A new perspective on vitamin B12 deficiency in rheumatology: a case-based review.

Vitamin B12 (cobalamin) deficiency is common in patients with rheumatic diseases. Pernicious anemia is a well-known cause, but recent reports suggest that autoimmune-derived deficiency may not be limited to this cause alone. Symptoms of low vitamin B12 concentration are often deceptive, mimicking and overlapping with symptoms of other conditions. Neuropsychiatric manifestations, anemia, and fatigue are frequently attributed to a rheumatic disease without further evaluation. In this study, we present three cases of patients with neuropathic pain, depression, fatigue, and muscle weakness, initially attributed to a rheumatic disease, which almost completely resolved after implementing vitamin B12 supplementation. Furthermore, we provide an overview of current scientific reports regarding the potential use of cobalamin in rheumatology. Treatment of pain and neuropathy, often very challenging in long-lasting rheumatic diseases, can be more effective after a course of vitamin B12, even when no apparent deficiency is detected in laboratory tests. Considering recent research demonstrating vitamin B12's nerve-protecting properties, we recommend that physicians should assess vitamin B12 levels early in the diagnostic process of rheumatic diseases. In specific cases, physicians should consider cobalamin supplementation regardless of vitamin B12 serum concentration.

[Diagnostic workup for polyneuropathy]. / Diagnostische Abklärung bei Polyneuropathie.

Polyneuropathy is a disease of the peripheral nervous system that usually results in distally emphasized, often symmetrical sensory and motor stimulation and deficits. These are often extremely painful. They can be divided into hereditary and acquired causes; inflammatory and infectious causes should be further differentiated among the acquired causes. A careful diagnostic workup is essential. Clinical signs and distribution patterns of symptoms can often already provide clues to the underlying aetiology. This review describes this workup, which in addition to the medical history and clinical examination always includes thorough laboratory diagnostics, electrophysiological examination and cerebrospinal fluid diagnostics. In individual cases, further diagnostic steps may be necessary in order to make the correct diagnosis.

Predictive value of ultrasonography in polyneuropathy diagnosis: electrophysiological and ultrasonographic analysis.

Peripheral neuropathy may cause serious complications such as foot ulcers and Charcot joint which can prevent by early diagnosis. We aimed to analyze the diagnostic value of ultrasonographic measurements of nerves and muscles in distal symmetric axonal polyneuropathy (DSAP). Study included 51 DSAP patients and 51 controls. Nerve conduction studies were performed. Median, ulnar, tibial, superficial peroneal, and sural nerves and the abductor pollicis brevis (APB), abductor digiti minimi (ADM), first dorsal interosseous (FDI), extensor digitorum brevis (EDB), abductor hallucis (AH) and tibialis anterior (TA) muscles were evaluated with ultrasound. The Toronto clinical scoring system (TCSS) was used to assess the severity of neuropathy. The median, ulnar, and tibial nerve cross-sectional areas (CSA) were higher in the DSAP group (p = 0.025, p = 0.011, p < 0.001 respectively) while superficial peroneal and sural nerve CSAs were not differed. Only AH and EDB ultrasonographic findings from the muscles differed between the two groups. Effect of diabetes and DSAP on sonographic findings were assessed with two-way ANOVA. Results indicated that only DSAP had a significant effect on sonographic nerve and muscle examination. The area under the ROC curve was 0.831 ± 0.042 for tibial nerve CSA (p < 0.001) with a cut-off value of 15.5 mm2 (sensitivity 74% and specificity 83%). Median, ulnar and tibial nerve CSAs were found to be larger in polyneuropathy patients and they were associated with the clinical and electrophysiological severity of polyneuropathy. ROC analysis showed that tibial nerve CSA may have a predictive value in the diagnosis of DSAP.

Urodynamic autonomic bladder dysfunction in women with complex chronic pelvic pain is associated with small fiber polyneuropathy.

AIMS: Small fiber neuropathy/polyneuropathy (SFN) has been found to be present in 64% of complex (refractory or multisystem) chronic pelvic pain (CPP) patients. The small fiber dysfunction seen in SFN can negatively impact autonomic control of micturition in addition to pain. This study investigated the clinical association of autonomic dysfunction (detrusor underactivity and primary bladder neck obstruction [BNO]) on video urodynamics (VUDS) with SFN in patients with CPP. METHODS: This was a retrospective observational study, querying data from patients with complex CPP. Inclusion criteria were: the presence of complex (refractory or multisystem) CPP, and completion of both (1) subspecialty autonomic neurology evaluation for SFN and (2) high-quality VUDS performed according to ICS standards. Autonomic bladder dysfunction (BNO or detrusor underactivity) on VUDS was compared to the presence of SFN. RESULTS: Thirty-two female patients with complex CPP met criteria. Of the 32, 23 (72%) were found to have SFN. Patient with autonomic bladder dysfunction (BNO or detrusor underactivity) were more likely to have SFN (OR = 9.5 [95% CI: 1.641, 55.00], p = 0.007). Post-void residual volume was higher in the SFN group (p = 0.011 [95% CI: 13.12, 94.0]) and symptoms of urge urinary incontinence were more likely to be present (p = 0.000 [95% CI: -3.4, -1.25]). CONCLUSIONS: Patients with complex CPP with autonomic bladder dysfunction are more likely to have SFN. This suggests patients with complex CPP should be considered for diagnosis and treatment of SFN, particularly if BNO or detrusor underactivity is noted on VUDS evaluation.

Not so Shocking: Electromyography in Pediatrics Remains Feasible and Diagnostically Useful.

BACKGROUND: Electrodiagnostic testing, including nerve conduction studies (NCS) and electromyography (EMG), assists with localizing lesions within the peripheral nervous system. NCS/EMG in children can be technically challenging and its relevance has been questioned in the era of affordable genetic testing. NCS/EMG provides information that may not be available in the examination of a young or developmentally delayed child. Our goal was to review the volume and referral sources of NCS/EMG studies and evaluate its feasibility and diagnostic yield at a pediatric tertiary care hospital. METHODS: Retrospective chart review of NCS/EMG studies done in pediatric patients at one center from 2014 to 2019. RESULTS: A total of 725 studies were performed, with a median age of 13.2 years (range 0-18 years). The annual number of studies remained constant throughout the study period. Neurologists and surgeons were the most common referral sources, but an increased number of referrals from geneticists was observed. Most (94.5%) NCS/EMG were done on awake patients, with only 5.5% of studies being terminated early due to tolerability of the patient. Of all studies, 326/725 (44%) demonstrated a neuromuscular abnormality, of which 63.5% (207/326) were acquired conditions. Mononeuropathies and polyneuropathies were the most common electrophysiologic diagnoses. DISCUSSION: Our study indicates that NCS/EMG remains a useful diagnostic tool, both for the diagnosis of acquired neuromuscular conditions but also as an adjunct for interpreting genetic results, as indicated by the recent increase in referrals from geneticists. Overall NCS/EMG is well tolerated and able to be performed without sedation in children of all ages.

Subgrouping of Peripheral Neuropathic Pain Patients According to Sensory Symptom Profile Using the Korean Version of the PainDETECT Questionnaire.

BACKGROUND: A culturally validated Korean version of the PainDETECT Questionnaire (PD-Q) was used to identify neuropathic pain components (NeP) in patients suffering from chronic pain. The purpose of this study was to determine if the Korean PD-Q can be used to subgroup patients with peripheral NeP according to sensory symptom profiles. METHODS: This study included 400 Korean patients with peripheral neuropathic pain diagnosed as probable or definite NeP. The total scores and subscores for each item in PD-Q were transformed into a Z-score for standardization. Hierarchical cluster analysis was performed to identify clusters of subjects by PD-Q scores. RESULTS: The mean total PD-Q score of the study participants was 14.57 ± 6.46. A hierarchical cluster analysis identified 5 clusters with distinct pain characteristic profiles. Cluster 1 had relatively severe burning and tingling sensations. The mean total PD-Q score for cluster 2 was the lowest of the 5 clusters. Cluster 3 tended to be vulnerable to pain in response to cold/heat stimulation. Cluster 4 showed relatively severe pain induced by physical stimuli, such as light touch or slight pressure. Cluster 5 had high scores for all NeP symptoms. CONCLUSION: This study demonstrates the ability of patients to cluster by symptoms using the Korean PD-Q. Subgrouping of peripheral neuropathic pain by sensory symptom profile may be useful in making effective drug treatment decisions.

COVID-19 Associated Guillain-Barré Syndrome: A Report of Nine New Cases and a Review of the Literature.

BACKGROUND: Guillain-Barré syndrome (GBS)-a rare condition characterized by acute-onset immune-mediated polyneuropathy-has been registered as a neurological manifestation of COVID-19, suggesting a possible link between these two conditions. METHODS: We report a case series of patients with COVID-19-related GBS hospitalized in the Neurology Department of Colentina Clinical Hospital, Bucharest, Romania, between March 2020 and March 2021. Several variables were analyzed, such as the mean interval between the onset of COVID-19 symptoms and neurological ones, clinical features, treatment course, and outcome. Further on, we conducted a thorough literature review based on the PubMed and ScienceDirect scientific databases. RESULTS: A total of 9 COVID-19 patients developed symptoms of GBS, out of which in 7, it manifested as an acute inflammatory demyelinating polyneuropathy (AIDP). Five patients presented respiratory failure, 2 requiring mechanical ventilation. All patients received a course of intravenous immunoglobulins, 2 additionally requiring plasma exchange. Upon discharge, all but 1 patient (who had not regained the ability to walk) had a positive outcome, and 1 died during admission. In the literature review, we analyzed the published sources at the time of writing. CONCLUSIONS: A link between COVID-19 and GBS might be possible; therefore, increased vigilance is required in the early identification of these cases for prompt diagnosis and treatment. Some notable differences such as an earlier onset of GBS symptoms, higher respiratory dysfunction, and higher mortality rates in COVID-19 patients have been observed between the presentation of GBS in the context of COVID-19 and GBS of other causes.

Pedobarographic Statistical Parametric Mapping may identify specific plantar pressure patterns in patients with diabetes mellitus among different degrees of peripheral neuropathy: A pilot study.

AIMS: Peripheral neuropathy (PN) in patients with diabetes can lead to changes in the distribution of plantar pressure during walking, which can be recorded with pedobarography. Compared to traditional spatial data reduction analysis, the pedobarographic Statistical Parametric Mapping (pSPM) allows comparison of the footprints with the advantage that sub-regions do not need to be defined a priori. Aim of the study was to test the potential of pSPM in identifying specific distribution of spatial pressure in different stages of PN. METHODS: PN was defined according to usual tools (i.e., tendon reflexes and sensory tests). Four groups were compared: patients with diabetes without PN (n = 24; 239 steps); with signs of mild PN (n = 12; 117 steps); with signs of severe PN (n = 6; 52 steps) and a control group without diabetes (n = 12; 124 steps). Traditional spatial data reduction and pSPM were performed to compare plantar pressures in the different groups. RESULTS: In patients with PN, traditional spatial data reduction analysis showed lower plantar pressures with PN severity. pSPM analysis is able to better define the initial changes: mild PN patients presents higher pressures on the anterior side of the metatarsal heads compared to patients without neuropathy. Patients with severe PN are characterised by higher pressures under the medial foot arch compared to other groups. CONCLUSIONS: pSPM may identify specific features of plantar pressure distribution during walking in patients with mild PN and may become a useful screening tool for a timely identification of this complication.

[Diagnostics and therapy of neuropathic pain]. / Diagnostik und Therapie neuropathischer Schmerzen.

Neuropathic pain is pain caused by a lesion or disease of the somatosensory nervous system. Scientific studies have shown that neuropathic pain is the result of complex altered signalling processes in the peripheral and central nervous system. Current forms of treatment of neuropathic pain are causally oriented but also aim at symptomatic analgesia by pharmacological and nonpharmacological methods. Furthermore, psychological pain management techniques are used in a supportive role. This review summarizes the contemporary diagnostics of neuropathic pain using frequent diseases as examples and presents the evidence from randomized controlled trials on the treatment of neuropathic pain. Treatment guidelines for pharmacological management of neuropathic pain include evidence-based use of antidepressants, anticonvulsants, opioids, capsaicin and lidocaine.

[Severe epigastric pain in a 59-year-old patient]. / Massivste epigastrische Schmerzen bei einem 59-jährigen Patienten.

Abdominal pain is a frequent cause of consultation to doctors' offices and emergency rooms. The most common differential diagnoses can be confirmed with readily available, cost-effective, and low-risk diagnostic tools such as laboratory tests, ultrasound, or gastroscopy. Additional diagnostic tests are required to exclude rare causes such as small, solid, or hematological malignancies, metabolic disorders, or polyneuropathies of varying origin. In the following, we present the case of a patient with severe epigastric pain due to neuroborreliosis, and recapitulate the diagnostic steps for clarifying abdominal pain using this example.

Electrodiagnostic accuracy in polyneuropathies: supervised learning algorithms as a tool for practitioners.

OBJECTIVE: The interpretation of electrophysiological findings may lead to misdiagnosis in polyneuropathies. We investigated the electrodiagnostic accuracy of three supervised learning algorithms (SLAs): shrinkage discriminant analysis, multinomial logistic regression, and support vector machine (SVM), and three expert and three trainee neurophysiologists. METHODS: We enrolled 434 subjects with the following diagnoses: chronic inflammatory demyelinating polyneuropathy (99), Charcot-Marie-Tooth disease type 1A (124), hereditary neuropathy with liability to pressure palsy (46), diabetic polyneuropathy (67), and controls (98). In each diagnostic class, 90% of subjects were used as training set for SLAs to establish the best performing SLA by tenfold cross validation procedure and 10% of subjects were employed as test set. Performance indicators were accuracy, precision, sensitivity, and specificity. RESULTS: SVM showed the highest overall diagnostic accuracy both in training and test sets (90.5 and 93.2%) and ranked first in a multidimensional comparison analysis. Overall accuracy of neurophysiologists ranged from 54.5 to 81.8%. CONCLUSIONS: This proof of principle study shows that SVM provides a high electrodiagnostic accuracy in polyneuropathies. We suggest that the use of SLAs in electrodiagnosis should be exploited to possibly provide a diagnostic support system especially helpful for the less experienced practitioners.

Performance and Self-reported Functioning of People With Chronic Idiopathic Axonal Polyneuropathy: A 4-Year Follow-up Study.

OBJECTIVE: To describe the course of performance of activities (observed and self-reported) of people with chronic idiopathic axonal polyneuropathy (CIAP) over 4 years and to assess the associations with muscle strength, sensory function, and psychological personal factors (intention, perceived behavior control [PBC], and feelings of depression or anxiety). DESIGN: Prospective observational study with measurement at baseline, 6 months, 1 year, and 4 years. SETTING: Outpatient neurology clinic. PARTICIPANTS: People with CIAP (N=92). MAIN OUTCOME MEASURES: Walking was measured using the shuttle-walk test (SWT), a pedometer (mean step count/d), and the "physical functioning" subscale of the Short Form-36 questionnaire. Muscle strength and sensory function were measured using a MicroFET handheld dynamometer and the Sensory Modality Sum score. Personal factors were assessed with the Hospital Anxiety and Depression Scale, and intention and PBC were assessed with a protocolized questionnaire. RESULTS: Multilevel model analysis showed a significant decrease over time in mean scores in performance of activities (SWT, step count), which was associated with older age and loss of muscle strength (SWT: ß=73.392, step count: ß=676.279, P<.001). Limitations in self-reported functioning (physical functioning) significantly increased and were associated with older age (ß=-0.916, P=.001), increased comorbidity (ß=-6.978, P=.024), loss of muscle strength (ß=7.074, P<.001), low PBC (ß=0.744, P<.001), and increased feelings of depression (ß=1.481, P<.001). CONCLUSIONS: Performance of activities of people with CIAP decreased over time (SWT, step count, physical functioning). Older age, loss of muscle strength, comorbidity, feelings of depression, and low perceived behavior control were associated with this decrease. However, there were considerable individual differences.

Beta-thalassemia major complicated by intracranial hemorrhage and critical illness polyneuropathy.

Intracranial hemorrhage (ICH) is rarely seen in patients with thalassemia. A seven-year-old male, known case of beta-thalassemia major, on irregular packed cell transfusions (elsewhere) and non-compliant with chelation therapy, presented with congestive cardiac failure (Hb-3 gm/dl). He received three packed red cell transfusions over 7 days (cumulative volume 40 cc/kg). On the 9th day, he developed projectile vomiting and two episodes of generalized tonic-clonic convulsions with altered sensorium. He had exaggerated deep tendon reflexes and extensor plantars. CT-scan of brain revealed bilateral acute frontal hematoma with diffuse subarachnoid hemorrhage (frontal and parietal). Coagulation profile was normal. CT-angiography of brain showed diffuse focal areas of reduced caliber of anterior cerebral, middle cerebral, and basilar and internal carotid arteries (likely to be a spasmodic reaction to subarachnoid hemorrhage). He required mechanical ventilation for 4 days and conservative management for the hemorrhage. However, on the 18th day, he developed one episode of generalized tonic-clonic convulsion and his sensorium deteriorated further (without any new ICH) and required repeat mechanical ventilation for 12 days. On the 28th day, he was noticed to have quadriplegia (while on a ventilator). Nerve conduction study (42nd day) revealed severe motor axonal neuropathy (suggesting critical illness polyneuropathy). He improved with physiotherapy and could sit upright and speak sentences at discharge (59th day). The child recovered completely after 3 months. It is wise not to transfuse more than 20 cc/kg of packed red cell volume during each admission and not more than once in a week (exception being congestive cardiac failure) for thalassemia patients.

[Neuropathic pain syndromes and channelopathies]. / Neuropathische Schmerzsyndrome bei Ionenkanalerkrankungen.

BACKGROUND: The causes for neuropathic pain are manifold and remain unexplained in the majority of cases. In recent years a growing number of pain syndromes have been attributed to mutations in genes encoding voltage-gated sodium channels. Hence, this group of rare diseases should be considered in the differential diagnostics of neuropathic pain. MATERIAL AND METHODS: Evaluation of topic-related literature and discussion of own experiences as well as consideration of current guidelines. RESULTS: Alterations in the electrical excitability of nociceptive neurons by pathogenic mutations in sodium channels lead to disease patterns, such as small fiber neuropathy and various pain syndromes. This article summarizes the knowledge on these genetic diseases and discusses the differential diagnosis of neuropathic pain. Current treatment concepts are presented and the predominantly experimental approaches to targeted modulation of sodium channels are discussed. CONCLUSION: The treatment of patients with chronic neuropathic pain requires interdisciplinary cooperation and is often difficult due to an unsatisfactory treatment response. Increasing knowledge on rare genetically determined channelopathies can contribute to the development of novel pharmaceuticals since ion channels are central players in the processing of pain.

What is the diagnostic accuracy of single nerve conduction studies and muscle ultrasound to identify critical illness polyneuromyopathy: a prospective cohort study.

BACKGROUND: Critical illness polyneuromyopathy (CIPNM) is a major cause of weakness in intensive care unit (ICU) patients, but current diagnostic tests are limited. We evaluated the generalizability and validity of single nerve conduction studies (NCS) and muscle ultrasound testing to identify CIPNM, and we also assessed the ability of muscle ultrasound to prognosticate patient outcomes. METHODS: This was a prospective cohort study of mechanically ventilated medical, cardiac, surgical, and neurosurgical ICU patients. We performed weekly strength testing, NCS, electromyography (EMG), and muscle ultrasound. We calculated the sensitivity, specificity, and other test characteristics of single NCS and muscle ultrasound, and we used multivariable regression models to assess the prognostic ability of muscle ultrasound. RESULTS: Ninety-five patients were enrolled. The incidence of probable CIPNM was 18% and did not differ significantly by type of ICU (p = 0.49). For diagnosing probable CIPNM, the peroneal motor NCS had a sensitivity of 94% (95% confidence interval (CI) 71-100%) and specificity of 91% (95% CI 82-96%), the sural sensory NCS had a sensitivity of 100% (95% CI 80-100%) and specificity of 42% (95% CI 31-54%), and abnormal muscle ultrasound echogenicity had a sensitivity of 82% (95% CI 48-98%) and specificity of 57% (95% CI 43-70%). Abnormal echogenicity was associated with reduced likelihood of discharge to home (9% vs 50%, p = 0.0001), fewer ICU-free days (median 3 (interquartile range 0-15) days vs 16 (9.3-19.3) days, p = 0.0002), and increased ICU mortality (42% vs 12%, p = 0.004). CONCLUSIONS: In a diverse cohort of critically ill patients, single NCS and muscle ultrasound achieved diagnostic accuracy for patients at risk for CIPNM. The routine utilization of these tests could be beneficial for all critically ill patients at risk for CIPNM.

Neuropathic pain is not adequately treated in the older general population: Results from the KORA F4 survey.

PURPOSE: We evaluated the pharmacological treatment of distal sensorimotor polyneuropathy (DSPN) among older subjects from the general population. METHODS: The study included subjects aged 61 to 82 years from the KORA F4 survey (2006-2008). DSPN was defined as the presence of bilaterally impaired foot-vibration perception and/or bilaterally impaired foot-pressure sensation. Pain intensity was assessed with the painDETECT questionnaire. RESULTS: From the included 1076 older persons, 172 (16%) persons reported pain in the lower extremities and DSPN was present in 150 (14%) subjects. Forty-eight people with pain in the lower extremities reported DSPN. Only 38% of the subjects with DSPN reporting an average pain level of ≥4 during the past 4 weeks received medical treatment, predominantly nonsteroidal anti-inflammatory drugs (NSAIDs 20% and opioids 12%). The medication of choice for neuropathic pain, antidepressants, anticonvulsants, and opioids was relatively being underused. However, opioids and neuropathy preparations were prescribed preferably for subjects with painful DSPN. CONCLUSIONS: In the older general population, only a small proportion of subjects with painful DSPN receive analgesic pharmacotherapy. Although not recommended by guidelines for the treatment of neuropathic pain, NSAIDs were the most frequently used class of analgesic drugs.

Recurrent Guillain-Barré Syndrome Following Urinary Tract Infection by Escherichia coli.

Recurrent Guillain-Barré syndrome (GBS) is a rare, immune-mediated disease of the peripheral nervous system. It has been reported to occur at intervals ranging from four months to 10 years; published case studies suggest that 1%-6% of patients who have had GBS will experience recurrent attacks. The most commonly identified infections coinciding with GBS are Campylobacter jejuni, Haemophilus influenzae, Mycoplasma pneumonia, and cytomegalovirus, while an antecedent infection with Escherichia coli is very uncommon. In this case report, we present a rare episode of recurrent GBS, which followed a urinary tract infection (UTI) by E. coli, and an accompanying literature review. A 75-year-old woman with a prior history of acute motor axonal neuropathy (AMAN), a subtype of GBS, presented with subsequent weakness of limbs and areflexia following 10 days of fever, frequency, and dysuria. Base on nerve conduction studies, cerebrospinal fluid analysis and other clinical investigation, we diagnosed the patient with recurrent GBS caused by E. coli. The patient recovered with mild subjective weakness following treatment of intravenous immunoglobulin with ceftriaxone. We suggest that E. coli causes UTI could be one of the diverse trigger factors involved in recurrent GBS.

[What gnaws at the heart and gets on the nerves]. / Was am Herzen nagt und auf die Nerven geht.

Transthyretin is a transport protein for thyroxine and retinol-binding protein, which is mainly produced in the liver. Hereditary transthyretin-related amyloidosis (ATTR) is caused by one of more than 120 point mutations in the transthyretin gene and inherited as an autosomal dominant disorder. The mutations cause a reduction in the stability of the tetrameric structure and dissociation into dimers and monomers as the rate-limiting step in amyloid formation is promoted. Clinical symptoms are related to the specific mutation, the age of onset, the ethnic background and environmental factors. The nerves, heart, eyes and intestines are paticularly affected. In general, two different age peaks are observed. An accumulation occurs at the age of 25-35 years with predominantly neurological symptoms. The second peak occurs between the ages of 55 and 65 years and is commonly associated with cardiac involvement with or without polyneuropathy. Characteristic for the nerve involvement are the symmetrical small fiber polyneuropathy and an autonomous polyneuropathy. The typical picture of cardiac involvement is biventricular hypertrophy with diastolic dysfunction finally resulting in restrictive cardiomyopathy. In addition to the symptomatic treatment for the alleviation of individual organ disorders, for many years liver transplantation was the only causal therapy of ATTR amyloidosis. Since 2011 tafamidis, a highly selective transthyretin stabilizer, has been the first drug approved for treatment of ATTR resulting in reduction of the progression of polyneuropathic symptoms. Other therapeutic approaches to reduce amyloid formation (patisiran and inotersen) effectively reduce transthyretin blood levels, leading to a reduction in polyneuropathy and improved quality of life. The approval is expected in 2018.

MULTIFOCAL MOTOR NEUROPATHY: CASE REPORTS.

- Multifocal motor neuropathy (MMN) is a chronic demyelinating neuropathy mainly characterized by multifocal distribution; affecting only motor nerve fibers of two or more peripheral nerves, with the absence of symptoms and signs of upper motor neuron; chronic, sometimes cascading progressive course; demyelination with partial block of motor conduction; immune-mediated pathogenesis and good response to intravenous immunoglobulin treatment (IVIG). The diagnosis of MMN is based on clinical, laboratory and electrophysiological characteristics. Steroids are ineffective in MMN and may lead to worsening of the disease. Similarly, therapeutic plasma exchange is negligibly effective in this neuropathy. However, more than 80% of patients with MMN experience improvement after IVIG. We present our three cases of MMN with positive response to IVIG.

Long-Term Effective Thalamic Deep Brain Stimulation for Neuropathic Tremor in Two Patients with Charcot-Marie-Tooth Disease.

BACKGROUND: It has been described that many Charcot-Marie-Tooth syndrome type 2 patients are affected by a very disabling type of tremor syndrome, the pathophysiology of which remains unclear. Deep brain stimulation (DBS) has been successfully applied to treat most types of tremors by implanting electrodes in the ventral intermediate nucleus of the thalamus (Vim). METHODS: We used DBS applied to the Vim in 2 patients with severe axonal inherited polyneuropathies who developed a disabling tremor. RESULTS: Both patients responded positively to stimulation, with a marked reduction of the tremor and with an improvement of their quality of life. CONCLUSION: We report 2 cases of tremor associated with a hereditary neuropathy with a good response to DBS.