Diseases Of Bone

Question 1

Def of osteomyelitis and classification

Answer 1

Inflammation of bone and bone marrow
It is classified into
Bacterial
Acute hematogenous suppurative
Acute non hematogenous suppurative
Chronic non specific
Chronic specific ( syphilitic and tuberculosis)
Non bacterial
Viral
Radiation

Question 2

Aetiology of acute haematogenous osteomyelitis

Answer 2

It is predisposed with trauma
It more common in children
The causative organism is staph aurous in 80-90% of cases and some cases with E.coli and salmonella

Question 3

Pathogenisis of osteomyelitis

Answer 3

1- mainly by blood spread through injuries
2- local spread from any suppurative foci in the body

Question 4

The most affected bones in osteomyelitis

Answer 4

Long bones then vertebrae

Question 5

The location of infection of osteomyelitis in long bones

Answer 5

The location is affected by vascular circulation and it is changed with age
Children : metaphyseal as its the most vascular part and the blood flow is slow and it is the most common part subjected to trauma

Infants and adults : epiphyseal

Question 6

Pathological features of osteomyelitis

Answer 6

1- the intial lesion is a suppurative foci in metaphysis
2- the spread of infection occurs by penetrating endosteum and reaching periosteum forms subperiosteal abcess
3- the subperiosteal abcess is ruptured forming multiple sinus
4- bone necrosis due to
~ bacterial toxins
~ ischemia due to stretching and compression of periosteul vessels
5- separation of the necrotic bone by osteoclast to be called sequestrum
6- new bone formation and its called “ involucurm “ with thicking of periosteum
7- the sinus appear as thick walled holes “ coloacae “ this occurs in chronic phases

Question 7

Complications of osteomyelitis

Answer 7

1- Pathological fracture
2- direct spread : myositis
3- blood spread : toxaemia pyemia and septicimia
4- chronic suppurative osteomyelitis which can be complicated by
~ secondary amylosidosis
~ squamous metaplasia which may later give a rise to squamous cell carcinoma

Question 8

Causes of acute non hematogenous osteomyelitis

Answer 8

1- infection of fractured bone
2- infection of skull bones dut to direct spread

Question 9

What is different in acute non hematogenous osteomyelitis

Answer 9

It resembles the pathology of the hematogenous but different in location and no subperiosteal abcess

Question 10

Causes of chronic non specific osteomyelitis

Answer 10

1- chronic following acute osteomyelitis
2- brodie abcess
3- sclerosing osteomyelitis of Garre

Question 11

What is bradie abcess

Answer 11

Localized form of osteomyelitis, it is a intraosseous cortical abcess surrounded by reactive sclerotic bone

Question 12

Common age, atielogy and complications of brodie abcess

Answer 12

1- young adults
2- mainly staphylococcal
3- patholgical fracture

Question 13

What is sclerosing osteomyelitis of garre
Common age
Pathogensis

Answer 13

It is specific type of chronic osteomyelitis
Mainly affect children and young adults
Typically affects the mandible and commonly associated with odontogenic infection resulting from dental caries

Question 14

Most common site of tuberculous osteomyelitis

Answer 14

In ends of long bones and vertebrae

Question 15

Tuberculosis in short bone

Answer 15

Tuberculous dactylitis

Question 16

Source of infection of tuberculous osteomyelitis in vertebrae

Answer 16

Blood borne infection

Question 17

Most common vertebrae in tuberculos osteomyelitis of vertebrae

Answer 17

Lower thoracic and upper lumbar and then cervical

Question 18

Pathology of tuberculous osteomyelitis of vertebrae

Answer 18

Destruction of two or more adjacent vertebrae as well as their intervertebral disc and this feature is an important radiological sign to differentiate between it and metastasis which keep the intervertebral disc

Question 19

Complications of tuberculous osteomyelitis of vertebrae

Answer 19

1- deformity
~ kyphosis : backward convex of vertebral column
~ lordosis: forward of vertebral colmunn
~ scoliosis: lateral curve of vertebral column
2-cold abcess : accumulations of caseating material in soft tissue without any sign of inflammation
3- spread of infection ( tuberculous arthritis)
4- paralysis of lower limb due to compression of spinal cord and numerous neuron roots by caseating meterial or abcesses or fracture
5- secondary amyloidosis

Question 20

Def of osteodstrophies

Answer 20

Abnormalities in bone growth and structure

Question 21

Def of fibrous displagia

Answer 21

1- replacement of bone by fibrous that characteristicly are prepared in concenric pattern containg tubercle
2- it can affect any bone at any age

Question 22

Types of fibrous dysplasia

Answer 22

Monostotic : one bome
Polyostotic : multiple but all bones
Albright syundrome : it has polyostotic lesion with skin pigmentation ( cafe au lait ) , sexual prematurity and endocrinopathies

Question 23

Gross picture of fibrous dysplasia

Answer 23

1- there is medullary fibrous proliferation which appears greyish and gritty with cortical thinning

Question 24

Microscopic picture of fibrous dysplasia

Answer 24

1- there is characteristic benign fibrous looking in concenric arrangement
2- there are curved and irregular trabcule bone Making fish hook or Chinese letter appearance
3- there is no osteoblast rimming around trabcule suggesting a maturation bone defect

Question 25

Complications of fibrous dysplasia

Answer 25

1- pathological fracture
2- sarcomatous transformation

Question 26

Name osteodystrophies

Answer 26

1- fibrous dysplasia
2- pagets disease ostitis deformans
3- osteoporosis
4- osetitis fibrosa cystica

Question 27

Pagets dieseae of bone def and most common age and sex

Answer 27

It is an osteoletic and osteosclerotic bone disease that can be monostotic or polyostotic

Male are more affected over the age of 50

Question 28

Aetiology of Paget’s disease

Answer 28

Unknown but it is suggested
1- due to viral infection
2- genetically determined

Question 29

Clinical picture of Paget’s disease

Answer 29

When it’s monostotic it is asymptomatic and can be discovered accidentally or radiologically but when it is polyostotic it is not and may produce pain , fracture and deformity and sarcomatous transformation

Question 30

Microscopic picture of Paget’s disease

Answer 30

3 stages
1- intial osteolytic stage : its characterized by areas of osteoclastic resorption produced by large number of osteoclasts
2- mixed osteolytic osteosclerotic stage : imbalance between osteoblasts forming new bone and osteoclast resorpting resulting in development of characteristic mosaic pattern or jigsaw puzzle appearance of bone
3- quiescent osteosclerotic stage : after many years excessive bone formation become more compact and dense producing osteosclerosis

Question 31

Def of osteoporosis

Answer 31

Common clinical syndrome involving multiple bones in which there is quantitative reduction of bone tissue mass

Question 32

Causes of osteoporosis

Answer 32

1- senility
2- post menopausal women
3- decreased mobility due to paralysis
4- cushing syndrome
5- prolonged corticosteroid therapy

Question 33

Complications of osteoporosis

Answer 33

1- bone deformity ( kyphosis)
2- pathological fracture

Question 34

What can cause ostetitis fibrosa cystica

Answer 34

Prolonged Hyperparathyrodism
The lesion is a manifestation of primary hyperparathyrodism
And less frequently as a result of secondary hyperparathyrodism such in chronic renal failure ( renal dystrophy)

Question 35

What are other bone diseases manifestations of hyperparathyrodism

Answer 35

1- susceptibility to fracture
2- skeletal defromity
3- joint pain
4- dysfunction