Bilateral and Diffuse Plantar Gout Presentation
While gout can occasionally present bilaterally and affect multiple joints simultaneously, bilateral involvement of the entire sole of the foot would be highly atypical and should prompt consideration of alternative diagnoses.
Typical Gout Presentation Patterns
The 2018 EULAR guidelines emphasize that typical gout flares present with monoarticular involvement of a foot (especially the first metatarsophalangeal joint) or ankle joint 1. The first MTP joint (podagra) is the initial joint affected in approximately half of all cases 2, 3.
Key Clinical Features Supporting Gout Diagnosis:
- Monoarticular involvement initially 1
- Rapid onset of severe pain and swelling (worst within <24 hours) 1
- Erythema overlying the affected joint 1
- Previous similar acute arthritis episodes 1
Polyarticular Gout: When Multiple Joints Are Involved
Gout can evolve to affect multiple joints, but this typically occurs with disease progression, not as an initial presentation 4. The American College of Rheumatology defines polyarticular gout as acute arthritis involving 3 separate large joints, or 4 or more joints affecting more than one "region" 4.
Factors Associated with Polyarticular Involvement:
- Longer disease duration and chronic hyperuricemia 4
- Presence of tophi (urate crystal accumulations) 4
- More advanced, inadequately treated disease 4
Bilateral Presentation: Rare but Possible
While bilateral involvement can occur, it is uncommon. A case report documented bilateral first MTP joint gout flares, but this was considered sufficiently unusual to warrant publication 5. The entire plantar surface of both feet would be extraordinarily atypical for gout and should raise suspicion for:
- Cellulitis or soft tissue infection
- Plantar fasciitis (bilateral)
- Inflammatory arthropathies (rheumatoid arthritis, psoriatic arthritis)
- Other crystal arthropathies
Diagnostic Approach for Atypical Presentations
When the presentation is atypical (such as bilateral diffuse foot involvement), synovial fluid aspiration with crystal identification becomes essential 1. The EULAR guidelines strongly recommend that any atypical presentation should be investigated by imaging, particularly ultrasound to seek features of MSU crystal deposition (double contour sign and tophi) 1.
Three-Step Diagnostic Algorithm:
- Step 1: Synovial fluid aspiration and MSU crystal identification (definitive diagnosis) 1
- Step 2: Clinical diagnosis based on typical features if aspiration not feasible 1
- Step 3: Imaging (ultrasound or DECT) when clinical diagnosis uncertain and crystal identification not possible 1
Critical Pitfall to Avoid
Do not diagnose gout based on hyperuricemia alone 1. The presence of elevated uric acid without crystal confirmation or highly typical clinical features is insufficient for diagnosis, particularly in atypical presentations like bilateral diffuse plantar involvement.
Bottom Line for Clinical Practice
If a patient presents with bilateral pain affecting the entire sole of both feet, this presentation is inconsistent with typical gout and warrants investigation for alternative diagnoses 1. Even in polyarticular gout, the pattern involves discrete joint involvement rather than diffuse plantar surface pain 4. Pursue definitive diagnosis through joint aspiration if any joint effusion is present, or consider imaging to evaluate for MSU deposits versus other pathology 1.