Relapsing Polychondritis

A rare autoimmune disorder characterised by recurrent episodic inflammation of cartilaginous structures throughout the body, principally the ears, nose, laryngotracheal tree and joints, with potential involvement of the eyes, cardiovascular system and inner ear. It carries genuine life threatening potential through airway collapse and cardiac valve involvement, and requires prompt recognition given the risk of catastrophic airway compromise if missed.

Pathophysiology

An autoimmune process targeting cartilage matrix components, principally type II collagen, with lymphocytic and neutrophilic infiltration of cartilage leading to chondrolysis and, over recurrent episodes, replacement of cartilage by fibrous tissue, producing structural collapse of previously rigid cartilaginous support structures, most dangerously in the airway.

Auricular chondritis is the commonest presenting feature, producing sudden painful, red, swollen inflammation of the pinna with sparing of the earlobe (which lacks cartilage), a highly characteristic distribution distinguishing it from infective causes such as cellulitis or perichondritis, which typically involve the whole ear including the lobe.

Nasal chondritis causes pain and inflammation of the nasal bridge, with recurrent episodes leading to saddle nose deformity from cartilage destruction.

Laryngotracheal involvement is the most dangerous manifestation, producing hoarseness, cough, stridor, tenderness over the thyroid and cricoid cartilage, and progressive airway narrowing that can cause life threatening obstruction, particularly with acute inflammatory episodes superimposed on chronic structural weakening.

Arthritis, typically non erosive, affecting large and small joints, is common and often the initial symptom prompting presentation.

Ocular involvement includes episcleritis, scleritis, uveitis and, rarely, orbital pseudotumour.

Audiovestibular involvement causes sensorineural hearing loss, tinnitus and vertigo from inner ear inflammation or vasculitis of the internal auditory artery.

Cardiovascular involvement includes aortic and mitral valve regurgitation from valvular cartilage like tissue destruction, and vasculitis affecting vessels of any size.

Association with myelodysplastic syndrome and other autoimmune diseases (systemic lupus erythematosus, vasculitis) occurs in a meaningful proportion, particularly in older patients, warranting screening.

Diagnosis is predominantly clinical, based on recurrent episodes of chondritis at characteristic sites (auricular, nasal, laryngotracheal, and at least two further sites including ocular inflammation, audiovestibular damage, seronegative inflammatory arthritis) meeting established clinical criteria, since no single diagnostic test exists.

Biopsy of affected cartilage shows characteristic perichondrial inflammation and chondrolysis, useful in atypical or diagnostically uncertain presentations, though rarely required when the clinical picture is classical.

Inflammatory markers are elevated during active flares but are non specific.

Pulmonary function testing with flow volume loops assesses for fixed or variable airway obstruction from laryngotracheal involvement, and is essential in any patient with respiratory symptoms.

Computed tomography of the airway, including dynamic expiratory imaging, evaluates tracheobronchial narrowing, wall thickening and malacia, guiding decisions about airway intervention.

Echocardiography screens for valvular involvement, and audiometry assesses audiovestibular disease.

Screen for associated haematological and autoimmune conditions given recognised associations, particularly in older patients or those with atypical blood counts.

Mild disease (isolated auricular or nasal chondritis, mild arthritis) is managed with nonsteroidal anti inflammatory drugs or low dose corticosteroids, with dapsone or colchicine considered as steroid sparing options for chronic mild disease.

Moderate to severe disease, including any laryngotracheal, ocular, audiovestibular or cardiovascular involvement, requires systemic corticosteroids at higher dose (prednisolone 0.5 to 1 mg per kg daily), with steroid sparing immunosuppression (methotrexate, azathioprine, mycophenolate) introduced for relapsing or steroid dependent disease.

Biologic therapy, particularly tumour necrosis factor inhibitors and, increasingly, interleukin 6 pathway inhibition (tocilizumab), is used for refractory disease not controlled by conventional immunosuppression.

Airway management is critical and requires close collaboration with otolaryngology and, where necessary, intensive care: acute severe airway inflammation may require high dose corticosteroids and airway monitoring, while progressive structural collapse from chronic disease may necessitate tracheostomy, airway stenting or, in severe cases, surgical reconstruction. A low threshold for airway assessment and multidisciplinary planning is essential given the potential for rapid deterioration.

Valve replacement surgery is required for haemodynamically significant valvular regurgitation.

Audiovestibular involvement is managed with corticosteroids for acute inflammatory hearing loss, with hearing aids or cochlear implantation for established sensorineural loss.

Long term multidisciplinary follow up (rheumatology, otolaryngology, respiratory medicine, cardiology, ophthalmology) given the unpredictable relapsing course and the potential for serious structural complications developing insidiously between recognised flares.