Bone and Joint Infections

How do you classify osteomyelitis?

1. hematogenous

2. contiguous

   1. normal vascularity (trauma)

   2. vascular insufficiency (diabetes)

3. chronic

What is the key to treating bone and joint infection?

source control

What are some systemic factors with the Cierny-Mader staging system?

• malnutrition

• renal and/or hepatic failure

• diabetes

• immunosuppression

What are some local factors with the Cierny-Mader staging system?

• venous stasis

• major vessel compromise

• arteritis

• scarring

• neuropathy

The most common type of infection with osteomyelitis is?

contiguous

The most common type of infection with infectious arthritis is?

hematogenous

What is the clinical presentation of osteomyelitis?

pain and tenderness of infected area

What is the clinical presentation of infectious arthritis?

Immobility of the joint, no point of tenderness

Most osteomyelitis in <1 year olds and 1-20 year olds occurs where?

The long bones

What are the common organisms of acute hematogenous osteo?

• S. aureus

• Streptococci

• Gram-negative rods (more seen in peds)

What are the common organisms of contiguous osteo?

• S. aureus

• Streptococci

• S. epidermidis

• gram-negative rods

• anaerobes

Contiguous osteo is more common in what ages?

>50 year olds

What defines chronic osteomyelitis?

• clinical signs >30 days

• open bone injury

• necrotic bone

True or false: chronic osteo is typically more than one pathogen

true

Diagnosis of osteomyelitis

• MRI

• leukocytosis

• increased ESR and C-reactive protein

• positive blood culture

• plain radiograph or bone scan (Tc-99)

• Ultrasound/CT

• histopathologic or microbiologic exam of bone

What organism is commonly isolated in infants < 1 year?

Group B strep

What organism is commonly isolated in infants 1-5 years?

Kingella kingae

Bartonella is commonly associated with which diseases?

HIV, kitten exposure

Salmonella is associated with what disease?

sickle cell disease

Enterobacteriaceae/pseudomonas is associated with which diseases?

• immunocompromised

• drug use

The treatment of osteomyelitis comes down to what 2 things?

1. ABX therapy

2. surgical debridement

What are the goals of ABX tx?

• resolution of infection

• eradication of organism

• prevention of long-term sequelae

What ABX characteristic is needed with osteomyelitis?

Bone penetration (high ABX doses)

How long do you treat osteomyelitis?

6 weeks or more

Do you use empiric or bacteria-specific treatment with osteomyelitis?

empiric with MRSA coverage

Which glycoprotein gets good bone penetration?

Linezolid (think of the ADR of thrombocytopenia)

Which ABX drug class(es) are great in bone marrow penetration?

• FQs

• tetracyclines

• linezolid

• Bactrim

• Clindamycin

Which ABXs have okay bone penetration?

• vancomycin

• beta lactams

• daptomycin

Empiric treatment of acute osteomyelitis for adults?

Vancomycin or daptomycin

Empiric treatment of acute osteomyelitis for children?

Vancomycin or clindamycin

Empiric treatment of acute osteomyelitis for adults at risk for Pseudomonas species (IVDU)

Vancomycin or Daptomycin PLUS Ceftazidime or Cefepime

When empirically treating acute osteomyelitis, if MSSA is isolated what ABX do you switch to from Ceftazidime and Cefepime?

Cefazolin (DOC)

For kids and infants with local CA-MRSA resistance >10% AND local clindamycin resistance >10%, what ABX should you use?

Vancomycin

If clindamycin is <10%, you can empirically use clindamycin

Dosing for MRSA osteomyelitis in adults (vancomycin)

15mg/kg/dose IV q12hr

When do you add rifampin to the vancomycin in MRSA osteo in adults?

If there are prosthetic joints

Dose of rifampin with vancomycin

600mg daily or 300mg BID

Dosing of rifampin with daptomycin

600mg daily or 300mg BID

Dosing of daptomycin in MRSA osteomyelitis in adults

6mg/kg IV once daily

higher doses (8-10mg/kg/dose) are often used

True or false: you can use rifampin alone and give it up front

false

Dosing of vancomycin in MRSA osteo in children

15mg/kg IV q6hr

Dosing of clindamycin in MRSA osteo in children

10-13 mg/kg IV q6-8hy

If stable with no bacteremia or IV infection AND if the resistance rate is low (<10%)

What are some alternatives for MRSA osteo in children?

• dapto

• linezolid

Duration of therapy in children for osteo?

4-6 weeks

What is the role of oral ABX in osteomyelitis?

• may be 1st line therapy in mild infections (outpatient)

• usually indicated after ~2 weeks of IV therapy in moderate

• earlier transition being considered with high-bioavailability ABXs

What are some cons of IV ABX?

• increased costs

• inconvenience

• risk of catheter-related complications

What is the oral “equivalent” for nafcillin or oxacillin?

dicloxacillin

What is the oral “equivalent” for cefazolin?

Keflex

What is the oral “equivalent” for Clindamycin?

Clindamycin

What is the oral “equivalent” for cipro or levo?

Cipro or levo

What is the oral “equivalent” for Extended spectrum penicillin or 3rd gen cephalosporin?

Augmentin or cefpodoxime

What is the oral “equivalent” for linezolid?

Linezolid

What are the common oral ABX for MRSA infections in children?

• clindamycin

• Bactrim

• Linezolid

What oral ABX for MRSA infections are used in adults?

• Bactrim 4mg/kg/dose BID + rifampin 600mg/day

• Linezolid 600mg BID

• Clindamycin 300- 450 mg q8hr

• FQ + rifampin

• Doxy/mino + rifampin

What are some additional therapies for osteomyelitis?

• surgical debridement

• antibiotic bead therapy

• hyperbaric oxygen therapy

What do you want to rule out in infectious arthritis?

gonococcal vs nongonococcal infection

True or false: infectious arthritis is usually monoarticular

true

Risk factors of infectious arthritis

• chronic illness

• rheumatoid art

• joint trauma/surgery

• joint prosthesis

• decreased cellular immunity

• IVDU

• systemic corticosteroid use

Clinical presentation of septic joint?

• acute systemic infection (sicker presenting)

• increased WBC, ESR

• positive blood culture

• painful, hot, swollen joint

How do you diagnose septic joint?

Aspiration of joint fluid

X-ray or MRI

What organism are we worried about in adolescents and adults 18-30 years of age that are sexually active?

neisseria gonorrhoeae

What additional organisms of present in septic joint?

• E.coli

• pseudomonas aeruginosa (IVDU)

• stap. epidermis (prosthetic joint infections)

• fungi

• viruses

Adults empiric treatment for septic joint

Vanc or dapto ± ceftriaxone

add ceftriaxone if 18- 30 (neisseria can cause septic joint)

IV drug use treatment of septic joint?

Vanc or dapto + cefepime or ceftazidime

Confirmed gonococcal septic arthritis treatment

Ceftriaxone 2gm IV daily

How long do you treat MRSA infectious arthritis in adults and children?

3-4 weeks (same as osteo)

How do we categorize Orthopedic device-related infections (ODRIs)?

• early onset (<2 months post-surgery) with a short duration of symptoms

• debridement with device retention

Monitoring parameters

• culture and susceptibility results

• clinical signs of inflammation

• WBC

• ESR

• compliance of outpatient therapy

• ADR (much higher risk due to longer durations)