Bone infection

Osteomylitis Definition:- inflammation of the bone or bone marrow caused by infection. Two types:- Pyogenic T.B osteomylitis

Pyogenic osteomylitis Causetive organisms:- Staphylococcus aureus Age :- Infants and children Organisms may infect bone through:- 1- Bloodstream, from local areas of infection (as in cellulitis). 2- Penetrating trauma e.g joint replacements or internal fixation of fractures.

Pyogenic osteomylitis Site of affection :- The most common site is tubular bones as they have the most rapid growth and the largest metaphysis Clinical picture:- With acute osteomyelitis, the presenting complaint is usually local pain, swelling, and warmth, often associated with fever and malaise. Affect children

Radiographic appearance of Osteomyleitis Radiographic changes after 10-14 days after onset of infection. Soft tissue swelling ( the earliest sign). Cortical thickening Irregularity of cortices Sclerosis

Radiographic appearance of Osteomyleitis Bone destruction in the metaphysis. Periosteal reaction, may become very extensive and surround the bone to form an involucrum.

Radiographic appearance of Osteomyleitis A part of original bone may die and form a separate dense fragment called sequestrum.

Radiographic appearance of Osteomyleitis Brodie’s abscess: It occurs when osteomylitis is partially treated . Brodie’s abscess is a spherical region of bone destruction, filled with pus or connective tissue, Oval translucency larger than 1cm surrounded by a heavily reactive sclerosis near end of long bones (metaphysis). Small sequestrum may be present. Loss of differentiation between the cortex and the medulla.

Brodie’s abscess Typical appearance of a Brodie's abscess is :- Lucency within the distal metaphysis with surrounding reactive sclerosis.

Role of radionuclide image Much more sensetive for detecting early disease Increased uptake after two to three days.

Role of ultrasound Demonstrate subperiosteal collection of pus well before bone changes on plain x-ray,

Role of MRI Shows the changes early as bone edema and pus accumuation. Detect the extent of the infection better than other modalities.

Role of CT May be used in selected cases to show sequestra

How to D.D between osteomyelitis and tumor It is not always possible. Clinical history . Initial films Ct and MRI , may be better in D.D as they detect the lesion better. Biopsy is needed in some cases.

T.B osteomyelitis Spine, followed by large joints. Produce large area of bone destruction. May be asymptomatic in early changes.

Alteration of trabecular pattern of bone

Paget’s disease Chronic progressive focal disease of bone. Characterized by excessive resorption followed by excessive formation of bone, with abnormal bone remodeling. The bone that is formed is abnormal, enlarged, and prone to fracture. This process results in extensive local vascularity and increased fibrous tissue in the bone marrow. Involvement is usually polyostotic and asymmetric. Sites of affection :- Pelvis, spine, skull, femur, and tibia.

Paget’s disease Clinical presentation:- Unknown aetiology Eldery patient Clinical presentation:- Majority are asymptomatic and diagnosed as an incidental finding Bone pain Fracture Deformity ( bowing ) of long bones

Paget’s disease Radiological features Long bones:- Cortical thickning Sclerosis Coarsened trabecular pattern Increase size of the bone Bowing of long bone

Paget’s disease Dense sclerosis involving the femoral head and neck . This is a high-risk area for insufficiency fracture.

Paget’s disease Late-stage Paget disease reveals a transverse fracture through the proximal femoral shaft (banana fracture).

Paget’s disease Skull :- A large lytic well defined area (osteoprosis circumscripta).

Paget’s disease

Paget’s disease Skull :- Many circumscribed patches of sclerotic bone in the calvarium giving a motteled appearance (cotton wool appearance).

Paget’s disease Advanced Paget's disease of the skull. Thickened inner and outer tables, new bone deposition (cotton-wool patch(

Paget’s disease Spine :- Picture Frame vertebral body (enlarged square vertebral body with peripheral sclerosis and inner lucency).

Paget’s disease Spine :- Densely sclerotic vertebral body (ivory vertebra)

Paget’s disease Pelvis :- Coarsened trabecular pattern Cortical thickning Enlargment of the pubis and ischium.

Paget’s disease Patchy sclerosis and coarsened trabecula characteristic of late-stage Paget disease. A fracture of the ischium inferior to the acetabulum (arrows) is present.

Paget’s disease Complications:- Pathological fracture Osteosarcoma

Generalized decrease in bone density (osteopenia)

Osteopenia is a nonspecific radiographic finding that indicates increased radiolucency of bone . Bone density may be difficult to assess because of technical factors (Kvp , mA)

Causes of generalized decrease in bone density (osteopenia) Osteoprosis Osteomalacia Hyperparathyrodism Multiple myeloma

Osteoprosis Reduction of calcium content due to deficiency of osteoid (unmineralized portion of the bone matrix forms prior to the maturation of bone tissue ). Increase % of fractures especially in the vertebral bodies and hips.

Causes of osteoprosis 1- Idiopathic :- Juvenile. Postmenopausal . Senile . 2- Cushing syndrome and steroid therapy. 3- D.M . 4- Arthritis. 5-Pregnancy. 6- Fracture.

Osteoprosis Clinical presentation:- Asymptomatic Bone pain Skeletal fracture

Radiographic diagnosis Most commonly seen in the spine. Overall decrease in bone density except the cortex still clear. Collapse of the vertebral bodies , so they appearing as wedged or biconcave . Widened of the intervertebral disc spaces , if Several vertebral bodies are affected. In long bones, there is thinning of the cortices.

Osteoprosis

Osteoprosis An osteoporotic spine, showing compression fractures in the L1 and L3 vertebral bodies.

Osteoprosis Two views of the lumbar spine taken 1 year apart demonstrate rapidly developing osteoporosis and multiple compression fractures .

Ricketes

Ricketes Rickets is a softening of bones in children leading to fractures and deformity Occur before epiphyseal closure., It is caused by a failure of osteoid to calcify (unmineralized portion of the bone matrix forms prior to the maturation of bone tissue ).

Ricketes Causes of rickets:- Dietery deficiency of vitamine D, or lack of exposure to sunlight , resulting in decreased production of endogenous vitamine D which is important for absorption of calcium , resulting in hypocalcemia Malabsorption leading to impaired absorption of calcium or vitamine D. Renal disease where rickets develops despite normal amount of vitamine D (vitamin D resistant rickets). Chronic renal faliure .

Ricketes Clinical picture :- Delayed growth Pain in the spine, pelvis and legs Bowed legs Abnormally curved spine

Radiological features of ricketes Commonly seen at the knee,wrists , and ankles. Fraying and indistinct margins of the metaphysis, causing a cupped appearance Increased distance between the visible epiphysis and calcified portion of metaphysis.

Ricketes Bowing and curvature of the bones occur because the undermineralized bone is soft Bulbous enlargement of the anterior ends of the ribs producing a (ricketry rosary appearance ). Greenstick fracture is common.

Osteomalacia

Osteomalacia Occurs in adults due to failure of osteoid to calcify .

Osteomalacia Radiological features Loss of bone density. Thinning of the cortex. Bone deformity due to bone softening e.g bowed of the femora and triradiate pelvis (bent inwards). The vertebral bodies are biconcave.

Osteomalacia Looser’s zone (pseudofractures) :- Are short lucent bands running through the cortex at right angles . may have sclertotic margin. Location :- scapula , femoral necks and pubic rami.

Ostomalacia Losser’s zone in the femoral neck

Generalized increase in bone density

Generalized increase in bone density Conditions that cause generalized increase in bone density :- Sclerotic metastasis Osteopetrosis Myelosclerosis

Osteopetrosis (marble bone disease) Congenital disorder of bone formation . The bones are densely sclerotic . The bones are brittle and may fracture but heal easily.

Osteopetrosis AP and lateral knee in a patient with osteopetrosis

Thank you