Pulmonary Alveolar Proteinosis

Key Features

• Lipoproteinaceous material accumulates within alveolar spaces

• May be primary (idiopathic) or secondary to

  • Immunodeficiency

  • Hematologic malignancies

  • Inhalation of mineral dusts

  • Lung infection (eg, tuberculosis, viral infection)

Clinical Findings

• Progressive dyspnea

• Chest radiograph shows bilateral alveolar infiltrates and chest CT features ground-glass opacities

• Spontaneous remission occurs in some; progressive respiratory insufficiency develops in others

• Pulmonary infection with Nocardia or fungi may occur

Diagnosis

• While chest radiograph shows bilateral alveolar infiltrates, chest CT features characteristic "crazy-paving," which refers to ground-glass opacities with superimposed interlobular and intralobular septal thickening

• Based on characteristic findings on bronchoalveolar lavage (BAL)

  • A milky appearance

  • Periodic acid-Schiff–positive lipoproteinaceous material, with typical clinical and radiographic features

• In secondary disease, an elevated anti-granulocyte-macrophage colony-stimulating factor (anti-GM-CSF) titer in serum or BAL fluid is highly sensitive and specific

• Biopsy is necessary in some cases

Treatment

• Therapy consists of periodic whole-lung lavage

• Inhalational or subcutaneous GM-CSF may benefit patients who cannot tolerate or who do not respond to whole-lung lavage