What is the diagnostic approach for relapsing polychondritis?

Diagnostic Approach for Relapsing Polychondritis

The diagnosis of relapsing polychondritis is primarily clinical, based on the identification of recurrent inflammation of cartilaginous structures, with auricular chondritis (89%), nasal chondritis (63%), and arthralgias (81%) being the most common manifestations. 1

Key Clinical Features to Evaluate

• Auricular chondritis: Inflammation of ear cartilage causing redness, swelling, and pain (spares the earlobe which lacks cartilage)
• Nasal chondritis: Inflammation of nasal cartilage leading to pain, swelling, and potential saddle nose deformity
• Respiratory tract involvement: Present in >50% of cases and associated with increased mortality
  • Persistent cough may be the first sign of respiratory involvement
  • Laryngotracheal stenosis may cause life-threatening airway obstruction
• Articular involvement: Non-erosive, asymmetric, potentially migratory arthritis (69-81% of patients)
• Ocular manifestations: Including episcleritis, scleritis, and uveitis
• Audiovestibular symptoms: Hearing loss, tinnitus, vertigo

Diagnostic Criteria

Several diagnostic criteria sets exist, with the McAdam criteria being widely used 1, 2:

1. McAdam criteria: Diagnosis requires 3 or more of:

   • Bilateral auricular chondritis
   • Non-erosive inflammatory polyarthritis
   • Nasal chondritis
   • Ocular inflammation
   • Respiratory tract chondritis
   • Audiovestibular damage

2. Modified Damiani and Levine criteria: Diagnosis requires one of:

   • Three or more McAdam criteria
   • One McAdam criterion plus histological confirmation
   • Chondritis at two or more separate anatomic locations with response to steroids or dapsone

Diagnostic Workup

1. Laboratory tests: No specific biomarker exists 3

   • Inflammatory markers (ESR, CRP) are often elevated but nonspecific
   • Autoantibodies (ANA, ANCA, RF) may be present but are nonspecific
   • Complete blood count to assess for associated conditions

2. Imaging studies:

   • CT scan: Essential for detecting respiratory involvement - may show thickening and stenosis of the tracheobronchial wall, cartilage collapse and calcification 1
   • Dynamic CT: Particularly useful for detecting dynamic airway collapse
   • PET-CT: May identify areas of active inflammation, especially in early or subtle disease 4

3. Pulmonary function tests:

   • Flow-volume loops: Essential for detecting subtle airway involvement 1
   • Inspiratory and expiratory curves to assess for fixed and dynamic airway obstruction

4. Direct visualization:

   • Laryngoscopy/bronchoscopy: To evaluate airway involvement and obtain biopsies if needed 4
   • Nasal endoscopy: To assess nasal cartilage involvement

5. Biopsy:

   • Not always required but can be supportive
   • Shows loss of basophilic staining of cartilage matrix, perichondrial inflammation
   • Cartilage destruction with replacement by fibrous tissue

Diagnostic Pitfalls and Challenges

• Diagnostic delay: Average delay of 55 weeks from symptom onset to diagnosis 4
• Mimickers: Consider other vasculitides (GPA, EGPA), infectious chondritis, relapsing perichondritis
• Incomplete presentations: Formal diagnosis cannot be established with certainty before the onset of chondritis, which can sometimes occur several years after the first signs 3
• Association with other conditions: Check for associated conditions like VEXAS syndrome, especially in men over 50 years 3

Monitoring Approach

• Regular pulmonary function tests to detect early airway involvement
• CT imaging to monitor disease progression in respiratory tract
• Audiometry for patients with audiovestibular symptoms
• Ophthalmologic evaluation for ocular involvement

Prognostic Considerations

Factors associated with poor prognosis include:

• Respiratory tract involvement
• Cardiovascular involvement
• Association with myelodysplasia/VEXAS syndrome (more common in men over 50) 3
• Ethnicity, nasal chondritis, laryngotracheal stricture, and elevated serum creatinine 4

Forms limited to the cartilage of the nose or ears generally have a better prognosis than those with systemic or respiratory involvement 3.