Transcript GA NAPNAP 2013 Musculoskeletal Infections: What You Need

Jorge Fabregas, MD
Children’s Orthopaedics of Atlanta
February 23,2012
Understand evaluation of patient
Incidence
Prevalencewith possible infection
Etiology
Treatment
 Septic Arthritis
 Osteomyelitis
 Soft Tissue Infections
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What defines infection?
 Fever
 Aspiration
 Pain
▪ cell count, diff, gram stain
 Radiographic changes
 Positive culture
▪ 20% no organism identified
 Swelling
 Warmth
 Irritable joint
 Pus
 Wound drainage
 ESR, CRP, WBC
Floyed and Steele 2003
 Positive blood culture
 Response to antibiotics
 Absence of other pathology
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Pain x 24 hours
Left sided limping, then inability to bear
weight
Crying, ill-appearing
Family brings to ED for evaluation
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No trauma
Possible fever
Low appetite
Upper respiratory infection 2 weeks ago
 no antibiotics
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No sick contacts
Goes to daycare
No PMH/PSH
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37.2, 131, 30, 97/72, 95% RA, 11.1kg
Ill-appearing
 Laying still
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Left hip flexed, abducted, externally rotated
 Left hip irritable
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No pain ROM knee or ankle
No tenderness knee and distal
Wiggles toes
Neurovascularly intact
CBC
 WBC 10.36, 63%
PMNs
 Hgb 12.4
 Plt 296
 ESR
 15
 CRP
 7.9
 Blood cultures
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Xray
 normal
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Ultrasound
 effusion
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MRI
 Effusion
 No osteo
 No abscess
 Perfusion
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OR for aspiration and I&D left hip
 Small amount of viscous, cloudy, bloody fluid
▪ Sent for culture and DNA studies
 Closed over drain
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Antibiotics
ID consult
PICC
Blood and synovial fluid cultures no growth to
date
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Inoculate directly into blood culture bottle to
enhance culture of fastidious organisms
 K. kingae
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WBC > 50,000/mm3 with predominance of
neutrophils (75%) consistent with infection
 WBC <25, 000 in 34%of patients
 WBC can be elevated in JRA
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Gram stain positive in 30-50% of patients
 Cultures positive in 50-80% of patients
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Low protein, high lactate and low glucose levels
compared to serum indicative of infection
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Fever 38.5
Refusal to bear weight
ESR 40 mm/hr
Serum WBC >12,000 cells/mm3
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4 predictors 99.6% (93%)
3 predictors 93.1% (72.8%)
2 predictors 40% (35%)
1 predictor 3% (9.5%)
CRP > 2.0 Caird et al JBJS 2006
 5 predictors 98%
 4 predictors 93%
 3 predictors 83%
Disease
Leukocytes (cells/mL)
Polymorphs (%)
Normal
<200
<25
Traumatic effusion
<5,000, many RBCs
<25
Toxic synovitis
5,000-15,000
<25
Acute rheumatic fever
10,000-15,000
50
JIA
15,000-80,000
75
Septic arthritis
>50,000
>75
• Wide range WBC possible, often lower with atypical organisms
• Organism identified 30% Lyon and Evanich JPO 1999
• No significant clinical or laboratory differences
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Surgical decompression of joint space
 Create capsular window to ensure continued
drainage
 Leave drain in place until drainage decreases
significantly
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If no rapid improvement of symptoms
▪ Reexploration
▪ Further diagnostic workup
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Incidence 1:5000
Sonnen and Henry 1996
 Acute hematogenous osteomyelitis, age < 13
 Septic arthritis twice as common Gutierrez 1997
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Most common in 1st decade
 ½ younger than 5 Gillespie 1987
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Lower extremity 70-90%
 Hip 54% Wang 2003
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Incidence decreasing
 Awareness, immunization, antibiotics
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Metaphysis may be
within the joint
capsule
 proximal part of the
femur, humerus, ankle
and proximal radius.
 result in the
coexistence of septic
arthritis and
osteomyelitis
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Newborns: infection can cross
the physis and enter epiphysis
and joint
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Capillaries on metaphyseal
side of growth plate do not
cross growth plate after 6 -18
months
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Trauma or URI may precede symptoms
Joint pain, fever, irritability, anorexia, limp
Redness, swelling, and warmth over affected
joint
Painful restricted ROM
Hip in flexion, abd, ER
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Blood culture positive 30-50%
Peripheral blood
 WBC, ESR and CRP elevated
▪ CRP occasionally not elevated, especially with K. kingae
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Radiology
 Evaluate for other causes: trauma, malignancy,
osteomyelitis
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Important to differentiate between septic joint and
transient synovitis
 Considerable overlap in clinical and lab findings
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Hip pain
Refuse to WB, limp
Pseudoparalysis
Hip held in flex, abd,
Recent viral illness
 Treatment varies dramatically
▪ NSAID’s vs Open arthrotomy
▪ Predominates in 5-10 year
old males
▪ Radiology usually normal
▪ US screening
▪ modality of choice for
joint effusion
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Staphylococcus aureus
 70-90% cases musculoskeletal infection Blyth JBJS 2001
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Newborns
 S. aureus, Group B strep, Gram negative rods
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Children
 S. aureus, Group A β-hemolytic strep, Strep pneumo, Kingella kingae,
(H. influenza)
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Adolescents
 Gonococcus
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Sickle cell
 Salmonella
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Foot puncture wound
 Pseudomonas
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Most antibiotics achieve high synovial fluid
concentrations
IV therapy until clinical improvement and CRP
returning to normal
 Uncomplicated septic joint (no concurrent osteo)
▪ 3-4 days of IV therapy followed by appropriate oral therapy
 Duration depends on response to therapy and on suspected
organism
▪ S. pneumoniae, K. Kingae, Hib, N. gonorrhhoeae treated for 2-3
weeks
▪ S. aureus or gram-negative enteric bacteria treated 3-4 weeks
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Young, previously healthy children
Aggressive skin, soft tissue, and bone infection
Risk factors
 Antibiotic use within the preceding year, crowded living
conditions, compromised skin integrity, participation in team
sports.
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mecA gene
 Resistance to methicillin and other β-lactam antibiotics
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Panton-Valentine leukocidin (PVL)
 Cytotoxin
 Lyses WBCs, promotes tissue necrosis, allows pathway for CA-
MRSA to proliferate in the host
 Associated with deep-seated and life threatening
infections
Review of all patients with CA-MRSA infections
requiring orthopaedic care
 27 previously healthy children (18 M, 9F) average age
9.3 years (3mo to 17.7 y)
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 History of minor trauma (n=4) or sports-related injury
(n=5) within 1 week of presentation in 9 of 27 patients
(33%).
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Clinical presentation involved an extremity in 23/27
 5 upper extremities and 18 lower extremities
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17 had temp > 38.5 at presentation, 6 over 40
Osteomyelitis 13, pyomyositis 11, septic arthritis 10,
soft tissue or subperiosteal abscess 6, multifocal
involvement 13
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2 patients treated w/ clindamycin developed
resistance
Significant long-term sequelae 9 patients (33%)
 4 chronic osteomyelitis requiring surgery 3-12 mo
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later
1 fixed elbow contracture in dominant arm
1 heterotopic ossification around the hip
1 destruction of hip due to osteo required THA
1 distal tibial physeal arrest elected amputation for
pain and deformity
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Proteases, peptidases,
collagenases released
 Leukocytes, synovial cells, cartilage
 Break down cellular and extracellular
structure of collagen
 Loss of glycosaminoglycans – 8 hours
▪ Softens cartilage
▪ Susceptible to increased wear
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Once catalytic enzymes released,
living bacteria are not necessary
for cartilage destruction to
continue
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Prematurity
Age less than 6 months
Delay in treatment > 4
days
Concurrant osteomyelitis
of femur
Septic dislocation of hip
joint
40% hip infections poor results
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Partial or complete destruction of the
proximal femoral physis
Osteonecrosis of the femoral head
Trochanteric overgrowth
Pseudarthrosis of the femoral neck
Complete dissolution of the femoral
neck and head
Progressive limb-length discrepancy
Varus or valgus alignment of the
femoral head
Unstable hip articulation
Hip dislocation
Ankylosis of the hip joint
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Fevers to 102
Twisted his R ankle last week
Unable to bear weight x 2 days
Seen at urgent care, dx arthralgia, Tylenol #3
Warts removed from left knee 1 month ago
 Cellulitis treated with antibiotics
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PMH: twin born 38 weeks via C-section
37.7 °C, 101, 18, 104/77, 100% RA, weight 46.9 kg
Ill-appearing
Generalized maculopapular rash
Right foot and ankle swelling, warmth,
maculopapular rash
 No open wounds
 No fluctuance
 Tender over ankle, distal tibia, distal fibula
 Ankle joint irritable
 Sensation intact
 DP and PT pulses palpable
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WBC 18.6, 58% PMNs
Hgb 15.8
Plt 215
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ESR 10
CRP 23
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Blood culture
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Bone scan may help localize
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Attempts to obtain culture should be made
 Blood and tissue cultures
▪ Blood cultures positive 30-50%
▪ Tissue critical for diagnosis of organism
▪ Culture and histopathology
 Inoculation of material directly into aerobic blood culture bottle
facilitates isolation of fastidious organisms
 Begin empiric therapy for “most likely” organism
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Right ankle, tibia, fibula
 Point of maximum tenderness
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Gross purulence
Gram positive cocci in clusters
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Aspiration
 Locate point of maximum tenderness &
swelling
▪ Usually metaphyseal
 16 or 18 gauge spinal needle to aspirate
▪ Extraperiosteally, subperiosteally, intraosseously.
 Positive in 60% cases (Biopsy 90%)
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Institution of appropriate antibiotic therapy
 Healthy neonate: Group B Streptococcus most
common (S. agalactiae)
▪ Oxacillin or cefotaxime
 High risk neonate: S. aureus most common
▪ Oxacillin or cefotaxime plus gentamycin
 Infants to 3 years: S. aureus, K. kingae
▪ Cefataxime or cetriaxone and PCN for K. kingae
 > 3 years: S. aureus
▪ Oxacillin
Diagnosis:
 clinical findings, and a high index of suspicion
essential.
 Unexplained bone pain with fever means
osteomyelitis until proven otherwise.
 onset is usually sudden
 30% to 50% of patients have had a recent or
concurrent nonmuscular infection.
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S. aureus most common in all age groups
 CA-MRSA becoming more common
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Infants <2 months
 S. agalactiae, Neisseria gonorrhoeae, gram-negative
enteric bacteria, Candida
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2 months – 5 years:
 S. aureus, S. pyogenes, S. pneumoniae and K. kingae
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> 5 years:
 S. aureus, S. pyogenes, N. gonorrhoeae
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Metaphysis
 Small terminal vessels beneath
physis – slow flow
 Few phagocytic cells
 Endothelial gaps
 Rapidly growing long bones
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Trauma 30-50% acute
hematogenous osteomyelitis
 iv S. aureus lead to infection in
metaphysis of injured rabbit Morrissy and
Haynes JPO 1989
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Inflammation
  Intramedullary pressure
 Communication with subperiostial space
 Ischemia/necrosis
 “Bone cellulitis”  “Bone abscess” Subperiosteal abscess
 Sinus tract to skin may form = cloaca (Latin: “sewer”)
 Inaccessible to antibiotics
▪ Chronic osteomyelitis
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ICU admission
 Coagulopathy, petechial rash
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I&D right fibula, wound vac placement
 Repeat I&D, vac placement
 Repeat I&D, closure over a drain
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Vancomycin, ceftriaxone → clindamycin →
oxacillin
ID consult
 Blood cultures: MSSA
 Fibula aspiration: MSSA
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Afebrile, CRP 7.6
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Bone loss
 Need for grafting
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Fracture
Growth disturbance
 Limb length inequality, angular
deformity
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Chronic osteomyelitis
DVT
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Ultrasound
 can detect fluid
collections or
abscess
 periostitis/surface
abnormalities
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Fast but less useful in early stages
Identifies cortical destruction, bony
sequestrum, extraosseous abscess or gas
CT Scan is helpful in chronic cases
 small areas of osteolysis (sequestra)
 foci of gas, minute foreign bodies
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Detect specific lesions or multiple lesions
Useful in initial 48-72 hours of symptom onset
 May have cold scan initially
▪ Vascular supply to bone is compromised
▪ Decreased uptake of isotope
 Tagged WBC scan can increase specificity for infection (80%)
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Positive in other illnesses causing increased osteoblastic
activity
 Malignancy, trauma, cellulitis, postsurgery, arthritis
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Preferred test by some pediatric infectious disease experts
 Less expensive than MRI
 Sedation not necessary
 Useful for multifocal or location of infection not obvious
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Most sensitive modality, but not
specific
 Soft tissue abscess, bone marrow
edema, bone destruction
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Preferred test for surgical planning
Limitations
 Expense
 Sedation in young children
 Inability to assess whether other bones
are affected
 Fracture or bone infarction may not be
easily distinguished from infection
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Retrospective review of CA-SA osteomyelitis cases since 2001
at Texas Children's Hospital
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199 children with CA-SA osteomyelitis
 MRI
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n=160
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sensitivity = 98%
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bone scintigraphy
n=35
53%
CONCLUSION: MRI is the preferred imaging modality for
the investigation of pediatric CA-SA musculoskeletal
infection because it offers superior sensitivity for
osteomyelitis compared to bone scintigraphy and detects
extraosseous complications that occur in a substantial
proportion of patients.
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Vanderbilt Children’s Hospital in Nashville, Tenn
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130 children with suspected musculoskeletal infections
34 patients underwent an MRI after diagnostic or therapeutic
intervention
96 patients had an MRI prior to any procedure
60% of patients had neither septic arthritis nor
osteomyelitis
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“The majority of the children in the study group had a
diagnostic or surgical procedure which could have been
avoided with early MRI evaluation.”
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No radiographic technique can make or
exclude diagnosis with certainty
 raise/lower suspicion when applied to a
specific clinical situation
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Cellulitis
 Diffuse leukocyte inflammation, hyperemia, edema
without abscess.
 Group A Beta hemolytic Strep or S. aureus
 IV or oral abx
 Surgical drainage if abscess forms
Puncture wound
 S. aureus, Pseudomonas if
athletic shoe
 Tetanus toxoid
 ER or surgical debridement
Life and limb threatening
Deceivingly benign presentation
Polymicrobial, Strep
Painful intense cellulitis
Skin Bullae and ecchymoses occur
later
 Definitive dx with biopsy
 CT, MRI, US
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 inflammation of fascial layer
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Emergent surgical debridement
 Grey necrotic fascia, muscle spared, foul smelling dishwater pus
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Repeat debridements
18% mortality in children even with aggressive treatment
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What looks like a septic joint may be osteomyelitis
Osteomyelitis easily complicated by septic arthritis
 Transphyseal vessels in neonates
 Periosteal abscess can invade joints where metaphysis
is contained within the joint capsule
▪ Hip, shoulder, ankle, elbow
CA-MRSA on the increase
Remember to think about potential clindamycin
resistance
 Consider DVT in children with high fever, high CRP and
older than 8 years old
▪ LE doppler studies
Consider K. kingae with negative cultures
 Culture correctly: fastidious organism
 PCN sensitive
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Infection is the Great Imitator
Evaluation of the patient includes
 H&P, ESR, CRP, WBC, imaging, aspiration
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Kocher criteria for septic hip
Obtain aspirate
Empiric antibiotics
Recognize osteomyelitis and septic arthritis
CA-MRSA is life and limb threatening
 Have high index of suspicion