Diffuse Neuropathy Research Articles

Imaging of Peripheral Nerves: AJR Expert Panel Narrative Review.

Peripheral nerve imaging provides information that can be critical to the diagnosis, staging, and management of peripheral neuropathies. MRI and ultrasound are the imaging modalities of choice for clinical evaluation of the peripheral nerves given their high soft tissue contrast and high resolution, respectively. This AJR Expert Panel Narrative Review describes MRI- and ultrasound-based techniques for peripheral nerve imaging; highlights considerations for imaging in the settings of trauma, entrapment syndromes, diffuse inflammatory neuropathies, and tumor; and discusses image-guided nerve interventions, focusing on nerve blocks and ablation.

An Uncommon Disease with a Common Presentation: Severe Back pain and Diffuse Neuropathy in Two Cases of Hereditary Neuropathy with Liability to Pressure Palsy

Introduction: Hereditary Neuropathy with liability to Pressure Palsy (HNPP) is an autosomal dominant genetic disorder characterized by multiple episodes of focal weakness and sensory loss caused by compression or trauma. HNPP is rare disorder and often exhibits cranial nerve involvement, sensorineural deafness and scoliosis. Individuals diagnosed with this condition typically exhibit a primary deficit of a single nerve palsy that can result in numbness, paresthesias, or weakness. Case Presentation: Two unrelated individuals with HNPP were evaluated with clinical, laboratory, electrophysiological and genetic testing. Case 1 was a 32-year-old man who presented with an episode of transient right arm weakness and severe back pain. Case 2 was a 46-year-old woman who presented with severe back pain and diffuse paresthesias, which was diagnosed as HNPP. Discussion: These cases present common symptoms that are uncommon for the typical HNPP patient. This report serves to contribute new information to the body of evidence describing HNPP. Conclusion: Although HNPP typically presents with transient compressive mononeuropathies, this study suggests that HNPP can present with various broad clinical presentations, including severe back pain. Neurologists need to broaden their spectrum of clinical presentations to help diagnose these rare conditions.

Evaluation of microvascular complications in patients with new diagnosis type 2 diabetes.

The incidence of microvascular complications such as diabetic retinopathy, diabetic nephropathy and diabetic neuropathy has increased in newly diagnosed diabetes patients. The aim of this study was to determine the factors affecting the incidence of microvascular complications in newly diagnosed patients with type 2 diabetes. This study was conducted on 97 newly diagnosed type 2 DM patients who applied to Malatya Training and Research Hospital Endocrinology outpatient clinic between September 2021 and July 2022. The patient files were reviewed retrospectively and their age, height, weight, body mass index (BMI), fasting/postprandial blood glucose measurements, serum HDL cholesterol, LDL cholesterol, total cholesterol, triglyceride, HbA1c levels, glomerular filtration rate (GFR) and complications of retinopathy, nephropathy, and neuropathy were recorded. Mann-Whitney U, t-test, Kruskal-Wallis, Binary logistic regression analysis, and Chi-square analysis were used to analyze the data. The mean age of the patients included in the study was 47.40±7.78 (min: 23 - max: 62). Non-proliferative retinopathy was observed in 74.2% of patients, proliferative retinopathy in 25.8%, diffuse neuropathy in 49.5% and mononeuropathy was detected in 9.3% of them. Fasting blood glucose, postprandial blood glucose and HbA1c values were found to be higher in patients with proliferative retinopathy than in patients without retinopathy. Fasting blood glucose, postprandial blood glucose and HbA1c values were found to be higher in patients with neuropathy than in patients without neuropathy. In addition, patients with mononeuropathy had statistically significantly higher HbA1c values than patients with diffuse-type neuropathy. It was found that the urine protein values of patients with mononeuropathy were significantly higher than those without neuropathy and those with diffuse neuropathy. Each 0.677-unit increase in HbA1c increases the risk of proliferative retinopathy 1.98-fold, and every 1.018-unit increase increases the risk of neuropathy 2.76-fold. Proliferative retinopathy and mononeuropathy rates were discovered to be higher in patients with a family history. Microvascular complications are common in newly diagnosed T2DM patients and an increase in HbA1c is a significant risk factor. Every newly diagnosed T2DM patient should be screened for microvascular complications.

Protein pyrrole adducts are associated with elevated glucose indices and clinical features of diabetic diffuse neuropathies.

IntroductionDiabetic neuropathy is the most prevalent complication of diabetes mellitus. Although the precise etiology of this neurological disorder has yet to be defined, elevated blood glucose promotes anerobic glycolysis; this produces excess advanced glycation end‐products, many of which have a pyrrole structure. Here, we test the hypothesis that protein pyrrole adducts are associated with elevated glucose indices and some clinical features of diabetic diffuse neuropathies.MethodWe investigated the levels of plasma pyrrole adducts and adjusted urinary pyrrole adducts in a group of elderly persons (n = 516, age 60–79) residing in the District of Luohu, Shenzhen, China between 2017 and 2018. Symptoms of distal symmetric polyneuropathy (DSPN) and resting heart rate, a measure of autonomic nervous system function, were collected from participants (n = 258) with elevated glucose indices.ResultProtein pyrrole adducts showed a strong correlation with glucose indices before and after adjustment for age and estimated glomerular filtration rates. Stratified analysis showed that the medians and interquartile values of pyrrole adducts grew as glucose indices of the subgroups increased. Participants with symptoms of DSPN and sinus tachycardia presented elevated levels of plasma pyrrole adducts.ConclusionThis study provides a novel link between glucose indices and the etiology of diabetic diffuse neuropathies.

Neuropathy Score Reporting and Data System: A Reporting Guideline for MRI of Peripheral Neuropathy With a Multicenter Validation Study.

BACKGROUND. A standardized guideline and scoring system would improve evaluation and reporting of peripheral neuropathy (PN) on MRI. OBJECTIVE. The objective of this study was to create and validate a neuropathy classification and grading system, which we named the Neuropathy Score Reporting and Data System (NS-RADS). METHODS. This retrospective study included 100 patients with nerve imaging studies and known clinical diagnoses. Experts crafted NS-RADS using mutually agreed-on qualitative criteria for the classification and grading of PN. Different classes were created to account for the spectrum of underlying pathologies: unremarkable (U), injury (I), neoplasia (N), entrapment (E), diffuse neuropathy (D), not otherwise specified (NOS), and postintervention state (PI). Subclasses were established to describe the severity or extent of the lesions. Validation testing was performed by 11 readers from 10 institutions with experience levels ranging from 3 to 18 years after residency. After initial reader training, cases were presented to readers who were blinded to the final clinical diagnoses. Interobserver agreement was assessed using correlation coefficients and the Conger kappa, and accuracy testing was performed. RESULTS. Final clinical diagnoses included normal (n = 5), nerve injury (n = 25), entrapment (n = 15), neoplasia (n = 33), diffuse neuropathy (n = 18), and persistent neuropathy after intervention (n = 4). The miscategorization rate for NS-RADS classes was 1.8%. Final diagnoses were correctly identified by readers in 71-88% of cases. Excellent inter-reader agreement was found on the NS-RADS pathology categorization (κ = 0.96; 95% CI, 0.93-0.98) as well as muscle pathology categorization (κ = 0.76; 95% CI, 0.68-0.82). The accuracy for determining milder versus more severe categories per radiologist ranged from 88% to 97% for nerve lesions and from 86% to 94% for muscle abnormalities. CONCLUSION. The proposed NS-RADS classification is accurate and reliable across different reader experience levels and a spectrum of PN conditions. CLINICAL IMPACT. NS-RADS can be used as a standardized guideline for reporting PN and improved multidisciplinary communications.

Neuropathy Score Reporting and Data System (NS-RADS): MRI Reporting Guideline of Peripheral Neuropathy Explained and Reviewed

A standardized guideline and scoring system should be used for the MR imaging diagnosis of peripheral neuropathy. The MR imaging-based Neuropathy Score Reporting and Data System (NS-RADS) is a newly devised classification system (in press in AJR) that can be used to communicate both type and severity of peripheral neuropathy in the light of clinical history and examination findings. The spectrum of neuropathic conditions and peripheral nerve disorders covered in this system includes nerve injury, entrapment, neoplasm, diffuse neuropathy, and post-interventional states. This classification system also describes the temporal MR imaging appearances of regional muscle denervation changes. This review article is based on the multicenter validation study pre-published in American journal of Roentgenology and discusses technical considerations of optimal MR imaging for peripheral nerve evaluation and discusses the NS-RADS classification and its severity scales with illustration of conditions that fall under each classification. The readers can gain knowledge of the NS-RADS classification system and learn to apply it in their practices for improved inter-disciplinary communications and timely patient management.

P-NE003. Frequency of carpal tunnel syndrome in patients having diabetes mellitus with neuropathy in a tertiary care hospital

Introduction. Carpal tunnel syndrome (CTS) is one of the most frequent entrapment neuropathies of the upper limb. Carpal tunnel syndrome (CTS) and diabetic polyneuropathy (DPN) are common conditions in patients with diabetes and therefore frequently occur concomitantly. Diagnosis of CTS in patients with DPN is important, as therapeutic interventions directed toward relief of CTS may be effective irrespective of diffuse neuropathy. Methods. This study was a hospital based descriptive cross sectional study done in BIRDEM general hospital between July, 2015 and June, 2016, for a period of twelve months. The initial clinical diagnosis of DPN was made and was confirmed by doing nerve conduction study. After having informed written consents, a standard preformed questionnaire was filled up for each case. Results. A total of 354 cases were finally analyzed with 153 (43.2%) patients being symptomatic and among those 54 (58.7%) had electrophysiology proven CTS. It was observed that 26.0% of patients established as having DPN also had CTS. The frequency of CTS among those with symptoms was significantly higher than in asymptomatic participants. Majority (38.4%) of patients belonged to the age group of 51-60 years. The mean age was found to be 55.99 ± 9.25 years with a range from 28 to 80 years. Among all cases of electrophysiology proven CTS (92 patients), females (53.3%) numbered greater in comparison to males (46.7%). Study subjects with CTS had significantly higher BMI, higher fasting blood sugar and higher HbA1c in comparison to patients without CTS. The mean compound motor action potential was not significantly different between patients with and without CTS. Conclusion. Given the high prevalence of CTS in subjects with DPN, it is recommended that therapeutic decisions should be made carefully after nerve conduction study and proper diagnosis.

Hand and Wrist Neuropathies: High-resolution Ultrasonography and MR Neurography.

High-resolution ultrasonography (US) and magnetic resonance neurography (MRN) have followed parallel paths for peripheral nerve imaging with little comparison of the two modalities. They seem equally effective to study a variety of neuropathies affecting large and small nerves in the wrist and hand. This article outlines the technical considerations of US and MRN and discusses normal and abnormal imaging appearances of hand and wrist nerves from etiologies such as entrapment, injury, tumor, and proximal and diffuse neuropathy, with specific case illustrations.

Ulnar nerve conduction study in healthy young adults from Punjab, India: Normative data

Background: Nerve conduction studies (NCSs) play a pivotal role in diagnosis of local nerve lesions and diffuse neuropathies serving as an extension of the clinical findings or examination .The neurophysiology laboratories in Punjab have to rely on data generated by studies from other Indian states and western literature, due to paucity of local NCS data. Aim: To establish the normative data for ulnar nerve conduction parameters in young Punjabis. Materials and Methods: As per the standardized technique, nerve conduction study was done on 320 participants (165 males and 155 females) aged 17-21 years. The data were analyzed separately for both genders using SPSS version 2.0, consisting of distal latencies and conduction velocities of sensory and motor divisions of ulnarnerve. Student's unpaired t-test was used for statistical analysis. Results: There was no effect of gender on ulnar nerve conduction parameters. For ulnar motor nerve, the values of distal Latency y and conduction velocity in males were 3.30± 1.18ms and 63.08±2.53 m/s respectively, whereas in Females, they were 3.42±0.30 ms and 62.95± 2.74 m/s. Also, for ulnar sensory nerve, the latency and velocity values in males were 2.63 ± 0.48 ms and 55.69 ± 3.14 m/s, whereas, in females, they were 2.51±0.28 ms and 55.50±3.72m/s, respectively. Conclusion: The data established in this study compared favorably with already existing data. For assessing the ulnar nerve abnormalities with greater accuracy in this population subset, the established data would help the local electrophysiology laboratories in the region.

The impact on large fibre function and small fibre function in patients with type 2 diabetes on benfotiamine therapy

Diabetes mellitus (DM) is the leading cause of neuropathy worldwide. Based on the data from several studies, sensorimotor polyneuropathy (diffuse and symmetric neuropathy) will develop within 10 years of the onset of DM in 40 % to 50 % of patients with type 1 and type 2 DM. In patients with type 2 DM, target blood glucose levels are associated with a reduced incidence of neuropathy. Objective — to study the correlation between the stage of diabetic peripheral polyneuropathy in type 2 diabetic patients, and the effects and efficacy of benfotiamine as transketolase activator. Materials and methods. In this study, 190 patients with type 2 DM were screened for DPN. DPN was confirmed in 105 patients displaying both clinical manifestations of neuropathy with a positive Diabetic Neuropathy Symptom (DNS) score and increased vibration perception threshold (VPT) on a biotensiometer. Based on the above stated criteria patients were divided into 4 groups: 1 — with positive DNS score, positive 10 g monofilament test score, VPT between 16—25 volts; 2 — with positive DNS score, positive 10 g monofilament test score, VPT between 26—35 volts; 3 — with positive DNS score, positive 10 g monofilament test score and VPT between 35—40 volts; 4 — control group with positive DNS score, negative 10 g monofilament test score and normal VPT value (n = 25 (23 %); 20 females and 5 males). The first 3 groups received benfotiamine 300 mg daily for 6 weeks, the control group was benfothiamine naïve. All the groups continued their antidiabetic medication. Results and discussion. The diabetic neuropathy score and vibration perception threshold was assessed in 105 patients (84 females and 21 males) with type 2 DM, before starting of benfotiamine 300 mg daily and after 6 weeks of therapy. Results of DNS: differences between group 3 and both group 1 and 2 were significant, but not between group 1 and 2. Patients in group 1 (n = 24), in females (n = 18) the DNS varied from 1—2, and in males (n = 6) the DNS varied from 1—3. After the 6 weeks,DNS score decreased in both females and males i.e. 1—1.25 and 1—2.5 correspondingly. Conclusions. The role of benfotiamine in clinical practice has been demonstrated in many clinical trials with variable trial design, patient groups and history of diabetes. In our study we found that patients with mild neuropathy and vibration perception threshold of 16—25 volts showed a reduction in VPT of up to 16 %, and the patients with moderate neuropathy and reduced vibration perception threshold of 26—35 volts were the ones who benefitted the most from benfotiamine therapy. Benfotiamine activates transketolase and thus helps in the reduction of AGEs formation and associated sugar induced metabolic stress.

Cortical atrophy and hypofibrinogenemia due to FGG and TBCD mutations in a single family: a case report

BackgroundBlended phenotypes or co-occurrence of independent phenotypically distinct conditions are extremely rare and are due to coincidence of multiple pathogenic mutations, especially due to consanguinity. Hereditary fibrinogen deficiencies result from mutations in the genes FGA, FGB, and FGG, encoding the three different polypeptide chains that comprise fibrinogen. Neurodevelopmental abnormalities have not been associated with fibrinogen deficiencies. In this study, we report an unusual patient with a combination of two independently inherited genetic conditions; fibrinogen deficiency and early onset cortical atrophy.Case presentationThe study describes a male child from consanguineous family presented with hypofibrinogenemia, diffuse cortical atrophy, microcephaly, hypertonia and axonal motor neuropathy. Through a combination of homozygosity mapping and exome sequencing, we identified bi-allelic pathogenic mutations in two genes: a homozygous novel truncating mutation in FGG (c.554del; p.Lys185Argfs*14) and a homozygous missense mutation in TBCD (c.1423G > A;p.Ala475Thr). Loss of function mutations in FGG have been associated with fibrinogen deficiency, while the c.1423G > A mutation in TBCD causes a novel syndrome of neurodegeneration and early onset encephalopathy.ConclusionsOur study highlights the importance of homozygosity mapping and exome sequencing in molecular prenatal diagnosis, especially when multiple gene mutations are responsible for the phenotype.

A Case of Significant Malnutrition Presenting as Acute Sensorimotor Axonal Neuropathy

Nutritional status is an important, but often overlooked, component of care for patients being seen in any number of subspecialty clinics. The neurologic ramifications of nutritional deficiencies tend to present in the later stages of prolonged malnutrition. A 34 year-old woman with a history of alcoholism presented to the emergency department with two weeks of worsening gait imbalance, diffuse paresthesia, allodynia, and weakness of all extremities. The physical examination yielded diffuse loss of sensation to all sensory modalities in a length-dependent manner and complete lack of deep tendon reflexes in all extremities. There was also mild 4/5 weakness of proximal musculature of upper and lower extremities. Nerve conduction studies showed a diffuse sensorimotor axonal neuropathy that was worse in the lower extremities compared to the upper extremities. Laboratory evaluation yielded significant deficiencies that included calcium, pyridoxine, vitamin E, folate, borderline low thiamine, and elevated homocysteine levels. This was a unique case of severe malnutrition manifesting as an acute diffuse axonal neuropathy. Lower socioeconomic status with concurrent alcohol use can lead to a bevy of neurologic conditions as seen in our patient.

Normative Data for Median Nerve Conduction in Healthy Young Adults from Punjab, India.

Background:Nerve conduction studies (NCSs) are essential for diagnosing various kinds of focal and diffuse neuropathies. Due to the paucity of local NCS data, electrodiagnostic laboratories in Punjab rely on values from Western and other Indian studies.Aim:This study was conducted to provide normative data for median nerve conduction parameters (motor and sensory) in Punjabi populace.Materials and Methods:A cross-sectional study was done on 290 participants (150 males and 140 females), aged 17–21 years, as per standardized protocol. The data were analyzed separately for both genders using SPSS version 20. It consisted of distal latencies and conduction velocities of motor and sensory divisions of median nerve. Student's unpaired t-test was used for statistical analysis.Results:There was no effect of gender on any of the median nerve conduction parameters. Height and weight had nonsignificant negative and positive correlation, respectively (P > 0.05), with conduction velocity in both motor and sensory median nerves. For median motor nerve, the values of distal latency and conduction velocity in males were 2.9 ± 0.16 ms and 60.25 ± 2.99 m/s, respectively, whereas, in females, they were 2.6 ± 0.43 ms and 59.83 ± 2.82 m/s. Similarly, for median sensory nerve, the latency and velocity values in males were 2.8 ± 0.56 ms and 54.81 ± 3.70 m/s, whereas, in females, they were 2.4 ± 0.33 ms and 54.56 ± 3.65 m/s, respectively.Conclusion:The data in this study compared favorably with already existing data. It would help the local electrodiagnostic laboratories in assessing the median nerve abnormalities with greater accuracy in this population subset.

Protocolo de manejo clínico de la neuropatía en el paciente oncológico

IntroductionIt is common for neuropathy to occur in cancer patients. It can appear in the initial phases due to the action of onconeural antibodies in paraneoplastic neurological syndromes, and then in the course of the disease due to infiltration and tumour growth in particular, and as a consequence of chemo and radiotherapy which is the most common cause of neuropathy in these patients. Vinca alkaloids and taxanes, platinum derivatives and thalidomide cause toxicity through various mechanisms (inhibition of axonal transport, damage to the sensitive dorsal lymph node, reversible or otherwise). DiagnosisDiagnosis, essentially by electromyography, enables definition of diffuse neuropathy (with axonal or demyelinating damage to the sensitive or motor components of the nerve) or a focal form. Other techniques (MRI, PET-CT) can complement diagnosis in focal forms. There is pain in 90% of cases due to the action of cytokines and sensitisation of the sympathetic nervous system. TreatmentAlthough few, there are treatment options that include methylcobalamin with acupuncture, alpha-lipoic acid, duloxetine and photomodulation.

Ultrasound in Neuromuscular Disorders.

Electrodiagnosis with nerve conduction studies and needle electromyography has been the standard method of diagnosis of neuromuscular conditions for over 80 years. Although ultrasound technology has been in existence for approximately the same time, application of this technology to assessment of the neuromuscular system only began in the 1980s. In the past 2 decades-mainly because of advances in resolution enabled by high frequency transducers and improved image processing-ultrasound has enabled the real-time, morphologic evaluation of focal and diffuse neuropathies, motor neuron diseases, and myopathies. Although methods of nerve and muscle assessment continue to evolve (i.e., Doppler imaging to evaluate intraneural and intramuscular blood flow), nerves have most commonly been evaluated based on their cross-sectional area, which seems to correlate with nerve swelling and pathology, particularly in focal and also in some diffuse neuropathies. Qualitative and more recently quantitative measures of muscle echogenicity have been used in the assessment of myopathies and motor neuron diseases. Collection of normal values in heterogeneous populations, extremes of age and patients with differing anthropometric profiles, has helped develop tables of normal values, thereby allowed ultrasound measurements to be judged against a reference standard, as has previously been established for nerve conduction studies.

Amyloid neuropathies.

Peripheral neuropathy is a common complication of many of the systemic amyloidoses. Although the cause of neuropathy is not entirely clear, it is likely related to amyloid deposition within the nerve. This may lead to focal, multifocal, or diffuse neuropathies involving sensory, motor and/or autonomic fibers. The presenting symptoms depend on the distribution of nerves affected. One of the most common phenotypes is sensorimotor polyneuropathy, which is characterized by symptoms of neuropathic pain, numbness, and in advanced cases weakness. Symptoms begin in the feet and ultimately progress to the proximal legs and hands. The most common focal neuropathy is a median neuropathy at the wrist, clinically known as carpal tunnel syndrome. Carpal tunnel symptoms may include pain and sensory disturbances in the lateral palm and fingers; hand weakness may ensue if the focal neuropathy is severe. Autonomic neuropathy may affect a variety of organ systems such as the cardiovascular, gastrointestinal, and genitourinary systems. Symptoms may be non-specific making the diagnosis of autonomic neuropathy more difficult to identify. However, it is important to recognize and distinguish autonomic neuropathy from diseases of the end-organs themselves. This article reviews the inherited and acquired amyloidoses that affect the peripheral nervous system including familial amyloid polyneuropathy, and primary, secondary and senile amyloidosis. We emphasize the clinical presentation of the neurologic aspects of these diseases, physical examination findings, appropriate diagnostic evaluation, treatment and prognosis.

Evaluation of central neuropathy in patients of chronic renal failure with normal hearing

Aims and Objective: The aim of the study was to study the involvement of inner ear and eighth nerve in patients of chronic renal failure (CRF) with normal hearing. Further, the mean absolute and inter-peak latencies were correlated with the duration of disease, blood urea level, and the severity of the disease. Materials and Methods: A total of 46 patients of CRF with normal hearing (29 males and 17 females) were included in the study. Majority of the patients were in 21 to 40 year age group. Mean absolute latencies of wave I, III, and V, and inter-peak wave latencies I-III, III-V, and I-V were calculated and compared with the mean wave latencies in 15 normal hearing age- and sex-matched control subjects. Student's t test was applied to evaluate the significance of delay in wave latencies. The patients were divided on the basis of the duration of disease (less than 2 years and more than 2 years), blood urea level (less than 200 mg% and more than 200 mg%), and severity of disease (Patients with glomerular filtration rate [GFR] less than 60 mL/min/1.73 m 2 but more than 10 mL and patients with GFR less than 10 mL/min/1.73 m 2). The significant differences between the hearing thresholds of these two groups were assessed using student's t test for unequal samples. Results: There was a statistically significant delay in absolute latencies of wave I, III, and V and inter-peak latencies I-III, III-V, and I-V. Mean wave latencies with values outside mean ± 2 SD of control were considered as abnormal. Abnormal absolute wave latencies and inter-peak latencies were present in 63.05% and 67.39% of cases, respectively. There was a significant delay in mean absolute latency of wave V and mean inter-peak latency of wave I-III, III-V, and I-V in patients of CRF with duration of disease more than 2 years as compared with patients of CRF with duration of disease less than 2 years. There was a significant delay in mean absolute latency of wave III and V and mean inter-peak latency of wave I-III, III-V, and I-V in patients of CRF with blood urea level more than 200 mg% as compared to patients of CRF with blood urea level less than 200 mg%. There was a significant delay in mean absolute latency of wave III and V and mean inter-peak latency of wave I-III, III-V, and I-V in patients of CRF with GFR less than 10 as compared with patients of CRF with GFR less than 60 but more than 10. Conclusion: The study suggests the involvement of central neural axis and auditory end organ in patients of CRF with normal hearing. It further establishes the role of brainstem evoked response audiometry in earlier detection of central neural axis and auditory end organ. As the duration of disease increases, inferior colliculus and auditory pathway is more prone to damage by uremic neuropathy. An increase in blood urea and decrease in GFR (severity of disease) leads to uremic neuropathy causing damage to superior olivary nucleus and inferior colliculus. Increased blood urea also causes delay in inter-peak latencies, suggesting diffuse axonal neuropathy in patients of CRF.

Voriconazole‐induced QT interval prolongation and torsades de pointes

The QT interval of the electrocardiogram (ECG) represents myocardial depolarization and repolarization. Prolongation of the QT interval corrected for heart rate (QTc interval) may result in life-threatening arrhythmias, such as polymorphous ventricular tachycardia (VT) of the torsades de pointes (TdP) type and ventricular fibrillation. 1 Long QT syndrome, sympathetic activation, sleep, marked bradycardia, a long list of certain drugs, hypocalcemia, hypokalemia, hypomagnesemia, myocarditis, diffuse myocardial disease, cerebrovascular injury, autonomic neuropathy, arsenic, organophosphates, severe malnutrition and HIV may prolong the QT interval. QTc interval is calculated using Bazett’s formula and should not exceed 440 ms except in infants. 1

Electrophysiological entrapment syndromes in chronic inflammatory demyelinating polyneuropathy

We do not know if peripheral nerves are more susceptible to entrapment syndromes in chronic inflammatory demyelinating polyneuropathy (CIDP). We studied 31 prospectively recruited patients with CIDP. We determined whether entrapment zones were more frequently affected by demyelination than adjacent segments. The median, ulnar, and fibular nerves were studied at the wrist, elbow, and fibular head bilaterally. Motor conduction velocity and motor conduction block were evaluated at entrapment sites and compared with contiguous segments. Demyelination was significantly more frequent for ulnar and fibular nerves away from entrapment sites. No significant difference was observed for median nerves. CIDP is not associated with increased frequency of demyelination at entrapment sites. The presence of diffuse entrapment neuropathies at compression sites does not favor a diagnosis of CIDP. Although electrophysiological study of entrapment sites is not diagnostically useful in CIDP, it may help distinguish it from other neuropathies and confirm clinically relevant, surgically treatable compressions.

Solitary localised hypertrophic neuropathy of the cauda equina

Localised hypertrophic neuropathy (LHN) is an uncommon non-neoplastic lesion, which is rare in the central nervous system. We report a patient with LHN of the cauda equina. Pre-operatively these lesions cannot be differentiated from schwannoma or other benign tumours or expansions of the nerve roots. Treatment is generally surgical, largely to confirm the diagnosis, and examination of the surgical specimen reveals an expansion of the nerve by “onion bulb” whorls of Schwann cells (S-100 positive). Multiple lesions may be associated with the generalised diffuse hypertrophic neuropathies or chronic inflammatory demyelinating polyneuropathies. It should be differentiated from intraneural perineuroma, which has a similar appearance but comprises perineural cells (epithelial membrane antigen positive). Adjuvant therapy is not required.