Shrinking lung syndrome: vanishing in non-rapid eye movement sleep.

Shrinking lung syndrome is a rare complication of systemic lupus erythematosus; its impact on sleep-disordered breathing is not well understood. We describe a case of a 36-year-old female with systemic lupus erythematosus experiencing shrinking lung syndrome and frequent pain crises. We review manifestations of her disease during non-rapid eye movement (NREM) and rapid eye movement sleep. Shrinking lung syndrome with its restrictive physiology and associated diaphragmatic myopathy is expected to decrease minute ventilation during NREM and rapid eye movement sleep. Normalization of respiratory rate during NREM, as opposed to rapid eye movement and awake state, should alert clinicians to dysfunctional breathing that is suppressed in NREM when cortical breathing is overridden by involuntary breathing. Recognition of dysfunctional breathing disorders by sleep providers is important for addressing all contributors to dyspnea in patients with systemic lupus erythematosus; polysomnogram can be a valuable tool in detecting incongruent ventilation parameters that deviate from expected NREM and rapid eye movement norms and point to dysfunctional breathing disorders. Abnormalities in respiratory rate and gas exchange that improve or vanish in NREM sleep can serve as an additional diagnostic clue of dysfunctional breathing disorders. CITATION: Saleh D, Loewen A. Shrinking lung syndrome: vanishing in non-rapid eye movement sleep.