor quality of life with death resulting by the age of ≈ 10.

79. Those who survive childbirth present with :
•failure to thrive
•cranial nerve entrapment
•snuffling (nasal sinus architecture abnormalities)
•hypercalcaemia
•pancytopaenia (anaemia, leukopaenia and thrombocytopaenia)
•hepatosplenomegaly (extramedullary haemopoesis)

80. Radiographic features
Plain film
Patients generally have a weak and dense skeleton which may have multiple healed fractures.
Metaphyseal splaying may also be apparent.
•mandible : characteristic triangular opacity representing calcification within the secondary condylar cartilage
ossification center.
•defective dentition with incomplete enamel formation and denatal caries.

81. Lateral radiograph of the skull reveals diffuse thickening of the calvarium, most significant in the region of the occiput. The partially
visualized upper cervical vertebrae and maxilla are also dense and thickened.

82. Severe bilateral optic canal narrowing (arrows) in a 4-yr-old patient with complete loss of vision in the left eye and 20/80 visual acuity in the right eye.

83. Autosomal dominant osteopetrosis
The autosomal dominant type is less severe than its autosomal recessive mate. Hence, it is also given the name "benign" or "adult"
since patients survive into adulthood.
•50% patients are asymptomatic
•Recurrent fractures
•Mild anemia
•Rarely cranial nerve palsy
X-ray findings
•Diffuse osteosclerosis
•Cortical thickening with medullary encroachment
•Erlenmeyer flask deformity = clublike long bones due to lack of tubulization + flaring of ends

84. Spine radiographs reveal the classic sandwich vertebrae of osteopetrosis (red arrows). This is manifested as thickening and sclerosis of the vertebral
endplates, and of the bone adjacent to the endplates.
There is also marked thickening of the posterior vertebrae (yellow arrows), especially in the vertebral arch.

85. Generalized increased density of the bones and alternating areas of increased and
decreased density in the metaphyses (bone-within-bone appearance).

86. CONCLUSION :
• Calcium ions play an important role in
many physiological functions - bone
rigidity, permeability, muscle contraction,
blood clotting, and prevention of many
disorders. But excess of calcium is harmful
to the body. Thus calcium balance in the
body should be maintained

87. Refrences
1} Guyton and Hall Medical Physiology 13th
edition
2} Davidson’s Prnciples and Practice of Medicine,
22nd
Edition
3} Oh’s Intensive Care Manual, 7th Edition by
Bersten.

88. Thank You…..