Churg-Strauss Syndrome

Churg-Strauss syndrome is a systemic vasculitis involving multiple organs. It is seen almost exclusively in patients with asthma, with a mean age of onset of ~40 years. Almost all patients have eosinophilia and up to 75% may have positive ANCA. Eosinophil infiltration into the endocardium induces endocardial thickening, thrombus formation, and myocardial dysfunction, which can be seen in up to 50% of patients. Peripheral neuropathy can also be seen.

The most common findings on radiographs are transient, patchy, nonsegmental opacities without a zonal predilection. Small noncavitary nodules or diffuse reticular opacities may also bee seen.

CT may reveal small (< 10 mm) centrilobular nodules (60% of cases), ground-glass opacities (50%), bronchial wall thickening (50%), bronchial dilatation (50%), consolidation (40%), interlobular septal thickening (40%), mosaic perfusion (50%), and unilateral or bilateral pleural effusion (50%).

Differential considerations include:

• Simple pulmonary eosinophilia: Löffler syndrome.
• Chronic eosinophilic pneumonia:
• Subacute hypersensitivity pneumonitis: May also have small centrilobular nodules or nodular ground-glass opacity.
• Metastatic calcification: May also have small centrilobular nodules or nodular ground-glass opacity.
• Microscopic polyangiitis: May also have small centrilobular nodules or nodular ground-glass opacity.
• Systemic lupus erythematosis: May also have small centrilobular nodules or nodular ground-glass opacity.
• Respiratory bronchiolitis-interstitial lung disease: May also have small centrilobular nodules or nodular ground-glass opacity.

References

Chung MP, Yi CA, Lee HY, Han J, Lee KS. Imaging of pulmonary vasculitis. Radiology. 2010 May;255(2):322-41.