Autonomic Dysfunction Presenting as Postural Orthostatic Tachycardia Syndrome in Patients with Multiple Sclerosis

BACKGROUND Autonomic dysfunction is common in patients suffering from multiple sclerosis (MS) and orthostatic dizziness occurs in almost 50% of these patients. However, there have been no reports on postural orthostatic tachycardia syndrome (POTS) in patients suffering from MS. METHODS The patients were included for analysis in this study if they had POTS with either a prior history of MS or having developed MS while being followed for POTS. Postural orthostatic tachycardia (POTS) is defined as symptoms of orthostatic intolerance(>6 months) accompanied by a heart rate increase of at least 30 beats/min (or a rate that exceeds 120 beats/min) that occurs in the first 10 minutes of upright posture or head up tilt test (HUTT) occurring in the absence of other chronic debilitating disorders. We identified nine patients with POTS who were suffering from MS as well. Each of these patients had been referred from various other centers for second opinions. RESULTS The mean age at the time of diagnosis of POTS was 49+/-9 years and eight of the 9 patients were women. Five patients (55%) had hyperlipidemia, 3 (33%) migraine and 2 (22%) patients had coronary artery disease and diabetes each. Fatigue and palpitations (on assuming upright posture) were the most common finding in our patients (9/9). All patients also had orthostatic dizziness. Syncope was seen in 5/9(55%) of patients. Four patients (44%), who did not have clear syncope, were having episodes of near syncope. The presence of POTS in our study population resulted in substantial limitation of daily activities. Following recognition and treatment of POTS, 6/9(66%), patients were able to resume daily activities of living. Their symptoms (especially fatigue and orthostatic intolerance) improved. The frequency and severity of syncope also improved. Three (33%) patients failed to show a good response to treatment. CONCLUSION Patients suffering from MS may manifest autonomic dysfunction by developing POTS. Early recognition and proper management may help improve the symptoms of POTS.