Characteristics of the Cerebrospinal Fluid in Septic Patients with Critical Illness Polyneuropathy - A Retrospective Cohort Study.

Background: Critical illness polyneuropathy (CIP) is a complex disease commonly occurring in septic patients which indicates a worse prognosis. Herein, we investigated the characteristics of cerebrospinal fluid (CSF) in septic patients with CIP. Methods: This retrospective study was conducted between Match 1, 2018, and July 1, 2022. Patients with sepsis who underwent a CSF examination and nerve electrophysiology were included. The levels of protein, glucose, lipopolysaccharide, white blood cell (WBC), interleukin (IL)-1, IL-6, IL-8, and tumor necrosis factor (TNF) α in CSF were measured. The fungi and bacteria in CSF were also assessed. Results: Among the 175 septic patients, 116 (66.3%) patients were diagnosed with CIP. 28-day Mortality in CIP patients was higher than that in non-CIP patients (25.0% vs. 10.2%, P = 0.02) which was confirmed by survival analysis. The results of propensity score matching analysis (PSMA) indicated a significant difference in the level of protein, WBC, IL-1, IL-6, IL-8, and TNFα present in the CSF between CIP patients and non-CIP patients. The results of the receiver operating characteristic (ROC) analysis showed that IL-1, WBC, TNFα, and their combined indicator had a good diagnostic value with an AUC > 0.8. Conclusion: The increase in the levels of WBC, IL-1, and TNFα in CSF might be an indicator of CIP in septic patients.

Chronic Inflammatory Demyelinating Polyneuropathy Following Lumbar Spine Surgery in a Patient With Sarcoidosis.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare relapsing-remitting autoimmune polyneuropathy that targets peripheral nerves and has been associated in the literature with sarcoidosis. The goal of this study is to report the clinical case of a 61-year-old man with sarcoidosis who developed CIDP following lumbar spine surgery. The patient presented at their clinic visit with lumbar back pain and underwent a dome laminoplasty at L2-3, L3-4, and L4-5 with no known complications. Approximately four hours postoperatively, he developed bilateral lower extremity weakness most prominent along the tibialis anterior and extensor hallucis longus (L4-S1) as well as saddle anesthesia. An MRI revealed no acute changes concerning compression. Electromyography (EMG) was performed six months postoperatively, which revealed absent F waves along the peroneal and tibial nerves as well as decreased amplitude consistent with an underlying axonal neuropathy. He was referred to a neurologist for a second opinion where a diagnosis of CIDP was made. Intravenous immune globulin treatment was initiated, and the patient felt improvement in his symptoms. This case highlights the association between sarcoidosis and CIDP and discusses the pathophysiology of the disease. In patients with sarcoidosis and weakness following lumbar surgery with a negative MRI, CIDP should be on the differential.

Clinical and molecular insights into A97S variants in hereditary transthyretin amyloid polyneuropathy in South China.

OBJECTIVE: This study aims to delineate the clinical profiles of the hereditary transthyretin amyloid polyneuropathy (ATTRv-PN) patients with A97S variant from southern China and the molecular characteristics of this mutant protein. METHODS: Fifteen ATTRv-PN patients with heterozygous A97S and one patient with homozygous A97S were included in the study. Serum TTR tetramer concentration was quantified through ultra-performance liquid chromatography. Stabilities of A97S-TTR were assessed through in vitro urea-mediated tryptophan fluorescence experiments, and nephelometry was employed in drug response assessment. RESULTS: All patients were late-onset (≥50 years) with a mean age of onset at 59.26 ± 5.06 years old. Patients displayed a mixed phenotype featuring sensory-motor neuropathy with autonomic dysfunction and cardiac involvement, such as palpitations and chest pain. Electrophysiological studies showed generally axonal impairment of sensory and motor nerves. Tafamidis-treated patients showed significantly higher TTR tetramer concentrations, approaching healthy controls' levels. In vitro assessment showed that A97S-TTR was more kinetically stable than the V122I-TTR, and tetramer stabilisers inhibited A97S-TTR amyloid formation by more than 70%. CONCLUSION: This study provides valuable insights into the clinical and molecular characteristics of ATTRv-PN patients with A97S from South China, particularly regarding the differences in disease progression and stability features.

Altered connectivity of central autonomic network: effects of dysautonomia in hereditary transthyretin amyloidosis with polyneuropathy.

BACKGROUND: Hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN) is a progressive fatal disorder caused by deposition of mutant transthyretin (TTR) amyloids mainly in the nerves and heart. Autonomic dysfunction is a major disabling manifestation, affecting 90% of patients with late-onset ATTRv-PN. The current study aimed to investigate brain functional alterations associated with dysautonomia due to peripheral autonomic nerve degeneration in ATTRv-PN. METHODS: Resting-state functional MRI data were acquired from 43 ATTRv-PN patients predominantly of A97S (p.A117S) genotype, and the functional connectivity of central autonomic regions was assessed. RESULTS: Compared with age-matched healthy controls, the ATTRv-PN patients exhibited (1) reduced functional connectivity of the central autonomic regions such as hypothalamus, amygdala, anterior insula, and middle cingulate cortex with brain areas of the limbic, frontal, and somatosensory systems, and (2) correlations of reduced functional autonomic connectivity with the severity of autonomic dysfunction especially orthostatic intolerance, decreased heart rate variability, and greater clinical disability. CONCLUSIONS: Our findings provide evidence linking peripheral autonomic dysfunction with altered connectivity in the central autonomic network in ATTRv-PN.

Differences in corneal nerve fiber density and fiber length in patients with painful chronic idiopathic axonal polyneuropathy and diabetic polyneuropathy.

INTRODUCTION/AIMS: Corneal confocal microscopy (CCM) detects small nerve fiber loss and correlates with skin biopsy findings in diabetic neuropathy. In chronic idiopathic axonal polyneuropathy (CIAP) this correlation is unknown. Therefore, we compared CCM and skin biopsy in patients with CIAP to healthy controls, patients with painful diabetic neuropathy (PDN) and diabetics without overt neuropathy (DM). METHODS: Participants with CIAP and suspected small fiber neuropathy (n = 15), PDN (n = 16), DM (n = 15), and healthy controls (n = 16) underwent skin biopsy and CCM testing. Inter-center intraclass correlation coefficients (ICC) were calculated for CCM parameters. RESULTS: Compared with healthy controls, patients with CIAP and PDN had significantly fewer nerve fibers in the skin (IENFD: 5.7 ± 2.3, 3.0 ± 1.8, 3.9 ± 1.5 fibers/mm, all p < .05). Corneal nerve parameters in CIAP (fiber density 23.8 ± 4.9 no./mm2, branch density 16.0 ± 8.8 no./mm2, fiber length 13.1 ± 2.6 mm/mm2) were not different from healthy controls (24.0 ± 6.8 no./mm2, 22.1 ± 9.7 no./mm2, 13.5 ± 3.5 mm/mm2, all p > .05). In patients with PDN, corneal nerve fiber density (17.8 ± 5.7 no./mm2) and fiber length (10.5 ± 2.7 mm/mm2) were reduced compared with healthy controls (p < .05). CCM results did not correlate with IENFD in CIAP patients. Inter-center ICC was 0.77 for fiber density and 0.87 for fiber length. DISCUSSION: In contrast to patients with PDN, corneal nerve parameters were not decreased in patients with CIAP and small nerve fiber damage. Therefore, CCM is not a good biomarker for small nerve fiber loss in CIAP patients.

Clinical and genetic profiles of patients with hereditary and wild-type transthyretin amyloidosis: the Transthyretin Cardiac Amyloidosis Registry in the state of São Paulo, Brazil (REACT-SP).

BACKGROUND: Transthyretin amyloidosis (ATTR) is a multisystem disease caused by the deposition of fibrillar protein in organs and tissues. ATTR genotypes and phenotypes are highly heterogeneous. We present data on physical signs and symptoms, cardiac and neurological assessments and genetic profile of patients enrolled in the Transthyretin Cardiac Amyloidosis Registry of the State of São Paulo, Brazil. RESULTS: Six hundred-forty-four patients were enrolled, 505 with the variant form (ATTRv) and 139 with wild-type (ATTRwt). Eleven different mutations were detected, the most common being Val50Met (47.5%) and V142Ile (39.2%). Overall, more than half of the patients presented cardiac involvement, and the difference in this proportion between the ATTRv and ATTRwt groups was significant (43.9 vs. 89.9%; p < 0.001). The prevalence of the neurological phenotype also differed between ATTRv and ATTRwt (56.8 vs. 31.7%; p < 0.001). The mixed phenotype was found in 25.6% of the population, without a significant difference between ATTRv and ATTRwt groups. A group of patients remained asymptomatic (10.4%), with a lower proportion of asymptomatic ATTRwt patients. CONCLUSIONS: This study details the clinical and genetic spectrum of patients with ATTR in São Paulo, Brazil. This preliminary analysis highlights the considerable phenotypic heterogeneity of neurological and cardiac manifestations in patients with variant and wild-type ATTR.

Effectiveness of patisiran after switching from tafamidis for the treatment of hereditary transthyretin-mediated amyloidosis with polyneuropathy.

BACKGROUND AND PURPOSE: Hereditary transthyretin-mediated amyloidosis with polyneuropathy (ATTRv-PN [v for variant]) is a rare, progressive disease associated with multisystemic impairments. This study assessed the real-world outcomes of patients with ATTRv-PN who switched from tafamidis to patisiran, as well as the reasons for the treatment switch. METHODS: This was a retrospective chart review study at a large expert referral center. Data were extracted from medical charts of patients with ATTRv-PN who switched from tafamidis to patisiran on or before 30 August 2019. Data elements included demographic and clinical characteristics, rationale for switch, and disease measures evaluated from tafamidis initiation through the 12-month patisiran treatment period. RESULTS: Among the 24 patients with ATTRv-PN included in the study, 50.0% had a V30M variant, and the mean (SD) age was 67.3 (8.0) years. During tafamidis treatment (mean [SD] = 30.1 [17.5] months) before switching to patisiran, patients worsened across multiple polyneuropathy measures, including walking ability, Neuropathy Impairment Score, and autonomic function. Neuropathic disease progression on tafamidis was the principal reason for switching to patisiran. After 12 months on patisiran (mean [SD] = 11.7 [1.4] months), patients experienced attenuated disease progression or improvement in the aforementioned measures of polyneuropathy. CONCLUSIONS: Switching from tafamidis to patisiran attenuated the rate of functional decline, and most patients experienced stabilization or improvement of at least one polyneuropathy measure within 12 months of patisiran treatment. Timely switch from tafamidis to patisiran can be beneficial to avoid rapid disease progression in patients with ATTRv-PN.

Indolent CD8-positive T-LPD of the peripheral nervous system in a 19-year-old man.

A 19-year-old man presented with recurrent intermittent fever, progressive limbs weakness, numbness, and atrophy for 5 years. Biopsy of the sural nerve, spleen, lymph nodes, bone marrow and labial gland revealed that monomorphic small lymphoid cells infiltrated diffusely and that there was severe loss of large myelinated nerve fibers. Immunohistochemically, these cells were mainly CD8-positive T cells and were positive for CD3 and CD57. This patient was diagnosed as indolent CD8-positive T lymphoproliferative disorder (indolent CD8-positive T-LPD), emphasizing the need for a broad differential diagnosis under these conditions, and nerve biopsy should be performed.

Prevention of taxane chemotherapy-induced nail changes and peripheral neuropathy by application of extremity cooling: a prospective single-centre study with intrapatient comparison.

PURPOSE: Common side effects of taxane chemotherapy are nail toxicity and peripheral neuropathy (CIPN) causing severe impact on the quality of life. Different methods of cryotherapy to prevent these side effects have been tested. We investigated the use of machine-controlled cooling of hands and feet to reduce nail toxicity and CIPN in patients receiving taxane chemotherapy. METHODS: Patients receiving Docetaxel (planned dose ≥ 300 mg/m2) or Paclitaxel (planned dose ≥ 720 mg/m2 - ) in the adjuvant or palliative setting of different cancers were included. The dominant hand and foot were cooled to approximately 10 °C using the Hilotherapy machine. The contralateral hand and foot were used as intrapatient comparison. The primary endpoint was the occurrence of any CIPN due to paclitaxel or nail toxicity due to Docetaxel. Both the intention to treat population (ITT) and the per protocol population (PPP) were analyzed. RESULTS: A total of 69 patients, 21 treated with Docetaxel and 48 with Paclitaxel, were included at our centre between 08/2020 and 08/2022. Nail toxicity due to Docetaxel was overall not significantly improved by cooling in the ITT or PPP but a significant benefit across visits was found for the ITT. CIPN due to Paclitaxel was numerically better in the ITT and significantly better in the PPP. A significant benefit of cooling on CIPN occurrence across visits was found for the ITT and the PPP. Cooling was very well tolerated. CONCLUSION: Cooling of hands and feet has a clinically meaningful impact on reducing occurrence of CIPN and nail toxicity on treatment with taxanes. Effects are more significant over time and are dose dependent. TRIAL REGISTRATION NUMBER: 2020-00381. Date of registration. 24th February 2020.

Treatment response in patients with clinical and supportive laboratory features of chronic inflammatory demyelinating polyneuropathy without demyelinative findings on nerve conduction studies: A retrospective study.

INTRODUCTION/AIMS: Not all patients with chronic inflammatory demyelinating polyneuropathy (CIDP) have evidence of demyelination on nerve conduction studies (NCS). Patients with "supportive" evidence of CIDP on cerebrospinal fluid (CSF), magnetic resonance imaging (MRI), ultrasound (US), or nerve biopsy but not on NCS, often receive immunomodulating therapy. We evaluated the treatment response of patients with clinical and supportive features of CIDP lacking NCS evidence of demyelination. METHODS: Retrospective chart review was conducted on 232 patients who met CIDP clinical criteria and were treated with disease-modifying therapy. Patients included did not have NCS criteria of demyelination, but did have supportive CSF, MRI, or US findings consistent with CIDP. A positive treatment response was defined as at least a one-point improvement in the modified Rankin scale (mRS), or a four-point increase in the Medical Research Council sum score (MRCSS). RESULTS: Twenty patients met criteria: 17 of the 18 (94%) patients with CSF protein >45 mg/dL, 6 of the 14 (43%) with MRI lumbosacral root or plexus enhancement, and 4 of the 6 (67%) with enlarged proximal nerves on US. Eighteen patients received intravenous immunoglobulin, 10 corticosteroids, one plasma exchange, and six other immunomodulatory therapies. Twelve patients had a positive treatment response on the MRCSS or mRS. The presence of MRI lumbosacral root or plexus enhancement was associated with a positive treatment response. DISCUSSION: A trial of immunomodulating treatment should be considered for patients with clinical features of CIDP in the absence of NCS evidence of demyelination, particularly when there is MRI lumbosacral root or plexus enhancement.

Hereditary Transthyretin Amyloidosis (hATTR) with Polyneuropathy Clusters Are Located in Ancient Mining Districts: A Possible Geochemical Origin of the Disease.

Hereditary transthyretin amyloidosis (hATTR) with polyneuropathy (formerly known as Familial Amyloid Polyneuropathy (FAP)) is an endemic amyloidosis involving the harmful aggregation of proteins, most commonly transthyretin (TTR) but sometimes also apolipoprotein A-1 or gelsolin. hATTR appears to be transmitted as an autosomal dominant trait. Over 100 point mutations have been identified, with the Val30Met substitution being the most common. Yet, the mechanism of pathogenesis and the overall origin of hATTR remain unclear. Here, we argue that hATTR could be related to harmful metal exposure. hATTR incidence is unevenly distributed globally, and the three largest defined clusters exist in Japan, Portugal, and Sweden. All three disease regions are also ancient mining districts with associated metal contamination of the local environment. There are two main mechanisms for how harmful metals, after uptake into tissues and body fluids, could induce hATTR. First, the metals could directly influence the expression, function, and/or aggregation of the proteins involved in hATTR pathology. Such metal-protein interactions might constitute molecular targets for anti-hATTR drug design. Second, metal exposure could induce hATTR -associated genetic mutations, which may have happened several generations ago. These two mechanisms can occur in parallel. In conclusion, the possibility that hATTR could be related to metal exposure in geochemically defined regions deserves further attention.

[A race against time: POEMS syndrome]. / "Verseny az idovel": a POEMS szindróma.

Background - POEMS syndrome is a potentially well manageable disease with an ascendant therapeutic arsenal nowadays. The early recognition of the syndrome is key to prevent serious multiorgan damage, and that is still a big challenge for physicians. With the following two case reports the authors aimed to highlight the consequences of late recognition of the disease and summarize the potential therapeutic options for POEMS syndrome.

Results - We have presented two patients’ cases with a long history of examination and treatment because of uncleared polyneuropathy. Through these cases we could see how serious could be the consequences of late diagnosis and despite multiorgan impairment there are still therapeutic options which could improve the patient’s condition. Although the diagnosis of POEMS syndrome is not easy, it must raise our mind the thought and be prudent when we start a treatment in polyneuropathy.

Monoclonal gammopathy-associated peripheral neuropathies: Uncovering pearls and challenges.

Monoclonal gammopathy-related peripheral neuropathies encompass a spectrum of clinical presentations in which the monoclonal protein directly damages the tissues, including the peripheral nervous system. Given the prevalence of both peripheral neuropathy and monoclonal gammopathy in the general population, these conditions may overlap in clinical practice, posing a challenge for clinicians in determining causality. Therefore, a comprehensive understanding of primary clinical syndromes and their neurophysiological patterns is of great importance for accurate differential diagnoses and effective treatment strategies. In this article, we examine the main forms of monoclonal gammopathies that affect the peripheral nerve. We explore the clinical and electrophysiological aspects and their correlation with each syndrome's corresponding monoclonal protein type. This knowledge is essential for healthcare professionals to diagnose better and manage patients presenting with monoclonal gammopathy-related peripheral nervous system involvement.

Patisiran for the treatment of patients with p.Ile88Leu hereditary transthyretin amyloidosis: an Italian real-life experience.

Objectives: Evidence on the activity of patisiran therapy in specific subgroups of patients with hereditary transthyretin amyloidosis variant (ATTRv) is still scarce. This prospective real-world study was designed to provide the first in-depth clinical data on the effectiveness of patisiran in patients with ATTRv reporting the p.Ile88Leu variant, the most widespread variant in the Emilia-Romagna regional area, which has been less represented in previous clinical trials. Patients and methods: This prospective study evaluated all the patients with genetically proven ATTRv (p.Ile88Leu) and polyneuropathy treated with patisiran in the Emilia-Romagna referral centers for ATTRv (Institute of Neurological Sciences in Bologna and Division of Neurology in Rimini) from March 2021 to April 2023. All subjects underwent clinical and neurological evaluations at baseline and after 9-12 months of treatment. Results: A total of 22 patients were included in the study; the median age was 73 years (IQR: 9), the age at diagnosis was 72 years (IQR: 10), and the disease duration was 1.6 years (IQR: 2.3). We observed stability of all considered neurological and cardiological parameters at 9-12 months after the beginning of patisiran treatment. Conclusion: Our findings support the clinical data regarding the effectiveness of patisiran in stabilizing the disease course and extend this activity to the subset of patients with the p.Ile88Leu variant.

Risk of peripheral neuropathy in patients with psoriasis and psoriatic arthritis. A prospective cohort study.

INTRODUCTION/AIMS: Laboratory and clinical data suggest a link between neurologically mediated inflammation and psoriasis, but the risk and features of peripheral neuropathy in psoriasis or psoriatic arthritis remain unknown. The aim of this exploratory study was to evaluate the risk and to describe the features of peripheral neuropathy in patients with psoriasis and psoriatic arthritis. METHODS: One hundred patients with psoriasis and/or psoriatic arthritis and 100 control subjects were consecutively enrolled. Diagnostic confirmation included electrophysiological examination, skin biopsy, and nerve ultrasound for confirmed polyneuropathy. RESULTS: Nine patients were diagnosed with confirmed polyneuropathy, while none of the control subjects had the condition (relative risk [RR] = 19.00, 95% confidence interval [CI] = 1.12-322.11). Specific relative risks for polyneuropathy were 22.09 (95% CI = 1.17-416.43) in psoriasis patients and 18.75 (95% CI = 1.07-327.62) in psoriatic arthritis patients. The observed polyneuropathy in all nine patients was length-dependent, symmetrical, and predominantly sensory, with minimal or no disability. Comorbidities and exposure to therapies known to increase the risk of polyneuropathy were more frequent in psoriasis and/or psoriatic arthritis patients compared to controls (42% vs. 4%, p = .0001). Analyzing data after excluding possible contributory causes, the risk of polyneuropathy in patients with psoriasis and/or psoriatic arthritis was not significant. DISCUSSION: Psoriasis and psoriatic arthritis appear to be associated with an increased risk of polyneuropathy. This increased risk seems to be linked to the higher prevalence of contributing factors for polyneuropathy, rather than a direct increase in neuropathy risk specifically related to psoriasis and psoriatic arthritis.

Cutaneous biomarkers of therapeutic efficacy in early treatment of hereditary ATTR amyloid polyneuropathy with tafamidis.

BACKGROUND: ATTR (ATTRv) amyloidosis neuropathy is characterized by progressive sensorimotor and autonomic nerve degeneration secondary to amyloid deposition caused by a misfolded transthyretin protein (TTR). Small nerve fiber neuropathy is an early clinical manifestation of this disease resulting from the dysfunction of the Aδ and C small nerve fibers. Tafamidis, a selective TTR stabilizer, has proven its efficacy in the earlier stages of hATTR. OBJECTIVES: To evaluate the clinical course and utility of cutaneous pathological biomarkers in patients with ATTR amyloidosis treated with tafamidis compared to control patients. METHODS: Forty patients diagnosed with early stages of ATTRv amyloidosis (polyneuropathy disability [PND] scores 0-II) underwent small and large nerve fiber neurological evaluations, and annual skin biopsies for intraepidermal nerve fiber density (IENFD) and amyloid deposition index (ADI) estimation. Thirty patients were allocated to receive tafamidis, and 10 patients served as controls. Tafamidis pharmacokinetics analysis was performed in patients who received the treatment. RESULTS: At baseline, 12% of patients in stage PND 0 and 28% in PND I displayed small nerve fiber denervation in the distal thigh, whereas 23% and 38%, respectively, in the distal leg. Similarly, 72% and 84% had amyloid deposition in the distal thigh and 56% and 69% in the distal leg. Following 1 year of treatment, the tafamidis group showed significant clinical improvement compared to the control group, revealed by the following mean differences (1) -9.3 versus -4 points (p = <.00) in the patient's neuropathy total symptom score 6 (NTSS-6) questionnaire, (2) -2.5 versus +2.8 points (p = <.00) in the Utah Early Neuropathy Score (UENS), and (3) +1.2°C versus -0.6 (p = .01) in cold detection thresholds. Among the patients who received tafamidis, 65% had stable or increased IENFD in their distal thigh and 27% in the distal leg. In contrast, all patients in the control group underwent denervation. The ADI either decreased or remained constant in 31% of the biopsies in the distal thigh and in 24% of the biopsies in the distal leg of the tafamidis-treated patients, whereas it rose across all the biopsies in the control group. At the 4-year follow-up, the tafamidis group continued to display less denervation in the distal thigh (mean difference [MD] of -3.0 vs. -9.3 fibers/mm) and the distal leg (mean difference [MD] -4.9 vs. -8.6 fibers/mm). ADI in tafamidis-treated patients was also lower in the distal thigh (10 vs. 30 amyloid/mm2) and the distal leg (23 vs. 40 amyloid/mm2) compared to control patients. Plasma tafamidis concentrations were higher in patients with IENFD improvement and in patients with reduced amyloid deposition. Patients without amyloid deposition in the distal leg at baseline displayed delayed disease progression at 4 years. CONCLUSIONS: Cutaneous IENFD and amyloid deposition assessments in the skin of the distal thigh and distal leg are valuable biomarkers for early diagnosis of ATTR amyloidosis and for measuring the progression of small nerve fiber neuropathy. Early treatment with tafamidis slows the clinical progression of the disease, skin denervation, and amyloid deposition in the skin. Higher plasma concentrations of tafamidis are associated with better disease outcomes, suggesting that increasing the drug dose could achieve better plasma concentrations and response rates. This study describes the longest small nerve fiber neuropathy therapeutic trial with tafamidis and is the first to report small fiber symptoms, function, and structural assessments as outcomes.

The multiple roles of nerve biopsy in the diagnosis and prognosis of suspected immune neuropathies.

INTRODUCTION: The value of a sural nerve biopsy for the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is controversial. Evidence-based recommendations for its implementation are lacking. We investigated factors leading to biopsy and analyzed biopsy outcomes and consequences, assessed the predictability of biopsy outcomes through clinical parameters to avoid unnecessary biopsies, and compared results with electrophysiological and clinical severity to determine their prognostic value. METHODS: 190 sural nerve biopsies were analyzed in two cohorts. One consisted of 163 biopsies and the second of 72 biopsies from the prospective Immune-mediated Neuropathies Biomaterial and Data registry (INHIBIT). Both have an intersection of 45 patients. 75 data sets from patients without biopsy were used. Analysis of nerve conduction studies, treatment, overall disability sum score (ODSS), biopsy outcomes, and diagnosis was performed. RESULTS: 51% of biopsied patients received the diagnosis CIDP (77% fulfilled EFNS/PNS criteria), 21% were not CIDP typical, and 27% were unspecific. Biopsied patients responded less frequently to immunotherapies at time of biopsy than non-biopsied patients (p = 0.003). Immunotherapy was initiated more frequently after biopsy (p < 0.001) and more often with intravenous immunoglobulins (p < 0.0001). 76% of all biopsied patients met the electrophysiological criteria for CIDP. Sensory nerve action potential amplitudes of 0 µV still provide 73% of histological diagnostic value. Histologic signs of degeneration predicted ODSS worsening after 1 year (p = 0.028) but disease severity did not correlate with histological damage severity. DISCUSSION: The main indication for nerve biopsy was the treatment of refractory cases of autoimmune neuropathies with the therapeutic consequence of treatment initiation or escalation. Sural biopsy also provided prognostic information. Even with extinguished sural SNAP, the biopsy can still have diagnostic value.

Deep Brain Stimulation Leads to Long-term Improvement of Neuropathic Tremor due to Chronic Inflammatory Demyelinating Polyneuropathy: A Case Report.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a peripheral neuropathy caused by immune-mediated demyelination, causing tremors in 3.9%-58% of affected patients. This neuropathic tremor may persist after treatment and is known to be refractory to conventional medication. We present two cases of neuropathic tremor due to CIDP in which deep brain stimulation (DBS) over a long-term period led to marked improvement. Case 1: A 66-year-old woman presented with severe 2-3-Hz resting, postural, and kinetic tremors of both hands. The tremor was refractory to medication but improved well after bilateral VIM-DBS. However, 2 months after the procedure, the tremor worsened and was accompanied by sensory disturbance in the extremities. A diagnosis of CIDP was made, and treatment with corticosteroids and intravenous immunoglobulin achieved remission 6 months later. Although there was residual tremor after CIDP remission, it has been well controlled by DBS for the last 10 years. Case 2: A 56-year-old man presented with a 6-year history of CIDP after developing sensory dullness and tremors in the extremities. The CIDP had gone into remission 1 year previously and the sensory deficits had improved, but the tremors had gradually worsened: severe 8-12-Hz postural, kinetic, and resting tremors were present in both upper extremities. Right VIM-DBS was performed and the tremors on the left side showed marked improvement. Over the next 8 years, the tremors were well controlled and there were no relapses of CIDP. DBS may achieve long-term improvement of neuropathic tremor caused by CIDP if the CIDP is in remission.

Progressive demyelinating polyneuropathy after hematopoietic cell transplantation in metachromatic leukodystrophy: a case series.

Metachromatic leukodystrophy (MLD) is a neuro-metabolic disorder due to arylsulfatase A deficiency, causing demyelination of the central and peripheral nervous system. Hematopoietic cell transplantation (HCT) can provide a symptomatic and survival benefit for pre-symptomatic and early symptomatic patients by stabilizing CNS disease. This case series, however, illustrates the occurrence of severely progressive polyneuropathy shortly after HCT in two patients with late-infantile, one with late-juvenile, and one with adult MLD, leading to the inability to walk or sit without support. The patients had demyelinating polyneuropathy before HCT, performed at the ages of 2 years in the first two patients and at 14 and 23 years in the other two patients. The myeloablative conditioning regimen consisted of busulfan, fludarabine and, in one case, rituximab, with anti-thymocyte globulin, cyclosporine, steroids, and/or mycophenolate mofetil for GvHD prophylaxis. Polyneuropathy after HCT progressed parallel with tapering immunosuppression and paralleled bouts of infection and graft-versus-host disease (GvHD). Differential diagnoses included MLD progression, neurological GvHD or another (auto)inflammatory cause. Laboratory, electroneurography and pathology investigations were inconclusive. In two patients, treatment with immunomodulatory drugs led to temporary improvement, but not sustained stabilization of polyneuropathy. One patient showed recovery to pre-HCT functioning, except for a Holmes-like tremor, for which a peripheral origin cannot be excluded. One patient showed marginal response to immunosuppressive treatment and died ten months after HCT due to respiratory failure. The extensive diagnostic and therapeutic attempts highlight the challenge of characterizing and treating progressive polyneuropathy in patients with MLD shortly after HCT. We advise to consider repeat electro-neurography and possibly peripheral nerve biopsy in such patients. Nerve conduction blocks, evidence of the presence of T lymphocytes and macrophages in the neuronal and surrounding nerve tissue, and beneficial effects of immunomodulatory drugs may indicate a partially (auto)immune-mediated pathology. Polyneuropathy may cause major residual disease burden after HCT. MLD patients with progressive polyneuropathy could potentially benefit from a more intensified immunomodulatory drug regime following HCT, especially at times of immune activation.

Value of multi-modality small fiber assessments in a genotypically diverse cohort of transthyretin-related amyloidosis in the early stages of disease.

INTRODUCTION: Transthyretin-related amyloidosis (ATTRv) is a progressive multisystem disorder, predominantly involving the peripheral nerve system (PNS) and heart. Quantification of small fiber damage may help guide treatment decisions, as amyloid deposits frequently affect those fibers early in disease course. Corneal confocal microscopy (CCM) is a promising method to monitor patients with ATTRv, due to similarities between corneal nerves and PNS, as the cornea is innervated by Aδ and C fibers. METHODS: We compared CCM measures from ATTRv patients to a group of healthy individuals, matched by age and gender. We then investigated the correlations between small fiber tests (SFT): CCM, LDI-Flare and CDT, COMPASS-31 and disability scales (RODS and ONLS) in patients. RESULTS: Of 20 patients (6 with V30M), mean age 50.3±15.3Y, 7 female (35%), six (30%) had polyneuropathy and 10 (50%) carpal tunnel syndrome. CDT was abnormal in 9 and LDI-flare in 6 patients. CCM was abnormal in 19 tested patients and significantly reduced when compared to controls (CNFL: 6.31±0.31 vs. 15.21±1.02mm/mm2, p<0.001). Mean COMPASS-31-scores were 22.27±22.84; RODS and ONLS were 38.15±12.33 and 2.05±2.3, with no significant differences between sub-group scores. Disease duration was significantly correlated with ONLS (0.43, p=0.05) and RODS (0.46, p=0.03). There were no significant correlations between measures of disability and SFT. CONCLUSIONS: In a diverse cohort of ATTRv patients, CCM was the most frequent abnormal measurement. CCM can be a useful test to triage patients in the early disease stages and with few or equivocal symptoms.