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IntroductionAutoimmune autonomic ganglionopathies (AAG) are an increasingly diagnosed cause of autonomic failure. In 50% of patients, nicotinic ganglionic acetylcholine receptor (α3-AchR) antibodies are found. The presentation includes orthostatic hypotension, gastrointestinal and bladder dysfunction, abnormal pupillary responses and sicca symptoms. Physiological changes are documented with serial autonomic function testing. Gold standard therapy is not well established; however treatment with repeated plasma exchange appears to alter disease course.We provide the first description of consecutive autonomic function tests of one patient with seronegative AAG versus one patient with seropositive AAG both treated with serial plasma exchanges.MethodsWe compare ten parameters – time tolerated in head up tilt (HUT), lowest tilt heart rate (HR), systolic and diastolic blood pressures (BP), HR Valsalva phase 2 and 4, Valsalva ratio, change in catecholamines, HR response to deep breathing and antibody titre.ResultsHUT time, Valsalva ratio and the lowest tilt diastolic BP correlate best with clinical course over time. The α3-AchR titre also correlates with clinical improvement in the seropositive AAG patient. ConclusionsWe propose that repeated HUT time, Valsalva ratio and lowest tilt diastolic BP should be recorded in patients with AAG to determine treatment response and to assist in deciding treatment continuation.

IntroductionPostprandial hypotension is often reported in Parkinson’s disease with autonomic failure (PD+AF) and Multiple System Atrophy (MSA). However there has been no study directly comparing this feature between these two disorders. The aim of this study was to evaluate cardiovascular autonomic responses before and after standard liquid meal ingestion in PD+AF and MSA.MethodsPatients underwent a liquid meal challenge using a previously described protocol. Blood pressure (BP) and heart rate (HR) were measured at intervals. All participants remained supine for 45 min after the liquid meal ingestion. They underwent 10 min head-up tilt (HUT) to 60° before and 45 min after the meal.Results22 MSA and 11 PD+AF patients were identified. Supine post-prandial hypotension was significantly more common in PD+AF compared to MSA (73% vs 36%; p0.05).ConclusionDespite the similar degree of orthostatic hypotension on supine and HUT, postprandial hypotension is more commonly present in patients with PD+AF compared to MSA. The increased tendency to post-prandial hypotension even while supine reflects the nature of post-ganglionic sympathetic denervation in PD.

Background and ObjectivesSudomotor impairment has been recognized as a key feature in differentiating Parkinson disease (PD) and multiple system atrophy–parkinsonian type (MSA-P), with the latter characterized by diffuse anhidrosis in prospective study, including patients in late stage of disease. We aimed to evaluate morphologic and functional postganglionic sudomotor involvement in patients with newly diagnosed MSA-P and PD to identify possible biomarkers that might be of help in differentiating the 2 conditions in the early stage.MethodsOne hundred patients with parkinsonism within 2 years from onset of motor symptoms were included in the study. At the time of recruitment, questionnaires to assess nonmotor, autonomic, and small fiber symptoms were administered, and patients underwent postganglionic sudomotor function assessment by the dynamic sweat test and punch skin biopsy from the distal leg. Skin samples were processed for indirect immunofluorescence with a panel of antibodies, including noradrenergic and cholinergic markers. The density of intraepidermal, sudomotor, and pilomotor nerve fibers was measured on confocal images with dedicated software. A follow-up visit 12 months after recruitment was performed to confirm the diagnosis.ResultsWe recruited 57 patients with PD (M/F 36/21, age 63.5 ± 9.4 years) and 43 patients with MSA-P (M/F 27/16, age 62.3 ± 9.0 years). Clinical scales and questionnaires showed a more severe clinical picture in patients with MSA-P compared to those with PD. Sweating output and intraepidermal, pilomotor, and sudomotor nerve densities, compared to controls, were lower in both groups but with a greater impairment in patients with MSA-P. Pilomotor and sudomotor nerve density correlated with sweating function and with nonmotor clinical symptoms. A composite sudomotor parameter defined as the arithmetic product of sweat production multiplied by the density of sudomotor fibers efficiently separated the 2 populations; the receiver operating characteristics curve showed an area under the curve of 0.83.DiscussionDynamic sweat test and the quantification of cutaneous autonomic nerves proved to be a sensitive morpho-functional approach to assess the postganglionic component of the sudomotor pathway, revealing a more severe involvement in MSA-P than in PD early in the disease course. This approach can be applied to differentiate the 2 conditions early.Classification of EvidenceThis study provides Class II evidence that postganglionic sudomotor morpho-functional assessment accurately distinguish patients with PD from patients with MSA-P.