Sleep apnea–hypopnea syndrome caused by ankylosing spondylitis: A case report

INTRODUCTION: Sleep apnea–hypopnea syndrome (SAHS) is a multifactorial disease characterized by recurrent hypopnea or respiratory interruption during sleep, which causes intermittent hypoxemia, hypercapnia, and sleep structure disturbances. An association between ankylosing spondylitis (AS) and the type of SAHS has rarely been reported in the literature. Here, we present a case of SAHS in a patient with AS and discuss the possible mechanism underlying the type of SAHS. PATIENT CONCERNS: A 46-year-old man presented with a 15-year history of AS. He had been receiving sulfasalazine for symptomatic relief and had never been on immunosuppressive therapy. DIAGNOSIS: The patient was diagnosed with SAHS in addition to AS. INTERVENTIONS: We instituted treatment with methylprednisolone (5 mg, oral, daily), leflumomide (20 mg, oral, daily), bicyclol tablets (25 mg, oral, 3 times a day), and ursodeoxycholic acid tablets (10 mg/kg, oral, daily). The patient received etanercept (50 mg, sc, once a week) as his condition deteriorated. In addition, for management of SAHS symptoms, the patient received nasal continuous positive airway pressure (CPAP) during sleep. OUTCOMES: Six months after commencement of the treatment, the clinical manifestations of SAHS and AS had significantly improved. CONCLUSIONS: We hypothesize that patients with AS are prone to sleep apnea due to airway compression, central depression of respiration, abnormal inflammatory responses. Hence, careful assessment toward potential SAHS symptoms should be considered especially in patients with AS.