Examkin

Soru

Zorluk: OrtaOrdering Imaging Studies

A 58-year-old man presents to the outpatient clinic for evaluation of a wound on his right foot that he first noticed two weeks ago. He has a 15-year history of type 2 diabetes mellitus complicated by peripheral neuropathy and stage 4 chronic kidney disease. The patient does not report any fever, chills, or systemic symptoms. Vital signs are within normal limits.

Physical examination of the right foot reveals a 2 cm×2 cm2 \text{ cm} \times 2 \text{ cm} ulcer on the plantar surface of the first metatarsophalangeal joint. The ulcer base is covered with fibrinous exudate, and there is 3 cm3 \text{ cm} of surrounding erythema, warmth, and induration. During wound exploration, a sterile metal probe is easily advanced through the ulcer base and palpates hard, gritty tissue. Dorsalis pedis and posterior tibial pulses are diminished but detectable via handheld Doppler.

Laboratory studies are as follows:

Laboratory StudyResult
Leukocyte count9,500/μL9,500/\mu \text{L}
Erythrocyte sedimentation rate75 mm/h75 \text{ mm/h}
Serum creatinine3.2 mg/dL3.2 \text{ mg/dL}
Estimated glomerular filtration rate18 mL/min/1.73 m218 \text{ mL/min/1.73 m}^2

Which of the following is the most appropriate initial imaging study to order for this patient?

  1. Plain radiography of the right footCevap
  2. B
    Magnetic resonance imaging of the right foot without intravenous contrast
  3. C
    Computed tomography angiography of the right lower extremity with intravenous contrast
  4. D
    Three-phase technetium-99m bone scintigraphy of the right foot
  5. E
    Arterial duplex ultrasonography of the right lower extremity

Cevap

Plain radiography of the right foot
The correct sequence for imaging suspected diabetic foot osteomyelitis begins with plain radiography. A positive probe-to-bone test in the setting of a chronic diabetic ulcer strongly predicts osteomyelitis. Despite plain radiography having limited sensitivity in the first 1 to 2 weeks of bone infection, it is universally recommended as the initial imaging test. It is cost-effective, readily available, and can quickly identify overt cortical destruction, periosteal reaction, radiopaque foreign bodies, tissue gas, and underlying biomechanical deformities such as Charcot neuroarthropathy. Advanced imaging is reserved for cases where clinical suspicion remains high despite negative or equivocal plain radiographs.

Adım Adım Çözüm

1
Analyze the clinical presentation and physical examination findings.
The patient has a chronic diabetic foot ulcer with a positive probe-to-bone test and elevated erythrocyte sedimentation rate, highly suggestive of underlying osteomyelitis.
Establishing the primary suspected diagnosis guides the subsequent algorithmic imaging workup.
2
Determine the appropriate initial diagnostic imaging step according to evidence-based guidelines.
Guidelines recommend plain radiography as the first-line imaging modality for all suspected diabetic foot infections.
Plain films are cost-effective, widely available, and provide a necessary baseline to rule out foreign bodies, soft tissue gas, and Charcot neuroarthropathy, even if early sensitivity for osteomyelitis is relatively low.
3
Evaluate the patient's comorbidities and how they impact alternative imaging choices.
The patient's stage 4 chronic kidney disease contraindicates tests requiring iodinated contrast, and forces the practitioner to be judicious with advanced imaging resources.
Advanced imaging such as magnetic resonance imaging should be deferred until initial plain films are reviewed, ensuring a step-wise and safe diagnostic approach.

Anahtar Kavram

The most appropriate initial imaging modality for suspected diabetic foot osteomyelitis is plain radiography, which establishes a baseline and can identify overt bone destruction, gas, or foreign bodies.
Tahmini Süre:1m 30s
Bu soruyu puanla

Konular

Ordering Imaging Studies

Bu konudan daha fazla soru