osteomyelitis

1. Bone Infections
DR.FAROUQ MAKKIE ALYOUZBAKI
ORTHOPEDIC SPECIALIST
NINEVAH MEDICAL COLLEGE
5TH STAGE LECTURE

2. Objectives
1. Osteomyelitis
• Epidemiology
• Clinical features
• Diagnosis
• Management

3. BLOOD SUPPLY OF THE BONE
Normal - endosteal/medullary 2/3-
3/4
internal external
Fracture - periosteal/external
majority
internal external

5. “…presence of bacteria & an
inflammatory response causing
progressive destruction of bone.”
Fears, RL, et al, 1998
“…suppurative process in bone
caused by a pyogenic organism”
Pelligrini, VD, et al, 1996
DEFENTION

6. Epidemiology
• Bimodal age distribution
• Under 20
• Over 50
• Pediatrics:
• boys>girls
• Usually no identifiable risk factors
• Adults:
• Usually have risk factors

7. Bone and Joint Infections
Mechanism
• Hematogenous seeding most common
• Seeding from a contiguous source of infection
• Direct inoculation of the bone, from surgery,
trauma or joint aspiration

8. Risk factors for bone and joint
infections
• diabetes mellitus
• sickle cell disease
• AIDS
• alcoholism
• IV drug abuse
• chronic corticosteroid use
• preexisting joint disease
• other immunosuppressed states
• postsurgical patients—especially those with prosthetic devices

9. Pathology
• Inflammation: congestion and rise of intraoseous
pressure causing intense pain and vascular obstruction.
• Suppuration (2nd-3rd day): pus within bone through
Volkman’s canals to subperiosteal abscess, along the
bone shaft and may burst into soft tissues or skin as a
discharging sinus.

10. Pathology
• Necrosis (1 weak): due to
localized bone ischemia.
Formation of sequestrum.
• New bone formation (2weaks):
on deep layers of the stripped
periostium (periosteal reaction),
formation of involucrum. May
contain a discharging bone
sinus (cloacae).
• Resolution: if diagnosed and
treated early. Otherwise it
becomes chronic osteomyelitis.

11. Pathogens
• Bacteria are most common
• Viruses, fungi and parasites are possible
• Staph aureus most common in all ages except neonate.
• H. influenzae b has essentially disappeared as a pathogen
in vaccinated children
• Gonococcal arthritis is the most common type of septic
arthritis in individuals under 30 years old

12. Pathogens
• Usually unimicrobial
• Polymicrobial (36 to 50%) more
likely in diabetic foot
osteomyelitis, posttraumatic
osteomyelitis, chronic
osteomyelitis, and chronic septic
arthritis

13. DON’T DELAY DIAGNOSIS
AND TREATMENT

14. Osteomyelitis: Presentation
• May be acute or chronic
• Pain over the affected bone
• In children: limp or refusal to weight
• Localized warmth, swelling, and erythema
• Fever is inconsistently present
• Systemic complaints often reported: headache, fatigue,
malaise, and anorexia

15. Osteomyelitis: Presentation
• Point tenderness over the infected segment
• Palpable warmth and soft-tissue swelling with
erythema may be present

16. Osteomyelitis: Diagnosis
• WBC is neither sensitive nor specific
• Values commonly range from normal to 15,000/mm3
• ESR usually elevated
• One series reported 90% sensitivity
• Very nonspecific however
• Can be used to follow treatment
• CRP
• yet another nonspecific marker of inflammation

17. Osteomyelitis: Diagnosis
• Plain films:
• Low sensitivity early in the disease
• 3-5 days: may detect soft tissue edema
• 7-10 days: >66% still have normal x-rays
• 30-50% of bone mineral must be lost to detect lucency on plain film
• By 28 days, >90% of plain films will be positive
• Characteristic finding: lucent lytic lesions of cortical bone destruction
• Advanced disease: lytic lesions are surrounded by dense, sclerotic bone,
and sequestra may be noted in chronic osteomyelitis.

18. Plain radiograph of tibia. Lucent areas in metaphysis are sites of
advanced osteomyelitis

19. Plain radiograph of humerus. Distal
portion of humerus has involucrum
formation, representing advanced
case of osteomyelitis.

20. Osteomyelitis: Diagnosis
• Bone Scan:
• More useful early on than plain radiographs
• Can detect osteomyelitis within 48 to 72 hours of disease onset
• Sensitivity 90% with technetium-99 scan
• False positive rate as high as 64%
• Trauma, surgery, tumours, soft tissue infection

21. Example of gallium (top) and
technetium (bottom) bone
scans in advanced osteomyelitis
of tibial metaphysis. Both scans
show increased radionuclide
uptake.

22. Osteomyelitis: Diagnosis
• CT
• Used for infection in bones that are difficult to visualize on plain
radiographs and bone scans: sternum, vertebrae, pelvic bones,
and calcaneus
• Appears as rarefaction, or lucent areas, on the CT scan images

23. Osteomyelitis: Diagnosis
• MRI
• Good for early detection
• Limited availability

24. Osteomyelitis: Diagnosis
• Microbiologic Diagnosis:
• Needle aspiration or surgical specimen is best
• Swab of draining wound or sinus is not adequate
• Blood cultures in untreated patients are positive ~50% of the
time

25. Differential Diagnosis
• Tumour:
• Osteoid osteoma, chondroblastoma, Ewing’s sarcoma,
metastases, lymphoma
• Trauma
• Myositis ossificans
• Cellulitis
• Eosinophilic granuloma

26. Osteomyelitis: Management
• IV Antibiotics
• Empiric broad spectrum initially
• Narrow appropriately when sensitivities available
• 4-6 weeks
• +/- Surgical debridement
• Often not needed for acute hematogenous osteomyelitis in
children
• Required in the diabetic foot or chronic osteomyelitis

27. Special considerations
• Diabetic foot:
• Usually chronic and polymicrobial
• Surgical debridement almost always required
• Amputation often required
• Sickle cell disease:
• Increased risk of osteomyelitis
• S. aureus and Salmonella species

28. Empiric Therapy
Osteomyelitis Pathogen Therapy
Neonates S. aureus,
Enterobacteriaceae
Cloxacillin +
Cefotaxime
Children S. aureus, Strep, H.
flu
Cloxacillin
Sickle cell S. aureus,
Salmonella sp.
Cloxacillin +
Cefotaxime
Post-op S.aureus,
Enterobacteriaceae
Cefazolin +/-
Gentamicin
Post-op spinal rods
or sternotomy
S. aureus,
Enterobacteriaceae,
Pseudomonas
Vancomycin +
Gentamicin
Nail puncture of foot Pseudomonas
aeruginosa
Piperacillin+Tobra or
Ceftazidime + Tobra

29. SURGICAL TREATMENT
The two main indications for
surgery in acute hematogenous
osteomyelitis are:
1. The presence of an abscess requiring
drainage
2. Failure of the patient to improve despite
appropriate intravenous antibiotic
treatment

30. SUBACUTE HEMATOGENOUS
OSTEOMYELITIS
More insidious onset and lacks
severity of symptoms
Indolent course hence diagnosis
delayed for more than two weeks.

31. SUBACUTE HEMATOGENOUS OSTEOMYELITIS
CLINICAL FEATURES
• The indolent course of subacute osteomyelitis is
due to:
• increased host resistance
• decreased bacterial virulence
• administration of antibiotics before the onset
of symptoms
• Systemic signs and symptoms are minimal
• Temperature is only mildly elevated
• Mild to moderate pain

32. SUBACUTE HEMATOGENOUS OSTEOMYELITIS
INVESTIGATIONS
White blood cell counts are generally
normal
ESR is elevated in only 50% of patients
Blood cultures are usually negative
Plain radiographs and bone scans
generally are positive

33. SUBACUTE HEMATOGENOUS OSTEOMYELITIS
BRODIE ABSCESS
• Localized form of subacute osteomyelitis
occuring most commonly in the long bones
of the lower extremeties
• Intermittent pain of long duration is most
times the presenting compliant, along with
tenderness over the affected area

34. Brodie abscess

35. SUBACUTE HEMATOGENOUS OSTEOMYELITIS
BRODIE ABSCESS
 On plain radiographs appears as a lytic
lesion with a rim of sclerotic bone
 S aureus is cultured in 50% of patients and
in 20% the culture is negative
 The condition requires open biopsy with
curetage to make the diagnosis

36. SUBACUTE HEMATOGENOUS OSTEOMYELITIS
TREATMENT
• Biopsy and curettage followed by treatment with
appropriate antibiotics for all lesions that seem to be
aggressive
• For lesions that seem to be a simple abscess in the
epiphysis or metaphysis biopsy is not recommended- IV
antibiotics for 48 hrs followed by a 6 week course of
oral antibiotics

37. CHRONIC OSTEOMYELITIS
• Hallmark is infected dead bone within a
compromised soft tissue envelope
• The infected foci within the bone are
surrounded by sclerotic, relatively avascular
bone covered by a thickened periosteum
and scarred muscle and subcutaneous
tissue

38. Classification of COM

39. Anatomical classification

40. Clinical evaluation COM
1. Skin and soft tissue integrity
2. Tenderness
3. Bone stability
4. Neurovascular status of limb
5. Presence of sinus

41. INVESTIGATIONS
1. Erythrocyte sedimentation rate
2. C reactive protein
3. WBC count only elevated in 35%
4. Biopsy for histological and microbiological
evaluation
Staphyloccocus species
Anaerobes and gram negative bacilli

42. Imaging studies in COM
Plain X rays shows
• Cortical
destruction
• Periosteal
reaction
• Sequestra
• Sinography

44. Sinography

45. Treatment of COM
Surgical treatment mainstay are
• Sequestrectomy
• Resection of scarred and
infected bone and soft tissue
• Radical debridement
• Resection margins >5mm

46. Treatment of COM
Antibiotic duration is controversial
• 6 week is the traditional duration
• 1 week IV, 6 weeks of oral therapy
• Antibiotic polymethyl methacrylate (PMMA)
beads as a temporary filler of dead space
• Biodegradable antibiotic delivery system

47. Thanks for your attention!