Rare rheumatic disorders: b. Relapsing polychondritis

Abstract

Relapsing polychondritis is a rare inflammatory disease of cartilagecontaining tissue. The respiratory manifestations comprise recurrent and usually progressive inflammation of the cartilage of the nose, larynx, airways and ribs. Involvement of the respiratory tract is of prognostic importance as it has been associated with the majority of deaths in this condition (McAdam et al, 1976). Pathologically, the affected cartilage shows loss of basophilic staining of the matrix, perichondrial inflammation and eventually destruction of cartilage with replacement by fibrous tissue. Narrowing of the airways results from inflammatory swelling during active stages of the disease and destruction of tracheal or bronchial cartilage with the formation of fibrous tissue and associated scarring. The functional abnormalities are due to varying combinations of structural narrowing of the airway lumen and loss of stability due to abnormally large dynamic changes in airway ~alibre during breathing. The airway narrowing may be localized to the larynx or to a narrow segment of trachea or can extend more distally along the cartilagecontaining airways. Narrowing of the airways may be complicated by secondary infection due to inadequate clearance of secretions which results from either impairment of mucociliary mechanisms or from diminished effectiveness of cough. Patients with respiratory tract involvement can present with hoarseness, dysphonia, cough, shortness of breath, a choking sensation or tenderness over the affected cartilages of the airway or ribs. Wheezing due to airway narrowing can lead to a mistaken diagnosis of asthma (Gibson and Davis, 1974). The important investigations to assess the severity and extent of airway involvement are functional and radiographic. In some patients bronchoscopy has been performed, allowing direct visualization of the extent of inflammation of the airway (Krell et al, 1986). Plain or computed tomography of the trachea and main bronchi helps determine the extent of the disease (Figure 1). The most useful functional information is obtained by examination of maximum expiratory and inspiratory flow-volume curves (Figure 2). Various combinations of limitation of maximal expiratory and inspiratory flow have been reported (Gibson and Davis, 1974; Mohsenifar et al, 1982; Krell et al, 1986), the exact pattern depending on the main site and