Bone Infections Medical ppt http://hastaneciyiz.blogspot.com

Outline

 Acute Osteomyelitis  Subacute Osteomyelitis  Post-Operative Infections

Defining

Osteomyelitis

What’s in a Name?

Osteomyelitis

(

Osteo

- bone,

Myelo

Marrow, and

–itis -

Inflammation)

Defining

Osteomyelitis

What is it?

It is an infection of the of the bone or bone marrow which leads to a subsequent Inflammatory process.

Defining

Osteomyelitis

Where does it come from?

Micro-Organisms may reach bones via the

Bloodstream

or by

Direct Invasion

.

Defining

Osteomyelitis

What affects it’s development?

 Organism involved  Host Factors (i.e. Age, Immunity, Diseases)  Site of Involvement (i.e. local factors)

Defining

Osteomyelitis

What affects it’s development?

 Organism involved  Host Factors (i.e. Age, Immunity, Diseases)  Site of Involvement (i.e. local factors)

I.

Acute Osteomyelitis

Types of Acute Osteomyelitis

II.

Hematogenous Osteomyelitis Direct Inoculation Osteomyelitis

Acute Osteomyelitis

Hematogenous Osteomyelitis:

 Bacterial seeding from the blood.  Seen primarily in Children.

 The most common site is the

Metaphysis

at the growing end of Long Bones in Children, and

The Vertebrae and pelvic

in Adults.

Acute Osteomyelitis

Direct Inoculation Osteomyelitis

 Direct contact of the tissue and bacteria as a result of an Open Fracture or Trauma.  Tend to involve multiple organisms.

Acute Osteomyelitis Causative Organisms:



Staphylococcus aureus (Mainly)

 Streptoccous pyogens or pneumoniae. (Less)  H.Influenzae (Young Children)  Salmonella (Sickle-Cell)

Acute Osteomyelitis

• •

Pathology:



Inflammation.

Earliest Change Increase interaosseous pressure leads to Pain.

• •  Suppuration.

Pus @ Medulla =Volkmann canals=>Surface => Subperiosteal Abscess=> spread along the shaft=> re-enter the bone or burst into the soft tissue May extend to Epiphysis and Metaphysis in Neonates and Children. May extend to Interverteberal Discs in Adults.

Acute Osteomyelitis

• Pathology: 

Necrosis.

Begin to see signs with in one week.

• •  New-bone formation.

Bone thickens to form an

involucrum

infected tissue.

enclosing the Perforation may occur converted acute into chronic osteomyelitis.

 Resolution.

Acute Osteomyelitis Clinical Features:

 Pain  Fever and Malaise  Tenderness  Restricted Joint Movement  Redness, Edema, Warmth (Signify Pus)  History preceding Skin Lesion or Sore Throat.

Acute Osteomyelitis Imaging:

 First 10 days X-Rays Show No Abnormality.

 By the end of the 2 nd Week signs of rarefaction of Metaphysis and New Bone Formation.  With Healing there is Sclerosis and thickening of Cortex.

 MRI may help to distinguish between Bone and Soft-Tissue Infection.

Acute Osteomyelitis Investigations:

 CBC   Leucocytosis C-reactive protein level usually is elevated  ESR usually is elevated

Investigations

1.

Lab studies 2.

Radiological studies

Lab studies

 CBC: leucocytosis  The C-reactive protein level usually is elevated (nonspecific but more useful than ESR).  ESR usually is elevated (90%) nonspecific.  Aspiration of the pus from the subperiosteal abscess and culture, and test sensitivity for antibiotics  Blood culture results are positive in only 50% of patients with hematogenous osteomyelitis.

Radiological studies

X-Ray:  First sign is soft-tissue edema at 3-5 days after infection.  Bony changes are not evident for 14-21 days:  1. early radiographic signs of rarefraction (thining of bony tissue sufficient to cause decreased density of bone) of the metaphysis and periosteal new bone formation 2. increasing ragged if treatment is delayed 3. sclerosis and thickening of the bone at healing Approximately 40-50% focal bone loss is necessary to cause detectable lucency on plain films.

 Plain-film radiograph showing osteomyelitis of the second metacarpal (arrow). Periosteal elevation, cortical disruption and medullary involvement are present.

 The above X-ray of the left ankle of a 10-year-old boy shows lucency in the tibial metaphysis secondary to acute hematogenous osteomyelitis (AHO).  The above X-ray of the right ankle of a 10-year old boy shows lucency in the tibial metaphysis secondary to acute hematogenous osteomyelitis (AHO).

Here is an X-ray of an AHO lesion extending into the growth plate.

Radiological studies

 MRI : Early detection and surgical localization of osteomyelitis. Sensitivity ranges from 90-100%.  Radionuclide bone scanning : A 3-phase bone scan with technetium 99m is probably the initial imaging modality of choice Show increase activity but it is a non specific sign of inflamation.

This MRI sagittal section shows the same AHO lesions with the right lesion extending into the growth plate.

Bone scans, both anterior (A) and lateral (B), showing the accumulation of radioactive tracer at the right ankle (arrow). This focal accumulation is characteristic of osteomyelitis.

Radiological studies

CT scan (spinal vertebral lesions, complex anatomy: pelvis, sternum, and calcaneus) Ultrasound In children with acute osteomyelitis. May demonstrate changes as early as 1-2 days after onset of symptoms. Abnormalities include soft tissue abscess or fluid collection and periosteal elevation. Ultrasonography allows for ultrasound-guided aspiration. It does not allow for evaluation of bone cortex

Diagnosis

Diagnosis requires 2 of the 4 following criteria: ◦ Localized classic physical findings of bony tenderness, with overlying soft-tissue erythema or edema. ◦ ◦ ◦ Purulent material on aspiration of affected bone. Positive findings of bone tissue or blood culture. Positive radiological imaging study.

Treatment

Principles of treatment: 1.

Analgesia an general supportive measures.

2.

Rest of the affected part 3.

Antibiotic treatment.

4.

Surgical eradication of pus and necrotic tissue(debridement).

Treatment

Antibiotic treatment: Start with IV antibiotics for 1-2 weeks then oral for 3-6 weeks.

Take cultures to detect the organism and its sensitivity pattern.

Start empirical treatment before the results came back, then modify it according to the results.

Treatment

Antibiotic choices:

Older children and adults (staph infection): fluloxacillin and fusidic acid.

MRSA: Vancomycin Children younger than 4 year-old or those with gram negative organisms: 3 rd generation cephalosporins.

Heroin addicts and immuno-compromised patients: more specific antibiotics.

Cont

…  Sickle cell anemia and osteomyelitis: fluoroquinolone antibiotic (not in children). A 3 rd cephalosporin (eg, ceftriaxone) is an alternative choice.  Nail puncture occurs through an athletic shoe (

S aureus Pseudomonas aeruginosa)

: ceftazidime or cefepime. Ciprofloxacin is an alternative treatment.

and  Trauma (

S aureus

, coliform bacilli, and

Pseudomonas aeruginosa

activity.

): nafcillin and ciprofloxacin. Alternatives include vancomycin and a 3rd cephalosporin with antipseudomonal

Treatment

# Drainage:  Subperiosteal abscess  Pyrexia and local tenderness more than 24 hour after adequate antibiotic treatment.

# Removal of prosthetic implants: If they become unstable after a trauma.

Or intractable infection following joint replacement.

# Severe cases may lead to the loss of a limb.

Prevention

 Improve immunity.

  1.

2.

3.

4.

Post-traumatic infection (regular wound dressing for established infection): Debridement of open fractures.

Stabilization of fractures.

Antibiotics.

Closure of exposed bone surfaces.

Postoperative infection: 1.

2.

3.

4.

Cleanest possible surgical environment.

Careful haemostasis.

Suction drainage.

Prophylactic antibiotics in high risk surgeries.

Subacute

Osteomyelitis

 Results from a less virulent Microorganism, or a patient with an elevated resistance.

  Occurs Mostly at the Distal Femur or Proximal Tibia On X-Ray we See Brodie’s Abcess : Small and Oval in shape It is surrounded by sclerotic bone Osteoma May be mistaken for Ostieoid

Subacute

Osteomyelitis

 An image depicting subacute osteomyelitis

Post Operative Infections

 Prophylaxis is KEY in prevention.

 Treated According to Infection

Post Operative Infections

 Not Uncommon, about a 5% incidence.

 1.

2.

3.

4.

5.

6.

7.

8.

Predisposed by: Debility Chronic disease Previous Infection Tight Dressing Corticosteroid Treatment Long Surgery Hematoma Foreign Material Implants Medical ppt http://hastaneciyiz.blogspot.com