INTRODUCTION SOURCES OF CALCIUM RDA OF CALCIUM FUNCTIONS OF CALCIUM CALCIUM BALANCE ABSORPTION OF CALCIUM EXCHANGE OF CALCIUM BETWEEN BONE AND ECF EXCRETION OF CALCIUM REGULATION OF PLASMA CALCIUM LEVEL APPLIED ASPECTS

1. CALCIUM METABOLISM
Presented by – Mahima Shanker
(Department of oral and maxillofacial
surgery)

2. CONTENTS
• INTRODUCTION
• SOURCES OF CALCIUM
• RDA OF CALCIUM
• FUNCTIONS OF CALCIUM
• CALCIUM BALANCE
• ABSORPTION OF CALCIUM
• EXCHANGE OF CALCIUM BETWEEN BONE AND ECF
• EXCRETION OF CALCIUM
• REGULATION OF PLASMA CALCIUM LEVEL
• APPLIED ASPECTS

3. INTRODUCTION
• Most abundant mineral in the human body
• Total - about 1 to 1.5 kg
• 99% seen in bone together with phosphate
• Small amounts - soft tissue, 1% extracellular fluid
Jaiswal JK. Calcium - how and why? J Biosci. 2001 Sep;26(3):357-63. doi: 10.1007/BF02703745. PMID: 11568481.

4. SOURCES OF CALCIUM

5. RECOMMENDED DAILY ALLOWANCE (RDA) OF CALCIUM BASED ON AGE
Al-Mahasneh, Majdi & Mousa, Hasan & Jalamneh, Heba & Hani, Isra & Zawahreh, Meryam. (2010). Evaluation of calcium content of drinking water supplies
and its effect on calcium deficit in Jordan. Desalination andWaterTreatment - DESALINWATERTREAT. 21. 181-188. 10.5004/dwt.2010.1378.
INFANTS
Birth-6months 200mg
6months-1year 260mg
CHILDREN/YOUNG ADULTS
1-10years 700-1000mg
11-24years 1100-1300mg
ADULT WOMEN
Pregnant/Lactating 1200-1500mg
Pre-menopausal 1000-1500mg
(50-64years)
Post-menopausal 1500mg
(>65years)
ADULT MEN
25-64years 1000mg
>65 years 1200mg

6. PHYSIOLOGICAL AND BIOCHEMICAL FUNCTIONS OF CALCIUM
• Development of Bones and teeth
• Calcium (Factor IV) is an integral part of the coagulation cascade
• During muscle contraction, myosin filament gets attached to actin filament - mediated by calcium
• Calcium regulates the activity of a number of intracellular proteins
• Essential for membrane potential and depolarization, synapses require calcium to release
neurotransmitters
• All processes that require exocytosis (eg - hormone secretion) require Calcium
• Calcium regulates membrane potential
Piste, Pravina & Sayaji, Didwagh & Avinash, Mokashi. (2012). Calcium and its Role in Human Body. Int J Res Pharm Biomed Sci. 4. 2229-3701.

8. CALCIUM BALANCE
• Calcium is fundamentally important to biological systems
• The normal daily turnover of calcium is maintained by an interplay of the following processes -
1. Absorption of ingested calcium
2. Exchange of calcium between bone and ECF
3. Secretion of calcium from ECF
4. Excretion of calcium

9. ABSORPTION OF CALCIUM
• Normally, at a daily intake of 1000mg of calcium, about 35%(350mg) is absorbed
• Calcium is taken in the diet as calcium phosphate, carbonate, tartarate
• About 40% of dietary calcium - absorbed from the gut
• Absorption occurs form the first, second part of duodenum
• Absorbed against a concentration gradient, requires energy
• Requires a carrier protein, helped by calcium-dependent ATPase
• Two mechanisms - Simple diffusion, An active transport - Process involving energy & Ca2+ pump
• Both processes require 1, 25 DHCC (Calcitriol) which regulates the synthesis of Ca-binding proteins,
transport

10. Factors causing increased absorption Factors causing decreased absorption

11. EXCHANGE OF CALCIUM BETWEEN BONE AND ECF
• ECF contains 1000mg of calcium - equilibrium with the calcium present in the bones
• Two types of exchange between ECF and bone -
1. Rapid Exchange - occurs between the ECF and the smaller 1% of readily exchangeable pool of
bone calcium. A large amount of calcium (around 20,000mg) per day moves in and out of this
pool.
2. Slow Exchange - occurs between the ECF and the larger (99% of total bone content) pool of
stable calcium.This exchange is the one concerned with bone remodelling by constant interplay
of bone resorption and deposition(around 50mg/day).

12. EXCRETION OF CALCIUM
• Same amount of calcium as absorbed from the gut, about 350mg - excreted to maintain balance.
• Excretion of calcium occurs in faecal matter, urine.

13. Excretion increased by -
• Low parathyroid hormone (PTH)
• High extracellular fluid volume
• High blood pressure
• Low plasma phosphate
• Metabolic alkalosis
Excretion decreased by -
• High parathyroid hormone
• Low extracellular fluid volume
• Low blood pressure
• High plasma phosphate
• Metabolic acidosis
• Vitamin D3

14. REGULATION OF PLASMA CALCIUM LEVEL
Calcitrophic Hormones
 Parathyroid hormone (PTH)
 Active form ofVitamin D (1,25-dihydroxycholecalciferol)
 Calcitonin
Parathyroid hormone related protein (PTHrP)
It is a local hormone that acts on PTH receptors and is
important for skeletal development in--utero.
Other hormones
 Growth hormones - STIMULATES - Deposition
 Growth factors - STIMULATES - Deposition
 Sex hormones - INHIBITS - Resorption
 Glucocorticoids - STIMULATES -Resorption

16. APPLIED ASPECTS
HYPERPARATHYROIDISM AND HYPERCALEMIA
Classification of Etiology
• PTH related
• Vitamin d related
• Malignancy related
• Associated with high bone turnover
• Associated with renal failure
Types
PRIMARY
• Parathyroid adenoma
• Parathyroid hyperplasia
• Parathyroid carcinoma
SECONDARY
Parathyroid hyperplasia
TERTIARY
Autonomous nodule + hyperplasia

17. ORAL MANIFESTATIONS
• Increased incidence of tori
• Reduction in cortical bone - osteoporosis
• Brown tumor -
Disorder of bone and mineral metabolism - diffuse and focal lesions in multiple bones
These lesions are termed brown tumors due to the presence of old hemorrhage within the lesion giving it a distinct brown
color
• According to Schour and Massler, malocclusion caused by sudden drifting with definite spacing may be one of the first
signs of the disease
Fatma LB, Barbouch S, Fethi BH, Imen BA, Karima K, Imed H, Fethi el Y, Fatma BM, Rim G, Taieb BA, Maiz HB, Adel K. Brown tumors in patients with
chronic renal failure and secondary hyperparathyroidism: report of 12 cases. Saudi J Kidney Dis Transpl. 2010 Jul;21(4):772-7. PMID: 20587894.

18. RADIOGRAPHIC FEATURES
• Normal trabecular pattern is lost, replaced by granular or ground glass appearance
• Moth eaten appearance of jaw bone
• Lamina dura is diminished or completely absent in 10% of cases
Higher risk of bone fracture
Recognize the presence of brown tumors
Jaw enlargement is treated using recontouring procedures
Disease should be considered whenever single or multiple
radiolucencies are observed on radiographs

19. TREATMENT
Watchful waiting -
In case calcium levels are only slightly elevated, kidneys are functioning normally and bone density is normal
Surgery -
Surgical removal of the problematic gland
The treatment of a Brown tumor - pharmacologic, surgical excision is sometimes necessary
Curettage of the lesion, wound packing allowing for secondary healing
Medications -
These include calcimimetics, hormone replacement therapy (post-menopausal women), bisphosphonates
HYPERCALCEMIA
Emergency treatment IV infusion - Mono and dihydrogen phosphate 500ml over 4-6hours
Long term Phosphate treatment Oral diphosphate – 100 to 300ml/day in divided doses
Jesse M. Jakubowski, InesVelez, Shawn A. McClure, "BrownTumor as a Result of Hyperparathyroidism in an End-Stage Renal Disease
Patient", Case Reports in Radiology, vol. 2011, Article ID 415476, 3 pages, 2011. https://doi.org/10.1155/2011/415476.

20. HYPOPARATHYROIDISM AND HYPOCALCEMIA
CHARACTERISTIC FEATURESOF HYPOPARATHYROIDISM -
HYPOCALCEMIA
Total serum calcium may be decreased to 4-8mg% and the ionized calcium to 3mg%.A 50% fall in the levels of ionized
calcium leads to a condition calledTetany
HYPERPHOSPHATEMIA
An increase in serum phosphate levels about 6-16mg%
CLASSIFICATION -
PARATHYROID HORMONE ABSENT
Hereditary hypoparathyroidism
Acquired hypoparathyroidism
PARATHYROID HORMONE INEFFECTIVE
Chronic renal failure
Lack ofVitamin D

21. CLINICAL FEATURES
• Neuromuscular irritability
• Numbness and tingling sensation
• Tetanic muscle contraction in hands, feet
• Spasm of muscles of larynx, consequent airway obstruction
• Seizures
• Marked dilatation of heart
• Changes in cellular enzyme activity
• Increased in membrane permeability in some cells
• Impaired blood clotting
ORAL MANIFESTATION
• Enamel hypoplasia & Dentin dysplasia
• Dryness of mucous membrane
• Angular chelitis
• Circumoral paraesthesia
• Disturbances in tooth eruption
• Root defects
• Hypodontia and impacted teeth
• Large pulp chambers in deciduous and permanent teeth
• Thickening of lamina dura in permanent teeth

22. RADIOGRAPHIC FEATURES
• Enamel hypoplasia
• External root resorption
• Delayed eruption
• Root dilacerations
MANAGEMENT
Administration of large quantities ofVitamin D, as high as 1,00,000 units/day along with intake of 1 to 2 g of Calcium

23. TETANY
Tetany is a clinical condition resulting from increased neuromuscular excitability
CAUSES
Hypocalcemia -
Extracellular calcium plays an important role in membrane integrity and excitability
Thus when concentration of ionic calcium is reduced to <50% of normal in ECF, cell membrane of neurons become more
permeable resulting in a series of action potentials
Hypomagnesaemia -
Magnesium ions are also associated with neuromuscular irritability
Alkalosis -
Reduces ionic calcium and also produces tetany

24. CLINICAL FEATURES
• Carpopedal spasm/Trousseau’s sign
• Laryngeal stridor
• Paraesthesia
• Chvostek’s sign
MANAGEMENT
An intravenous injection of 20ml of 10% Calcium gluconate - correct hypocalcemia, relieves tetany

25. RICKETS
• Occurs in children between 6months - 2years of age
• Lack of calcium causes failure of mineralization
• Most critical areas affected are the centres of endochondral ossification at epiphyseal plates
TYPES OF RICKETS
• Nutritional
• Vitamin D resistant
• Vitamin D dependant
• Oncogenous
CLINICAL FEATURES
• Craniotabes - small rounded areas in the membranous bones of the skull, yield under finger pressure
• Widening of wrist due to epiphyseal widening of lower end of radius bone
• Collapse of chest wall occurs due to flattening of sides of thorax with prominent sternum (pigeon chest)
• Rickety rosary - beading of chostochondral junction of ribs
• Frontal bossing and posterior flattening of skull
• Bowing of legs or knock knee occurs when the child begins to walk
• Kyphosis and pelvic deformities are seen

27. ORAL MANIFESTATIONS
• Developmental anomalies of enamel and dentin
• Delayed eruption
• Malalignment of teeth
• High caries index
• Enamel hypoplasia
RADIOGRAPHIC FEATURES
• Hypo calcification of teeth and presence of large pulp chambers
• Loss of alveolar bone
• Metaphyseal widening

28. MANAGEMENT
Vitamin D
0.5 to 1g/day for children 2-4years
1 to 4g/day for children >4years
Parenteral administration of Phosphate
0.08mmol/kg body weight over 6 hours
Early diagnosis and treatment prevents limb deformities
Corrective osteotomies for deformed limbs deferred until radiologically healed rickets is noted and serum alkaline
phosphatase levels are normal

29. OSTEOMALACIA
• Adult counterpart of rickets
• Characterized by defective mineralization of adult bones in which epiphyseal growth
plates are already closed
ETIOLOGY
• Inadequate calcium absorption
• Phosphate deficiency due to renal loss
CLINICAL FEATURES
• Pain and chronic fatigue
• Muscle weakness
• Waddling gait
• Bones become soft, especially involved are pelvic girdle, ribs and femur.
• Pseudo fractures seen in flat bones (ribs, scapula) and ends of long bones (femur)
RADIOGRAPHIC FEATURES
• Pseudo fractures
• Biconcave vertebral bodies
• Femoral neck fractures

30. OSTEOPOROSIS
Osteoporosis - Porous bone, is a disease in which the density and quality of bone are reduced. As the bones become more
porous and fragile, the risk of fracture is greatly increased.
CHARACTERISTIC FEATURES
• Bone density is reduced
• Incidence of fractures is increased
• Serum calcium and phosphate levels are normal with excess urine excretion
ETIOLOGY
• Estrogen deficiency in post-menopausal women
• Nutritional deficiency
• DecreasedVitamin D synthesis
• Chronic kidney disease
• Long term corticosteroid therapy
• Hyperparathyroidism

31. CONSIDERATIONS
• Osteoporosis affects trabecular bone more than cortical bone, thus maxilla is more affected
• Dental implants to be placed with caution
MANAGEMENT
• Calcium: 1200mg/day
• Vitamin D: 800-1000 IU
• Hormone replacement therapy in post menopausal women
• Bisphosphonates
• Calcitonin

32. Isales CM. Role of the oral and maxillofacial surgeon in the diagnosis and treatment of patients with osteoporosis. Oral Maxillofac Surg
Clin North Am. 2007 Nov;19(4):475-85, v. doi: 10.1016/j.coms.2007.06.003. PMID: 18088899.
Implants placed in patients with systemic osteoporosis do not present higher failure rates than those placed in patients
without osteoporosis. However there is increased marginal bone loss than those in control groups
Compromised bone strength affects anchorage of implants and impaired bone growth and late remodelling could impair
strength. Antiresorptive agents (Bisphosphonates), bone forming agents (PTH Peptides), dual effect agents (Strontium
ranelate), future anabolic agents present as therapeutic options
Absorption of calcium falls with age after about 60 years and everyone over 80 years has significant malabsorption due to
vitamin D deficiency

33. REFERENCES
• Jaiswal JK. Calcium - how and why? J Biosci. 2001 Sep;26(3):357-63. doi: 10.1007/BF02703745. PMID: 11568481.
• Al-Mahasneh, Majdi & Mousa, Hasan & Jalamneh, Heba & Hani, Isra & Zawahreh, Meryam. (2010). Evaluation of calcium content of drinking
water supplies and its effect on calcium deficit in Jordan.21. 181-188. 10.5004/dwt.2010.1378.
• Piste, Pravina & Sayaji, Didwagh & Avinash, Mokashi. (2012). Calcium and its Role in Human Body. Int J Res Pharm Biomed Sci. 4. 2229-3701.
• Fatma LB, Barbouch S, Fethi BH, Imen BA, Karima K, Imed H, Fethi elY, Fatma BM, Rim G,Taieb BA, Maiz HB, Adel K. Brown tumors in patients
with chronic renal failure and secondary hyperparathyroidism: report of 12 cases. Saudi J Kidney Dis Transpl. 2010 Jul;21(4):772-7. PMID:
20587894.
• Jesse M. Jakubowski, InesVelez, ShawnA. McClure, "BrownTumor as a Result of Hyperparathyroidism in an End-Stage Renal Disease Patient",
Case Reports in Radiology, vol. 2011, Article ID 415476, 3 pages, 2011. https://doi.org/10.1155/2011/415476.
• Isales CM. Role of the oral and maxillofacial surgeon in the diagnosis and treatment of patients with osteoporosis. Oral Maxillofac Surg Clin
North Am. 2007 Nov;19(4):475-85, v. doi: 10.1016/j.coms.2007.06.003. PMID: 18088899.
• ShafersTextbook of oral pathology - 6th edition
• Guyton and HallTextbook of medical physiology - 11th edition
• KDTripathi Essentials of Pharmacology for Dentistry - 3rd edition