What clinical features help delineate prognosis in Relapsing Polychondritis?
• Nasal chondritis is associated with airway involvement and should prompt additional evaluation of the respiratory tree with CT or MRI scan imaging regardless of pulmonary symptoms.
• Airway involvement is associated with higher rates of infection as well as ICU admissions.
• Renal involvement has traditionally been associated with a worse prognosis, but prior studies may have included patients with missed diagnoses of ANCA-associated vasculitis (see Question 16).
• Vasculitis is associated with a higher mortality.
• Male sex is associated with a higher mortality (independent from other risk factors).
• Cardiac involvement is associated with a higher mortality.
• MDS (and other hematologic malignancies) are associated with higher mortality. In a large series of 200 patients with RPC, over 10% had concurrent MDS. Patients are more commonly men, typically over the age of 60 years, and have higher rates of cutaneous involvement than RPC patients without MDS (75% versus 25%). Neutrophilic dermatoses, including Sweet’s syndrome, may be especially common in patients with RPC and myelodysplasia.
In 1976, McAdam et al. reported that the 5- and 10-year survival rates of 112 patients with RPC were 74% and 55%, respectively. Infection and systemic vasculitis were the major causes of death. More recent cohorts have demonstrated improved 10-year survival rates of >90%, although among patients with concurrent MDS, survival may be as low as 50%. A recent series of 142 patients with RPC (followed for an average of 13 years) identified three distinct phenotypes based on clinical features and prognosis:
1) Hematologic phenotype (MDS & less common hematologic malignancies): worst prognosis with 58% 10-year mortality and over 50% of patients with a serious infection as well as an ICU admission during the study period. A large number of clinical manifestations of RPC (80% of patients with eight or more manifestations) was seen in this phenotype grouping, with the exception of tracheobronchial involvement.
2) Respiratory phenotype (characterized by laryngotracheal or bronchial tree involvement): moderate rates of serious infection (35%) and ICU admission (27%), but mortality similar to the “mild phenotype.”
3) Mild phenotype (absence of hematologic disorder and respiratory tree involvement): low rates of serious infection (6%), ICU admission (2%), and death (4%).