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Diffuse Lung Disease

Clinical Evaluation of the Chest Radiograph

Radiographic patterns

Interstitial - reticulonodular

Known cause - inorganic dust (pneumoconiosis), organic dust (hypersensitivity pneumonitis), iatrogenic (drugs, radiation therapy)

Unknown cause - sarcoidosis, idiopathic pulmonary fibrosis, pulmonary fibrosis with connective tissue disease

Alveolar - fluffy, often with air bronchograms

Acute - cardiogenic pulmonary edema, non-cardiogenic pulmonary edema (ARDS), diffuse alveolar pneumonia, alveolar hemorrhage

Subacute or chronic - bronchioloalveolar cell carcinoma, lymphoma, pulmonary alveolar proteinosis, desquamative interstitial pneumonitis

Nodular - often suggests hematogenous origin

Disseminated malignancy, tuberculosis, fungal disease, pneumoconiosis, eosinophilic granuloma

Lower lobe - associated with connective tissue, asbestosis

Upper lobe - silicosis, eosinophilic granuloma

Non-anatomic margins - radiation-induced pulmonary

Peripheral distribution - chronic eosinophilic pneumonia; occasionally bronchiolitis obliterans with organizing pneumonia

With hilar adenopathy -

With pleural - asbestosis, RA, lupus. In AIDS, suggestive of KS.

Diagnosis and Treatment of Diffuse Lung Disease

Idiopathic pulmonary fibrosis (IPF)

Original description of Hamman-Rich syndrome was an acute interstitial pneumonia with rapid progression and death

Sarcoidosis

Despite common finding of depressed cell-mediated immunity with cutaneous anergy, cell-mediated immune processes are enhanced locally in the

Bronchoalveolar lavage - increased lymphocytes with increased CD4/CD₈ ratio

Pattern of parenchymal infiltrates on chest X-ray can be reticulonodular, nodular, or alveolar

Endobronchial involvement can cause chronic cough and/or airflow obstruction

Angiotensin converting enzyme levels - generally not useful for diagnosis or for following activity

Standard treatment is still corticosteroids; results with cyclosporine have been disappointing. ? role for methotrexate.

Hypersensitivity pneumonitis

Examples - air conditioner or humidifier

Pathology shows mononuclear cell infiltrate with poorly formed granulomas

Distinction between acute hypersensitivity pneumonitis (fever, cough, dyspnea, pulmonary infiltrates hours after exposure) and chronic hypersensitivity (mimics other forms of chronic interstitial)

Bronchoalveolar lavage (BAL) fluid shows lymphocytosis with low CD4/CD8 ratio

Eosinophilic granuloma (histiocytosis X)

Atypical histiocytes (Langerhans' cells) in infiltrate; variety of cell types in infiltrate with scattered eosinophils

May have airflow obstruction; may have surprisingly normal volumes for degree of interstitial seen on radiograph

Chest X-ray and CT scan may show numerous small cysts and nodules; eventual progression to fibrosis

Lymphangioleiomyomatosis

Exclusively in women, almost all of childbearing age

Atypical smooth muscle proliferation around lymphatics, bronchioles, small pulmonary vessels

Treatment - alteration of hormonal milieu, e.g., progesterone, oophorectomy

Chronic eosinophilic pneumonia

Often in patients with underlying asthma

Term refers to eosinophils in the pulmonary, infiltrate, which is i

Bronchiolitis obliterans with organizing pneumonia (BOOP)

Pathology - fibrous plugs in small airways; organizing inflammatory. infiltrate in pulmonary, parenchyma

Can be idiopathic (often called cryptogenic organizing pneumonitis), related to infection, associated with connective tissue

Subacute illness with dyspnea, cough, constitutional symptoms