Could this patient with recent streptococcal infection, elevated antistreptolysin O titre, high C-reactive protein and migratory large-joint polyarthritis but no clinical or laboratory evidence of tuberculosis have Poncet’s disease?

No, This Is Not Poncet's Disease

This patient's clinical presentation is consistent with acute rheumatic fever (ARF) or post-streptococcal reactive arthritis (PSRA), not Poncet's disease, because Poncet's disease requires documented active tuberculosis—which this patient explicitly lacks—while the elevated antistreptolysin O titre and recent streptococcal infection point directly to a post-streptococcal syndrome. 1, 2

Why Poncet's Disease Is Excluded

• Poncet's disease is defined as reactive polyarthritis occurring in the presence of active tuberculosis elsewhere in the body—it is a sterile, aseptic arthritis that develops as a complication of extrapulmonary or pulmonary TB. 3, 4, 5
• The patient has no clinical or laboratory evidence of tuberculosis, which is an absolute requirement for diagnosing Poncet's disease. 4, 5
• In Poncet's disease, Mantoux testing is positive in approximately 81% of cases, and acid-fast bacilli or mycobacterial DNA can be demonstrated in affected tissues (e.g., lymph nodes, pleural fluid). 5, 6
• The arthritis in Poncet's disease is typically non-erosive, non-deforming, and resolves dramatically within days of starting anti-tuberculous therapy—not with antibiotics targeting streptococcal infection. 4, 5

What This Patient Actually Has

Most Likely: Acute Rheumatic Fever (ARF)

• The revised Jones Criteria (2015) require documented recent group A streptococcal (GAS) infection plus either 2 major manifestations or 1 major + 2 minor manifestations. 1, 2
• This patient has:
  • Documented recent GAS infection (elevated ASO titre). 1, 2
  • Migratory large-joint polyarthritis (a major criterion). 1, 2
  • Elevated C-reactive protein (a minor criterion). 1, 2
• If the patient is from a moderate-to-high-risk population (ARF incidence >2 per 100,000 school-aged children per year or RHD prevalence >1 per 1,000 population per year), then polyarthritis alone as a major criterion plus elevated CRP as a minor criterion would require only one additional minor manifestation (e.g., fever ≥38°C or prolonged PR interval) to meet diagnostic criteria. 1, 2
• In low-risk populations, polyarthritis is a major criterion, but the patient would need either another major criterion or one additional minor criterion beyond elevated CRP. 1, 2

Alternative: Post-Streptococcal Reactive Arthritis (PSRA)

• PSRA is defined as inflammatory arthritis of ≥1 joint associated with recent GAS infection in a patient who does not fulfill the Jones criteria for ARF. 7, 8
• PSRA typically occurs within 10 days of a GAS infection (versus 14–21 days for ARF), causes acute asymmetrical non-migratory polyarthritis (versus the migratory pattern of ARF), and does not respond readily to aspirin (unlike ARF). 7, 8
• PSRA can involve small joints, large joints, or the axial skeleton, and may be associated with extraarticular manifestations such as erythema nodosum, uveitis, or glomerulonephritis. 8
• Critical pitfall: Some patients initially diagnosed with PSRA later develop valvular heart disease, so these patients should be observed carefully for several months for clinical evidence of carditis and may warrant 12 months of secondary prophylaxis. 7

Diagnostic Algorithm

1. Confirm recent GAS infection:

   • Positive throat culture or rapid antigen detection test. 1, 2
   • Elevated or rising ASO titre or elevated anti-DNase B titre (combined testing detects up to 98% of proven streptococcal cases). 1

2. Assess population risk:

   • Low-risk: ARF incidence ≤2 per 100,000 school-aged children per year or RHD prevalence ≤1 per 1,000 population per year. 1, 2
   • Moderate-to-high-risk: Exceeds the above thresholds. 1, 2

3. Apply the revised Jones Criteria:

   • Major criteria (low-risk): Carditis (clinical or subclinical by echo), polyarthritis, chorea, erythema marginatum, subcutaneous nodules. 1, 2
   • Major criteria (moderate-to-high-risk): Add monoarthritis and polyarthralgia (after exclusion of other causes). 1, 2
   • Minor criteria (low-risk): Polyarthralgia, fever ≥38.5°C, ESR ≥60 mm/h or CRP ≥3.0 mg/dL, prolonged PR interval. 1, 2
   • Minor criteria (moderate-to-high-risk): Monoarthralgia, fever ≥38°C, ESR ≥30 mm/h or CRP ≥3.0 mg/dL, prolonged PR interval. 1, 2

4. Perform echocardiography with Doppler in all suspected cases:

   • Subclinical carditis detected by echo now counts as a major manifestation. 1, 2
   • Pathological mitral regurgitation: Jet visible in ≥2 planes, length >1 cm, holosystolic, peak velocity >2.5 m/s. 1, 2
   • Pathological aortic regurgitation: Jet visible in ≥2 planes, holodiastolic, peak velocity >2.5 m/s. 1, 2
   • Critical pitfall: Measure blood pressure at the time of echo because systemic pressure influences jet characteristics; peak velocity <3.0 m/s is more likely physiological regurgitation. 1

5. Exclude alternative diagnoses:

   • Tuberculosis (Poncet's disease requires active TB). 3, 4, 5
   • Septic arthritis (aspirate joint fluid if monoarthritis or oligoarthritis). 7
   • Autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis). 7
   • Viral arthritis (parvovirus B19, hepatitis C, HIV). 7
   • Infective endocarditis (if valvular abnormalities are present). 1, 2

6. If Jones criteria are not fully met but suspicion remains high:

   • Consider 12 months of secondary prophylaxis followed by repeat detailed history, physical examination, and echocardiography. 1, 2
   • If recurrent joint symptoms occur in a patient adherent to prophylaxis without serologic evidence of GAS infection and without echocardiographic valvulitis, the symptoms are likely unrelated to ARF. 1, 2

Key Pitfalls to Avoid

• Do not diagnose Poncet's disease without documented active tuberculosis. Poncet's disease is a reactive arthritis complicating TB, not a post-streptococcal syndrome. 3, 4, 5
• Do not count a joint manifestation as both a major and a minor criterion in the same patient. Polyarthritis is a major criterion; polyarthralgia is a minor criterion (or a major criterion in moderate-to-high-risk populations after exclusion of other causes). 1, 2
• Do not overlook subclinical carditis. Perform echocardiography with Doppler in all suspected cases of ARF, as subclinical carditis is now a major manifestation. 1, 2
• Do not misinterpret physiological regurgitation as pathological. Differentiate rheumatic valvulitis from congenital valve abnormalities (e.g., bicuspid aortic valve, mitral valve prolapse) and infective endocarditis. 1, 2
• Do not assume PSRA is benign. Some patients with PSRA later develop valvular heart disease, so careful follow-up for several months is warranted. 7