Citations

AbstractIntroduction/AimsRecently, our group found an association between diabetes mellitus (DM) and lumbosacral radiculoplexus neuropathy (LRPN) in Olmsted County, Minnesota; we found a higher risk (odds ratio [OR], 7.91) for developing LRPN in diabetic compared with nondiabetic patients. However, the influence of other comorbidities and anthropomorphic variables was not studied.MethodsDemographic and clinical data from 59 LRPN patients and 177 age/sex‐matched controls were extracted using the Rochester LRPN epidemiological study. Differences between groups were compared by chi‐square/Fisher exact test or Wilcoxon rank‐sum test. Uni‐ and multivariate logistic regression analysis were performed.ResultsFactors predictive of LRPN on univariate analysis were DM (OR, 7.91; 95% confidence interval [CI], 4.11‐15.21), dementia (OR, 6.36; 95% CI, 1.13‐35.67), stroke (OR, 3.81; 95% CI, 1.32‐11.01), dyslipidemia (OR, 2.844; 95% CI, 1.53‐5.27), comorbid autoimmune disorders (OR, 2.72; 95% CI, 1.07‐6.93), hypertension (OR, 2.25; 95% CI, 1.2‐4.13), obesity (OR, 2.05; 95% CI, 1.11–3.8), body mass index (BMI) (OR, 1.1; 95% CI, 1.04‐1.15), and weight (OR, 1.02; 95% CI, 1.009‐1.037). On multivariate logistic regression analysis only DM (OR, 8.03; 95% CI, 3.86‐16.7), comorbid autoimmune disorders (OR, 4.58; 95% CI, 1.45‐14.7), stroke (OR, 4.13; 95% CI, 1.2‐14.25), and BMI (OR, 1.07; 95% CI, 1.01‐1.13) were risk factors for LRPN.DiscussionDM is the strongest risk factor for the development of LRPN, followed by comorbid autoimmune disorders, stroke, and higher BMI. Altered metabolism and immune dysfunction seem to be the most influential factors in the development of LRPN.

Injury of the afferent limb of the baroreflex from neck radiation causes radiation-induced afferent baroreflex failure (R-ABF). Identification and management of R-ABF is challenging. We aimed to investigate the pattern of autonomic dysfunction on standardized autonomic testing in patients with probable R-ABF. We retrospectively analyzed all autonomic reflex screens performed at Mayo Clinic in Rochester, MN, between 2000 and 2020 in patients with probable R-ABF. Additional tests reviewed included ambulatory blood pressure monitoring, plasma norepinephrine, and thermoregulatory sweat test. We identified 90 patients with probable R-ABF. Median total composite autonomic severity score (range, 0–10) was 7 (interquartile range, 6–7). Cardiovascular adrenergic impairment was seen in 85 patients (94.4%), increased blood pressure recovery time after Valsalva maneuver in 71 patients (78.9%; median 17.4 seconds), and orthostatic hypotension in 68 patients (75.6%). Cardiovagal impairment was demonstrated by abnormal heart rate responses to deep breathing (79.5%), Valsalva ratio (87.2%), and vagal baroreflex sensitivity (57.9%). Plasma norepinephrine was elevated and rose appropriately upon standing (722–1207 pg/mL). Ambulatory blood pressure monitoring revealed hypertension, postural hypotension, hypertensive surges, tachycardia, and absence of nocturnal dipping. Blood pressure lability correlated with impaired vagal baroreflex function. Postganglionic sympathetic sudomotor function was normal in most cases; the most frequent thermoregulatory sweat test finding was focal neck anhidrosis (78.9%). Standardized autonomic testing in R-ABF demonstrates cardiovascular adrenergic impairment with orthostatic hypotension, blood pressure lability, and elevated plasma norepinephrine. Cardiovagal impairment is common, while sudomotor deficits are limited to direct radiation effects.

AbstractBackgroundMultiple mononeuropathy is a rare presentation of primary (AL) amyloidosis and nerve biopsy is usually needed for diagnosis. Conventional imaging is useful to identify proximal nerve involvement but may be inadequate. We report a patient with multiple mononeuropathy whose presentation was suggestive of AL amyloid neuropathy and in whom repeated tissue biopsies were negative for amyloid (including two sensory nerves and one muscle).MethodsThe patient underwent magnetic resonance imaging (MRI) and whole body 18F‐florbetapir positron emission tomography (PET)/MRI.ResultsWhole body 18F‐florbetapir PET/MRI revealed abnormal low‐level florbetapir uptake in the right proximal tibial and peroneal nerves, which provided a target for a sciatic bifurcation fascicular nerve biopsy that was diagnostic of AL amyloidosis.Conclusions 18F‐florbetapir PET/MRI imaging is a promising diagnostic tool for patients with suspected peripheral nerve amyloidosis (including multiple mononeuropathy) in whom conventional imaging and nerve and muscle biopsies miss the pathology.