The child with a limp MARVIN B HARPER MD DIVISION OF EMERGENCY MEDICINE BOSTON CHILDREN’S HOSPITAL HARVARD MEDICAL SCHOOL No conflicts of interest No financial disclosures Case 18 month old otherwise well limping since this afternoon. Mom notes some limping but mostly child doesn’t want to stand. She isn’t sure which leg has pain PE: afebrile, antalgic gait favoring the left leg. No swelling noted. Seems to have some pain to palpation of the left lower leg. Toddlers fracture Herman and Martinek. Pediatr in Rev. 2015 Case 3 year old male woke up this morning with complaint of pain in the right leg. Still active and playing but can be seen to be limping. PE afebrile, when sitting still is active and playful. Refuses to fully bear weight on right leg when walking. Allows some flexion/extension at the right hip but seems to have pain with full flexion/extension Given ibuprofen with improvement of symptoms No further studies done Focus diagnoses in the ED In the ED focus on diagnosis of ¡ Fracture ¡ Infection (bone, joint, post-infectious) ¡ SCFE ¡ Tumors ¡ +/- Developmental hip dysplasia Not generally ED diagnosis ¡ Leg length discrepancy ¡ Cerebral palsy ¡ Contractures ¡ Rheumatologic causes Differential diagnosis for septic arthritis Trauma Leukemia Hemarthrosis, Tumor Osteomyelitis, Henoch-Schönlein Reactive effusion purpura Pyomyositis Sickle cell anemia w/VOC Septic bursitis Rheumatologic (e.g. JRA) Lyme Acute rheumatic fever SCFE Legg-Calvé-Perthes Etiology – differential diagnosis for joint concern Age 1 – 3 years ‘Toddler’ Age 11 - 16 years ¡ Toddler’s fracture ¡ SCFE ¡ Transient synovitis ¡ Avascular necrosis of the hip ¡ Infection ¡ Chondromalacia ÷ Arthritis, osteomyelitis, ¡ Neoplasm pyomyositis ¡ GC arthritis ¡ Developmental hip dysplasia Any age ¡ Lyme Age 4-10 years ¡ Leukemia ¡ Transient synovitis ¡ Legg-Calve Perthes History, geography and exam Underlying predisposing condition Lyme endemic area or other exposures Physical examination ¡ Fever? ¡ Antalgic gait? ¡ Focal lower extremity pain? ÷Will child bear weight on each leg? ÷Will child bear weight on foot? ÷Will child kneel or crawl without pain? ¡ Exam of joints Imaging Generally the history and examination will direct the focus to bone, joint or muscle or some combination ¡ Severity of symptoms ¡ Presence or absence of fever Driven by history and examination ¡ Worried about muscle, bone, joint, soft tissue or bursa? ¡ Most often plain films or ultrasound ¡ Occasionally MR ¡ Rare technecium 99 bone scan Transient synovitis Age 18 mo’s – 12 years Males 2:1 over females Common in children ¡ 0.2% per child/year in Sweden Often post-infectious ¡ viruses, gut pathogens, many bacteria Pain often waxes and wanes Great overlap in the values for WBC, ESR, CRP Diagnosis of exclusion Sites of septic arthritis in children Hip, knee, ankle combined 85% From a series of 130 culture positive pediatric cases Pääkkönen M , Peltola H Arch Dis Child 2012 Septic arthritis Age distriBution Anatomic site Pathogens Peltola H et al. Clin Infect Dis. 2009 Septic arthritis in Texas NOI = no organism isolated Branson et al. PIDJ 2017 Septic arthritis - outcomes Long term morbidity is variable by pathogen and delay to treatment Estimated that 10-25% have some residual joint dysfunction Risk highest for infections due to S. aureus and or in young infants Septic arthritis Pathophysiology ¡ Hematogenous H&P ¡ Fever, pain in the joint with movement ¡ Swelling, redness ¡ When the hip is involved ÷ mildly flexed and externally rotated ¡ Recent trauma is common (20%) but no different than controls Septic arthritis – lab findings CBC with diff, CRP, ESR, blood cultures, (lyme) ¡ Leukocytosis ¡ Elevated CRP (if normal will be elevated within 12-24 hours of onset of symptoms) ¡ ESR >20 mm/hr in the majority Septic arthritis Imaging ¡ Plain radiographs ÷ Fracture, mass, demineralization but likely normal ¡ Ultrasound ÷ Most useful for the hip (and shoulder) as other joints effusions are commonly clinically evident ÷ MRI if concern for associated osteomyelitis or pyomyositis Arthrocentesis ¡ Cell counts, culture , +/- PCR Kingella Infectious arthritis In Boston we send lyme serology on any patient with arthritis regardless of cell count unless bacteria isolated ¡ Send lyme regardless of month of the year Remember that malignancies, Rheumatic Fever, and osteomyelitis can all give arthritis ¡ Consider the possibility of reactive arthritis Septic arthritis - diagnosis Culture source Rate positive Blood 40% Joint fluid 50% Either blood or joint 60 - 70% fluid Gram stain of joint fluid positive in ~50%. Intrepreting the joint fluid Etiology WBC /mm3 WBC/mm3 (variable) Viral 15,000 300 – 50,000 Bacterial >50,000 200 – 300,000 Lyme >20,000 100 – 150,000 TB 10,000 – 20,000 400 – 140,000 Transient synovitis or septic arthritis Kocher rules Fever Non-weight bearing ESR >40 mm/hr Serum WBC > 12,000 If all four criteria met >99% septic arthritis Successfully validated in subsequent BCH group Results not reproducible at other institutions ¡ Performance of this rule is also not as good for Kingella infections (Yagupsky et al J Pediatr 2014) Kocher et al. J Bone Joint Surg Am 1999 and 2004 Transient synovitis or septic arthritis Singhal et al. J of Bone Joint Surg Br 2011 Differentiating causes of arthritis CRP ESR Thompson A et al. Pediatrics 2009;123:959-965 Differentiating causes of arthritis Joint WBC Thompson A et al. Pediatrics 2009;123:959-965 Joint fluid Septic Lyme Other • WBC arthritis arthritis arthritis • ANC 56% of lyme patients with >50K WBC Variable WBC for septic arthritis Dart et. al. Pediatrics 2018 Limp - Joint pain Septic arthritis identified – am I done? Risk of adjacent infections in septic arthritis Welling et al; Clin Orthop Relat Res 2018 Risk of adjacent infections in septic arthritis Age 4 Symptoms 3 CRP 2 Platelets ANC 1 Sensitivity 86% (32/37)for adjacent infection Only 5% (3) unnecessary scans per algorithm AUC 0.93 Welling et al; Clin Orthop Relat Res 2018 Risk of adjacent infections in septic arthritis Five variables ¡ age above 3.6 y (Welling 4) ¡ CRP > 13.8 mg/L (Welling 8.9) ¡ duration of symptoms >3 d (Welling same) ¡ platelets ≤314K cells/µL (Welling <310K) ¡ Patients with >= 3 risk factors are high risk for septic arthritis with adjacent infection ¡ (Does not include Welling ANC >7.2K cells/µL) ÷(sensitivity: 90%, specificity: 67%, positive predictive value: 80%, negative predictive value: 83%) Rosenfeld et al, J Pediatr Orthop 2016 Osteomyelitis Osteomyelitis !Children ¡ hematogenous by far most common Most commonly acute Peak in late summer and early autumn 1/3 of pediatric cases occur in the first 2 yrs of life >90% have only a single bone involved Organisms causing hematogenous osteomyelitis Children > 6 months of age ¡ S. aureus 80% ¡ GABHS 5-10% ¡ S. pneumoniae 1-5% ¡ H. influenzae b <2% ¡ others: Salmonella, E. coli, P. aeruginosa, Klebsiella, fungi/yeast, anaerobes Osteomyelitis - clinical presentation Focal pain - constant (may fluctuate with load) ¡ occurs in >90% ¡ onset is gradual inflammatory signs (redness, warmth, swelling) usually do not appear until there is pus in the tissues OUTSIDE the bone ¡ historically 2/3 of of patients have evidence of local soft tissue inflammation at the time of diagnosis The spine, pelvis and hips are often more difficult and localized inflammation more easily concealed Osteomyelitis - clinical presentation Fever is not a constant feature ¡ approx 2/3 of children have fever ÷2/3 of those with fever have low grade fever (<39 degrees C) Fever is less common in neonates and adults Osteomyelitis - clinical presentation 100% 80% 60% 40% 20% 0% Pain Fever DROM Trauma Limping Swelling WarmthAnemia Erythema Sex (male) Tenderness Medical history Underlying disease Abx before admissionFever, pain, limping and local inflammation Saavedra-Lozano et al, J Ped Ortho 2008 Differential diagnosis Fairly limited by history and examination ¡ Malignancy – primary or secondary ÷ Osteosarcoma, Ewing’s, neuroblastoma, leukemia etc ¡ Fracture ÷ Acute or chronic ¡ Chronic recurrent multifocal osteomyelitis ¡ Histiocytosis X Skeletal DistriBution of Acute Osteomyelitis in Children Peltola H, Pääkkönen M. NEJM 2014 Skeletal DistriBution of Acute Osteomyelitis in Children Peltola H, Pääkkönen M. NEJM 2014 Osteomyelitis CRP ¡ 98% have elevated CRP (>2 mg/dL) ESR ¡ 90% have elevated ESR (>20mm/hr) WBC ¡ only 34% with WBC > 12,000 /mm3 Osteomyelitis Blood culture ¡ positive in 35-40% Bone aspirate ¡ positive in 35-40% Blood culture AND bone aspirate ¡ Positive in at least one specimen for 50- 70% ¡ Blood the only positive culture in 10-15% ¡ Aspirate the only positive culture in 25- 30% CRP and ESR in uncomplicated hematogenous osteomyelitis 90 80 •• • CRP (mg/L) 70 • 60 • ESR (mm/h) • 50 • • • 40 • 30 • • 20 • • 10 • •• • • 0 • • • • 0 5 10 15 20 25 30 Days from diagnosis Unkila-Kalllio et al. Pediatrics 1994 Staphylococcus aureus osteomyelitis distal right humerus of a 12-month-old infant. Conrad D A Pediatrics in Review 2010 Findings on plain radiographs with osteomyelitis vary with time First week ¡ Mild blurring of deep muscles/tissue planes 10-14 days ¡ Erosion or bony destruction - area of lucency ÷requires 30-40% bone loss over ~1cm ¡ Periostial reaction - new bone parallel to cortex in the metaphysis separated by a thin lucent line 2 - 10 mm wide >= 3 weeks ¡ Sequestra - encapsulation of dead bone by new bone Imaging: plain radiographs Generally no need for further