Autonomic impairment in primary lateral sclerosis.

PURPOSE: Prior studies reported evidence of autonomic involvement in motor neuron disease and suggested more severe dysfunction in upper motor neuron predominant syndromes. Hence, we sought to characterize autonomic impairment in primary lateral sclerosis. METHODS: Neurological evaluations, thermoregulatory sweat tests, and autonomic reflex screens were analyzed retrospectively in 34 primary lateral sclerosis patients (28 definite and 6 probable). Patients with other potential causes of autonomic failure and patients with autonomic testing results compromised by artifact were excluded. RESULTS: A total of 17 patients reported autonomic symptoms. Orthostatic lightheadedness was most frequent (8 patients), followed by bladder (7), bowel (5), and erectile dysfunction (3). The autonomic reflex screens of 33 patients were reviewed; 20 patients had abnormal studies. The thermoregulatory sweat tests of 19 patients were reviewed; 11 patients had abnormal studies. Composite Autonomic Severity Score was calculated for 33 patients and found abnormal in 20/33 patients (60.6%): 15/20 patients (75%) had mild impairment, and 5/20 patients (25%) had moderate impairment. The frequencies of testing abnormalities were: sudomotor 18/20 (90%), cardiovagal 9/20 (45%), and adrenergic 6/20 (30%). Sweat loss pattern analysis showed global, regional, and mixed patterns to be more common than length-dependent and distal patterns. CONCLUSION: We found evidence of frequent autonomic dysfunction in primary lateral sclerosis, which is generally of modest severity akin to prior reports for amyotrophic lateral sclerosis, but more commonly in a pattern consistent with preganglionic/ganglionic localization. This suggests that primary lateral sclerosis, as with amyotrophic lateral sclerosis, is a multisystem disease that affects the autonomic nervous system.

TS-HDS autoantibody: clinical characterization and utility from real-world tertiary care center experience.

OBJECTIVES: To evaluate clinical utility of trisulfated-heparin disaccharide (TS-HDS) IgM testing from real-world tertiary care center experience. METHODS: Medical records of patients with positive TS-HDS antibodies who were evaluated at Mayo Clinic from 2009 to 2022 were reviewed. RESULTS: Seventy-seven patients (50 females) had positive TS-HDS antibody. Median age was 48 (9-77) years. Median titer was 25,000 (range 11,000-350,000). Twenty-six patients (34%) did not have objective evidence of peripheral neuropathy. Nine patients (12%) had other known causes of neuropathy. Among the remaining 42 patients, half presented with subacute progressive course; the other half had chronic indolent course. Most common phenotypes were length-dependent peripheral neuropathy (n = 20, 48%), length-dependent small-fiber neuropathy (n = 11, 26%), and non-length-dependent small-fiber neuropathy (n = 7, 17%). Nerve biopsies showed epineurial inflammatory cell collections in 2 but no interstitial abnormalities in the remaining 7. The majority of intraepidermal nerve fiber densities (7/10), thermoregulatory sweat tests (12/21) and autonomic reflex screens (27/49) were normal. Post-immunotherapy improvement in mRS/INCAT disability score/pain was only seen in 13/42 (31%) TS-HDS IgM positive patients. Patients presenting with sensory ganglionopathy, non-length dependent small-fiber neuropathy, or subacute progressive neuropathy with and without TS-HDS antibody responded similarly to immunotherapy (40% vs 80%, p = 0.30). DISCUSSION: TS-HDS IgM has limited phenotypic or disease specificity; it was found to be positive among patients with various neuropathy phenotypes as well as patients without objective evidence of neuropathy. Clinical improvement with immunotherapy, although was observed in a small proportion of TS-HDS IgM seropositive patients, was not more frequent when compared to seronegative patients with similar presentations.

Amyloid-like IgM deposition neuropathy with multiple mononeuropathies and generalized neuropathy.

Amyloid-like IgM deposition neuropathy is a distinct entity in the setting of IgM monoclonal gammopathy in which endoneurial perivascular entire IgM-particle accumulation leads to a painful sensory followed by motor peripheral neuropathy. We report a 77-year-old man presenting with progressive multiple mononeuropathies starting with painless right foot drop. Electrodiagnostic studies showed severe axonal sensory-motor neuropathy superimposed by multiple mononeuropathies. Laboratory investigations were remarkable for biclonal gammopathy of IgM kappa, IgA lambda and severe sudomotor and mild cardiovagal autonomic dysfunction. A right sural nerve biopsy showed multifocal axonal neuropathy, prominent microvasculitis, and prominent large endoneurial deposits of Congo-red negative amorphous material. Laser dissected mass spectrometry-based proteomics identified IgM kappa deposit without serum amyloid-P protein. This case has several distinctive features, including motor preceding sensory involvement, prominent IgM-kappa proteinaceous deposits replacing most of the endoneurium, a prominent inflammatory component, and improvement of motor strength after immunotherapy.

Utility of Carpal Tunnel Release and Ulnar Decompression in CMT1A and HNPP.

INTRODUCTION/AIMS: Carpal and cubital tunnel syndrome (CTS, CuTS) are common among patients with hereditary neuropathy with liability to pressure-palsies (HNPP) and Charcot-Marie-Tooth type 1A (CMT1A) and may impact quality of life. We aimed to evaluate the utility of nerve decompression surgeries in these patients. METHODS: Medical records were reviewed for patients with PMP22 mutations confirmed in Mayo Clinic laboratories from January 1999 to December 2020, who had CTS and CuTS and underwent surgical decompression. RESULTS: CTS occurred in 53.3% of HNPP and 11.5% of CMT1A, while CuTS was present in 43.3% of HNPP and 5.8% of CMT1A patients. CTS decompression occurred in 10-HNPP and 5-CMT1A patients, and CuTS decompression with/without transposition was performed in 5-HNPP and 1-CMT1A patients. In HNPP, electrodiagnostic studies identified median neuropathy at the wrist in 9/10 patients and ultrasound showed focal enlargements at the carpal and cubital tunnels. In CMT1A, median and ulnar sensory responses were all absent, and the nerves were diffusely enlarged. After CTS surgery, pain, sensory loss, and strength improved in 4/5 CMT1A, and 6/10 HNPP patients. Of clinical, electrophysiologic and ultrasound findings, only activity-provoked features significantly correlated with CTS surgical benefit in HNPP patients (odds ratio = 117.0:95% confidence interval, 1.94 > 999.99, p = 0.01). One CMT1A and one HNPP patient improved with CuTS surgery while 2 HNPP patients worsened. DISCUSSION: CTS symptom improvement post-surgery can be seen in CMT1A and (less frequent) in HNPP patients. CuTS surgery commonly worsened course in HNPP. Activity-provoked symptoms in HNPP best informed benefits from CTS surgery.

Risk factors for lumbosacral radiculoplexus neuropathy.

INTRODUCTION/AIMS: Recently, 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. METHODS: Demographic 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. RESULTS: Factors 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. DISCUSSION: DM 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.

Standardized Autonomic Testing in Patients With Probable Radiation-Induced Afferent Baroreflex Failure.

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.

Small Fiber Neuropathy Incidence, Prevalence, Longitudinal Impairments, and Disability.

BACKGROUND AND OBJECTIVES: There are limited population-based data on small fiber neuropathy (SFN). We wished to determine SFN incidence, prevalence, comorbid conditions, longitudinal impairments, and disabilities. METHODS: Test-confirmed patients with SFN in Olmsted, Minnesota, and adjacent counties were compared 3:1 to matched controls (January 1, 1998-December 31, 2017). RESULTS: Ninety-four patients with SFN were identified, with an incidence of 1.3/100,000/y that increased over the study period and a prevalence of 13.3 per 100,000. Average follow-up was 6.1 years (0.7-43 years), and mean onset age was 54 years (range 14-83 years). Female sex (67%), obesity (body mass index mean 30.4 vs 28.5 kg/m2), insomnia (86% vs 54%), analgesic-opioid prescriptions (72% vs 46%), hypertriglyceridemia (180 mg/dL mean vs 147 mg/dL), and diabetes (51% vs 22%, p < 0.001) were more common (odds ratio 3.8-9.0, all p < 0.03). Patients with SFN did not self-identify as disabled with a median modified Rankin Scale score of 1.0 (range 0-6) vs 0.0 (0-6) for controls (p = 0.04). Higher Charlson comorbid conditions (median 6, range 3-9) occurred vs controls (median 3, range 1-9, p < 0.001). Myocardial infarctions occurred in 46% vs 27% of controls (p < 0.0001). Classifications included idiopathic (70%); diabetes (15%); Sjögren disease (2%); AL-amyloid (1%); transthyretin-amyloid (1%); Fabry disease (1%); lupus (1%); postviral (1%); Lewy body (1%), and multifactorial (5%). Foot ulcers occurred in 17, with 71% having diabetes. Large fiber neuropathy developed in 36%, on average 5.3 years (range 0.2-14.3 years) from SFN onset. Median onset Composite Autonomic Severity Score (CASS) was 3 (change per year 0.08, range 0-2.0). Median Neuropathy Impairment Scale (NIS) score was 2 at onset (range 0-8, change per year 1.0, range -7.9 to +23.3). NIS score and CASS change >1 point per year occurred in only AL-amyloid, hereditary transthyretin-amyloid, Fabry, uncontrolled diabetes, and Lewy body. Death after symptom onset was higher in patients with SFN (19%) vs controls (12%, p < 0.001), 50% secondary to diabetes complications. DISCUSSION: Isolated SFN is uncommon but increasing in incidence. Most patients do not develop major neurologic impairments and disability but have multiple comorbid conditions, including cardiovascular ischemic events, and increased mortality from SFN onsets. Development of large fiber involvements and diabetes are common over time. Targeted testing facilitates interventional therapies for diabetes but also rheumatologic and rare genetic forms.

Stress and central autonomic network.

The central autonomic network (CAN) plays a critical role in the stress response, which is triggered by challenges on the homeostasis (physiological stressors) or unpleasant social or environmental situations. This review focuses on the role of areas of the CAN including the insular and anterior cingulate cortices, extended amygdala, hypothalamus, periaqueductal gray and locus coeruleus in the stress response. These areas are interconnected and affect sympathetic or parasympathetic output via their influence on premotor or preganglionic autonomic neurons in the lower brainstem and spinal cord. The insula integrates multiple inputs to create a sense of the physiological state of the body, whereas the anterior cingulate initiates predictive visceromotor commands. The amygdala and bed nucleus of the stria terminalis provide automatic emotional tagging and trigger automatic survival responses to threat via their outputs to the hypothalamus, periaqueductal gray, and lower brainstem. Several regions of the hypothalamus, including the paraventricular nucleus, dorsomedial nucleus and lateral hypothalamic area participate in different patterns of stress response according to the type of stimulus and projections to premotor and preganglionic autonomic neurons. The periaqueductal gray initiates different patterns of autonomic, pain modulatory, and motor responses, including the "fight or flight" or "playing dead" responses. The locus coeruleus promotes emotional learning in the amygdala associated with states of anxiety. Neurons of the C1 area of the rostral ventrolateral medulla elicit sympathoexcitatory responses to internal stressors such as hypoxia and inflammation. The ventromedial medulla, including the nucleus raphe pallidus, initiates sympathoexcitatory responses to social and other external stressors.

Pure Motor Onset and IgM-Gammopathy Occurrence in Multifocal Acquired Demyelinating Sensory and Motor Neuropathy.

OBJECTIVES: To longitudinally investigate patients with multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy, quantifying timing and location of sensory involvements in motor-onset patients, along with clinico-histopathological and electrophysiological findings to ascertain differences in patients with and without monoclonal gammopathy of uncertain significance (MGUS). METHODS: Patients with MADSAM neuropathy seen at Mayo Clinic and tested for monoclonal gammopathy and ganglioside antibodies, were retrospectively reviewed (January 1st, 2007-December 31st, 2018). RESULTS: Of 76 patients with MADSAM, 53% had pure motor, 16% pure sensory, 30% sensorimotor and 1% cranial nerve onsets. Motor-onset patients were initially diagnosed as multifocal motor neuropathy (MMN). MGUS occurred in 25% (89% IgM subtype), associating with ganglioside autoantibodies (p<0.001) and higher IgM titers (p<0.04). Median time to sensory involvements (confirmed by electrophysiology) in motor-onset patients was 18 months (range: 6-180). Compared to initial motor nerve involvements, subsequent sensory findings were within the same territory 35% (14/40), outside 20% (8/40), or both 45% (18/40). Brachial and lumbosacral plexus MRI was abnormal in 87% (34/39) and 84% (21/25), respectively, identifying hypertrophy and increased T2 signal predominantly in brachial plexus trunks (64%), divisions (69%), and cords (69%), and intrapelvic sciatic (64%) and femoral (44%) nerves. Proximal fascicular nerve biopsies (n=9) more frequently demonstrated onion-bulb pathology (p=0.001) and endoneurial inflammation (p=0.01) than distal biopsies (n=17). MRI and biopsy findings were similar amongst patient subgroups. Initial Inflammatory Neuropathy Cause and Treatment (INCAT) disability scores were higher in patients with MGUS relative to without (p=0.02). Long-term treatment responsiveness by INCAT score reduction ≥1 or motor Neuropathy Impairment Score (mNIS) >8 point reduction occurred in 75% (49/65) irrespective of MGUS or motor-onsets. Most required ongoing immunotherapy (86%). Patients with MGUS more commonly required dual-agent immunotherapy for stability (p=0.02). DISCUSSION: Pure motor-onsets are the most common MADSAM presentation. Long-term follow-up, repeat electrophysiology and nerve pathology help distinguish motor-onset MADSAM from MMN. Better long-term immunotherapy responsiveness occurs in motor-onset MADSAM compared to MMN reports. Patients having MGUS commonly require dual immunotherapy. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that most clinical, electrophysiological, and histopathological findings were similar between patients with MADSAM with and without monoclonal gammopathy of unknown significance.

Natural History of Afferent Baroreflex Failure in Adults.

OBJECTIVE: To describe the natural history of afferent baroreflex failure (ABF) based on systematic review of clinical and laboratory data in patients with a diagnosis of ABF at Mayo Clinic Rochester. METHODS: We performed a retrospective chart review of all patients who underwent standardized autonomic reflex testing between 2000 and 2020 and had confirmation of the diagnosis of ABF by an autonomic disorders specialist. Patients were identified using a data repository of medical records. Variables included demographic, all-cause mortality, medications, ABF manifestations, comorbidities, and laboratory (autonomic testing, blood pressure monitoring, echocardiogram, brain imaging, plasma catecholamines, serum sodium level, and kidney function tests). RESULTS: A total of 104 patients with ABF were identified. Head and neck radiation was the most common etiology (86.5%), followed by neck surgery (5.8%) and other causes (7.7%). The most common findings were hypertension (87.5%), fluctuating blood pressure (78.8%), orthostatic hypotension (91.3%), syncope (58.6%), headache (22.1%), and tachycardia (20.2%). Patients commonly received antihypertensives (66.3%), pressor agents (41.3%), or a combination of both (19.2%). The median latency from completion of radiation to ABF was longer compared to the latency in the surgery group (p < 0.0001). Comorbidities, including complications from neck radiation, were frequently seen and all-cause mortality was 39.4% over a 20-year period. CONCLUSIONS: ABF should be suspected in patients with prior head and neck cancer treated by radiation or surgery who present with labile hypertension and orthostatic hypotension. Management may require both antihypertensive and pressor medications. The morbidity and mortality in ABF are high.

Antibody Testing for Suspected Autoimmune Autonomic Dysfunction and Small Fiber Neuropathies.

SUMMARY: Autonomic dysfunction and small fiber neuropathies are heterogeneous disorders with a wide array of potential etiologies. As with other neurologic diseases, autoantibodies specific to neural tissue, either in the setting of cancer or systemic autoimmunity, may cause autonomic abnormalities. Given the complex and varied functions of the autonomic nervous system, however, the presentation of these conditions may be quite variable. This, in addition to pitfalls of autonomic testing especially for the novice, can lead to inaccuracies in recognizing and characterizing these conditions. We now have a large number of autoantibodies available for testing with more in the pipeline thanks to unprecedented developments in the field of neuroimmunology. Those have been very helpful in uncovering potentially treatable mechanisms of autonomic disease, but also pose a challenge to the clinician given their multiplicity and variable specificity. Growing knowledge regarding autoimmune autonomic implications and the autonomic specificities of each antibody, in addition to the increasing attention to the relevance of antibody titers are of utmost importance for clinicians concerned with autonomic neurology. This review attempts to shed a light on the frequently encountered antibodies in relation to autonomic dysfunction.

Autonomic dysfunction following COVID-19 infection: an early experience.

PURPOSE: Post-COVID-19 syndrome is a poorly understood aspect of the current pandemic, with clinical features that overlap with symptoms of autonomic/small fiber dysfunction. An early systematic analysis of autonomic dysfunction following COVID-19 is lacking and may provide initial insights into the spectrum of this condition. METHODS: We conducted a retrospective review of all patients with confirmed history of COVID-19 infection referred for autonomic testing for symptoms concerning for para-/postinfectious autonomic dysfunction at Mayo Clinic Rochester or Jacksonville between March 2020 and January 2021. RESULTS: We identified 27 patients fulfilling the search criteria. Symptoms developed between 0 and 122 days following the acute infection and included lightheadedness (93%), orthostatic headache (22%), syncope (11%), hyperhidrosis (11%), and burning pain (11%). Sudomotor function was abnormal in 36%, cardiovagal function in 27%, and cardiovascular adrenergic function in 7%. The most common clinical scenario was orthostatic symptoms without tachycardia or hypotension (41%); 22% of patients fulfilled the criteria for postural tachycardia syndrome (POTS), and 11% had borderline findings to support orthostatic intolerance. One patient each was diagnosed with autoimmune autonomic ganglionopathy, inappropriate sinus tachycardia, vasodepressor syncope, cough/vasovagal syncope, exacerbation of preexisting orthostatic hypotension, exacerbation of sensory and autonomic neuropathy, and exacerbation of small fiber neuropathy. CONCLUSION: Abnormalities on autonomic testing were seen in the majority of patients but were mild in most cases. The most common finding was orthostatic intolerance, often without objective hemodynamic abnormalities on testing. Unmasking/exacerbation of preexisting conditions was seen. The temporal association between infection and autonomic symptoms implies a causal relationship, which however cannot be proven by this study.

Clinical presentation and autonomic profile in Ross syndrome.

BACKGROUND: Ross syndrome is a rare disorder characterized by tonic pupils, hyporeflexia, and segmental anhidrosis. We sought to characterize the clinical presentation, associated autoimmune disorders, and autonomic profile in patients with Ross syndrome to further elucidate its pathophysiology. METHODS: We performed a retrospective chart review of all patients who underwent a thermoregulatory sweat test (TST) between 1998 and 2020 and had confirmation of the diagnosis of Ross syndrome by an autonomic disorders specialist. Standardized autonomic reflex testing was reviewed when available. RESULTS: Twenty-six patients with Ross syndrome were identified. The most common initial reported manifestation was an abnormal segmental sweating response in 16 patients (described as hyperhidrosis in 12 patients and anhidrosis in 4 patients) while a tonic pupil was the initial manifestation in 10 patients. Other commonly reported symptoms included fatigue, chronic cough, and increased urinary frequency. An associated autoimmune disorder was identified in one patient. Positive autoantibodies were found in a minority of patients often with unclear clinical significance. Distributions of anhidrosis encountered were segmental (n = 15), widespread (n = 7), and global (n = 4). Well-circumscribed small areas of preserved sweating within areas of anhidrosis were observed in the majority of patients (88.5%). Anhidrosis progressed slowly over time and sudomotor dysfunction was predominantly (post)ganglionic. Cardiovagal and adrenergic functions were preserved in most patients. CONCLUSIONS: The pattern of autonomic dysfunction in Ross syndrome is suggestive of a limited autonomic ganglioneuropathy. Sudomotor impairment is prominent and should be the focus of symptomatic management; however, clinicians should be aware of symptoms beyond the classic triad.

Expanding the Spectrum of Chronic Immune Sensory Polyradiculopathy: CISP-Plus.

OBJECTIVE: Sensory loss with normal nerve conduction studies (NCS) from focal sensory root inflammatory demyelination is characteristic of chronic immune sensory polyradiculopathy (CISP). However, nonpure cases involving motor and distal sensory nerves exist (CISP-plus). We hypothesize that CISP-plus and CISP are fundamentally part of the same syndrome through comparison of clinical, neurophysiologic, and pathologic features. METHODS: CISP-plus (primary dorsal root with lesser motor and sensory nerve involvement) and CISP cases were retrospectively analyzed (1986-2019). RESULTS: We identified 44 CISP-plus and 28 CISP cases (n = 72) with 86% (38/44) of patients with CISP-plus and 79% (22/28) of patients with CISP experiencing imbalance. On examination, large fiber sensory loss was present in 98% (43/44) of patients with CISP-plus and 96% (27/28) of patients with CISP. Gait ataxia was evident in 93% (41/44) of patients with CISP-plus and 79% (22/28) of patients with CISP. Mild distal weakness was common in CISP-plus (75%, 33/44). NCS showed mild abnormalities in all patients with CISP-plus and were normal (by definition) in all patients with CISP. Elevated CSF protein, slowing of somatosensory evoked potentials, and MRI root enhancement occurred in most CISP-plus and CISP cases. Eleven CISP-plus nerve biopsies showed loss of large myelinated fibers and onion-bulb formations, most prominent in rootlet biopsies. Immunotherapy resulted in marked improvement of gait ataxia in 84% (27/32) of patients with CISP-plus and 93% (13/14) of patients with CISP with return to normal neurologic examination in half (25/46). CONCLUSION: The recognition of CISP-plus expands the spectrum of CIDP by combining CISP-plus (predominant sensory polyradiculopathy with mild motor and sensory nerve involvement) with pure CISP (focal sensory polyradiculopathy) together as proximal sensory CIDP.

Peripheral neuroimmune interactions: selected review and some clinical implications.

PURPOSE: To provide a brief and focused review on peripheral neuroimmune interactions and their implications for some clinical disorders. METHODS: Narrative review of the literature including of English-language articles published between 1985 and 2021 using PubMed and MEDLINE. RESULTS: Many studies on experimental models and in vitro indicate that there are close interactions between the neural and immune systems. Processes from sensory afferents and autonomic efferents co-localize with immune cells and interact at discrete anatomical sites forming neuroimmune units. These neuroimmune interactions are bidirectional and mediated by a wide range of soluble factors including neuropeptides, classical neurotransmitters, cytokines, and other molecules that mediate complex cross-talk among nerves and immune cells. Small-diameter sensory afferents express a wide range of receptors that respond directly to tissue damage or pathogen signals and to chemokines, cytokines, or other molecules released from immune cells. Reciprocally, immune cells respond to neurotransmitters released from nociceptive and autonomic fibers. Neuroimmune interactions operate both at peripheral tissues and at the level of the central nervous system. Both centrally and peripherally, glial cells have a major active role in this bidirectional communication. CONCLUSIONS: Peripheral neuroimmune interactions are complex and importantly contribute to the pathophysiology of several disorders, including skin, respiratory, and intestinal inflammatory disorders typically associated with pain and altered barrier function. These interactions may be relevant for persistence of symptoms in disorders associated with intense immune activation.

Novel imaging techniques using 18 F-florbetapir PET/MRI can guide fascicular nerve biopsy in amyloid multiple mononeuropathy.

BACKGROUND: Multiple 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). METHODS: The patient underwent magnetic resonance imaging (MRI) and whole body 18 F-florbetapir positron emission tomography (PET)/MRI. RESULTS: Whole body 18 F-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: 18 F-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.

Reversible Conduction Failure in Chronic Immune-Mediated Sensorimotor and Autonomic Polyneuropathy.

Reversible conduction failure (RCF) has been described in several subtypes of Guillain-Barre syndrome and is typically observed within the first 10 weeks. We describe the presence of RCF lasting for at least 9 months or longer without secondary axonal degeneration in a case of chronic sensorimotor and autonomic polyneuropathy. A 63-year-old woman presented with lower back pain, limb pain, paresthesia, and weakness after a sinus infection. She was diagnosed with mild Guillain-Barre syndrome and treated symptomatically. Four months later, she developed symptoms of dysautonomia and worsening neuropathic pain, and treatment with intravenous immunoglobulin led to significant clinical improvement. Electrodiagnostic study revealed significant improvement, manifesting as increased response amplitudes, improved conduction velocities, shortening of distal latencies, and reduction of sensory and motor response durations without temporal dispersion, thus fitting to the RCF definition. Detection of RCF may have further important implications in the evaluation and management of chronic immune-mediated polyneuropathy.