Relapsing polychondritis

Clinical History

A 23-year-old Italian male patient came to our department with worsening dyspnoea, which arose about six months before. He also complained of recent-onset wheezing, stridor and left hypoacusia.

Imaging Findings

The patient underwent a chest radiograph, which showed no parenchymal lesions but detected tracheal and main left bronchial narrowing (Fig. 1).
A chest CT without contrast medium was subsequently performed to study the tracheobronchial tree. CT detected severe airway involvement and structural abnormalities: subglottic stenosis, tracheal and main left bronchial lumen narrowing, tracheobronchial wall thickening, disruption and calcifications of airway cartilage. CT also revealed calcifications of costal cartilages and findings related to arthritis of the third and fourth chondro-sternal joint (Fig. 2, 3). Expiratory CT was not performed to avoid excessive X-ray exposure in a young patient. A PET scan that showed low metabolic hyperactivity (SUV 3-5) of costal cartilages, and high metabolic hyperactivity of the left part of cricoid cartilage (Fig. 4). These findings were compatible with an inflammatory process in the above mentioned areas.

Discussion

Relapsing polychondritis is a rare, chronic, systemic inflammatory disease and is classified as an autoimmune connective tissue disorder. It has no age or sex prediliction, but it generally occurs between the fourth and fifth decades of life [1].
It is characterised by recurrent and diffuse inflammation of cartilaginous structures that can lead to progressive degeneration and destruction of cartilage; cicatricial fibrosis, calcifications and sometimes malacia can be severe outcomes of this chronic inflammatory process. The disease frequently involves external ear, nose, larynx, tracheobronchial tree and joints [2].
Aetiopathogenesis is still unknown, even though an immune-mediated mechanism is hypothesized: chronic inflammation is probably due to an autoimmune response, since antibodies against type II collagen are found in these patients [3].
The most frequent clinical features are dyspnoea, wheezing and stridor, cough and dysphonia, due to upper and lower airways chondritis (70% of patients) [4]; in fact, chronic inflammation causes airway narrowing and cartilaginous collapse that lead to respiratory distress. Respiratory failure and pneumonia are the two major causes of death [1].
Other clinical findings consist of recurrent inflammation with pain and swelling of nose and external ear, which can gradually result in deformities (auricular and nasal chondritis), hypoacusia (audiovestibular damage), ocular inflammation and inflammatory arthropathy of peripheral joints. Patients can sometimes present cardiovascular involvement as systemic vasculitis, aortic and mitral valvular insufficiency, aortic aneurysm [5].
CT is the most important imaging technique; typical findings are tracheobronchial wall thickening and luminal narrowing, unusual calcifications and cartilaginous disruption. Functional airway abnormalities like malacia and air-trapping can manifest in patients with normal inspiratory CT, and can represent the only signs of disease at early stages; these findings can be detected only with dynamic expiratory CT, that is why expiratory CT should become routine in the evaluation of these patients. Multiplanar reconstruction and three-dimensional renderings are also very informative[6, 7].
The following differential diagnosis should be considered: amyloidosis (narrowing due to multifocal or diffuse submucosal infiltrates), sarcoidosis (external compression caused by enlarged lymph nodes or granulomas of the trachea and main-stem bronchi) and tracheopathia osteochondroplastica (calcified nodules protrude into airway lumen causing thickening and narrowing) [8].
Therapeutic options include steroids and more aggressive immunosuppressors; therapy should be started at early stages in order to delay disease progression, especially in patients with respiratory involvement that portends a worse prognosis. Unfortunately early diagnosis is quite uncommon. In case of severe tracheobronchial narrowing, a metallic stent can be placed [9].

Differential Diagnosis List

Final Diagnosis

Relapsing polychondritis

URL:	https://www.eurorad.org/case/9756
DOI:	10.1594/EURORAD/CASE.9756
ISSN:	1563-4086