How to differentiate big toe bursitis from gout based on history and physical examination?

Differentiating Big Toe Bursitis from Gout

Gout is far more likely than bursitis when acute inflammation affects the big toe, and the diagnosis can be made clinically with high accuracy using specific historical and examination features, though joint aspiration remains the gold standard when feasible.

Key Clinical Features That Distinguish Gout

Temporal Pattern of Onset

• Gout characteristically reaches maximum pain intensity within 6-12 hours of onset, which is highly suggestive of crystal inflammation 1
• The rapid development of severe pain, swelling, and tenderness within 24 hours strongly favors gout over bursitis 1, 2
• Bursitis typically develops more gradually over days, particularly when related to chronic microtrauma 3

Location and Joint Involvement

• Podagra (first metatarsophalangeal joint involvement) occurs in 50% of initial gout attacks and is the most characteristic presentation 4
• Gout affects the joint itself, causing true arthritis with joint line tenderness and restricted range of motion 1
• Bursitis affects periarticular structures (bursae around joints) rather than the joint space itself, with tenderness localized to the bursal area 3

Physical Examination Findings

• Overlying erythema is highly suggestive of gout when combined with rapid-onset severe pain 1
• Gout produces exquisite tenderness that may prevent even light touch or bedsheet contact 4
• The presence of visible or palpable tophi has 99% specificity for gout, though only 30% sensitivity 5
• Bursitis presents with a fluctuant, localized swelling over the bursa rather than diffuse joint swelling 3

Clinical Diagnostic Algorithm

High-Probability Features for Gout (Use This Scoring Approach)

The following features, when present together, achieve >80% sensitivity and specificity for gout 1:

• More than 1 previous attack of acute arthritis (recurrent pattern) 1
• Maximum inflammation developing within 1 day 1
• Redness observed over the affected joint 1
• Painful or swollen first metatarsophalangeal joint specifically 1
• Hyperuricemia present (though not diagnostic alone) 1, 2
• Male sex (odds ratio 7.64) 1

Associated Risk Factors That Support Gout

• Diuretic use (relative risk 1.72) 1
• Obesity (relative risk 3.81) 1
• Hypertension (relative risk 3.93) 1
• Chronic kidney disease (relative risk 4.95) 1
• Alcohol consumption, particularly beer 1
• Diet high in meat and seafood 1

Critical Pitfall: Ruling Out Septic Arthritis

The most important diagnostic consideration is excluding septic arthritis, which can coexist with gout in 5-10% of cases 5, 6. This is particularly crucial because:

• Septic bursitis and gout can present identically with acute pain, swelling, and erythema 3, 6
• If septic arthritis cannot be excluded clinically, joint aspiration with Gram stain and culture is mandatory regardless of gout suspicion 2
• Elderly patients, those with severe comorbidity, or immunodeficiency require aspiration to rule out infection 6
• Even when monosodium urate crystals are identified, Gram stain and culture should still be performed 5, 2

When Joint Aspiration Is Indicated

Aspiration should be performed when:

• Septic arthritis cannot be clinically excluded 2, 6
• First presentation without prior documented gout 1
• Atypical features are present 1
• Patient has risk factors for infection (immunosuppression, diabetes, chronic illness) 6

Aspiration findings:

• Monosodium urate crystals appear needle-shaped and negatively birefringent under polarized microscopy, providing definitive diagnosis with sensitivity 63-78% and specificity 93-100% 1, 5

When Clinical Diagnosis Alone Is Acceptable

For typical recurrent podagra with hyperuricemia, clinical diagnosis is reasonably accurate (strength of recommendation 95%) 1, particularly when:

• Patient has documented history of crystal-proven gout 1
• Classic podagra presentation with rapid onset 1
• No fever or systemic signs suggesting infection 3
• Multiple characteristic risk factors present 1

Practical Examination Approach

1. Assess onset timing: If maximum pain occurred within 6-12 hours, strongly favor gout 1
2. Palpate carefully: Joint line tenderness = arthritis (gout); localized bursal fluctuance = bursitis 3
3. Check for tophi: Examine ears, olecranon, fingers for pathognomonic tophi 5, 4
4. Evaluate for infection risk: Fever, systemic symptoms, immunocompromise mandate aspiration 6
5. Review medications and comorbidities: Diuretics, kidney disease, hypertension strongly support gout 1

Bursitis of the big toe is uncommon compared to gout; when periarticular inflammation occurs in this location with rapid onset and erythema, gout should be the primary consideration until proven otherwise 4, 3.