The diagnosis of RP is best made by clinical manifestations, since there is no test diagnostic of RP. The diagnosis can be delayed for more than a year in up to two-thirds of patients, due to uncharacteristic symptoms. Diagnostic criteria have been proposed by McAdam et al. and modified by others (Table 3) (18,19,32).
Laboratory tests are nonspecific but can be supportive of the diagnosis. Anemia of chronic disease, mild leukocytosis, and thrombocytosis can be seen. Eosinophilia is seen in 10% of cases. Elevation of acute phase reactants (erythrocyte sedimentation rate, C-reactive protein), complement levels, and a polyclonal gammopathy are commonly seen. Urinalysis can show microscopic hematuria and proteinuria in up to 25% of patients. Although occasionally positive, tests for rheumatoid factor, antinuclear antibodies, antiphospholipid antibodies, and antineutrophil cytoplasmic antibodies are usually negative, unless the patient has another coexistent autoimmune disease. Antibodies to types II, IX, and XI collagen and matrillin-1 are found in less than 50% of patients (10,11,33). The titer of anticollagen II antibodies and levels of urinary type II collagen neoepitope reflecting catabolism of hyaline cartilage reportedly reflect disease activity, but are not routinely available (34).
Evaluation for upper and lower airway involvement should include a chest radiograph and pulmonary function testing with spirometry, including inspiratory and expiratory flow-volume loops (35). Computed tomography can identify lesions in the larynx, trachea, and lobar/segmental bronchi (Fig. 4) (36). Endobronchial ultrasound may show edema in the cartilage consistent with inflammation (37). Magnetic resonance imaging is useful to distinguish fibrosis from inflammation in the involved airways and the ascending aorta (38). Doppler echocardiography is used to assess the cardiac valves and function. Radio-nucleotide bone scan can show tracer accumulation in affected cartilaginous regions (39). Biopsy of the ear cartilage is not pathognomonic but can support a diagnosis; however, it is unnecessary if clinical manifestations are diagnostic of RP.
The differential diagnosis of patients presenting with auricular or nasal cartilage inflammation includes several important diseases that can mimic RP. Auricular inflammation may be secondary to an acute bacterial infection or a chronic infection such as
TABLE 3 Diagnostic Criteria for RP
For diagnosis of RP, patients must have one of the following
1. Three of the following clinical findings: Bilateral auricular chondritis
Nonerosive, seronegative inflammatory polyarthritis
Respiratory tract chondritis
Cochlear and/or vestibular dysfunction
2. One or more of the above clinical findings with positive histologic confirmation
3. Chondritis at two or more separate anatomic sites with response to corticosteroid and/or dapsone
Abbreviation: RP, relapsing polychondritis.
tuberculosis, fungal disease, syphilis, or leprosy. Acute bacterial infections typically involve the earlobe in addition to the pinna and are associated with regional lymphadenopathy. Nasal cartilage inflammation and destruction (saddle nose deformity) can be due to chronic granulomatous infection, Wegener's granulomatosis, lymphomatoid granulomatosis, lethal midline granuloma, carcinoma, or cocaine abuse. Upper and lower airway lesions causing narrowing can be due to prolonged endotracheal intubation, Wegener's granulomatosis, sarcoidosis, localized amyloidosis, and chronic granulomatous infections, as well as other rarer diseases. Wegener' s and other granulomatous diseases are discussed in detail in Chapter 8; sarcoidosis is discussed in Chapter 6.
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