An unusual cause of delirium.

Sleep disordered breathing (SDB) including obstructive sleep apnea (OSA), central sleep apnea (CSA), and Cheyne-Stokes breathing is common in patients with congestive heart failure (CHF). In a study of 81 males with an ejection fraction (EF) < 45%, 51% of patients had documented SDB with the majority of cases representing CSA. Studies suggest that SDB is an independent risk factor for increased morbidity and mortality in the setting of CHF. Like OSA, CSA frequently presents with nighttime awakenings, nocturnal hypoxia, and daytime somnolence, but only OSA has been reported to present with delirium. We present a patient with clear manifestations of CSA with frank delirium that improved only after BPAP therapy.