A retrospective review of autonomic screening tests conducted at a Tertiary General Hospital

Autonomic screening tests (AST) are useful for assessing autonomic dysfunction. Our aim was to delineate the referral pattern, abnormalities, technical difficulties and final diagnoses of ASTs at a Tertiary General Hospital. Referring diagnoses was classified into: orthostatic symptoms, assessment of known/suspected disease associated with dysautonomia, thermoregulatory complaints and neurological disorders. Medication history, patient cooperation and test results were collated. Usefulness of AST in answering the clinical questions was ranked on a 3-point scale. 248 patients were studied. Orthostatic symptoms were the commonest referring diagnosis (71.4%) followed by assessment of a known/suspected disease associated with dysautonomia (13.3%), thermoregulatory complaints (7.7%) and neurological disorders (7.3%). 49.6% of ASTs were abnormal, 40.7% were normal and 9.7% were inconclusive. The first 2 referral categories had the highest proportion of abnormal ASTs while only 5.3% of patients with thermoregulatory complaints had abnormal AST. The most frequent final diagnosis was orthostatic hypotension (OH). It was seen in 31.7% of the cohort; however, 41% of these were attributed to medications. With regard to answering the clinical question, ASTs were very helpful in 56.0% and not helpful in 9.3%. 58.0% of inconclusive ASTs were attributed to poor performance of test maneuvers, 8.0% to medications, 17.0% to both and 17.0% to irregular heart rhythms and pacemakers. 34.7% of patients with diabetes mellitus and 38.2% of patients with Parkinsonism had signs of autonomic dysfunction. About 7% of diabetic and a quarter of Parkinsonism patients had OH secondary to medications. We believe these findings can contribute to better application of AST.