WEEK OBJECTIVE 5 (OSTEOMYELITIS)

1. Line out classification and features of various form of musculoskeletal infection*will be answered by Maggie later

2. Describe the pathological features of pyogenic and granulomatous osteomyelitisSystemic disease.Symptoms: bone pain, fever, malaise, local swelling, dull continuous back pain which increases on straining.

Risk factors: diabetes, hemodialysis, injected drugs, AIDS, etc.

Lee and Waldvogel classification: Acute vs chronic Hematogenous vs contigious Presence of vascular insufficiency

Acute pyogenic osteomyelitis Staphylococcus aureus (methicilin sensitive) Eschericia coli neonates Salmonella patient with sickle cell

-Infants: (di metaphysis, bisa menyebar ke epifisis dan joint capsule)Infection cortical bones periosteum subperiotsteal abscess and draining sinuses detachment of periosteum ischemic necrosis-di org dewasa deattachment periosteum jarang terjadi karena periosteum sudah melekat kuat ke articular.

Chronic Osteoclast activation, fibroblast proliferation and new bone formation. Necrosis bone sequestrum Reactive new bone involucrum Brodie abscess(?)

The primary site of infection is usually in the metaphysial region, from which the infection may spread to involve the cortex and form a subperiosteal abscess; may spread into the medullary cavity; or, rarely, may spread into the adjacent joint space.

Tuberculous Osteomyelitis

Tuberculous = Pott Disease = Spinal Tuberculosis

Mycobacterium tuberculosis attack synovium (high 02 pressure) adjacent epiphysis granulomatous inflammatory reaction (caseous necrosis and extensice bone destruction)

Special Symptoms: night sweating

radiologic classification for primary subacute osteomyelitis

modified classification of subacute osteomyelitis. Type I is metaphyseal. Type Ia is a punched-out central metaphyseal lesion. Type Ib is an eccentric metaphyseal cortical erosion. Type II is diaphyseal. Type IIa is a localized cortical and periosteal reaction. Type IIb is a medullary abscess in the diaphysis without cortical destruction but with onionskin periosteal reaction. Type III is epiphyseal. Type IIIa is a primary epiphyseal osteomyelitis. Type IIIb is a lesion that crosses the epiphysis and involves both the epiphysis and the metaphysis. Type IV is a metaphyseal equivalent. Type IVa involves the vertebral body with an erosive or destructive process. Type IVb involves the flat bones of the pelvis. Type IVc involves the small bones, such as the tarsal bones.

Harrison's Online > Part 8. Infectious Diseases > Section 2. Clinical Syndromes. Community-Acquired Infections > Chapter 126. Osteomyelitis > Osteomyelitis: Introduction > Treatment: Osteomyelitis >

3. Explain the pathogenesis and principles of treatment of musculoskeletal infectionPATHOGENESIS

PRINCIPLE S OF TREATMENTTo get rid of the infection and reduce damage to the bone and surrounding tissues.

Bed rest or local rest for the infected area of the body. Antibiotics are given to destroy the bacteria causing the infection. Antibiotics

are taken for at least 4 - 6 weeks, often through an IV rather than mouth. Surgery may be needed to remove dead bone tissue if there is an infection

that does not go away.

4. Line out the common causative organism of bone and joint infectionsTable 1 Usual infectious causes of pediatric osteomyelitis and pyogenic arthritis

Age Organism

Infants 0-2 months

Staphylococcus aureusStreptococcus agalactiaeGram-negative enteric bacteriaCandida

Less than and five years

S. aureusStreptococcus pyogenesStreptococcus pneumoniaeKingella kingaeHaemophilus influenza type b

More than five yearsS. aureusS. pyogenes

Adolescent Neisseria gonorrhoeae

Table 2 Other microbiologic causes of bone or joint infection in childrenRisk Factor Organism

OsteomyelitisExposure to farm animals Coxiella burnettiKitten exposure BartonellaTravel/contact Mycobacterium tuberculosisSinusitis/mastoiditis/dental abscess AnaerobesPuncture wound foot Pseudomonas, Staphylococcus aureusSickle cell disease Salmonella, S. aureus

Travel or residence in endemic area immunosuppression

Coccidioides immitisBlastomyces dermatidisHistoplasma capsulatumCryptococcus neoformans

Chronic granulomatous disease Aspergillus, S. aureus, SerratiaArthritis

Tick exposure in an endemic area Borrelia burgdorferiTravel/ Contact M. tuberculosisRat exposure Streptobacillus moniliformis

Spirillum minusViral infection Rubella, parvovirus B19, varicella zoater,

hepatitis B

Travel or residence in endemic area immunosuppression

C. immitisB. dermatitidisH. capsulatumC. neoformans

Newborn with intravascular line Candida

5. Describe the clinical symptoms of musculoskeletal infection severe and constant pain in bone muscle spam and local tenderness, swelling, warmth fever septicemia (malaise, anorexia, fever) In spine, pyogenic infection usually occurs in lumbar and cervical region but

tuberculosis usually occurs in thoracic region ESR and WBC elevated in lab test irregular bone shape that could mimic bone lesion such as Langerhans cell

histiocytosis, Ewing’s sarcoma, and osteosarcoma or the presence of obvious sequestra, pathological dislocation, osteolytic lession and narrowing of the joints in the radiographic examination

other symptoms may occur; loss of appetite, excessive sweating, swelling of the ankles, feet and legs

6. Explain the principle of antibacterial therapy in musculoskeletal infection

7. Table 126–2 Antibiotics for the Treatment of Osteomyelitis8.

Organism Antimicrobial Agent

Dosing Comments

Methicillin-susceptibleStaphylococcus aureus

Oxacillin or nafcillin

2 g IV q6h May be more active than cephalosporins

More difficult than cephalosporins to administer for long periods

Cephalosporins Cefazolin: 2 g IV q8h

Ceftriaxone: 1–2 g IV q24h

Ceftriaxone advantageous with OPAT

Clindamycina 600–900 mg IV q8h

Not well studied for osteomyelitis

Oral form possible (300–600 mg oral q8h)

Resistance significant and increasing

Toxicity different from that

of  -lactam antibiotics

Methicillin-resistant S. aureus

Vancomycin 15 mg/kg IV q12h Strains with an MIC of 

2  g/mL may not respond well.

Daptomycina 4–6 mg/kg IV q24h

Promising, but concern about adverse effects with prolonged therapy

Linezolida 600 mg IV or PO q12h

Effectiveness and adverse effects with prolonged therapy unclear

Bacteriostatic

Streptococci Penicillin 5 mU IV q6h or 20 mU/d by continuous infusion

Not all streptococci are susceptible

Ceftriaxone (1 g/d IV or IM) and ampicillin (12 g/d IV) are alternatives

Enterococci Penicillin

plus gentamicin

As above

5 mg/kg daily IV

If strain is susceptible

Vancomycin As above If strain is susceptible

Enterobacteriaceae (E. coli, Klebsiella, other)

Ceftriaxone or another cephalosporin

Ciprofloxacin

As above

400 mg IV q8–12h

If strain is susceptible

500–750 mg q8–12h if strain is susceptible

Pseudomonas Ciprofloxacin As above Resistance may develop

aeruginosa during therapy; if strain is resistant, drugs to consider include cefepime and ceftazidime

aNot approved for use in osteomyelitis by the U.S. Food and Drug Administration.

Abbreviations: MIC, minimal inhibitory concentration; OPAT, outpatient parenteral antimicrobial therapy.