EMLA-Induced Skin Wrinkling for the Detection of Diabetic Neuropathy

Upper-limb dysfunction in cancer survivors with chemotherapy-induced peripheral neurotoxicity

INTRODUCTION

Upper-limb symptoms are often reported in the context of chemotherapy-induced peripheral neurotoxicity (CIPN), but objective quantification of functional deficits is often lacking. We examined and compared a range of neurophysiological and functional assessments of the upper-limb in the assessment of CIPN severity.

METHODS

Cross-sectional assessment of neurotoxic chemotherapy-treated patients was undertaken using patient-reported and clinically-graded CIPN measures. Upper-limb functional assessments comprised of assessing fine motor skills, sensory perception, and neurophysiological measures of the median nerve. Group comparisons between participants who reported absence or presence of upper-limb functional deficits were investigated.

RESULTS

60 participants who were 11.5 (IQR = 4.0-26.0) months post-neurotoxic chemotherapy treatment reported CIPN. 65% (n = 39) reported upper-limb CIPN symptoms. Reduction in fine motor skills, sensory perception and median nerve SNAP amplitudes were associated with higher CIPN severity. Participants who self-reported presence of upper-limb functional deficits had worse CIPN severity across all measures, compared to participants who reported no upper-limb functional deficits.

CONCLUSIONS

Participants who reported upper-limb symptoms and functional deficits had worse CIPN severity and quality-of-life. There is a high burden of upper-limb dysfunction long after neurotoxic chemotherapy treatment cessation. Focus on research into supportive care and rehabilitation options to improve upper-limb function is warranted to improve patient quality-of-life.

Assessment of autonomic nervous system dysfunction associated with peripheral neuropathies in the context of clinical neurophysiology practice

Peripheral neuropathies may involve the small diameter nerve fibers of the autonomic nervous system. In the presence of clinical signs compatible with dysautonomia, it is very difficult to affirm that these signs are really linked to an alteration in postganglionic autonomic innervation, and not to a lesion of the central nervous system or to a direct damage to the tissues and innervated organs. Also, in the context of the investigation of peripheral neuropathies, there is an interest in performing objective and quantitative assessment of distal autonomic innervation. The corresponding autonomic tests are mainly based on the exploration of sudomotor or vasomotor disorders of the limb extremities. In this article, we provide an overview of the various tests available for the study of the autonomic nervous system in clinical practice, including vasomotor reactivity tests, in particular based on laser Doppler techniques, and sudomotor tests, based on axon-reflexes produced by iontophoresis of cholinergic drugs or on the simpler measurement of electrochemical skin conductance by the Sudoscan® device.

Prevalence and Risk Factors of Peripheral Neuropathy in Parkinson's Disease

Introduction

A lesser studied aspect of Parkinson's disease (PD) is its associated peripheral sensory-motor neuropathy. Peripheral neuropathy is an intriguing aspect of PD, a problem not given sufficient attention and which if tackled properly could make a difference to the multifaceted sufferings of the PD patient. Studies regarding the prevalence of peripheral neuropathy and its risk factors in patients with PD are scarce from the Indian subcontinent.

Methods

This prospective observational study was conducted in a tertiary care teaching hospital in South India. Patients diagnosed with idiopathic Parkinson's disease (IPD) were screened and enrolled. All the patients underwent detailed evaluation of symptoms, signs, and electrophysiology (Nerve conduction study, Sympathetic skin response), stimulated skin wrinkling with Eutectic Mixture of Local Anesthetics. Patients found to have large/small fiber neuropathy underwent additional tests to exclude other causes of neuropathy.

Results

A total of 154 patients with IPD were enrolled in the study (mean age: 61.96 ± 9.15 years, mean duration of disease was 4.08 ± 3.16 years). The mean Hoehn and Yahr (H and Y) score was 2.3 ± 0.825 and the mean Unified Parkinsons Disease Rating Scale (UPDRS)-3 score in the ON state was 23.07 ± 11.14. The mean cumulative levodopa dose was 482.68 ± 651.76 (median: 292; range: 4728.57) grams. Peripheral neuropathy was found in 49 patients (31.8%), large fiber in 28 (18.2%) and small fiber in 47 (30.5%); an overlap of large and small fiber neuropathy was seen in 26 patients (16.9%). Around 34% of patients had serum homocysteine levels >20 mg/dl. In univariate analysis, duration of disease, levodopa cumulative dose, serum homocysteine level, H and Y score, UPDRS-3 ON score, Toronto Clinical Neuropathy Score (P < 0.001 for all), age at presentation, and rigidity predominant presentation (P = 0.02 for both) were associated with large fiber neuropathy. All of these variables were also associated with the presence of small fiber neuropathy (P = 0.004 for age at presentation and P < 0.001 for rest), except the type of PD presentation. However, in multivariate logistic regression analysis, only duration of disease, levodopa cumulative dose, and H and Y score were associated with the presence of large and small fiber neuropathy.

Conclusions

In our cohort, majority of the patients were in early-stage PD and around one-fifth and one-third of patients suffer from large and small fiber polyneuropathy, respectively. Large and small fiber neuropathy in PD is mainly associated with duration of disease, levodopa cumulative dose, and H and Y score.

The applicability of the digit wrinkle scan to quantify sympathetic nerve function

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Normative values for stimulated skin wrinkling are age-dependent.

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Stimulated skin wrinkling has never been evaluated quantitatively.

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The clinical application of the stimulated skin wrinkling in an ordinal fashion is doubtful.

Objective

Stimulated skin wrinkling test (SSW) has been launched as a non-invasive diagnostic procedure. However, no normative age dependent values have been reported that can be applied in clinical practice. The objectives of the study were to (1) collect age-dependent normative values according to the 5-point scale assessment for the SSW, to (2) determine reliability scores for the obtained norm values, and to (3) introduce a new digital method for SSW assessment, the Digit Wrinkle Scan© (DWS©) for detection of wrinkles in a more quantitative manner.

Methods

Firstly, 82 healthy participants were included, divided in 5 age groups. The participants underwent SSW using lidocaine and prilocaine topical cream. Secondly, 35 healthy participants were included to test whether the DWS© could be a novel manner to assess the grade of wrinkling quantitatively. We determined the inter-observer reliability of both methods. Also, the intra-observer reliability was calculated for the DWS©.

Results

We found a decrease in normative values over age. The inter-observer reliability of assessment by the 5-point scale method was moderate after SSW (Cohen’s k: 0.53). Results of the DWS© indicate that total wrinkle length per mm² showed moderate to good agreement for the 4th and 5th digits after SSW, and a low agreement for the other digits.

Conclusions

Age-dependent normative values were obtained according to the 5-point scale, but its clinical application is doubtful since we found a moderate inter-observer reliability. We introduced the DWS© as a possible new method in order to quantify the grade of wrinkling.

Significance

We found unsatisfactory reliability scores, which hampers its usefulness for clinical practice.

Review of the Role of the Brain in Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a common, debilitating, and dose-limiting side effect of many chemotherapy regimens yet has limited treatments due to incomplete knowledge of its pathophysiology. Research on the pathophysiology of CIPN has focused on peripheral nerves because CIPN symptoms are felt in the hands and feet. However, better understanding the role of the brain in CIPN may accelerate understanding, diagnosing, and treating CIPN. The goals of this review are to (1) investigate the role of the brain in CIPN, and (2) use this knowledge to inform future research and treatment of CIPN. We identified 16 papers using brain interventions in animal models of CIPN and five papers using brain imaging in humans or monkeys with CIPN. These studies suggest that CIPN is partly caused by (1) brain hyperactivity, (2) reduced GABAergic inhibition, (3) neuroinflammation, and (4) overactivation of GPCR/MAPK pathways. These four features were observed in several brain regions including the thalamus, periaqueductal gray, anterior cingulate cortex, somatosensory cortex, and insula. We discuss how to leverage this knowledge for future preclinical research, clinical research, and brain-based treatments for CIPN.

Brief Report: Demographic and Genetic Associations With Markers of Small and Large Fiber Sensory Neuropathy in HIV Patients Treated Without Stavudine

Neurotoxic antiretroviral therapy (ART) such as stavudine has been now replaced with safer therapies, reducing the prevalence of neuropathy from 34% to 15% in HIV+ Indonesians. However, it is unclear whether the residual cases display damage to small or large nerve fibers and whether both are influenced by known risk factors, including alleles of CAMKK2 associated with neuropathy in HIV patients. The encoded protein influences the growth and repair of nerve fibers. HIV-positive adults on ART for >12 months without exposure to stavudine were screened for neuropathy using the AIDS Clinical Trials Group Brief Peripheral Neuropathy Screen (BPNS). Large fiber neuropathy was assessed by nerve conduction (NC) and small fiber neuropathy using stimulated skin wrinkling (SSW) applied to the fingers. CAMKK2 alleles were assessed by TaqMan OpenArray technology. Neuropathy diagnoses were more common with SSW than BPNS (49/173 vs 26/185, χ; P = 0.0009), with poor alignment between these outcomes (P = 0.60). NC and BPNS diagnosed neuropathy at similar frequencies (29/151 vs 26/185; P = 0.12) and were aligned (P < 0.0001). In bivariate analyses, all diagnoses were associated with patients' age and persistent HIV replication, with minor effects from CD4 T-cell counts and time on ART. CAMKK2 alleles associated with neuropathy diagnosed with BPNS and SSW but not NC. Multivariable analyses confirmed the importance of age and HIV replication, with distinct CAMKK2 polymorphisms affecting BPNS and SSW. Paradoxically, height was protective against skin wrinkling. Overall the data link CAMKK2 genotypes with small rather than large fiber damage. SSW may reflect pathology distinct from that identified using BPNS.

ZeOxaNMulti Trial: A Randomized, Double-Blinded, Placebo-Controlled Trial of Oral PMA-zeolite to prevent Chemotherapy-Induced Side Effects, in particular, Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is the most frequently reported adverse effect of oxaliplatin. In this study, we set out to evaluate the role of the panaceo-micro-activation (PMA) zeolite in the reduction of the incidence of CIPN and hematological and liver toxicity. The possible impact of the PMA-zeolite as an adjuvant therapeutic agent is based on its detoxification properties toward agents promoting the development of neuropathy (e.g., ammonium—recognized as a neurotoxic agent produced by tumors), as well as its positive impact on immunity and oxidative stress through its effects in the gastrointestinal tract. From April 2015 to October 2018, a total of 120 patients (pts) diagnosed with predominantly colorectal cancer requiring oxaliplatin-based chemotherapy were randomized to receive either the PMA-zeolite (Multizeo Med) or placebo while undergoing oxaliplatin-based chemotherapy. A nerve-conduction study (NCS) was planned at the baseline, after three and six months of chemotherapy, to evaluate CIPN. Furthermore, the evaluation of hematological and liver toxicity was performed during every cycle of chemotherapy. 70.6% and 64.3% of patients developed CIPN in the placebo and the PMA-zeolite group, respectively. Patients treated with the PMA-zeolite were able to undergo more cycles of chemotherapy (p = 0.03), which also indicates a significant improvement in tolerance to the therapy. The group treated with the PMA-zeolite showed a lower CIPN (although not statistically significant within the whole group of subjects) compared to patients receiving placebo. This advantage was, however, statistically significant in men (p = 0.047). In addition, supplementation with the PMA-zeolite resulted in a lower incidence of severe-grade hematological toxicity (trend toward statistical significance of p = 0.09 was observed). Cancer patients may benefit from the therapy with the appropriate certified zeolite-products (e.g., the PMA-zeolite) for human use in CIPN. The lower CIPN (statistically significant results in the male subgroup) was accompanied by a trend of lower incidence of severe-grade hematological toxicity. Furthermore, these benefits led to a better tolerance toward chemotherapy (increase in cycles) and allow an improved compliance with the oncological treatment protocol.

Safety and tolerability of cryocompression as a method of enhanced limb hypothermia to reduce taxane-induced peripheral neuropathy

Purpose

Severe peripheral neuropathy is a common dose-limiting toxicity of taxane chemotherapy, with no effective treatment. Frozen gloves have shown to reduce the severity of neuropathy in several studies but comes with the incidence of undesired side effects such as cold intolerance and frostbite in extreme cases. A device with thermoregulatory features which can safely deliver tolerable amounts of cooling while ensuring efficacy is required to overcome the deficiencies of frozen gloves. The role of continuous-flow cooling in prevention of neurotoxicity caused by paclitaxel has been previously described. This study hypothesized that cryocompression (addition of dynamic pressure to cooling) may allow for delivery of lower temperatures with similar tolerance and potentially improve efficacy.

Method

A proof-of-concept study was conducted in cancer patients receiving taxane chemotherapy. Each subject underwent four-limb cryocompression with each chemotherapy infusion (three hours) for a maximum of 12 cycles. Cryocompression was administered at 16 °C and cyclic pressure (5–15 mmHg). Skin surface temperature and tolerance scores were recorded. Neuropathy was assessed using clinician-graded peripheral sensory neuropathy scores, total neuropathy score (TNS) and nerve conduction studies (NCS) conducted before (NCS_pre), after completion (NCS_post) and 3 months post-chemotherapy (NCS_3m). Results were retrospectively compared with patients who underwent paclitaxel chemotherapy along with continuous-flow cooling and controls with no hypothermia.

Results

In total, 13 patients underwent 142 cycles of cryocompression concomitant with chemotherapy. Limb hypothermia was well tolerated, and only 1 out of 13 patients required an intra-cycle temperature increase, with no early termination of cryocompression in any subject. Mean skin temperature reduction of 3.8 ± 1.7 °C was achieved. Cryocompression demonstrated significantly greater skin temperature reductions compared to continuous-flow cooling and control (p < 0.0001). None of the patients experienced severe neuropathy (clinician-assessed neuropathy scores of grade 2 or higher). NCS analysis showed preservation of motor amplitudes at NCS_3m in subjects who underwent cryocompression, compared to the controls who showed significant deterioration (NCS_3m cryocompression vs. NCS_3m control: ankle stimulation: 8.1 ± 21.4%, p = 0.004; below fibula head stimulation: 12.7 ± 25.6%, p = 0.0008; above fibula head stimulation: 9.4 ± 24.3%, p = 0.002). Cryocompression did not significantly affect taxane-induced changes in sensory nerve amplitudes.

Conclusion

When compared to continuous-flow cooling, cryocompression permitted delivery of lower temperatures with similar tolerability. The lower skin surface temperatures achieved potentially lead to improved efficacy in neurotoxicity amelioration. Larger studies investigating cryocompression are required to validate these findings.

Electronic supplementary material

The online version of this article (10.1007/s00520-019-05177-2) contains supplementary material, which is available to authorized users.

Diagnosis and management of sensory polyneuropathy

Sensory polyneuropathies, which are caused by dysfunction of peripheral sensory nerve fibers, are a heterogeneous group of disorders that range from the common diabetic neuropathy to the rare sensory neuronopathies. The presenting symptoms, acuity, time course, severity, and subsequent morbidity vary and depend on the type of fiber that is affected and the underlying cause. Damage to small thinly myelinated and unmyelinated nerve fibers results in neuropathic pain, whereas damage to large myelinated sensory afferents results in proprioceptive deficits and ataxia. The causes of these disorders are diverse and include metabolic, toxic, infectious, inflammatory, autoimmune, and genetic conditions. Idiopathic sensory polyneuropathies are common although they should be considered a diagnosis of exclusion. The diagnostic evaluation involves electrophysiologic testing including nerve conduction studies, histopathologic analysis of nerve tissue, serum studies, and sometimes autonomic testing and cerebrospinal fluid analysis. The treatment of these diseases depends on the underlying cause and may include immunotherapy, mitigation of risk factors, symptomatic treatment, and gene therapy, such as the recently developed RNA interference and antisense oligonucleotide therapies for transthyretin familial amyloid polyneuropathy. Many of these disorders have no directed treatment, in which case management remains symptomatic and supportive. More research is needed into the underlying pathophysiology of nerve damage in these polyneuropathies to guide advances in treatment.

Are we mis-estimating chemotherapy-induced peripheral neuropathy? Analysis of assessment methodologies from a prospective, multinational, longitudinal cohort study of patients receiving neurotoxic chemotherapy

Background

There are inconsistencies in the literature regarding the prevalence and assessment of chemotherapy-induced peripheral neuropathy (CIPN). This study explored CIPN natural history and its characteristics in patients receiving taxane- and platinum-based chemotherapy.

Patients and methods

Multi-country multisite prospective longitudinal observational study. Patients were assessed before commencing and three weekly during chemotherapy for up to six cycles, and at 6,9, and 12 months using clinician-based scales (NCI-CTCAE; WHO-CIPN criterion), objective assessments (cotton wool test;10 g monofilament); patient-reported outcome measures (FACT/GOG-Ntx; EORTC-CIPN20), and Nerve Conduction Studies.

Results

In total, 343 patients were recruited in the cohort, providing 2399 observations. There was wide variation in CIPN prevalence rates using different assessments (14.2–53.4%). Prevalence of sensory neuropathy (and associated symptom profile) was also different in each type of chemotherapy, with paclitaxel (up to 63%) and oxaliplatin (up to 71.4%) showing the highest CIPN rates in most assessments and a more complex symptom profile. Peak prevalence was around the 6-month assessment (up to 71.4%). Motor neurotoxicity was common, particularly in the docetaxel subgroup (up to 22.1%; detected by NCI-CTCAE). There were relatively moderately-to-low correlations between scales (r_s = 0.15,p < 0.05-r_s = 0.48 p < 0.001), suggesting that they measure different neurotoxicity aspects from each other. Cumulative chemotherapy dose was not associated with onset and course of CIPN.

Conclusion

The historical variation reported in CIPN incidence and prevalence is possibly confounded by disagreement between assessment modalities. Clinical practice should consider assessment of motor neuropathy for neurotoxic chemotherapy. Current scales may not be all appropriate to measure CIPN in a valid way, and a combination of scales are needed.

Assessment of autonomic innervation of the foot in familial amyloid polyneuropathy

BACKGROUND AND PURPOSE

Distal involvement of autonomic nerve fibers is critical in familial amyloid polyneuropathy (FAP) due to transthyretin (TTR) mutation. This study compares different methods for assessing autonomic foot innervation in TTR-FAP patients.

METHODS

Three groups of seven TTR-FAP patients were included, according to disease severity: clinically asymptomatic, moderate or advanced neuropathy. The autonomic investigation included the eutectic mixture of local anesthetics test and laser Doppler flowmetry for vasomotor aspects and the Sudoscan® (measuring electrochemical skin conductance) and Neuropad® test for sudomotor aspects. Somatic innervation was assessed by performing nerve conduction studies, quantitative sensory testing [including vibration, cold and warm detection threshold (WDT) measurements] and laser evoked potentials.

RESULTS

The results of all neurophysiological tests varied according to TTR-FAP severity (P ≤ 0.01, Kruskal-Wallis test), except for the eutectic mixture of local anesthetics test and laser Doppler flowmetry variables. In addition, the sudomotor tests (Sudoscan or Neuropad) or WDT measurement provided early markers of neuropathy in two of the seven asymptomatic carriers. Finally, all neurophysiological results correlated with the Neuropathy Impairment Score (r values between -0.88 and -0.66, P < 0.005, Spearman test), except the cold detection threshold.

CONCLUSIONS

The Neuropad test could be used to detect TTR-FAP onset, but confirmation requires electrochemical skin conductance and WDT measurement. The Sudoscan technique, but not the Neuropad test (at least assessed at a fixed time point), could be valuable to follow the progression of the neuropathy. Follow-up investigation should also include large-fiber investigation (e.g. nerve conduction studies and vibration detection threshold). Conversely, reliable tests for assessing vasomotor disturbances in limb extremities of TTR-FAP patients are still awaited.

Early detection of peripheral neuropathy using stimulated skin wrinkling test in human immunodeficiency virus infected patients: A cross-sectional study

Peripheral neuropathy is a common condition of human immunodeficiency virus (HIV)-infected patients, which often remains undetected. We assessed the performance of stimulated skin wrinkling-eutectic mixture of local anesthetic (SSW-EMLA) test compared with brief peripheral neuropathy screening (BPNS) to detect HIV neuropathy.This is a cross-sectional study conducted in HIV-positive patients. A modified skin wrinkling grading was used to assess SSW-EMLA effect. BPNS-detectable neuropathy was assessed by a combination of neuropathy severity scoring scale (subjective) and objective method of sensory and tendon reflex examination. The SSW-EMLA test accuracy with reference to BPNS was assessed using sensitivity and specificity and predictive values.In a total of 99 HIV patients, 61.6% were males and the majority age group were between 30 and 40 years (52%). The neuropathy detection was SSW-EMLA test 36.4% versus BPNS 15.2% (P = .04). The sensitivity of SSW-EMLA test was 60.0% [95% confidence interval (95% CI) 34.5-81.7], specificity 67% (95% CI 63.3-3-71.7), and overall accuracy of 66.7% (95% CI 58.9-73.2).The SSW-EMLA test detected many more peripheral neuropathy cases than BPNS in HIV patients and has potential as an alternative test for screening for HIV neuropathy in resource-constraint hospitals in Indonesia.

Early detection of neuropathy in leprosy: a comparison of five tests for field settings

Background

Early detection and treatment of neuropathy in leprosy is important to prevent disabilities. A recent study showed that the Nerve Conduction Studies (NCS) and Warm Detection Thresholds (WDT) tests can detect leprosy neuropathy the earliest. These two tests are not practical under field conditions, however, because they require climate-controlled rooms and highly trained staff and are expensive. We assessed the usefulness of alternative test methods and their sensitivity and specificity to detect neuropathy at an early stage.

Methods

Through a literature search we identified five alternative devices that appeared user-friendly, more affordable, portable and/or battery-operated: the Neuropad®, Vibratip™, NC-Stat®DPNCheck™, NeuroQuick and the Thermal Sensibility Tester (TST), assessing respectively sweat function, vibration sensation, nerve conduction, cold sensation and warm sensation. In leprosy patients in Bangladesh, the posterior tibial and sural nerves that tested normal for the monofilament test and voluntary muscle test were assessed with the NCS and WDT as reference standard tests. The alternative devices were then tested on 94 nerves with abnormal WDT and/or NCS results and on 94 unaffected nerves. Sensitivity and specificity were the main outcomes.

Results

The NeuroQuick and the TST showed very good sensitivity and specificity. On the sural nerve, the NeuroQuick had both a sensitivity and a specificity of 86%. The TST had a sensitivity of 83% and a specificity of 82%. Both the NC-Stat®DPNCheck™ and Vibratip™ had a high specificity (88% and 100%), but a low sensitivity (16% and 0%). On the posterior tibial nerve, the NeuroQuick and the TST also showed good sensitivity, but the sensitivity was lower than for the sural nerve. The Neuropad® had a sensitivity of 56% and a specificity of 61%.

Conclusions

The NeuroQuick and TST are good candidates for further field-testing for reliability and reproducibility. The feasibility of production on a larger scale should be examined.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-017-0330-2) contains supplementary material, which is available to authorized users.

Limb Hypothermia for Preventing Paclitaxel-Induced Peripheral Neuropathy in Breast Cancer Patients: A Pilot Study

BACKGROUND

Peripheral neuropathy (PN) due to paclitaxel is a common dose-limiting toxicity with no effective prevention or treatment. We hypothesize that continuous-flow limb hypothermia can reduce paclitaxel-induced PN.

PATIENTS AND METHODS

An internally controlled pilot trial was conducted to investigate the neuroprotective effect of continuous-flow limb hypothermia in breast cancer patients receiving weekly paclitaxel. Patients underwent limb hypothermia of one limb for a duration of 3 h with every paclitaxel infusion, with the contralateral limb used as control. PN was primarily assessed using nerve conduction studies (NCSs) before the start of chemotherapy, and after 1, 3, and 6 months. Skin temperature and tolerability to hypothermia were monitored using validated scores.

RESULTS

Twenty patients underwent a total of 218 cycles of continuous-flow limb hypothermia at a coolant temperature of 22°C. Continuous-flow limb hypothermia achieved mean skin temperature reduction of 1.5 ± 0.7°C and was well tolerated, with no premature termination of cooling due to intolerance. Grade 3 PN occurred in 2 patients (10%), grade 2 in 2 (10%), and grade 1 in 12 (60%). Significant correlation was observed between amount of skin cooling and motor nerve amplitude preservation at 6 months (p < 0.0005). Sensory velocity and amplitude in the cooled limbs were less preserved than in the control limbs, but the difference did not attain statistical significance. One patient with a history of diabetes mellitus had significant preservation of compound muscle action potential in the cooled limb on NCS analysis.

CONCLUSION

This study suggests that continuous limb hypothermia accompanying paclitaxel infusion may reduce paclitaxel-induced PN and have therapeutic potential in select patients and warrants further investigation. The method is safe and well tolerated.

Small fiber neuropathy: Getting bigger!

Etiological and clinical heterogeneity of small fiber neuropathy (SFN) precludes a unifying approach and necessitates reliance on recognizable clinical syndromes. Symptoms of SFN arise from dysfunction in nociception, temperature, and autonomic modalities. This review focuses on SFN involving nociception and temperature, examining epidemiology, etiology, clinical presentation, diagnosis, pathophysiology, and management. Prevalence of SFN is 52.95 per 100,000 population, and diabetes and idiopathic are the most common etiologies. Dysesthesia, allodynia, pain, burning, and coldness sensations frequently present in a length-dependent pattern. Additional autonomic features in gastrointestinal, urinary, or cardiovascular systems are frequent but poorly objectified. SFN is diagnosed by intraepidermal nerve fiber density and quantitative sensory and autonomic tests in combination with normal nerve conduction. Pathophysiological understanding centers on sodium channel dysfunction, and genetic forms are beginning to be understood. Treatment is directed at the underlying etiology supported by symptomatic treatment using antidepressants and anticonvulsants. Little is known about long-term outcomes, and systematic cohort studies are needed.

Stimulated skin wrinkling as an indicator of limb sympathetic function

Skin wrinkling upon water immersion has been used as an indicator of limb nerve function for more than 80years. Until recently, routine use of the test has been hampered by a poor understanding of the physiology and lack of standardization. The process underlying stimulated skin wrinkling has been recently identified as dependent on digital vasoconstriction mediated via sympathetic nerve fibers. Vasoconstriction is postulated to drive wrinkling through loss of digit volume, which induces a negative pressure in the digit pulp and exerts a downward pull on the overlying skin and ultimately results in wrinkles. Improved test standardization has been achieved through substituting water with EMLA for inducing skin wrinkling. This has made testing much easier and has helped implement stimulated skin wrinkling as a practical routine clinical bedside test. A literature search identified 10 studies of sufficient quality for evaluating stimulated skin wrinkling as a diagnostic test of sympathetic under or over function. Seven studies provide level 1 or 2 evidence as a diagnostic test of small fiber neuropathy and three provide level 1 or 2 evidence for cystic fibrosis. There is reasonable evidence allowing the test to be employed as a simple and effective marker for small fiber neuropathy and cystic fibrosis.