Osteomyelitis

Prof. Mamoun Kremli

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

Types of Osteomyelitis

Acute Sub-acute Chronic

Non-specific: any organism Specific: example: Tb

Hematogenous: from blood stream Contiguous: from nearby tissue

Acute Osteomyelitis

5

Prevalence:

Children 1: 5000 Sickle cell patients 3.6: 1000 Post puncture wound to foot

Higher in developing countries

Common patients

Almost invariably children, Adults:

Post open trauma Post surgery Debilitating disease Drug addicts: IV injection sites

www.firstaidreference.com/

www.winnipegsun.com/

Etiology – source of infection

Micro-Organisms may reach bones via: Bloodstream, (commonest) from another infection

(e.g. tonsilitis, otitis media, umbilical,..),

http://dermatlas.med.jhmi.edu/http://en.wikipedia.org/wiki/Tonsillitis

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

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

http://taycoleahcf.blogspot.com/ http://eorif.com/General/

Etiology – causative Organisms

Staphylococcus Aureus (mainly) Streptococcus Pyogenes (less) Streptococcus Pneumoniae (less)

Children < 4 yrs: H influenzae

In Sickle cell disease: Salmonella

Common sites

Children: Metaphysis of long bone: Femur, Tibia, Humerus

Older patients: Vertebral bone Any other bone

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

Pathology

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

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.

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 infantsand where metaphysis isintra-articular 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 openingsto outside, (cloacae)

Copyright © Mosby, Inc., an affiliate of Elsevier Inc.

Pathology

Necrosis: results in dead bone (Sequestrum) New bone formation (involucrum) encloses

infected tissue and could have openings to outside (cloacae)

http://osteomyelitis.stanford.edu/http://www.uaz.edu.mx/histo/pathology/

Sequestrum Involucrum

Histopathology

Dense inflammatory cell infiltrate in the marrow space

Adjacent bony trabeculae are necrotic note the absence of

osteocytes in lacunae

Pathology

Resolution: Sclerosis, thickening of bone Deformity Chronic Osteomyelitis

Pathology

http://blackpoppymag.wordpress.com/2011/03/21/osteomyelitis/

Microabscessin Metaphysis

Abscess spreadsPresure increases

Abscess spreadssubperiosteally

Necrotic boneresults from

cutoff blood supply

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

http://www.ptolemy.ca/ http://dermatlas.med.jhmi.edu/

Radiology

First 10 days X-Rays Show No Abnormality.

By the end of the 2 weeks, signs of: Rarefaction of

Metaphysis, and

http://www.steadyhealth.com/

http://ortho.host56.com/

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)

http://www.steadyhealth.com/

http://ortho.host56.com/

Radiology

With Healing there is Sclerosis and thickening of Cortex.

http://connect.in.com/osteomyelitis

Diagnosis

Clinical

Diagnosis

Clinical X-ray:

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%)

Radiological studies

MRI : Early detection and

surgical localization of OM

helps to distinguish between bone and soft-tissue infection

Sensitivity ranges from 90-100%.

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

http://ortho.host56.com/

Radiological studies

Radionuclide bone scanning : More sensitive than X-rays (early detection)

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

http://reference.medscape.com/

Treatment

Aim of treatment Should detect and treat early and properly to stop

the progression of pathology

Treatment

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

(debridement).

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

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.

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

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.

Follow-Up

Clinical symptoms and signs Repeat WBC and ESR

Should return to normal levels Follow up films

radiologic recovery slower than clinical recovery

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

Complications

Chronic Osteomyelitis

http://digitalmedicine.com.np/

Special consideration

Chronic Osteomyelitis in Diabetic foot Poor sensation Poor blood supply Poor resistance Poor healing

Jose R. Jimenez MD, UTHCT

Summary - Osteomyelitis

What is osteomyelitis Etiology Pathology Investigations and diagnosis Treatment

http://www.sarcoma.org/pathology