Post on 20-Jun-2015
Deded Yudha Pranathadr. Bambang Gunawan, SpOT
Blood Calcium, Phosphorus, and Magnesium
Basic Orthopaedic Tutorial
Regulator: PTH ; 1,25 (OH)2 vit D ; Calcitonin
The metabolically active tissues :1. Bones2. Kidneys3. Intestine
CALCIUM
Normal level: 9.0 – 10.4 mg / 100 mL
99%
1%
Absorption Active transport – duodenum▪ Require ATP & regulated by vit D
Passive diffusion – jejunum
Reabsorption 98% ca reabsobed in kidney
Calcium Diet
Dietary requirement Children : 600 mg/ day Adolescent & young adult : 1300 mg / day Adult : 750 mg / day Pregnant women : 1500 mg / day Lactating women : 2000 mg /day Post menopausal women : 1500 mg / day Patients w/ a long bone fracture: 1500 mg /
day
Functions of Calcium
Controls internal regulation of function of all cells
Regulates cell membrane permeability, nerve excitability, muscle contraction, and gland secretion
Regulates synthetic and secretory functions of PTH and thyroid C cells (for calcitonin)
Control adhesiveness between cells Controls the hardness and rigidity of
bones and teeth through hydroxyapatite
Calcium homeostasis
Normal Calcium and Phosphate Metabolism
Ca Related Metabolic Bone DiseasesDisease Etiology
Hypercalcemia
HyperPTH PTH overproduction -adenoma
Familial syndromes PTH overproduction - Multiple endocrine neoplasia type I and II
Hypocalcemia
HypoPTH PTH underproduction – idiopathic, iatrogenic
Pseudohypoparathyroidism / Albright syndrome
PTH receptor abnormality
Renal Osteodystrophy CRF – Pi excretion ↓
Rickets (Osteomalacia) Nutritional, vit D dependent, vit D resistant
Renal osteodystrophy
Phosphate (Pi)Normal level : 2.8 – 4.0 mg/dL
85% boneReabsorption kidney (renal tubular) 70 –
90%Stimulated by 1,25 (OH)2 DInhibited by PTHDaily requirements: 1000 – 1500 mg/ day
Together with Ca – normal bone metabolism
Phosphate homeostasis
Small role in bone homeostasis Required for parathyroid hormone secretion. Efficient peripheral action of PTH
◦ cofactor
Magnesium
Thank you