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bronchoalveolar lavage (BAL)
The collection of alveolar lavage specimens during bronchoscopy.
Indications:
1) pulmonary infection*
a) Pneumocystis carinii
b) tuberculosis
c) mycoses
d) other infections
2) alveolar proteinosis
3) pulmonary Langerhans cell granuloma
4) lymphangitic pulmonary metastases (carcinomatosis)
5) cell counts in diagnosis of parenchymal lung disease
6) alveolar hemorrhage [3]
7) cytology for pulmonary neoplasm
* procedure of choice for assessment of infectious entities in pulmonary disease
Contraindications:
- not useful for:
- sarcoidosis
- idiopathic pulmonary fibrosis
- mass lesions, pulmonary nodules, lymphadenopathy
Procedure:
- instillation of 100-150 mL of normal saline into the diseased segment(s) of the lung & aspirating the saline back via the bronchoscope
- the aspirated specimens can be examined under the microscope much as sputum may be analyzed
Laboratory:
- microscopic examination
- in normal persons, a BAL cell count shows 93% alveolar macrophages & 7% lymphocytes
- granulocytes & macrophages are rarely observed in the absence of infectious pulmonary disease
- BAL CD4/CD8 ratio
- reversed in patients with:
- AIDS
- lymphocytic interstitial pneumonitis
- hypersensitivity pneumonitis (many)
- increased in patients with sarcoidosis (non-specific)
- miscellaneous labs
- protein in lower respiratory specimen
Notes:
- contamination by upper airway flora may occur
Related
culture of bronchial or transtracheal aspirate/lavage
sputum (phlegm)
General
bronchoscopic procedure
lavage
References
- Introduction to Clinical Imaging, Radiology Syllabus, UCSF,
1993
- Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed)
Lippincott-Raven, Philadelphia, 1998, pg 737-38
- Medical Knowledge Self Assessment Program (MKSAP) 11, 18.
American College of Physicians, Philadelphia 1998, 2018.