Table 16.2.
BAL pattern, most important diagnoses, remarks
| BAL pattern | Diagnosis | Remarks |
|---|---|---|
| Lymphocytic | Hypersensitivity pneumonitis | Highest numbers of lymphocytes |
| Highest cell counts | ||
| Lymphocytosis >50% | ||
| Low CD4/CD8 most common | ||
| Foamy macrophages | ||
| Plasma cells may be present (antigen exposure) and transient neutrophil count | ||
| Sarcoidosis | Mostly isolated moderate lymphocytosis | |
| Neutrophils and mast cells may be present | ||
| CD4/CD8 ratio >3.5, but high variability | ||
| Consider transbronchial lung biopsy | ||
| Consider EBUS-TBNA | ||
| Nonspecific interstitial pneumonia | Cellular variant | |
| Higher lymphocyte count | ||
| Lower neutrophil count | ||
| Eosinophils may be present | ||
| Cryptogenic organizing pneumonia | Lymphocytes dominantly increased | |
| Neutrophils, eosinophils, and mast cells increased | ||
| Typical symptoms and radiological findings | ||
| Drug-induced lung disease | Dominance of CD8+ cells | |
| Silicosis | Dust particles in alveolar macrophages | |
| Tuberculosis | Staining/cultures for Mycobacteria | |
| Radiological appearance | ||
| Neutrophilic | Idiopathic pulmonary fibrosis | HRCT findings |
| Moderate increased neutrophil count (10–30%) in 70–90% of patients | ||
| Eosinophils slightly increased (in 40–60% of patients) | ||
| Neutrophils >2× eosinophils | ||
| Collagen vascular disease | Dominantly increased neutrophils | |
| Asbestosis | Asbestos bodies (negative in 10–15%) | |
| Bacterial infection | Bacteria on staining and cultures | |
| Eosinophilic | Eosinophilic pneumonia | Eosinophils >25% (up to 90%) |
| Eosinophils > neutrophils | ||
| Plasma cells may be present | ||
| Radiological criteria on HRCT | ||
| Churg–Strauss syndrome | Moderate eosinophilia | |
| Allergic bronchopulmonary aspergillosis | Staining for Aspergillus+ | |
| Criteria for ABPA | ||
| Drug-induced lung disease | Very variable | |
| Mixed | Predominant pattern may lead to diagnosis |