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Figures A and B are the AP and lateral radiographs of a 10-year-old female who presents to the office with 1-2 months of worsening left ankle pain. She does not recall any trauma. Physical exam demonstrates tenderness at the medial left ankle, but no instability. An MRI is obtained and shown in Figure C. The patient undergoes CT-guided biopsy and the histology slides are shown in figures D and E. What is the most likely diagnosis?
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A 5-year-old boy presents with temperature of 104 degrees Fahrenheit and painful weight bearing on the left lower extremity for one day. Hip motion is painless, but knee motion is painful. Peripheral white blood cell count is 21,000 per microliter (reference range [rr] 4,500-13,500). Erythrocyte sedimentation rate is 35 mm/hr (rr 0-10 mm/hr). C-reactive protein (CRP) is 72 mg/L (rr 0-9 mg/L). An aspirate of the knee was performed successfully with a scant amount of clear synovial fluid with a cell count of 1,000. Figures A, B and C show axial T1 fat saturated, sagittal T1 fat saturated and coronal short tau inversion recovery magnetic resonance imaging (MRI) images of the left femur. After being fully treated for this condition, what study may be needed in late-term follow-up if clinically indicated?
Standing, full-length, bilateral lower extremity roentgenogram to evaluate for growth disturbance of the distal femur
MRI of the hip to evaluate for progression of osteonecrosis and allow for staging
MRI of the femur to evaluate for recurrence of osteosarcoma
Positron emission tomographic scan of the body to evaluate for the presence of metastasis
Parathyroid hormone serology to evaluate for secondary hyperparathyroidism
An 8-year-old girl presents to the emergency room with a 4-day history of limp and temperature 100.7 F. Lab results show a white blood cell count of 13,000 cells/µL (reference range, 4500-11000 cells/µL), hematocrit 33% (reference range, 41%-50%), and C-reactive protein of 14 mg/L (reference range, 0.08-3.1 mg/L). MR imaging demonstrates osteomyelitis of the proximal tibia without an abscess. During the work-up in the ER, the patient became hypotensive. What is the mechanism of action of the empiric antibiotic appropriate for this patient?
Binding to penicillin-specific binding proteins in the bacterial cell wall
Binding to the D-Ala-D-Ala residues in the bacterial cell wall
Inhibition of bacterial topoisomerase and DNA gyrase
Inhibition of nucleic acid synthesis
Binding to 30S ribosomal proteins
A 9-year-old boy was placed in a short leg splint in an emergency department after twisting his ankle during recess. He presents 10 days later with increasing pain and fevers up to 39 degrees C over the last 3 days. The splint is removed revealing intact skin integrity with notable swelling and erythema overlying the distal fibula. Lab results include a C-reactive protein level of 12mg/L (normal 0-3.2 mg/L), erythrocyte sedimentation rate of 38mm/h (normal 0-20mm/h) and a white blood cell count of 12.3 K/mm3(normal 4.3 -11.4 K/mm3). Radiographs are included in Figures A and B. MRI images include T1, T2 and post-contrast in Figures C-E, respectively. What is next step in management?
Irrigation and debridement of distal fibular osteomyelitis
Place in short leg walking cast for 3 weeks
Begin oral antibiotics and follow up in 2 weeks
Perform stress radiographs to assess integrity of the syndesmosis
Transition to lace up ankle brace and begin functional rehab
A 9-year-old boy is being treated for acute hematogenous osteomyelitis of the distal tibia with appropriate IV antibiotic therapy. After three days of treatment, he fails to show any clinical improvement. Advanced imaging is obtained and reveals a 1.5x1.5cm abscess in the distal tibia. The patient subsequently undergoes formal open surgical debridement, without complications. Following surgery, serial evaluations of which of the following studies is the most expeditious method to determine the early success of treatment?
White blood cell count
Erythrocyte sedimentation rate
A 6 year-old boy develops tenderness at the right heel and avoids putting weight on the right extremity after stepping on a nail 2 weeks ago while wearing tennis shoes. His mother notes that he has had a fever of 39.0. Calcaneal osteomyelitis caused by a puncture wound has an increased rate of which of the following compared to hematogenous osteomyelitis?
Presence of Group A Streptococcus infection
Presence of Coliforms infection
Presence of Haemophilus infection
Presence of Pseudomonas infection
Presence of Group B Streptococcus infection
Sequestrum is defined as which of the following?
reactive bone in acute osteomyelitis
reactive bone in chronic osteomyelitis
necrotic bone providing a nidus for infection in chronic osteomyelitis
healthy bone adjacent to chronic osteomyelitis
healthy bone adjacent to acute osteomyelitis
A pediatric patient has just been diagnosed with osteomyelitis of the femur. All of the following are risk factors for the development of deep venous thrombosis EXCEPT?
Surgical treatment of osteomyelitis
CRP > 6
Methicillin-resistant staphylococcus aureus
Fever of greater than 38.5 degrees Celsius
Patient age greater than 8-years-old
A 6-year-old boy with acute hematogenous osteomyelitis of the distal femur is being treated with intravenous antibiotics. The most expeditious method to determine the early success or failure of treatment is by serial evaluations of which of the following studies?
CBC count with differential
C-reactive protein (CRP)
A 2-year-old girl has had a 2-day history of fever and refuses to move her left shoulder following varicella. Laboratory studies show an erythrocyte sedimentation rate of 75 mm/h and a peripheral WBC count of 18,000/mmP3P. What is the most common organism in this scenario?
Group A beta-hemolytic streptococcus
Group B streptococcus
An afebrile 8-year-old Ethiopian girl presented with a limp. Two years earlier, she had had mild trauma followed by a “bone infection” and had received short courses of oral antibiotics. Examination revealed a small, pus-secreting wound on the anterior aspect of her left thigh. Her blood count was normal, but her erythrocyte sedimentation rate was 48 mm. A radiograph and computed tomographic scan are shown in Figure A and B respectively. What do the blue arrowheads identify in both of these imaging studies?
In which of the following patients with osteomyelitis of the tibia is surgical debridement the next best step in treatment?
A 9-year old girl with new-onset pain and fever
A 7-year-old lethargic boy with a CRP of 20 mg/L that does not decline after a week of nafcillin and vancomycin
A 7-year-old girl with three days of pain, fever, and a WBC of 21,000/mm3 who presents to the ER
An 8-year-old boy whose pain and fever have decreased after 24 hours of ampicillin
An 8-year old lethargic girl with a WBC of 21,000/mm3 and a CRP of 9 after 24 hours of gentamicin
A 7-year-old boy complains of worsening left knee pain over the last 2 weeks. He has been unable to bear weight through the left lower extremity for the past 24 hours. The knee and lower leg are warm and tender to palpation. Current temperature is 100.9 degrees Fahrenheit, and CRP is 11 mg/dL (nml <1). A radiograph is provided in Figure A. A joint aspiration yields 2 mL's of synovial fluid demonstrating a cell count of 2,500 and no organisms on gram stain. Which of the following is the most appropriate next step in management?
Repeat aspiration of the left knee
Observation with repeat radiographs in one week
Magnetic resonance imaging (MRI)
Begin intravenous broad-spectrum antibiotics and obtain an infectiouse disease consult
Exploratory surgical arthrotomy
A 7-year-old boy presents with right elbow and left wrist swelling for the past 3 months. Clinical photos of the elbow and wrist are shown in Figures A and B, and radiographs in Figures C and D. His parents report that he has had night sweats and a loss of appetite, and physical examination is notable for bilateral axillary lymphadenopathy. Leukocyte count is normal but the ESR is elevated. The child undergoes a diagnostic biopsy shown in Figure E. What is the most likely diagnosis?
Multicentric giant cell tumor
Polyostotic mycobacterial infection
A 10-year-old boy complains of two days of worsening right knee pain. He has been unable to ambulate on the leg since waking up this morning. He denies any recent trauma to the leg. Physical exam is notable for focal tenderness over the distal femur without a palpable fluid collection. His ESR is 68 mm/hr (normal <15) and CRP is 14 mg/dL (normal <1). His temperature is currently 101.2 degrees F. Radiographs are provided in Figures A and B. An aspiration of the knee yielding 7 mL of straw colored fluid reveals 1700 nucleated cells per mL, and no organisms on gram stain. Which of the following is the most appropriate next step?
MRI of the knee
Observation with follow-up ESR, CRP, and repeat aspiration in 1-2 days
Oral cephalosporin and follow-up in 10 days
Surgical arthrotomy, debridement, and irrigation procedure
Chest, abdomen, and pelvis CT
A 14-year-old boy presents 6 months after spraining his right ankle. Radiographs obtained at the time of injury are shown in Figure A. He returns to clinic with persistent right ankle pain. The patient denies fevers, and has an ESR of 35 mm/h (nl 0-20). CRP and WBC are normal. Current radiographs and MRI images are shown in Figures B, C, and D. What is the next most appropriate step in management?
Casting of the ankle and observation
CT of the tibia
Oral antibiotic therapy, with outpatient follow-up in 6 weeks
Biopsy and culture of the tibial lesion
Urgent ankle arthrotomy
Septic arthritis in pediatric patients may occur secondary to direct intra-articular spread from metaphyseal osteomyelitis. This can occur in all the following joints EXCEPT?
An 8-year-old boy twists his right leg while playing soccer 6 days ago. Initial radiographs on the day of injury were negative, and the patient was placed into a knee immobilizer by his pediatrician. Despite being non-weightbearing on crutches, his pain has continued to worsen, and he presented to the ER with a low grade fever and irratibility. A current bone scan and MRI is shown in Figure A and B. Examination shows no knee effusion but there is tenderness to palpation over the proximal tibia. Current WBC and ESR is normal and CRP is elevated. What is the next most appropriate initial step in management?
Long leg cast and continued non-weightbearing to the extremity
Chest CT scan and referral to an orthopaedic oncologist
Neoadjuvant chemotherapy followed by surgical resection
Percutaneous biopsy with culture and antibiotics
Percutaneous pinning of the physeal fracture and long leg cast placement
A 13-year-old girl reported left ankle pain after falling while playing soccer 3 weeks ago. The pain initially improved, but for the past 10 days she has had increased pain. She reports a decreased appetite. Her temperature is 38.9 degrees celsius and her white blood cell count is normal. The ESR and CRP are elevated and blood cultures have been drawn and are pending. Current ankle radiographs are normal and T1 and T2 MRI images are shown in Figures A and B, respectively. What is the most appropriate next step in treatment?
Discharge home on non-steroidal anti-inflammatory drug (NSAID) and short leg non-weightbearing cast
Discharge home on oral antibiotics with serial ESR and CRP in an outpatient setting
Admit to hospital for percutaneous aspiration for culture and intravenous antibiotics with serial ESR and CRP
Admit to hospital for percutaneous biopsy and referral to orthopaedic oncologist
Admit to hospital for percutaneous screw fixation of distal tibia fracture