Relapsing polychondritis with isolated tracheal involvement and airway-only symptoms

18F-FAPI versus 18F-FDG PET/CT in the Diagnosis of Relapsing Polychondritis

Relapsing polychondritis (RP) is a rare immune-mediated systemic inflammatory disease with diverse clinical manifestations. Independent involvement of the respiratory system in RP is uncommon. In the event of respiratory involvement as the initial airway-only manifestation, the diagnosis of RP is challenging and might be delayed, and patients with respiratory involvement exhibit a poor prognosis. However, no specific diagnostic method is currently available for RP with respiratory system involvement as the main clinical manifestation. We present a 49-year-old female with the complaint of chronic dry cough accompanied by shortness of breath after exercise that has persisted for over a year. The patient was treated using corticosteroids. The patient's symptoms improved rapidly with the administration of 5 days of methylprednisolone sodium succinate at a dose of 40 mg/day. The treatment was then switched to methylprednisolone tablets at a dose of 40 mg/day, and the dosage was reduced by 4 mg every week until the cessation of therapy. Meanwhile, oral cyclophosphamide tablets were administered once every day at a dose of 100 mg each time. After 1 month of treatment, the symptoms of cough disappeared, the modified british medical research council (mMRC) grade dropped from 4 to 2, and the COPD assessment test (CAT) score dropped from 30 to 17. Repeated CT of the chest revealed that the tracheal wall thickening had alleviated. No recurrence was revealed in the follow-up visit 12 months after drug withdrawal. The patient underwent 18F-FDG PET/CT examination before hormone and immunosuppressive therapy, and 18F-FAPI PET/CT examination was performed 5 days later. The 18F-FDG PET/CT method revealed slight thickening of the local wall of the trachea and the left and right main bronchus, with no increase in the FDG metabolism, and no abnormalities in the rest of the cartilage. 18F-FAPI PET-CT imaging showed increased FAPI uptake in various parts of the body, including trachea and bronchus. The present study reports that compared to 18F-FDG PET/CT, the 18F-FAPI PET/CT revealed more lesions and provided a better image contrast, suggesting the latter as a suitable diagnostic method for RP, which could assist in improving the clinical management of RP patients.

Characteristics and Clinical Outcomes of 295 Patients With Relapsing Polychondritis

OBJECTIVE

This study analyzes the clinical features of Chinese patients with relapsing polychondritis (RP).

METHODS

The clinical data of 295 patients with RP at Beijing Tongren Hospital were retrospectively analyzed.

RESULTS

The mean age of onset was 41.0 ± 15.0 years. The sex ratio was 1:1. Up to 70.5% of the patients had airway involvement during the disease course; among them, the larynx was most commonly affected (82.2%). One-quarter (25.7%) of the patients with laryngeal involvement underwent tracheotomy as a result of progressive dyspnea or acute laryngeal obstruction. Younger age at onset and respiratory symptoms at initial presentation were independent risk factors for tracheotomy in patients with RP with laryngeal involvement. The risk of tracheotomy in patients who presented with respiratory symptoms was 2.35 times higher than that of patients who presented with other symptoms (HR 2.35, 95% CI 1.23-4.50, P = 0.01). The risk of tracheotomy increased by 4.8% for every 1-year decrease in the age at onset (HR 0.95, 95% CI 0.93-0.97, P < 0.001). The incidence of lower respiratory tract infection was much higher in patients with airway involvement than in those without airway involvement. The main cause of death was respiratory failure as a result of airway obstruction.

CONCLUSION

There is a high prevalence of airway involvement in Chinese patients with RP. Laryngeal involvement is associated with a high risk of death. More attention should be paid to patients with RP with laryngeal involvement who are young at disease onset and present with respiratory symptoms.