Shrinking lung syndrome

Shrinking lung syndrome refers to a rare thoracic complication of systemic lupus erythematosus (SLE) characterized by:

• unexplained dyspnea
• restrictive pattern on pulmonary function tests
• elevated hemidiaphragm

Epidemiology

As with SLE in general, it is thought to carry a increased female predilection. It is an uncommon manifestation ⁵ that primarily occurs during the later stage of disease.

Clinical presentation

If symptomatic, patients present with progressive dyspnea.

Pathology

The etiology of shrinking lung syndrome is not known, but thought to implicate all the components of the respiratory system, inclusive of the upper airways, lung parenchyma, pulmonary vasculature, pleura, and respiratory muscles.

Radiographic features

Plain radiograph

Chest x-ray often shows small but clear lungs with diaphragmatic elevation ^2,5. Occasional basal atelectasis may be present ². 

CT

CT chest often shows reduced lung volumes with diaphragmatic elevation +/- occasional basal atelectasis but without any major parenchymal lung or pleural disease ². 

Treatment and prognosis

Shrinking lung syndrome may cause significant morbidity and occasional mortality. There is no definitive therapy, while corticosteroids and other immunosuppression (e.g. rituximab) may lessen symptoms and improve pulmonary function in some patients ^4,5.

History and etymology

The term was initially coined by B.I. Hoffbrand and E.R. Beck in 1965 ⁴.