Abstract
Lesions of the cervical spine often appear in rheumatoid arthritis (RA) and may result in sudden death owing to compression of the medulla oblongata and the spinal cord due to subluxation of the upper cervical spine. Recent research in sudden death has focused on sleep apnea syndrome (SAS) ; however, few reports address the effects of complications of SAS in RA. To investigate factors in the occurrence of SAS in RA, we studied findings obtained on polygraphy during sleep, radiography of the cervical spine, and magnetic resonance imaging (MRI) . Subjects were 7 RA patients (imen, 6 women) : 5 cases were stage IlI, 2 cases were stage N, 1 case was class 2, and 6 cases were class 3. We diagnosed SAS when apnea occured more than five times in 1 hour. Three cases were diagnosed as SAS: 1 case was caused by anterior subluxation and 1 case was caused by both anterior and vertical subluxation. In each case compression of the ventral part of the lower medulla was found on MRI. Another case showed the secondary symptom of micrognathia caused by destruction of the mandibular joint. Sleep apnea was not observed in patients who had no compression of the ventral part of the lower medulla. It has been suggested that a respiratory rhythm generator is present in the ventral part of the lower medulla; therefore, the compression of the ventral part of the lower medulla observed on MRI is one of the factors in SAS regardless of the direction of subluxation.
