1. Osteomyelitis
Prof. Mamoun Kremli

2. Definition Osteomyelitis Osteo: bone, myelo: bone marrow,
itis: inflammation
An inflammation of the bone caused by an infecting organism (infection)
Mostly bacterial, can be fungal

3. Types of Osteomyelitis
Acute
Sub-acute
Chronic
Non-specific: any organism
Specific: example: Tb
Hematogenous: from blood stream
Contiguous: from nearby tissue

4. Acute Osteomyelitis

5. Prevalence: Children 1: 5000 Sickle cell patients 3.6: 1000
Post puncture wound to foot
Higher in developing countries

6. Common patients Almost invariably children, Adults: Post open trauma
Post surgery
Debilitating disease
Drug addicts: IV injection sites

7. Etiology – source of infection
Micro-Organisms may reach bones via:
Bloodstream, (commonest) from another infection (e.g. tonsilitis, otitis media, umbilical,..),

8. Etiology – source of infection
Micro-Organisms may reach bones via:
Bloodstream, (commonest) from another infection (e.g. tonsilitis, otitis media, umbilical,..), or
Direct Invasion from neighboring tissues,
Fayad L M et al. Radiographics 2007;27

9. Etiology – source of infection
Micro-Organisms may reach bones via
Bloodstream, (commonest) from another infection (e.g. tonsilitis, otitis media, umbilical,..), or
Direct Invasion from neighboring tissues, or
Direct to exposed bone in open fxs or operations

10. Etiology – causative Organisms
Staphylococcus Aureus (mainly)
Streptococcus Pyogenes (less)
Streptococcus Pneumoniae (less)
Children < 4 yrs:
H influenzae
In Sickle cell disease:
Salmonella

11. Common sites Children: Older patients:
Metaphysis of long bone: Femur, Tibia, Humerus
Older patients:
Vertebral bone
Any other bone

12. Common sites Why in metaphysis of long bone?:
Sluggish blood flow through loop-ended vessels and sinusoidal venous system
Poor collateral circulation
Susceptibility of this region to trauma - hematoma
Deficiency of phagocytic cells

13. Pathology Pathology varies – depends on: Age, Site of infection,
Virulence of organism,
Host response

14. Copyright © Mosby, Inc., an affiliate of Elsevier Inc.
Pathology
Innoculation by organisms in bone marrow
Inflammation:
Infiltration of neutrophils to bone
Vessels are congested, with
hyperemia
Exudates increase pressure
(painful)
Copyright © Mosby, Inc., an affiliate of Elsevier Inc.

15. Copyright © Mosby, Inc., an affiliate of Elsevier Inc.
Pathology
Suppuration: (day 2-5)
Increased pressure, leads to thrombosed vessels and cause bone necrosis
Periosteum elevated by the
subperiosteal abscess,
reducing blood supply further,
and causing bone necrosis
Could spread to joints in infants
and where metaphysis is
intra-articular
Copyright © Mosby, Inc., an affiliate of Elsevier Inc.

16. Copyright © Mosby, Inc., an affiliate of Elsevier Inc.
Pathology
Necrosis:
formation of Sequestrum (dead bone)
New bone formation (involucrum)
encloses infected tissue
and could have openings
to outside, (cloacae)
Copyright © Mosby, Inc., an affiliate of Elsevier Inc.

17. Pathology – 3: Necrosis Long bones get blood from three sources:
Nutrient artery
Periosteum, and
Surrounding soft tissues (minor amount)

18. Pathology Necrosis: results in dead bone (Sequestrum)
New bone formation (involucrum) encloses infected tissue and could have openings to outside (cloacae)
Sequestrum
Involucrum

19. Histopathology Dense inflammatory cell infiltrate in the marrow space
Adjacent bony trabeculae are necrotic
note the absence of osteocytes in lacunae
Figure Acute osteomyelitis. Microscopic section showing a dense inflammatory cell infiltrate in the marrow space. The adjacent bony trabeculae are necrotic (note the absence of osteocytes in lacunae).

20. Pathology Resolution: Sclerosis, thickening of bone Deformity
Chronic Osteomyelitis

21. Pathology

22. Pathology Necrotic bone results from cutoff blood supply Microabscess
in Metaphysis
Abscess spreads
subperiosteally
Abscess spreads
Presure increases

23. Pathology

24. Clinical features Typical patient, with history of trauma
Pain, malaise, fever, decreased mobility
Recent history of infection
Local tenderness
Local redness, swelling (late sign), differentiate from cellulitis

25. Radiology First 10 days X-Rays Show No Abnormality.
By the end of the 2 weeks, signs of:
Rarefaction of Metaphysis, and

26. Radiology First 10 days X-Rays Show No Abnormality.
By the end of the 2 weeks, signs of:
Rarefaction of Metaphysis, and
New Bone Formation (periosteal reaction)

27. Radiology With Healing there is Sclerosis and thickening of Cortex.

28. Diagnosis
Clinical

29. Diagnosis Clinical X-ray: US, MRI, Bone scan, CBC, ESR, CRP
soft tissue swelling,
periosteal reaction (at 2 weeks)
patchy rarefaction of metaphysis
US, MRI, Bone scan,
CBC, ESR, CRP
Aspiration of bone
Blood C/S (positive only in 50%)

30. Radiological studies MRI :
Early detection and surgical localization of OM
helps to distinguish between bone and soft-tissue infection
Sensitivity ranges from %.

31. Radiological studies Radionuclide bone scanning :
Technetium 99m bone scan is probably the initial imaging modality of choice
Show increase activity
but it is non-specific

32. Radiological studies Radionuclide bone scanning :
More sensitive than X-rays (early detection)

33. Investigation CBC: increased WBC ESR: raised
CRP: high (more specific and more sensitive)
Bone aspiration:
Diagnostic,
Identifies bacteria by culture
Check sensitivity for antibiotic choice

34. Treatment Aim of treatment
Should detect and treat early and properly to stop the progression of pathology

35. Treatment Principles of treatment:
Analgesia an general supportive measures.
Rest of the affected part
Antibiotic treatment.
Surgical eradication of pus and necrotic tissue (debridement).

36. Treatment Antibiotic treatment:
Start with IV antibiotics for 2-3 weeks then oral for 3-6 weeks.
Take cultures to detect the organism and its sensitivity pattern.
Start empirical treatment before culture result, then modify treatment according to the result of culture and sensitivity

37. 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:
3rd generation cephalosporins.
Drug addicts and immuno-compromised patients: more specific antibiotics.

38. Treatment
Surgery:
If fever and local tenderness persist for more than 24 hour after adequate antibiotic treatment.
Drilling, drainage of pus and debridement of bone and removal of sequestrum

39. Treatment Removal of implants and prosthesis:
If they become unstable after a trauma.
Or intractable infection following joint replacement.
Severe cases may lead to the loss of a limb.

40. Follow-Up Clinical symptoms and signs Repeat WBC and ESR
Should return to normal levels
Follow up films
radiologic recovery slower than clinical recovery

41. Complications Bacteremia and metastatic infection
Septic arthritis of neighboring joint
Pathological fracture
Altered bone growth
Loosening of the implant:
fixation / prosthesis
Bone abscess
Chronic osteomyelitis

42. Complications
Chronic Osteomyelitis

43. Special consideration
Chronic Osteomyelitis in Diabetic foot
Poor sensation
Poor blood supply
Poor resistance
Poor healing
Jose R. Jimenez MD, UTHCT

44. Summary - Osteomyelitis
What is osteomyelitis
Etiology
Pathology
Investigations and diagnosis
Treatment