Chronic airspace disease: Review of the causes and key computed tomography findings

Table 4 Clinical, laboratory and imaging findings, and prognosis/treatment of miscellaneous causes of chronic airspace disease

Causes of chronic airspace disease/ General category	Clinical information	Laboratory findings	Imaging findings	Prognosis and treatment
Lipoid pneumonia/ Miscellaneous	Usually elderly individuals; History of chronic inflammation in primary (endogenous) form; History of chronic constipation and aspiration in the secondary (exogenous) form		Chronic consolidative and GGOs; Nodules and masses; More in the dependent portions of the lungs; May or may not have fat attenuation	Biopsy may be needed in lipid poor cases to exclude malignancy
Alveolar hemorrhage/ Miscellaneous	May have history of vasculitides, connective tissue disorders, or coagulation disorders		GGO or consolidation in the acute phase; GGO and interlobular septal thickening in subacute phase; May develop fibrosis if recurrent or chronic; Opacities may show subtle or major changes in appearance (migratory)	Supportive treatment; Treatment of underlying disease
PAP/ Miscellaneous	Due to abnormal intra-alveolar accumulation of surfactant-like material; More common in smokers		Crazy-paving which is due to combination of GGO and smooth interlobular septal thickening; This finding is very suggestive but not pathognomonic; Usually bilateral and extensive, with more severe involvement of the lower lobes	Whole-lung bronchoalveolar lavage to remove alveolar material; Variable prognosis, ranging from improvement with treatment to a chronic and terminal course.

GGO: Ground glass opacity; PAP: Pulmonary alveolar proteinosis.