Osteomalacia

1. RICKETS &
OSTEOMALACIA
Def.: reduction in bone mineralization !

2. OSTEOMALACIA and RICKETS
Clinical syndromes that result from inade
quate bone mineralization

3. Vitamin D Deficiency
Osteomalacia & Rickets
 Osteomalacia occurs in adults
 Rickets occurs in children
 Defective mineralization of the skeleton

4. VITAMIN D DEFICIENCY
 Vitamin D deficiency leads to decreased absorptio
n of calcium by the GI tract.
 As serum calcium starts to fall, secondary hyperpar
athyroidism occurs.

5. VITAMIN D DEFICIENCY
 Elevated Pth levels may maintain serum calcium in
the normal range, but at the cost of phosphaturia,
hypophosphatemia and increased bone reabsorptio
n
 Low serum phosphate results in inadequate bone
mineralization and osteopenia.

6. VITAMIN D DEFICIENCY
 In severe cases, secondary hyperparathyroidism is
not adequate to maintain serum calcium levels, an
d hypocalcemia occurs.

7. OSTEOMALACIA,RICKETS
Regulation of Calcium & Phosphate Metabolism:
Peak bone mass at 16-25 years.
Bone loss 0.3- 0.5% per year (2-3% per year after 6th decade).
1. Parathyroid Hormone (PTH)
2. Vitamin D3
3. Calcitonin
4. Other Hormones: Est
rogen: Prevents bone loss
Corticosteroids: Increases bone loss
Thyroid hormones: Leads to osteoporosis
Growth hormones: Cause positive calcium balance
Growth factors

8. Biochemistry of Vitamin D3 – Bri
ef Review
 Vitamin D3 (cholecalciferol) is synthesize
d in the skin, with UV light, from 7-dehy
drocholesterol
 Vitamin D3 is hydroxylated twice – first i
n the liver, to 25-hydroxycholecalciferol, t
hen in the kidney, to 1, 25-dihydroxychol
ecalciferol, the most potent form of Vita
min D

9. Vitamin D (cont’)
 Primary role of Vitamin D
 Increase calcium and phosphate absorption from the
intestines
 Other tissues that Vitamin D acts on
 Parathyroid glands
 Bone, Kidneys
 Skin, Brain, Pituitary
 Lymphocytes,Tumors

10. Other conditions that can cause Oste
omalacia
 Hereditary or acquired disorders of vitamin D meta
bolism
 Kidney failure and acidosis
 Phosphate depletion associated with not enough ph
osphates in the diet
 Cancer
 Side effects of medications used to treat seizures (D
ilantin)
 Liver disease

11. RICKETS, OSTEOMALACIA
PATHOLOGY:
Sufficient osteoid, poor mineralization
(Rickets is found only in children prior to the closure of the growt
h plates, while OSTEOMALACIA occurs in persons of any ag
e. Any child with rickets also has osteomalacia, while the rever
se is not necessarily true).

12. RICKETS, OSTEOMALACIA
CAUSES:
1. Nutritional deficiency
1. Vit D
2. chelators of calcium- phytates, oxalates, phosphorous
3. Antacid abuse, causing reduced dietary phosphate binding
2. GI Absorption defects
1. Post gastrectomy
2. Biliary disease (reduced absorption of Vitamins )
3. Small bowel disease
4. liver disease
3. Renal tubular defects
4. Renal osteodystrophy
5. Miscellaneous causes

13. Vitamin D Deficiency
Osteomalacia & Rickets (cont’)
 Secondary to many things, including
 Vitamin D deficiency as discussed above
 Dietary calcium deficiency
 Phosphorus deficiency
 Aluminum toxicity
 Hypophosphatasia
 Fibrogenesis imperfecta ossium

14. Clinical features
 Osteomalacia in adults starts insidiously as aches and pains in the lu
mbar (lower back) region and thighs, spreading later to the arms and
ribs.
 Pain is non-radiating, symmetrical, and accompanied by tenderness i
n the involved bones.
 Proximal muscles are weak, and there is difficulty in climbing up sta
irs and getting up from a squatting position.
 Physical signs include deformities like and lordosis.
 Pathologic fractures due to weight bearing may develop.
 Most of the time, the only alleged symptom is chronic and bone ach
es are not spontaneous but only revealed by pressure or shocks.

15. RICKETS, OSTEOMALACIA
CLINICAL FEATURES:
 Rickets - Tet
any , convulsions, failure to thrive, restles
sness, muscular flaccidity. Flattening of
skull (craniotabes), Thickening of wris
ts from epiphyseal overgrowth, Stunted growth,
Rickety rosary, spinal curvature, C
oxa vara, bowing, # of long bones
 Osteomalacia, - Aches and pains, muscle weakness loss of hei
ght, stress #s.

16. Manifestations of Osteomalacia
 Localized bone pain
 Difficulty walking
 Low back pain
 Fractures are common, and delayed healing occu
rs
 Muscular weakness
 Weight loss
 Progressive deformities of the spine (kyphosis)

17. Rickets, clinical manifestations
 Skeletal findings:
1. Delay in closure of the fontanelles.
2. Parietal & frontal bossing.
3. Craniotabes ( soft skull bones).
4. Enlargement of the costochondral junction (rachitic rosary).
5. The development of Harrison sulcus ( caused by pull of the diaphragmatic attachments
to the lower ribs).
6. Enlargement of the wrist & bowing of the distal radius & ulna.
7. Progressive lateral bowing of the femur & tibia.

18. RICKETS, OSTEOMALACIA
XRAY FINDINGS:
RICKETS
Thickening and widening of
physes, C
upping of metaphysis, Wide
metaphysis, Bowing of
diaphysis, Blurred trabecula
e.

19. RICKETS, OSTEOMALACIA
XRAY FINDINGS:
OSTEOMALACIA
Loosers zones - incomplete str
ess # with healing lacking ca
lcium, on compression side
of long bones.
Codfish vertebrae due to press
ure of discs
Trefoil pelvis, due to indentatio
n of acetabulae stress #s

21. Osteomalacia & Rickets – Clinica
l Manifestations
 Asymptomatic at onset
 Muscle weakness, especially of pe
lvic girdle
 Bone pain
 Atraumatic fractures
 X-rays assist in diagnosis

22. RICKETS, OSTEOMALACIA
INVESTIGATIONS:
BLOOD TESTS Calci
um Reduced, Phosphate r
educed Alkalline Phosph
atase increased Urinary excretion of c
alcium diminished
Calcium phosphate products (= serum [Ca] x serum [PO4]) norm
ally 30. In rickets and osteomalacia is less than 24

23. Osteomalacia & Rickets - Diagno
sis
 Other laboratory abnormalities may include
 Hypocalcemia
 Hypophosphatemia
 Elevated serum alkaline phosphatase

24. Biochemical findings in rickets
 Alkaline phosphatase usually is ↑in all forms of rickets.
 Serum phosphorus concentrations usually are↓ in both hypocalcemic and hyp
ophosphatemic rickets.
 Serum Ca is ↓only in hypocalcemic rickets.
 Serum parathyroid hormone typically is ↑in hypocalcemic rickets, in contrast i
t is N in hypophosphatemic rickets.
 25-OH vitamin D reflect the amount of vitamin D stored in the body, and is
↓in vit D deficiency.
 1,25-OH2 vitamin D can be↓, N or ↑in hypocalcemic rickets and usually is N
or slightly ↑in hypophosphatemic rickets.

25. Osteomalacia & Rickets - Diagno
sis
 Bone biopsy is diagnostic
 Serum 25-hydroxycholecalciferol <50nmol/L in
dicates Vitamin D deficiency

26. OSTEOMALACIA:
EVALUATION
 Careful diet and sunlight history
 Renal function
 Fecal fat determination
 Anti IgA tissue transglutaminase antibodies.
Small bowel biopsy

27. RICKETS, OSTEOMALACIA
MANAGEMENT:
Depends on the cause
Nutritional Vitami
n D deficiency Dietary che
lators of calcium
Phytates
Oxalates Phospho
rus deficiency (unusual)
Antacid abuse
 Treatment- vitamin D (50000u/w`/up to 3-12 w) and Calciu
m (1.5-2g/day)

28. RICKETS, OSTEOMALACIA
MANAGEMENT:
Depends on the cause
Gastro-intestinal absorption defects Po
st-gastrectomy Biliary
disease Enteric abs
orption defects
Short bowel syndrome
Rapid onset (gluten-sensitive enteropathy) Inflamm
atory bowel disease
Crohns
Celiac

29. RICKETS, OSTEOMALACIA
MANAGEMENT:
Depends on the cause
Renal tubular defects Vita
min D dependant
type I
type II
Treatment; High levels of vit D
Vitam
in D resistant (familial hypophosphatemic rickets)
Treatment; Phosphate 1-3 gm daily, Vit D3 high dose
Fanconi syndrome I, II, III R
enal tubular acidosis

30. Vitamin D Deficiency - Treatmen
t
 50,000 IU of oral Vitamin D2, once or twic
e weekly for 6 – 12 w, followed by 1000 IU
/day
 Appropriate exposure to sunlight
 Phosphate and Calcium replacement, if nee
ded