Prevalence and clinical features of rheumatoid arthritis (RA)-associated lung diseases

Disease phenotypeClinical featuresPrevalence
Parenchymal lung disease
 UIP patternRadiographic pattern: subpleural, basal predominant reticular opacities, honeycombing, minimal ground-glass opacity, architectural distortion with traction bronchiectasis
Associated with worse outcomes compared to other disease patterns in RA
 NSIP patternExtensive ground-glass opacity, traction bronchiectasis, subpleural sparing
Lower risk of disease progression and better treatment response compared with UIP
 Organising pneumoniaFocal ground-glass opacities, consolidations, reversed halo sign0–11%
 Other (e.g. LIP or DIP)Thin-walled cysts, centrilobular nodules, ground-glass attenuation, peribronchovascular septal thickening, upper-lobe predominantRare
 Rheumatoid nodulesMay be single or multiple and range in size, typically asymptomatic unless they cavitate or rupture, in which case infection, pleural effusion or bronchopleural fistula may occur<1% radiographically, 30% on autopsy specimens
 Caplan's syndromeComplication that occurs in those with pneumoconiosis from occupational exposure to coal, silica or asbestos
Sudden development of multiple nodules, from 0.5 to several centimetres in diameter, distributed throughout the lungs but predominantly at the lung periphery
<1% in the USA by autopsy
Airway disease
 Upper airway
  CricoarytenoiditisArthritis of the cricoarytenoid joint leading to mid-line adduction of vocal cords with resultant hoarseness and/or stridor32–75% via laryngoscopy
54–72% on CT scans
 Lower airway
  BronchiectasisAssociated with chronic infectionPresent on HRCT in ∼30%, though many cases clinically silent
  Bronchiolitis (constrictive or follicular)Female sex, high RF titre and long disease durationBy pulmonary function testing or radiographic pattern: 8–30%
Pleural disease
 Pleural effusionMiddle-aged males with positive RF and rheumatoid nodules
Rheumatoid effusion: classically sterile, exudative fluid with low pH (<7.3), glucose <60, and elevated LDH
Symptomatic in 3–5%, though present in up to 70% in autopsy studies

UIP: usual interstitial pneumonia; NSIP: nonspecific interstitial pneumonia; LIP: lymphocytic interstitial pneumonia; DIP: desquamative interstitial pneumonia; CT: computed tomography; HRCT: high-resolution CT; RF: rheumatoid factor; LDH: lactate dehydrogenase. Data from [9, 10, 12–21].