MRI Utility in Suspected Septic Arthritis of the Metacarpophalangeal Joint

Clinical Presentation and Diagnosis

An 84-year-old female presents with classic signs of possible septic arthritis, including a red, swollen, painful 2nd MCP joint, altered mental status, subjective fevers, elevated inflammatory markers, and no leukocytosis, according to the American College of Radiology 1, 2
The patient has concurrent viral pneumonia, which could represent either a separate process or a source for hematogenous seeding of the joint, as noted by the American College of Radiology 1

MRI is the preferred imaging modality for evaluation of suspected septic arthritis with high sensitivity and specificity, as recommended by the American College of Radiology 1, 2
MRI can detect early inflammatory changes in the joint and surrounding tissues that may not be visible on radiographs, according to the American College of Radiology 1
MRI can help differentiate septic arthritis from other inflammatory conditions affecting the joint, as suggested by the American College of Radiology 4

According to the American College of Radiology Appropriateness Criteria, MRI is highly sensitive in detecting joint inflammation and can help exclude osteomyelitis when negative 1, 6
MRI can detect associated osteomyelitis, which is found in approximately 70% of patients with septic arthritis, as reported by the American College of Radiology 5
MRI can identify soft tissue abscesses that may require drainage, which occur in up to 28% of cases with bone infections, according to the American College of Radiology 5

Positive MRI findings consistent with septic arthritis would support the need for empiric antibiotic therapy and potential surgical consultation, as recommended by the American College of Radiology and Radiology 3, 1
MRI can help identify complications requiring surgical intervention, such as extensive abscess formation, according to Radiology 3