Relapsing Polychondritis
A rare, clinically heterogeneous, multisystemic inflammatory disease characterized by inflammation of the cartilage and proteoglycan rich structures leading to cartilage damage along with joint, ocular and cardiovascular involvement.
Epidemiology
The prevalence and annual incidence of Relapsing polychondritis (RP) are not known. The estimated incidence is 1/285,000. The sex ratio appears to be equal and all ethnic groups seem to be affected (with more cases reported among Caucasians).
Clinical description
Onset is generally sudden and most commonly occurs in the 5th decade of life (age 40 to 55). Cases with early and late onset do occur. RP follows a flaring and remitting course. Clinical manifestations vary from intermittent auricular and nasal chondritis, to occasional organ or life-threatening complications. Unilateral or bilateral external ear inflammation with pain, tenderness, swelling, erythema, and discoloration, limited to the cartilaginous portion of the pinna with characteristic sparing of the lobule, is one of the hallmark features of RP (90-95% of patients). Auricular collapse or inflammation of vestibular structures can lead to conductive or sensorineural hearing loss. Other associated complications include nausea, vomiting, tinnitus, vertigo and ataxia. Nasal chondritis with sudden pain and tenderness is found at some stage of the disease in more than 50% of patients. Nasal cartilage may be severely damaged resulting in saddle nose deformity. Some patients develop potentially serious laryngotracheal involvement with hoarseness, aphonia, stridor and wheezing, dyspnea, or even airway collapse. Joint pain lasting weeks or months is found in most patients (>70%) and is often the presenting feature (30%). Cardiovascular manifestations (25-50%) include large vessel vasculitis, aneurysmal involvement, and aortic or mitral valve disease. Ocular manifestations reported are proptosis, conjunctivitis, ulcerative keratitis, episcleritis/scleritis, uveitis, and periorbital edema. Cutaneous manifestations that may precede chondritis include aphthosis, nodules, purpura, and papules. Neurological manifestations are due to vasculitis of central or peripheral nervous system. Renal involvement is rare. MAGIC syndrome represents a subset of patients with RP who also have mouth and genital ulcers, which are features of Behçet disease.
Etiology
The exact etiopathogenesis of RP is not known but it is thought to be an immune-mediated disease. A complex cytokine network is thought to be involved in the recruitment of infiltrating cells in RP lesions.
Diagnostic methods
There is no single blood or imaging test that can be used to diagnose this condition. The diagnosis is generally based upon the detection of a combination of clinical presentations. According to the most accepted and widely used diagnostic criteria, three of the following six features are required to make a diagnosis of RP: bilateral auricular chondritis, nonerosive seronegative inflammatory polyarthritis, nasal chondritis, ocular inflammation, respiratory tract chondritis, and audiovestibular damage.
Differential diagnosis
Differential diagnoses include granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, Behçet disease, and leprosy.
Management and treatment
Treatment is primarily symptomatic and no standard therapeutic protocol has been established due to the rarity of the disease. In less severe cases, non-steroidal anti-inflammatory drugs, dapsone, and colchicine may be used. In severe cases with organic involvement, systemic corticosteroids (oral prednisolone or rarely intravenous methylprednisolone) are required. Methotrexate, azathioprine, cyclosporine and chlorambucil may constitute an alternative. Use of biological agents like anti TNFs, tocilizumab, anakinra, rituximab and abatacept has been reported with various efficacy in case reports and small case series. A relapsing polychondritis disease activity index (RPDAI) and damage index (RPDAM) has been validated for assessing disease activity and damage respectively.
Prognosis
Prognosis is generally good in the majority of cases, but the disease may occasionally follow a severe, life-threatening course, with respiratory complications (tracheal collapse and infections) as the primary cause of mortality. Cardiovascular involvement may also lead to a fatal outcome.