[Systemic lupus erythematosus presenting as severe alveolar hypoventilation and the shrinking lung syndrome]

The shrinking lung syndrome (SLS) is a rare complication of systemic lupus erythematosus.

A 69-year-old man presented with exertional dyspnoea, muscle weakness, and weight loss of 15kg in 6months. Pulmonary function tests revealed a restrictive lung disorder, with a dramatic decrease in maximal inspiratory pressure (17% of theoretical value), and alveolar hypoventilation (pH 7.43; PaCO₂ 55mmHg). A thoracic CT-scan showed bilateral diaphragmatic elevation. The creatinine phophokinase level was increased at 280U/L. Progress was marked by a rapidly increasing respiratory acidosis (pH 7.24, PaCO₂ 109mmHg) requiring invasive ventilation. Auto-immune studies revealed positive anti-nuclear antibodies (1/800) and positive anti-native DNA antibody at 45U/L. Treatment with systemic corticosteroids led to an initial improvement but it was not possible to discontinue mechanical ventilation. The outcome was fatal. Autopsy did not reveal any other cause and a diagnosis of the SLS associated with lupus was confirmed.

The interesting features of this case report consist of: 1) the presentation of the SLS as an alveolar hypoventilation with a fatal outcome, 2) the presentation of systemic lupus as SLS.