Orthostatic heart rate changes in patients with autonomic failure caused by neurodegenerative synucleinopathies.

OBJECTIVE: Blunted tachycardia during hypotension is a characteristic feature of patients with autonomic failure, but the range has not been defined. This study reports the range of orthostatic heart rate (HR) changes in patients with autonomic failure caused by neurodegenerative synucleinopathies. METHODS: Patients evaluated at sites of the U.S. Autonomic Consortium (NCT01799915) underwent standardized autonomic function tests and full neurological evaluation. RESULTS: We identified 402 patients with orthostatic hypotension (OH) who had normal sinus rhythm. Of these, 378 had impaired sympathetic activation (ie, neurogenic OH) and based on their neurological examination were diagnosed with Parkinson disease, dementia with Lewy bodies, pure autonomic failure, or multiple system atrophy. The remaining 24 patients had preserved sympathetic activation and their OH was classified as nonneurogenic, due to volume depletion, anemia, or polypharmacy. Patients with neurogenic OH had twice the fall in systolic blood pressure (SBP; -44 ± 25 vs -21 ± 14 mmHg [mean ± standard deviation], p < 0.0001) but only one-third of the increase in HR of those with nonneurogenic OH (8 ± 8 vs 25 ± 11 beats per minute [bpm], p < 0.0001). A ΔHR/ΔSBP ratio of 0.492 bpm/mmHg had excellent sensitivity (91.3%) and specificity (88.4%) to distinguish between patients with neurogenic from nonneurogenic OH (area under the curve = 0.96, p < 0.0001). Within patients with neurogenic OH, HR increased more in those with multiple system atrophy (p = 0.0003), but there was considerable overlap with patients with Lewy body disorders. INTERPRETATION: A blunted HR increase during hypotension suggests a neurogenic cause. A ΔHR/ΔSBP ratio < 0.5 bpm/mmHg is diagnostic of neurogenic OH. Ann Neurol 2018;83:522-531.

A case series of REM sleep behavior disorder in pure autonomic failure.

PURPOSE: Data on the prevalence of RBD in patients with PAF are limited, with discrepancies in the literature regarding prevalence. We aimed to provide further data on this association with a series of eight patients with PAF. METHODS: We reviewed the electronic medical records of all patients seen at the Stanford neurology clinics from 2012 to 2016 who were given a provisional diagnosis of PAF (343 patients), and further screened by procedure codes to identify those patients who underwent both attended video-polysomonography and autonomic testing (18 patients), and met strict exclusionary criteria (8 patients). RESULTS: The mean age of our patients was 69 years, and 63 % were women. The mean duration of autonomic symptoms was 11.2 years, and the mean duration of dream enactment was 3.75 years. All patients demonstrated evidence of adrenergic failure on autonomic testing. Five out of 8 (63 %) met diagnostic criteria for RBD, confirmed on vPSG. CONCLUSIONS: Our series supports the concept that RBD in PAF may be more common than previously reported, and that the presence of RBD suggests brainstem involvement in some cases of PAF. In addition, the timing of RBD symptoms relative to the emergence of autonomic symptoms may be useful to help distinguish these conditions.

Residual sympathetic tone is associated with reduced insulin sensitivity in patients with autonomic failure.

PURPOSE: Parkinson disease, an α-synucleinopathy, is associated with reduced insulin sensitivity, impaired glucose tolerance, and diabetes mellitus. Importantly, these metabolic alterations have been shown to contribute to disease progression. The purpose of this study was to determine if reduced insulin sensitivity is also present in other α-synucleinopathies associated with autonomic failure. METHODS: We studied 19 patients with multiple system atrophy and 26 patients with pure autonomic failure. For comparison, we studied 8 healthy controls matched for body mass index. Insulin sensitivity and beta cell function were calculated using fasting glucose and insulin levels according to the homeostatic model assessment 2. A multiple linear regression model was performed to determine factors that predict insulin sensitivity in autonomic failure. RESULTS: There was a significant difference in insulin sensitivity among groups (P = 0.048). This difference was due to lower insulin sensitivity in multiple system atrophy patients: 64% [interquartile range (IQR), 43 to 117] compared to healthy controls 139% (IQR, 83 to 212), P = 0.032. The main factor that contributed to the reduced insulin sensitivity was the presence of supine hypertension and residual sympathetic tone. CONCLUSIONS: Multiple system atrophy patients have reduced insulin sensitivity that is associated with residual sympathetic activation and supine hypertension. These patients may therefore be at high risk for development of impaired glucose tolerance and diabetes mellitus.

Hyposmia in pure autonomic failure.

BACKGROUND: Parkinson disease (PD), multiple system atrophy (MSA), and pure autonomic failure (PAF) all present with varying degrees of dysautonomia and are pathologically characterized by accumulation of alpha-synuclein. Hyposmia and olfactory pathway pathology are found in PD and MSA. We tested odor identification in 16 patients with PAF and compared the results with those found in patients with PD, patients with MSA, and control subjects. METHODS: The University of Pennsylvania Smell Identification Test (UPSIT) was used to evaluate the sense of smell in 16 patients with PAF, 14 patients with MSA, 191 patients with PD, and 145 control subjects. Multiple linear regression analyses were used to evaluate the effect of the diseases on the mean UPSIT score when adjusted for age, sex, and smoking habit. RESULTS: The mean UPSIT score was higher in the controls than in patients with PAF (p < 0.001) or MSA (p < 0.001); it was lower in patients with PD than in patients with PAF (p = 0.005) or patients with MSA (p = 0.006); and no difference was found between patients with MSA and patients with PAF (p = 0.9) when adjusted for age, gender, and smoking habits. CONCLUSIONS: Hyposmia may be a feature of pure autonomic failure (PAF), but to a lesser degree than that found in Parkinson disease. Further research into the olfactory pathways in patients with PAF is warranted.

A Japanese case of autoimmune autonomic ganglionopathy (AAG) and a review of AAG cases in Japan.

A 29-year-old woman presented with acute, pure autonomic (both sympathetic and parasympathetic) failure and positive antibody to ganglionic nicotinic acetylcholine receptor; the diagnosis was autoimmune autonomic ganglionopathy (AAG). She had typical symptoms of AAG, although the patient also had coughing episodes and psychiatric symptoms, which are not typical of AAG in Western countries but are common in AAG cases in Japan. In a review of the Japanese literature, 29 cases of AAG had been reported. AAG patients in Japan were younger and more male predominant than in Western countries. Of the patients in these 29 cases, 10 (34.5%) had coughing episodes and 12 (41.4%) had psychiatric symptoms.