[Neurophysiologic study in patients with rheumatoid arthritis with atlantoaxial subluxation].

INTRODUCTION Radiological studies show that 80% of rheumatoid arthritis (RA) patients with more than 10 years present spinal afflictions and 40% of those patients will present neurological deterioration. The somatesthetic evoked potential (SEP) and the transcranial magnetic stimulation (TMS) are neurophysiologic studies that may be useful in early diagnosis of neurological damage. OBJECTIVE To compare the results of the neurophysiologic studies (SEP and TMS) carried out on patients affected with RA without neurological clinic, with or without atlantoaxial suluxation (AAS), and in this way evaluate the efficacy of early diagnosis of the affection of the spinal medulla by electrodiagnostic methods. MATERIAL AND METHODS Cases and controls study that included 29 patients affected with RA of more than 3 years evolution. All of the patients had 2 electrophysiological techniques carried out on them: SEP and TMS in the neurophysiologic laboratory. RESULTS 29 patients participated in the study, of which 21 were females and 8 males. In the group affected with AAS 2 patients presented anomaly in the SEP (11.7%) and 7 in the TMS (41.1%). In the group without AAS 2 presented an altered TMS (16.6%), but no alteration in the SEP. No patient affected or not with AAS, presented alteration of both electrophysiological tests. No significant differences were found between the positivity of the RF or the presence of erosions and the affection of the atloaxoid joint. No differences between the age of outset or years of evolution and the AAS. CONCLUSIONS In our study patients with AAS showed a greater trend towards the presence of alterations in the electrophysiological studies than the patients without AAS.