Calcium

1. CALCIUM METABOLISM
RICKETS
PRESENTED BY Dr. HARSHITH B
MODERATOR- Dr.GOPINATH .K. M
PROFESSOR,
Department of Orthopedic
RRMCH, Bangalore

2. CALCIUM METABOLISM
 INTRODUCTION
 SOURCES
 DISTRIBUTION
 ABSORPTION
 REGULATION
 ROLE OF CALCIUM IN BONE
MINERALIZATION

4. INTRODUCTION
 Most abundant mineral in the human body
 It is deposited in either cortical or trabecular
bone.
 It has a twin role of structural and metabolic
importance.
 Total calcium content of body is 1 kg – 2kg

5.  Only one gram is found in ECF and plasma and
remainder is in the skeleton.
 Provides bone its hardness and strength.
 Helps in blood coagulation, neuromuscular
excitability, enzyme actions- insulin, parathyroid
hormone, calcitonin, vasopressin.

7. Dietary requirement for elemental calcium
 Approximately 600 mg/day for children.
 Approximately 1300 mg/day for adolescents and
young adults (ages 10–25 years).
 750 mg/day for adults ages 25–50 years.
 1200–1500 for adults over age 50 years.

8.  1500 mg/day for pregnant women
 2000 mg/day for lactating women
 1500 mg/day for postmenopausal women and for
the patient with a healing fracture in a long bone

9. CALCIUM IN PLASMA &
INTERSTITIAL FLUID

10.  Bone mineral is constantly reabsorbed and
deposited (500 mg – in & out)
 All plasma calcium exchanges with bone calcium
every 20 minutes
 Sulkowitch test for calcium in urine is important
tool for diagnosis of calcium stores

11. FACTORS INCREASING
CALCIUM ABSORPTION
•VITAMIN D
•PARATHYROID HORMONE
•ACIDIC ENVIRONMENT IN
STOMACH
•MILK LACTOSE
•EXERCISE
• PROTEIN RICH DIET
FACTORS
DECREASING CALCIUM
ABSORPTION
•EXCESS PHOSPHORUS
•STRESS
•CAFFINE
•LACK OF EXERCISE
•VITAMIN D DEFICIENCY
•CALCITONIN

12. ABSORPTION
Average diet – 1000mg / day
 1/3 rd calcium in diet is absorbed as calcium
phosphate, carbonate & tartarate
 Maximum – children & pregnant women
 Calcium absorption occurs by
Active transport(duodenum/jejunum)
Passive diffusion(ileum)

13. Interactions
 Phosphate : Calcium excretion in the urine.
 Caffeine: urinary and fecal excretion of calcium.
 Sodium: sodium intake, loss of calcium in urine.
 Iron: calcium have inhibitory effects on iron
absorption .

14. CALCITONIN
 The major stimulus of calcitionin secretion is a
rise in plasma ca2+ levels.
 Calcitionin is a physiological antagonist to PTH
with regards to ca2+ homeostasis.
 Calcitonin acts to decrease plasma ca2+ level

15. CALCITONIN
 While PTH and vitamin D act to increase plasma
ca2+ only calcitonin causes a decrease in plasma
ca2+.
 Promotes deposite of ca2+ into bone (inhibits
osteoclast).
 Calcitonin is syntesized and secreted by the
parafollicular cells of the thyroid gland.

16. Parathyroid Hormone
 Increases ca2+ in blood
 Increases ca2+ resorption from the bone
 Stimulates osteoclast.
 Increases number of osteoclasts.
 Increases ca2+ resorption from nephron
 Control of secretion:
Necessary for fine control of ca2+ plasma levels

17. Parathyroid Hormone
 PTH is synthesized and secreted by the
parathyroid gland while lie posterior to the thyroid
glands.
 The chief cells in the parathyroid gland are the
principal site of PTH synthesis.
 It is the Major of ca homeostasis in humans.

18. Regulation of PTH
 The dominant regulator of PTH is plasma ca2+.
 Secretion of PTH is inversely related to ca2+.
 Maximum secretion of PTH occurs at plasma
ca2+ below 3.5 mg/dl.
 At Ca2+ above 5.5 mg/dl, PTH Secretion is
maximally inhibited.

19. Regulation of PTH
 When ca2+ falls, Camp rises and PTH is
secreted.
 1,25-(OH)2-D inhibits PTH gene expression,
providing another level of feed back control of
PTH.
 Despite close connection between ca2+ and po4,
no direct control of PTH is excreted by phosphate
levels.

22. Bone cells

25. Important causes of
hypocalcemia
 Hypoparathyroidism
 Secondaries in the bone
 Sarcoidosis
 Multiple myeloma
 Hyperproteinemia
 Vitamin D intoxication
 Production of PTH like hormone by neoplasm of
ovary, kidney, lung, etc.

26. Clinical features of
hypocalcemia
 Enhanced neuromuscular irritability
 Neurologic features such as tingling, tetany,
numbness (fingers and toes),muscle cramps
 Chvostek’s sign
 Carpal spasm may be induced by inflation of a
blood pressure cuff to 20 mmHg above the
patient’s systolic blood pressure for 3 min
(Trousseau’s sign).
 prolongation of the QT interval

27. CHEVSTOCK SIGN

28. Trousseau’s sign

30. Important causes of
hypercalcemia
 Hyperparathyroidism
 Chronic renal insufficiency
 Rickets
 Osteomalacia
 Nephrosis
 Malabsorption syndrome
 Celiac disease
 Sprue

31. VITAMIN D

32. VITAMIN D
 It is a fat soluble vitamin synthesized in the body
 1 billion people are suffering from vitamin d
deficiency
 96.7% asian – indian population have vitamin d
deficiency
 It resembles sterols like structure & functions like
hormone

34. PLANT
SOURCE
ANIMAL
SOURC
E

35. REQUIREMENTS OF VITAMIN
D
 CHILDREN – 400 IU /DAY
 ADULTS – 200 IU /DAY
 PREGNANT WOMAN – 10 microgram/day
 >60 years age(males & females) – 600 IU/day

36. THE FUNCTIONS OF VITAMIN
D
 Maintains adequate levels of the calcium and
phosphorus
 Support metabolic functions
 Bone mineralisation
 Neuromuscular transmissions

37. SYNTHESIS OF VITAMIN D

38. 7 DEHYDROCHLESTEROL
CONVERSION INTO VITAMIN D

39. VITAMIN D BINDING PROTIEN
 Liver
 Synthesized by – hepatic parenchymal cells
 Multifunctional protien found in the plasma
 Glycosylated alpha globulin component
 Chromosome 4 gc gene
 Binds to cholcalciferol and calcitriol
 Acts as transporter

40. IN HEPATIC PARENCHYMAL
CELLS
VITAMIN D3
25 HYDROXYLASE
ENZYME
25-

41. 25 HYDROXYCHOLECALCIFEROL
 Also known as calcidiol
 Major circulating and storage form
 95% stores in parenchymal cells in mitochondria
 5% circulates in the blood bound to the albumin

42. IN KIDNEY
25
HYDROXYCHOLECALCIFEROL
ALPHA 1
HYDROXYLASE
1,25 – DIHYDROXYVITAMIN D

43. LOW SERUM CALCIUM
STIMULATE SECRETION PTH
SECRETES CY27B AT PCT LEVEL
ACTIVATES ALPHA 1 HYDROXYLASE
SECRETION

44. DOWN REGULATION OF VITAMIN D
INCREASE IN 1,25 DIHYDROXY VITAMIN D
VITAMIN D 24 HYDROXYLASE SYNTHESIS
1. REDUCE ALPHA 1 HYDROXYLASE SYNTHESIS
2. INACTIVATES OTHER METABOLITES OF VIT D

45. METABOLISM

46. ACTIONS OF VITAMIN D

47. • Maintenance of serum calcium
and serum phosphorus
• kidney - renal tubular Reabsorption of
phosphate
• on parathyroid- supression of PTH secretion
• Mineralization of the bone
• Intestine absorption of calcium

48. DEFICIENCYOFVITAMIND
 DEFICIENT PRODUCTION IN THE SKIN
 LACK OF THE DIETARY INTAKE
 ACCELERATED LOSS OF VIT-D
 IMPAIRED VITAMIN D ACTION
 BIOLOGICAL EFFECTS 1,25,(OH)2D
 INTESTINE MALABSORPTION
 INTESTINAL BY-PASS SURGERY
 DRUGS

50. VITAMIN D LEVEL FALLS
REDUCTION OF CALCIUM ABSORPTION FROM THE GUT
ACTIVATES SECTRETION OF PTH
RESTORE CALCIUM LEVELS BY STIMULATION 1,25(OH)2D
1. REDUCE RENAL CALCIUM EXCRETION
2. INCREASE BONE RESORPTION

51. IN PROLONGED CASES
RESERVES –DEPLETED
HYPOCALCEMIA
DEMINERALIZATION OF SKELETON
RICKETS AND OSTEOMALACIA

52. RICKETS
 It is disease of infancy and childhood due to
insufficiency of calcium and clinically characterized
by softened and deformed bones
 Most common metabolic disease
 Basic pathology-’poor mineralization’
 Occurs before epiphyseal fusion

53. ETIOLOGY
 Vitamin D deficiency
 Intestinal diseases such as steatorrhea , celiac
disease
 Antiepileptic drugs
 Winter season in non tropical regions

54. TYPES OF RICKETS
VITAMIN D DEFICIENCY RICKETS
VITAMIN D RESISTANT RICKETS
 Familial hypophosphotemia rickets
 Renal tubular acidosis
RENAL OSTEODYSTROPHY (CKD)

56. PATHOLOGY
 Active stage
 Healing stage

57. PATHOLOGICAL CHANGES
 Abnormal overgrowth of fibroblasts
 Defective microvasculature
 Overgrowth of epiphyseal cartilage
 Deformity of bones due to loss structural rigidity

58. CLINICAL
FEATURES

59.  Abdomen protruberent
 Bowing of weight bearing bones

60. Costochondral junction prominence
RACHITIC ROSARY
Overgrowth of cartilage
or osteoid tissue
Costochondral junction
Deformity of the chest
RACHITIC ROSARY

61. Cranoitabes
FRONTAL BOSSING
Excess osteoid
deposition
Square shaped
head
Frontal bossing

62. CRANIOTABES
The softened occipital
bones
Flattened parietal
bones
Release of pressure
Elastic recoil snaps
bone back into original

63. Enamel defect in teeth and
delayed dentition

64. WEAK METAPHYSEAL
AREAS OF RIBS
PULL OF RESPIRATORY
MUSCLES
INWARD BENDING
PROTRUSION OF
STERNUM
Forward sternum- Pigeon chest (Pectus
carinatum )

65. Growth plate widening

66. HARRISON GROOVE
Inward pull of margin
of diaphragm
Gridles thoracic cavity
at lower margin of rib
cage
HARRISON GROOVE

67. KNEE DEFORMITIES
 GENU VARUM GENU VALGUM

69. LONG STANDING CASES
 HYPOCALCEMIA
 HYPERPARATHYROIDISM
 OSTEOPENIA
 PROXIMAL MYOPATHY

73. INVESTIGATIONS

74.  MOST SPECIFIC TEST- SERUM 25(OH)D LEVELS
 IF < 37 nmol/L (<15ng/ml), ASSOCIATED WITH
INCREASE IN PTH AND LOW BONE DENSITY

75. BIOCHEMICAL CHANGES
 DECREASED - SERUM TOTAL & IONIZED
CALCIUM VALUES
 DECREASED - CALCIUM EXCRETION
 DECREASED - PHOSPHORUS VALUES
 INCREASED - PTH LEVELS
 INCREASED - ALKALINE PHOSPHATASE LEVELS

76. TYPES OF
RICKETS
CALCIU
M
PHOSPHA
TE
ALP PTH 25(OH)
VIT D
1,25(OH)
VIT D
NUTRITION
AL
N/D N/D
VIT D
RESISTENT
VIT D
DEPENDEN
T TYPE I
VIT D
DEPENDEN
T II
N
RENAL
OSTEO
DYSTROPH
Y
N/D N

77. RADIOLOGY
 Widened & expanded growth plates
 Cupping, splaying,flare
 Focal radiolucent areas
 Pseudo fractures
 After epiphyseal fusion – decreased cortical thickness
& radiolucency
 Radionuclide bone scan – multiple hot spots in ribs &
pelvis
(If presence of features of metastasis – confirm with
bone biopsy)

78. CUPPING AND SPLAYING
CUPPING and FRAYING

80. MANAGEMENT OF
RICKETS

81. TREATMENT
 While treating rickets /osteomalacia concerned
about impaired calcium homeostasis
 In very young patients
1. Correct metabolic defect
2. Correction with splinting and bracing

82. MEDICAL MANAGEMENT

83. RECOMMENDED DOSAGE
 Vitamin d – 600 IU – 800 IU (depending on age
and severity)
 Cholecalciferol supplements (oral/im)
 Treating the underlying disorder

84. PATIENTS WITH ALPHA 1
HYDROXYLASE DEFICIENCY
 1,25(OH)2D3(CALCITRIOL -0.25-0.5 ug/DAY)
 1ALPHA HYDROXY VITAMIN D2(HECTROL)-
2.5-5ug/DAY

85. ALWAYS ADD CALCIUM
SUPPLEMENTATION
CALCIUM 1.2-2
gm/DAY

86. OTHER FORMS OF CALCIUM
 CALCIUM CARBONATE(40% elemental calcium)
eg- antacids
 CALCIUM CITRATE (21% elemental calcium)
eg- orange,grapes
 CALCIUM GLUCONATE(9% elemental calcium)
 CALCIUM LACTATE (13% elemental calcium)
eg- aged cheese
 Since carbonate and citrate forms of calcium have
more elemental component, opting for supplements
containing these forms would be prefered

87. EFFECTIVE METHODS TO
MONITOR TREATMENT
Measure:
 S.Calcium levels
 Urinary calcium levels
 24hr urinary excretion – 100-250 mg/24hrs
 <100 mg/day indicates deficency in intestine
absorption
 >250 mg/day leads to nephrolithiasis

88. SURGICAL MANAGEMENT

89. INDICATIONS
 Pain and disability
 Patients with valgus/varus limb alignment(<15
degrees)
 Posterolateral instabilty
 Life expectancy
 Intelligent and active patients
 Motivated patients

90. IF SURGERY NOT
PERFORMED
 Joint problems +++
 Early teens-
 Osteochondritis lesions occur in knee
 Late degenreative changes present with shielding of
articular cartilage
 Old pts –
 Incapacitating stiffness & immobility along with
calcification of ligaments

91. TIBIAL OSTEOTOMIES
 The best performed surgical procedure
 Performed at proximal metaphysis to correct varus
deformity
 They should be performed close to maturity for good
results
 Early osteotomies keep joint in positional and functional

92. BEFORE SURGERY
 Management of metabolic defect
 Discontinue vitamin d before 3 weeks
AFTER SURGERY
 Mobilization of patient as quickly as possible

93. IN GENU VARUM
 Indications-
Lateral bowing +
Internal torsion+
 Osteotomy of tibia and fibula near apex

94. SUPRACONDYLAR OSTEOTOMY OF
FEMUR

95. PROPHYLAXIS
 Specific antenatal prophylactic dose
500-1000 IU/DAY OF VITAMIN D3 @ 28 weeks of
pregnancy
(Total dose administered- 1,35000-18,00000IU)
 Infants –VIT D -700iu/day @ 10 days of age
 WHO recommended in children
(unfavourable conditions)-2 lakh IU (im)
 Regular exposure to sun and periodic dosing are most
practical approach in devolping countries

96. REFERENCES
 CAMPBELLS TEXTBOOK OF ORTHOPAEDIC
SURGERY
 MERCERS ORTHOPAEDICS
 TUREK’S ORTHOPAEDICS
 HARRISON PRINCIPLES
 GANONG PHYSIOLOGY
 ROBBINS PATHOLOGY
 HARPERS BIOCHEMISTRY
 LIPPINCOTT BIOCHEMISTRY

97. THANK YOU