Frequency Of Abnormal Autonomic Testing In Multiple Sclerosis Patients

Background: Non-specific symptoms such as dizziness, heat-intolerance and fatigue are common amongst MS patients. Despite the potential for multifactorial causes, in some patients these symptoms may reflect autonomic dysfunction with important treatment opportunities.  Though autonomic dysfunction has been described in MS, there are few systematic and quantitative reports.

Objectives: 1) Review the indications for referral for autonomic testing in MS patients at our institution; 2) determine the frequency of documented autonomic symptoms and review their association with CNS disease burden/course; and 3) determine the pattern and severity of abnormal autonomic findings.

Methods: Clinical, imaging and autonomic testing data were collected via a retrospective chart review of patients with ICD-9 code 340 (MS) who received autonomic reflex screening (ARS). Findings on comprehensive autonomic testing were recorded and the Composite Autonomic Scoring Scale (CASS) was calculated. Descriptive analysis of symptom profile, lesion location, disease course and ARS results is presented.

Results: 33 patients with ICD-9 code 340 received neurological ARS (from 1/2005-12/2012): 19 MS, 1 NMO, and 2 CIS, while 11 were later determined not to have CNS demyelinating disease. Of the remaining 22 patients, 12 (55%) had an abnormal ARS (1 SPMS, 8 RRMS, 1 PPMS, 1 NMO, 1 CIS); 2 were uninterpretable due to medication effect. Of those with abnormal ARS, CASS ranged from 1-7 (mean 2.3, median 1.0). Fatigue (50% total, 50% with abnormal ARS) and lightheadedness (36% total, 33% with abnormal ARS) were the most frequently reported symptoms. For most symptoms, ARS was abnormal in <50%, whereas 100% of those who reported abnormal sweating had abnormal ARS (n=4). 6 of the patients with abnormal ARS had complete brain and spinal cord imaging. 6/6 had multifocal cerebral lesions, 2/6 mild brainstem lesion burden, 3/6 mild to moderate cervical cord lesions and 2/6 widespread cord involvement.

Conclusions: Our results add to MS autonomic research by employing a comprehensive reflex screen and standardized scoring tool. This data suggests that objective autonomic dysfunction can be detected in >50% of MS patients reporting autonomic symptoms. While the pathophysiologic role of autonomic abnormalities in MS remains unclear, such dysfunction is relevant, as it may be under-recognized and warrant more frequent ARS in clinical practice. Accordingly, ARS abnormalities may offer direct treatment opportunities and influence rehabilitation techniques.