• Subacute or chronic inflammatory polyarthropathy of unknown cause
  
• Thoracic involvement more common in males
  
• Major findings are pleural disease, interstitial fibrosis with honeycombing, micronodules, small and large nodules, and airway disease
  
• HRCT useful to show character and extent of pleuropulmonary and airway disease (obliterative bronchiolitis, BOOP, follicular bronchiolitis, bronchiectasis)
  
• Interstitial lung disease can be UIP or NSIP, the latter having a better prognosis
  
• Treatment - steroids and immunosuppressive drugs
  
• Complications include pneumonia, empyema, drug reaction, amyloid, cor pulmonale

Chest radiography

Pleural Disease

• Pleural thickening (20%)
  
• Pleural effusion, mostly in males (3%)
  
  • Small to large
    
  • Usually unilateral, can be bilateral
    
  • Transient, persistent or relapsing
    
  • Fibrothorax
    
  • Susceptible to empyema
    
• Pneumothorax - rare

Parenchymal Disease

• Reticulonodular and irregular linear opacities, lower zones (<10%)
  
• Distortion, honeycombing, progressive loss of volume
  
• Upper lobe fibrobullous disease, rare
  
• Rheumatoid nodules, rare
  
  • Solitary or multiple
    
  • 5 mm to 7cm
    
  • Peripheral
    
  • Wax and wane
    
  • May cavitate, thick smooth wall
    
  • May calcify
    
• Caplan’s syndrome – rare
  
  • Hypersensitivity reaction to dust
  • Coal miners, rheumatoid arthritis, large rounded nodules (0.5 to 5 cm)
    
  • Redefined to include
    
    • Silica, asbestos, dolomite, carbon
      
    • Serologic and not clinical RA

Airway Disease

• Obliterative Bronchiolitis - normal or hyperinflation
  
• BOOP – same as idiopathic BOOP
  
• Follicular bronchiolitis – diffuse reticulonodular pattern
  
• Bronchiectasis
  
• Upper airway disease

CT/HRCT

Pleural Disease - most common

• Pleural thickening or effusion
• May be associated with pericarditis, interstitial fibrosis, interstitial pneumonia or lung nodules

Parenchymal Disease

• Pulmonary fibrosis indistinguishable from UIP,
  
  • Basilar and peripheral progresses in some to diffuse and central
    
  • Intralobular lines, irregular thickened interlobular septa
    
  • Honeycombing (10%), mostly at bases, distortion
    
  • Ground glass opacities (14%)
    
• Consolidation (6%)
  
• Nodules (22%) – micronodules (centrilobular, peribronchial, subpleural)
  
• Nodules/masses
  
  • Resemble neoplasm, discrete, rounded or lobulated, subpleural.
    

Airway Disease

• Obliterative Bronchiolitis – mosaic pattern, bronchiectasis
  
• BOOP – see idiopathic BOOP
  
• Follicular bronchiolitis – nodules < 1 cm; centrilobular, subpleural, peribronchial; centrilobular branching pattern
  
• Bronchiectasis
  
• Upper airway disease
  

Other findings

• Cor pulmonale, lymphadenopathy, sclerosing mediastinitis, pericarditis
  

• Lung
  
  • IPF
    
  • Scleroderma
    
  • Asbestosis
    
  • Drug Reaction
    
  • BOOP
    
  • Hypersensitivity pneumonitis
    
• Pleural
  
• Metastases
  
• Empyema
  
• Mesothelioma
  
• Hemothorax, old
  
• Empyema, old
  
• Differentiation
  • Hand films, changes of RA
    
  • Chest x-ray: erosion of distal clavicles

• Subacute or chronic inflammatory polyarthropathy of unknown cause
  
• Possible inflammatory, immunologic, hormonal, and genetic factors

  Pleural Disease
  

  • Pleural biopsy – may show rheumatoid nodules
    
  • Pleural fluid - lymphocytes, acutely neutrophils and eosinophils

  Interstitial Lung Disease (<10%)
  

  • Pulmonary fibrosis, either UIP or NSIP
    • UIP
      
      • Temporally inhomogeneous
        
      • Interstitial lymphocytes, histiocytes, plasma cells adjacent to bronchioles and interlobular septa
        
      • Fibrosis, honeycombing
        
      • Lymphoid aggregates
    • NSIP
      
      • Temporally homogeneous
        
      • More cellular
        
      • Less fibrotic, less honeycombing
        
      • Better prognosis
  • Airway disease - obliterative Bronchiolitis, BOOP, follicular bronchiolitis bronchiectasis, upper airway disease
  • Other lung disease
  • Necrobiotic nodules, lymphoid hyperplasia, bronchocentric granulomatosis, apical fibrosis and cavitation, drug related lung disease, vasculitis (rare), cor pulmonale, ARDS
    
  • May have increased risk for lung cancer, as with UIP

• RA is 3x more common in females,
  
• Extraarticular RA - more common in males, age 50-60 years
  
• Thoracic disease may develop before, at onset or after onset of arthritis
  
• Insidious onset, relapses and remissions
  
• Asymptomatic, or dyspnea, cough, pleuritic pain, finger clubbing, hemoptysis, infection, bronchopleural fistula, pneumothorax
  
• Most have arthritis; positive rheumatoid factor (80%), and cutaneous nodules
  
• Pleural fluid - high protein, low glucose, low pH, high LDH, high RF, low complement
  
• PFTs - restrictive defect, reduced diffusing capacity, sometimes obstructive defect
  
• Treatment
  • Steroids
  • Iimmunosuppresant drugs
    
• Variable prognosis, 5 year survival 40%
  
  • Death from infection, respiratory failure, cor pulmonale, amyloid

Turner-Warwick M , Evans RC. Pulmonary manifestations of rheumatoid disease Clin Rheum Dis 3:549-564, 1977
Remy-Jardin M, Remy J, Cortet B, et al. Lung changes in rheumatoid arthritis: CT findings Radiology 193:375-382, 1994