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Flashcards in Bones Deck (16):
1

Metabolic bone diseases (5)

Osteoporosis
Osteomalacia
Hyperparathyroidism
Paget's disease
Renal osteodystrophy

2

Osteoporosis

Age related or due to drugs/disease.
Decreased bone density.
DEXA scan: T > 2.5 SD below mean.
Low impact fractures, back pain.
RF: old, woman, smoking, skinny, diet, no oestrogen.
XR: NAD
Histology: loss of cancellous bone
Biochem: NAD.

3

Osteomalacia

Vit D def - dietary, sunlight, malabsorption, genetic.
Reduced bone mineralisation.
Adults: bone pain, prowimal muscle weakness;
Children: bone pain, bowed legs, frontal bossing, pigeon chest, delayed walking.
XR: Looser's zones (like fractures), splayed metaphyses.
Histology: excess of unmineralised bone (osteoid).
Biochem: low PO4, ^ALP.

4

Hyperparathyroidism
(re: bones)

^PTH, ^Ca.
Due to adenoma, hyperplasia, carcinoma, MEN.
Osteitis fibrosa cystica.
Sx of ^Ca.
XR: Brown's tumours, salt and pepper skull, subperiostial bone resorption in phalanges.
Histology: Osteitis fibrosa cycstica =
Biochem: ^Ca, ?^ALP, ?low PO4.

5

Paget's disease (bone)

Disorder of bone turnover: see both lytic and sclerotic lesions.
Bone pain, big head, microfractures, nerve compression, deafness, high output cardiac failure.
Old white people, no gender bias.
Histology: huge osteoclasts (>100 nuclei), mosaic pattern of lamellar bone.
Biochem: ^^^ALP.

6

Renal osteodystrophy

All the other skeletal changes, with CKD (secondary ^PTH).
Disease features vary wth exact form of bone disease.
Biochem: ^PTH, but ^PO4 and low Ca because renal failure.

7

Non-neoplastic bone diseases (5)

Gout and pseudogout,
Trauma,
Osteomyelitis,
Osteorthritis,
Rheumatoid arthritis.

8

Gout

Middle aged men.
RF: psoriasis, alcohol, diuretics, inherited metabolic abonormalities.
Affects big toe MTP (podagra), knee.
Tophi are pathagnomonic.
Urate crystals. Needle shape.
Negatively birefriengent in polarised light.
Tx: colchicine in acute, allopurinol long term.

9

Pseudogout

Old.
Idiopathic.
Knee and shoulder.
Calcium pyrophosphate crystals. Rhomboid.
Positively birefringent.
Tx: NSAIDs or intra-articular steroids.

10

Osteomyelitis

Adults:
Staph aureus, epiphysis, verebrae, dental abscess or diabetic ulcer.
Children:
Haemophilus or GBS, metaphyses of long bones.
Presentation: pain, swelling, fever etc.
XR: Lytic destruction 10 days in.
(Rare causes: TB, syphilis).

11

Malignant Neoplastic bone diseases (4)

Osteosarcoma,
Chondrosarcoma,
Ewing's sarcoma,
Giant cell (borderline malignancy)

12

Benign bone tumours (7)

Osteoid osteoma,
Osteoma,
Enchondroma,
Ostechondroma,
Fibrous dyplasia,
Simple bone cyst,
Osteoblastoma.

13

Oseosarcoma

Adolescents.
Mostly knee.
Malignant mesenchymal cells with ALP.
XR: elevated periosteum (Codman's triangle), Sunburst appearance.

14

Ewing's sarcoma

Adolescents.
Long bones, pelvis.
Sheets of small round cells, CD99 +ve, 11:22 translocn.
XR: onion skinning of periosteum.

15

Giant cell tumour of bone

Women 20-40yo.
Knee epiphysis.
Osteoclast-type multinucleate giant cells on background of spindle/ovoid cells.
XR: lytic (lucent) lesions right up to articular surface.

16

Chondrosarcoma

>40yo.
Axial skeleton, femur, tibia, pelvis.
Malignant chondrocytes (cartilage).
XR: Lytic lesions with fluffy calcification.