In the name of God

Osteomalacia Mohsen Mardani-Kivi Assistant Professor, Orthopedic Department, Guilan University of Medical Sciences

Case 33 year old Asian lady Presents with 3 /12 months history of generalised bony pain PMH  depression D/Hx  sertraline P/Ex  generalised bony tenderness Joints  normal ROM, no inflammation

Investigations Hb 12.9 ( )Calcium 2.18 ( ) WBC4.7 ( )Phosphate 0.79 ( ) Plt253 ( )Albumin39 (35-50) ESR 12Alk Phos172 (25-96) Clotting NormalTotal protein 72 (60-80) Urea 4.2 ( )LFTsnormal Creat85 (35-120)

Diagnosis?

Definition Osteomalacia is the general term for the softening of the bones due to defective bone mineralization.

Definition Osteomalacia in children is known as rickets, and because of this, it is often restricted to the milder, adult form of the disease. It may show signs as diffuse body pains, muscle weakness, and fragility of the bones.

General characteristics Osteomalacia is derived from Greek: –osteo  bone –malacia  softness most commonly found in: –dark-skinned –diet-disbalanced subjects (mainly lactating females). Age: adults Site: WEIGHT-BEARING BONES such as vertebral bodies and femoral neck

General characteristics

Physiology Normal bone metabolism: CA CALCIUM  99% in bone. Main functions  muscle /nerve function, clotting. Plasma calcium  50% free, 50% bound to albumin. Dietary needs: –Kids: 600mg/day –Adolescent1300mg/day, –Adult:750mg/day –Pregnancy:1500mg/day, –Breastfeeding:2g/day, –Fractures:1500mg/day Absorbed in duodenum (active transport) and jejunum (diffusion), 98% reabsorbed in kidney prox. tubule, may be excreted in stool.

Physiology Normal bone metabolism: PHOSPHATE PHOSPHATE  85% in bone. Functions: metabolite and buffer in enzyme systems. Plasma phosphate mainly unbound. Daily requirement: 1-1.5g/day

Physiology Regulation of Calcium & Phosphate Metabolism: Peak bone mass at years. Bone loss % per year (2-3% per year after 6 th decade). 1.Parathyroid Hormone (PTH) 2.Vitamin D3 3.Calcitonin 4.Other Hormones: Estrogen: Prevents bone loss Corticosteroids: Increases bone loss Thyroid hormones: Leads to osteoporosis Growth hormones: Cause positive calcium balance Growth factors

Physiology

Adults with osteomalacia experience only mild bowing of long bones; however, stress resistance of bones is reduced, and gross or microscopic fractures Responsible metabolic disturbances are vitamin D defi­ciency, phosphate deficiency, and mineralization defects. Mineralization of osteoid is reduced while bone mass remains normal.

Physiology Serum Ca & Phosphate in equilibrium with Ca & Phosphate in bone. CaPhosphate Constant Product

Physiology

Patho physiology Kidney disease Defect in phosphate execration No hydroxylation of Vit.D3

Patho physiology Hypocalcaemia So, Stimulation of PTH Bone.. Relase of Ca. Kidney Ca absorption

Etiology Calcium deficiency –Hypo-phosphataemia –Defect in Vitamin D metabolism Nutritional –Diet: oily fish, eggs, breakfast cereals –Antacid abuse, causing reduced dietary phosphate binding underexposure to sunlight –Elderly individuals with minimal sun exposure –Dark skin, skin covering when outside

Etiology Calcium deficiency –Hypo-phosphataemia –Defect in Vitamin D metabolism intestinal mal-absorption –Coeliac –Intestinal bypass –Post-Gastrectomy –Chronic pancreatitis –Biliary disease (reduced absorption of Vitamins) –Small bowel disease

Calcium deficiency –Hypo-phosphataemia –Defect in Vitamin D metabolism liver & kidney diseases –Fat mal-absorption syndromes –Kidney failure: RTA, Renal osteodystrophy Epilepsy: phenytoin, phenobarbitorate Genetic disease Etiology

Other Etiologies: –Receptor Defects –Altered phosphate homeostasis Etiology

Pathology Sufficient osteoid Poor mineralization

Symptoms & Signs Bone pain, backache Muscle weakness Vertebral collapse: kyphosis loss of height Deformities & stress fractures

Osteomalacia in adults starts insidiously as aches and pains in the lumbar region and thighs, spreading later to the arms and ribs. Pain is non-radiating, symmetrical, and accompanied by tenderness in the involved bones. Proximal muscles are weak, and there is difficulty in climbing up stairs and getting up from a squatting position Symptoms & Signs

Physical signs include deformities like lordosis. Pathologic fractures due to weight bearing may develop. Most of the time, the only alleged symptom is chronic and bony ache which is only revealed by pressure or shocks. Symptoms & Signs

Rickets –Tetanus, convulsions, failure to thrive –restlessness, muscular flaccidity –Flattening of skull (craniotabes) –Thickening of wrists from epiphyseal overgrowth, Stunted growth, Rickety rosary, spinal curvature, Coxa vara, bowing, –Fx of long bones Osteomalacia –Aches and pains –muscle weakness loss of height –stress fx Symptoms & Signs

1.Hypo-calcaemia 2.Hypo-calcuria 3.High alkaline phosphatase biochemistry

Work up for Osteomalacia Ca, P, Alk ph 24 h urinary Ca 25 (OH) Vit-D 1, 25 (OH) Vit-D PTH Bone Biopsy biochemistry

1- ca P = Nl Alk ph 2- ca = Nl P Alk ph 3- ca P Alk ph 24 h Urinary ca < 100 mg / 24 h 24 h Urinary Hydroxyproline Excretion biochemistry

* Rickets - Growth plate widening & thickening - Metaphyseal cupping - Diaphyseal deformities * Osteomalacia - Looser zone, biconcave vertebra, protrusio acetabuli - Spontaneous fractures *Signs of secondary hyperparathyroidism X-ray

Loosers zones – incomplete stress Fx with healing lacking calcium, on compression side of long bones. Codfish vertebrae due to pressure of discs Trefoil pelvis, due to indentation of acetabulae stress fx X-ray

Loosers zones X-ray

Depends on the cause Nutritional Vitamin D deficiency Dietary chelators of calcium Phytates Oxalates Phosphorus deficiency (unusual) Antacid abuse Treatment

Depends on the cause Gastro-intestinal absorption defects Post-gastrectomy Biliary disease Enteric absorption defects Short bowel syndrome Rapid onset (gluten-sensitive enteropathy) Inflammatory bowel disease Crohns Celiac Treatment

Depends on the cause Renal tubular defects Vitamin D dependant type I type II Treatment; High levels of vit D Vitamin D resistant (familial hypophosphatemic rickets) Treatment; Phosphate 1-3 gm daily, Vit D3 high dose Fanconi syndrome I, II, III Renal tubular acidosis Treatment

Depends on the cause Renal Osteodystrophy – in chronic renal failure Miscellaneous Hypophosphatasia Anticonvulsant therapy SURGERY For deformities Treatment

Osteomalacia Treatment Vitamin D (5000u) Calcium supplements (3g/day) Fracture management Correct deformity if needed

Natural sources cheese, sardines, salmon, dark leafy vegetables & sesame seeds. Treatment