Unusual Respiratory Manifestations of Ankylosing Spondylitis – A Case Report

A male patient, 54 years old, was initially admitted to the hospital because of fatigue he felt during the last month and swelling of the lower legs. Upon hospital admittance, gas exchange analysis showed global respiratory failure: pO₂=6.1 kPa, pCO₂=10.9 kPa, pH=7.35, A-a gradient = 1.0. Due to the existence of hypercapnia and decompensated respiratory acidosis, the patient was connected to a device for non-invasive mechanical ventilation. Reduced chest mobility was noticed, and the respiratory index value was decreased. Radiographs of the chest and thoracic and lumbo-sacral spine showed marked changes on the spine attributable to ankylosing spondylitis (AS). Radiographs of the sacroiliac joints showed reduced sacroiliac joint intraarticular space with signs of subchondral sclerosis. The diagnosis of AS was set on the basis of New York Criteria (bilateral sacroiliitis, grade 3) and clinical criteria (back pain, lumbar spine limitation and chest expansion limitation). HLA typing (HLA B27 +) confirmed the diagnosis of AS. Pulmonary function test proved severe restrictive syndrome. Polysomnography verified the existence of severe obstructive sleep apnoea (AHI =73). This was a patient with newly diagnosed AS, with consequent severe restrictive syndrome and global respiratory failure with severe obstructive sleep apnoea. Thee patient was discharged from the hospital with a NIV (global respiratory failure) device for home use during the night.