Table 2. Clinical features of respiratory bronchiolitis-interstitial lung disease (RB-ILD), desquamative interstitial pneumonia (DIP) and pulmonary Langerhans’ cell histiocytosis (PLCH) in comparison with combined pulmonary fibrosis and emphysema (CPFE).
RB-ILD | DIP | PLCH | CPFE | |
Smoking | 100% | 90% | >90% | 100% (heavy smokers) |
Age | 3rd to 5th decade | 3rd to 5th decade | 3rd to 4th decade | 6th to 7th decade |
Sex M:F | Slight male dominance | Nearly 2:1 | 1:1 | Almost all male |
Onset | Insidious | Insidious | Insidious | Insidious |
Presenting symptoms | Dyspnoea and cough | Dyspnoea and cough | Dyspnoea, cough and acute chest pain (when pneumothorax is present) | Dyspnoea and cough |
Systemic involvement | No | Possible, rare | Possible | No |
Crackles | ∼50% | 60% | Usually absent | 87% basal |
Clubbing | Rare | Nearly 50% | Exceptional | 43% |
Pulmonary function | Mixed defect or normal; reduced DL,CO | Restrictive; reduced DL,CO | Obstructive or restrictive; reduced DL,CO (especially in patients with vascular involvement) | Sub-normal pulmonary volumes; severe reduction of DL,CO |
Pulmonary hypertension | No | Rare | Possible | 47% at diagnosis; between 50% and 90% |
Desaturation on 6MWT | No | Possible | Rare | Frequent |
Spontaneous improvement | Possible | Occasionally | Possible | No |
Treatment | Smoking cessation | Smoking cessation and steroids | Smoking cessation and steroids? | Smoking cessation |
Response to steroids | Good | Good | Fair | None |
Prognosis | Good | Good | Good | Poor (5-yr survival is 55%) |
Complete recovery possible | Yes | Yes | Yes | No |
Correlation with lung cancer or other neoplasms | No | Rare | Frequent | Frequent (near 50%) |
M: male; F: female; 6MWT: 6-min walk test; DL,CO: diffusing capacity of the lung for carbon monoxide.