Osteomyelitis

Osteomyelitis

Bone infection
By Dr. Ihsan Alshamy

Types ( classification )according to mechanism of infection

exogenous

open fracture

Surgery

Penetrating injuries

Endogenous ( hematogenous)

bacteremia in blood

According to duration of the disease
Acute ( less than 2 weeks)


Subacute (2-3 weeks )

Chronic ( more than 3 weeks )

Acute hematogenous osteomyelitis
Incidence:
88% occurs in children
(Because the children is more subjected to trauma and the developed hematoma may acts as a media for bacterial growth)

12% occurs in adults

(especially common in immune compromised adult patients )

Acute hematogenous osteomyelitis

It is common around the knee joint
Proximal tibia and lower femur

50% around knee

Acute hematogenous osteomyelitis

It is common in the metaphysis of long bones.
Pathogenesis :
1.Due to vascular stasis. The metaphysial blood vessels twist back in sharp hairpin loops pattern before it enter large sinusoidal veins, it gives time for the bacteria to escape from the vessels to the bone.


2. Relative decrease in phagocytes number in metaphysis.

pathology

Clinical features

High grade fever
Swelling( signs of inflammation)
Limitation of movement ( pseudoparalyasis )

Investigation

Increase WBC count (neutrophil series)


Increase ESR

Increase C-reactive protein level

Blood culture

Positive only in 60%

Bone aspirate

If purulent material is aspirated , this will confirm the diagnosis and necessitate surgical drainage and clearance .

The aspirate should be sent for :

White cell count
Gram stain
Culture and sensitivity


Staphylococcus aureus : 80% of cases

Streptococcus hemolyticus : 10%

Salmonella : common in patients with sickle cell anemia.

Hemophilus influenzae : common in patients below 5 years

Radiography

* Early is negative only soft tissue swelling.

* After 2 weeks will shows rarefaction of the bone

* After 3 weeks new bone formation ( periosteal new bone formation )( involucrum)

Bone scan

Will shows Increase uptake of radioactive material ( hot spot).

it is 90% - 95% diagnostic and positive in the first 24-48 hours.

low specificity
Can not differentiates Between infection and tumor.

Management

RESTS
R : rest in bed and splint to alleviate pain and prevent pathological fracture.
E : elevation of the limb.
S : systemic ( fluid and blood transfusion).
T : treatment ( antibiotics).
S : surgery


Antibiotics
* should be started according to the results of bone aspirate or blood culture

* empirical treatment should be started as early as possible according to the best guess (the most probable organism ) and modified then according to the result of culture and sensitivity test.

* The principle of treatment is initial 2-4 weeks of intravenous antibiotics , followed by 4-6 weeks of oral antibiotics.

Indication of surgery

• If there is no improvement after 36 hours from starting the conservative treatment.
2 . If pus comes out during aspiration.

Surgery

Drain any subperiostial pus collection.

If you don’t fined pus: open the bone either by multiple drills or by making bone window.

Complications

• Septic arthritis
2. Chronic osteomyelitis.
3. Pathological fracture.
4. Epiphyseal damage and growth disturbance.


Complications
Septic arthritis
especially in intraarticular metaphyses ( sholder , elbow , hip)

Complications

Pathological fracture

Complications

Chronic osteomyelitis
( persistant discharging sinus and bone sequestra )

Complications

Epiphyseal damage and growth disturbance, common in infants and neonates

Thank you