Clinical, electrophysiologic and pathologic findings in 10 patients with myotonic dystrophy 2

BACKGROUND

Myotonic dystrophy type 2 (DM2) is an autosomal dominant, multisystem disorder caused by a CCTG tetranucleotide repeat expansion located in intron 1 of the zinc finger protein 9 gene (ZNF9 gene) on chromosome 3q 21.3.

OBJECTIVES

To describe the clinical, electrophysiologic and pathologic findings in patients with myotonic dystrophy 2.

METHODS

We evaluated 10 patients genetically, clinically and electrophysiologically during the years 2007 to 2008.

RESULTS

All patients were of Jewish European ancestry. Among affected individuals, eight patients had symptoms of proximal muscle weakness, two had muscle pain, and two exhibited myotonia. On physical examination six patients had severe weakness of hip flexor muscles. Seven individuals underwent cataract surgery, and cardiac involvement was seen in one case. On the initial electromyographic (EMG) examination five patients demonstrated myotonic discharges; repeated studies showed these discharges in nine cases. Six muscle biopsies showed non-specific pathological changes. Seven patients had an affected first-degree relative with either a diagnosed or an undiagnosed muscular disorder consistent with an autosomal dominant trait.

CONCLUSIONS

DM2 may often present with proximal muscle weakness without myotonia. EMG may initially fail to show myotonic discharges, but these discharges may eventually show in most cases on repeated EMG. Thus, DM2 may be underdiagnosed and should be included in the differential diagnosis of adult patients of Jewish European ancestry presenting with proximal lower limb weakness.

The proteomic profile of hereditary inclusion body myopathy

Hereditary inclusion body myopathy (HIBM) is an adult onset, slowly progressive distal and proximal myopathy. Although the causing gene, GNE, encodes for a key enzyme in the biosynthesis of sialic acid, its primary function in HIBM remains unknown. The goal of this study was to unravel new clues on the biological pathways leading to HIBM by proteomic comparison. Muscle cultures and biopsies were analyzed by two dimensional gel electrophoresis (2-DE) and the same biopsy extracts by isobaric tag for relative and absolute quantitation (iTRAQ). Proteins that were differentially expressed in all HIBM specimens versus all controls in each analysis were identified by mass spectrometry. The muscle cultures 2-DE analysis yielded 41 such proteins, while the biopsies 2-DE analysis showed 26 differentially expressed proteins. Out of the 400 proteins identified in biopsies by iTRAQ, 41 showed altered expression. In spite of the different nature of specimens (muscle primary cultures versus muscle biopsies) and of the different methods applied (2D gels versus iTRAQ) the differentially expressed proteins identified in each of the three analyses where related mainly to the same pathways, ubiquitination, stress response and mitochondrial processes, but the most robust cluster (30%) was assigned to cytoskeleton and sarcomere organization. Taken together, these findings indicate a possible novel function of GNE in the muscle filamentous apparatus that could be involved in the pathogenesis of HIBM.

Chronic non-paroxysmal neuropathic pain - Novel phenotype of mutation in the sodium channel SCN9A gene

BACKGROUND

Gain-of-function mutations in the SCN9A gene (encoding to NaV1.7 voltage-gated sodium channel) cause two rare paroxysmal pain disorders: inherited erythromelalgia (IEM) and paroxysmal extreme pain disorder (PEDP). These phenotypes are characterized by episodic extreme localized pain with cutaneous autonomic signs. So far, no other phenotypes have been associated with mutation in the SCN9A gene.

OBJECTIVE

To investigate mutations in the SCN9A gene in patients with chronic non-paroxysmal neuropathic pain.

PATIENTS

9 patients with chronic severe unexplained neuropathic pain.

RESULTS

Of the nine patients one had predicted pathologic mutations in the SCN9A gene. This patient had a heterozygous change of n.4648 T-C in exon 27 resulting in a substitution of W1550R, a highly conserved amino acid, predicting damage in the transmembrane S2 region, repeat IV. This mutation was not found in 50 controls.

CONCLUSIONS

SCN9A mutations cause pain syndromes other than IEM and PEPD. These mutations should be considered in patients with resistant unexplained chronic neuropathic pain.

Prevalence of central nervous system diseases--a large retrospective cohort study of adolescents

At age sixteen, most Israeli nationals must undergo medical evaluation for compulsory military duty. All potential conscripts are referred to the Israel Defense Forces (IDF) recruiting office. Therefore, medical screening of a vast number of adolescents is performed, offering a unique opportunity to study the prevalence of neurological diseases in an entire age cohort. Hence, screening is not affected by diagnostic or methodological bias. We performed a retrospective neuroepidemiological large cohort study of adolescents from the database of the Israel Defense Forces recruiting office during the years 1998-2002. The survey included 409 492 adolescents, among them 162 079 (39.5%) females. The most prevalent diagnoses were: headache (754 per 10 000 adolescents), permanent brain damage (197 per 10 000), epilepsy (167 per 10 000) and movement and coordination disorders (36 per 10 000). These were followed by cranial nerve disorders, sleep disorders, cranio-spinal bone defects, and chronic progressive CNS disorders. The relative risk for male adolescents within the specific disease groups was higher for movement-coordination, sleep and cranial nerve disorders. Multivariate analysis revealed gender and severity prevalence and sex-grade, or year-grade interactions in the distinct groups of diseases. This study provides important information on the prevalence of neurological diseases in adolescents and demonstrates some significant epidemiological trends.

Long-term glutamate supplementation failed to protect against peripheral neurotoxicity of paclitaxel

Toxic peripheral neuropathy is still a significant limiting factor for chemotherapy with paclitaxel (PAC), although glutamate and its closely related amino acid glutamine were claimed to ameliorate PAC neurotoxicity. This pilot trial aimed to evaluate the role of glutamate supplementation for preventing PAC-induced peripheral neuropathy in a randomized, placebo-controlled, double-blinded clinical and electro-diagnostic study. Forty-three ovarian cancer patients were available for analysis following six cycles of the same PAC-containing regimen: 23 had been supplemented by glutamate all along the treatment period, at a daily dose of three times 500 mg (group G), and 20 had received a placebo (group P). Patients were evaluated by neurological examinations, questionnaires and sensory-motor nerve conduction studies. There was no significant difference in the frequency of signs or symptoms between the two groups although neurotoxicity symptoms presented mostly with lower scores of severity in group G. However, this difference reached statistical significance only with regard to reported pain sensation (P = 0.011). Also the frequency of abnormal electro-diagnostic findings showed similarity between the two groups (G: 7/23 = 30.4%; P: 6/20 = 30%). This pilot study leads to the conclusion that glutamate supplementation at the chosen regimen fails to protect against peripheral neurotoxicity of PAC.

Treatment of status epilepticus and acute repetitive seizures with i.v. valproic acid vs phenytoin

OBJECTIVE

To evaluate the efficacy and tolerability of the treatment with valproic acid (VPA) in patients with status epilepticus (SE) or acute repetitive seizures (ARS) comparing it with phenytoin (PHT) treatment.

MATERIALS AND METHODS

Patients with SE or ARS were treated in a consecutive manner with either VPA or PHT intravenously. The primary endpoint was defined as clinical seizure cessation; the secondary endpoint was evaluation of drug tolerability.

RESULTS

Seventy-four adult patients with SE or ARS participated in the study, 49 with VPA i.v. and 25 PHT i.v. In 43 (87.8%) of the VPA patients, the seizures discontinued, and no rescue medication was needed. Similar results were found in the PHT group in which seizures of 22 (88%) patients were well controlled. Side effects were found in 12% of the PHT group, and in none of the VPA group.

CONCLUSIONS

VPA i.v. seems to be effective and well tolerated in adult patients with SE or ARS.

Acute painful neuropathy induced by rapid correction of serum glucose levels in diabetic patients

We report on acute painful neuropathy following reduction of high serum glucose levels in six diabetic patients, aged 27-52 (5 males). Initial glucose levels ranging between 270 and 600 mg/dL decreased to 60-160 mg/dL following insulin, pharmacologic or dietary treatment. Four patients had long-standing untreated diabetes (3-5 years). All six patients experienced severe excruciating neuropathic pain 2-4 weeks after initiation of treatment. Pain was generalized in all, starting in the feet in 4 cases. Pain intensity prompted the use of combination therapy with various anti-neuropathic pain agents. Symptoms gradually improved in all patients, allowing discontinuation of symptomatic therapy within 3-8 months. We conclude that acute painful neuropathy can complicate the correction of high glucose levels in diabetic patients. Therefore, careful correction of glucose levels should be considered in patients with long-standing uncontrolled diabetes.

Lamotrigine and catamenial epilepsy

Catamenial epilepsy (CE) is characterized by epileptic seizures in the female occurring rhythmatically with the menstrual cycle. Hormonal mechanisms have been proposed as a cause of this epileptic form. Few reports about the efficacy of anti-epileptic drugs (AEDs) have been published. We studied prospectively women with CE who were treated with lamotrigine (LTG) for a period of 3 months in order to evaluate its efficacy, measuring the progesterone levels before and after LTG at the same time. LTG seemed to be efficacious in 66% of women, meaning the disappearance of seizures or reduction of 50% or more of the number of seizures. The reported side effects were few and mild, and the drug was well tolerated. Serum progesterone levels were found to rise during LTG treatment.

Steroid-responsive myopathy: immune-mediated necrotizing myopathy or polymyositis without inflammation?

OBJECTIVE

To describe the clinical course and steroid responsiveness of a patient with subacute proximal symmetric weakness, very high serum creatine kinase activity, and myopathic pattern with fibrillations in the electromyogram, whose muscle biopsy showed necrotizing myopathy, with practically no inflammation.

DESIGN

Case report.

SETTING

Academic research.

RESULTS

Diagnosis of muscular dystrophy was suggested; nevertheless, steroid treatment was initiated, and the patient recovered and gained normal strength. However, after a few years he stopped treatment, and all symptoms recurred. He developed severe proximal weakness of all limbs. Another biopsy showed similar findings, with no inflammation; still, he responded favorably to steroids and immunosuppressive medications. Currently on a low dose of prednisone and methotrexate, he has no neurological deficit.

CONCLUSION

The absence of inflammation in muscle biopsy may lead to misdiagnosis of muscular dystrophy; however, if the clinical impression is that of inflammatory myopathy, an immunomodulatory treatment should be initiated. During the past century, there has been much controversy about the diagnosis of polymyositis (PM). The debate is still ongoing. We present hereby a patient with typical course and clinical features of PM who underwent two muscle biopsies, several years apart, which showed necrotizing myopathy, practically without inflammation, leading to misdiagnosis of muscular dystrophy. This report brings up the dispute regarding the role of muscle biopsy in the diagnosis of PM.

Minocycline treatment in acute stroke: an open-label, evaluator-blinded study

BACKGROUND

Ischemic animal model studies have shown a neuroprotective effect of minocycline.

OBJECTIVE

To analyze the effect of minocycline treatment in human acute ischemic stroke.

METHODS

We performed an open-label, evaluator-blinded study. Minocycline at a dosage of 200 mg was administered orally for 5 days. The therapeutic window of time was 6 to 24 hours after onset of stroke. Data from NIH Stroke Scale (NIHSS), modified Rankin Scale (mRS), and Barthel Index (BI) were evaluated. The primary objective was to compare changes from baseline to day 90 in NIHSS in the minocycline group vs placebo.

RESULTS

One hundred fifty-two patients were included in the study. Seventy-four patients received minocycline treatment, and 77 received placebo. NIHSS and mRS were significantly lower and BI scores were significantly higher in minocycline-treated patients. This pattern was already apparent on day 7 and day 30 of follow-up. Deaths, myocardial infarctions, recurrent strokes, and hemorrhagic transformations during follow-up did not differ by treatment group.

CONCLUSIONS

Patients with acute stroke had significantly better outcome with minocycline treatment compared with placebo. The findings suggest a potential benefit of minocycline in acute ischemic stroke.

Dysferlinopathy in the Jews of the Caucasus: a frequent mutation in the dysferlin gene

Dysferlin encoding gene (DYS) is mutated in the autosomal recessive disorders Miyoshi myopathy, Limb Girdle Muscular Dystrophy type 2B (LGMD2B) and distal anterior compartment myopathy, causing dysferlin deficiency in muscle biopsy. Three ethnic clusters have previously been described in Dysferlinopathy: the Libyan Jewish population originating in the area of Tripoli, Italian and Spanish populations. We report another cluster of this muscular dystrophy in Israel among Jews of the Caucasus region. A genomic analysis of the dysferlin coding sequence performed in patients from this ethnic group, who demonstrated an absence of dysferlin expression in muscle biopsy, revealed a homozygous frameshift mutation of G deletion at codon 927 (2779delG) predicting a truncated protein and a complete loss of functional protein. The possible existence of a founder effect is strengthened by our finding of a 4% carrier frequency in this community. These findings are important for genetic counseling and also enable a molecular diagnosis of LGMD2B in Jews of the Caucasus region.

The Effect of Duloxetine on Primary Pain Symptoms in Parkinson Disease

OBJECTIVES

To study the effect of duloxetine (Cymbalta), a selective serotonin and norepinephrine reuptake inhibitor, on pain symptoms in Parkinson Disease (PD).

METHODS/PATIENTS

Twenty-three patients with PD with painful phenomena were treated with duloxetine for 6 weeks in an open-label design. Assessments were performed before and at treatment completion and consisted of a Visual Analogue Scale, the Brief Pain Inventory, Short-Form McGill Pain Questionnaire, Parkinson Disease Quality of Life Questionnaire-39-item version, and motor part of the Unified Parkinson Disease Rating Scale. Pain threshold was assessed by quantitative sensory tests.

RESULTS

Thirteen of the 20 patients who completed the study reported varying degrees of pain relief. The mean Visual Analogue Scale, Brief Pain Inventory, and Short-Form McGill Pain Questionnaire scores decreased significantly. There was no change in pain threshold after treatment.

CONCLUSIONS

Duloxetine seems to be effective for the treatment of central pain in PD.

Monotherapy of Lamotrigine Versus Carbamazepine in Patients With Poststroke Seizure

OBJECTIVES

The incidence of seizures is known to be high in the elderly. The most common cause of an unprovoked seizure in the elderly population is stroke. These patients require effective and well-tolerated antiepileptic treatment because they frequently experience other medical conditions and use other medications that can interact with the antiepileptic treatment. The aim of the study was to analyze the tolerability and efficacy of lamotrigine (LTG) versus sustained-release carbamazepine (CBZ) treatment in newly diagnosed symptomatic poststroke seizure.

METHODS

Sixty-four patients with a first post episode of seizures were randomized in a 1:1 ratio to either LTG or CBZ treatment and were followed up prospectively for up to 12 months for efficacy and tolerability of the drugs.

RESULTS

More patients in the LTG group were seizure-free (72%) versus those in the CBZ group (44%; P = 0.06), but the numbers did not reach statistical significance because of a relative small number of study patients. The number of patients who withdraw from the study because of adverse events was statistically significantly less in the LTG group (3%) compared with the CBZ group (31%; P = 0.02).

CONCLUSIONS

The LTG treatment in poststroke seizures versus CBZ treatment is a relatively better-tolerated drug and can be acceptable as initial treatment in this specific group of patients.

Evaluation of cutaneous autonomic innervation in idiopathic sensory small-fiber neuropathy

To evaluate the loss of autonomic nerve fibers in patients with clinical pure small-fiber sensory neuropathy, we performed skin punch biopsies in 17 and 15 age- and sex-matched controls. Biopsies were taken 10 cm above the lateral malleolus, and 5-mum sections were stained with hematoxylin and eosin and the panaxonal marker protein gene product (PGP) 9.5. Positively stained fibers, represented as dots, innervating the erector pili muscles, arterioles, and sweat glands (SG) were counted. The ratios between the number of nerve fibers and nuclei of each structure were calculated. The autonomic innervation was significantly reduced in the patients' group compared with controls in all the examined autonomic-innervated structures: SG (0.27 +/- 0.15 vs. 0.66 +/- 0.37, p = 0.001), arterioles (0.38 +/- 0.32 vs. 0.86 +/- 0.45, p=0.002), and the erector pili muscle (0.58 +/- 0.27 vs. 1.23 +/- 0.87, p = 0.036). Our results suggest that autonomic involvement occurs in patients with sensory small-fiber neuropathy and that punch skin biopsy using thin sections is a simple and convenient method to detect these dermal autonomic small-fiber abnormalities.

Clinical Correlates of Occipital Intermittent Rhythmic Delta Activity (OIRDA) in Children

PURPOSE

The clinical significance of occipital intermittent rhythmic delta activity (OIRDA) on the electroencephalogram has not been fully established. Recent studies suggest that this pattern occurs almost exclusively in children and is probably of epileptic origin in most cases. We sought to characterize the electrographic features and clinical correlates of occipital intermittent rhythmic delta activity.

METHODS

A review of 697 consecutive pediatric electroencephalograms detected occipital intermittent rhythmic delta activity in 24 studies. Mean patient age was 7.96 years.

RESULTS

Recent convulsions and absence seizures constituted the main indications for the study. Concomitant, independent epileptiform activity was noted in half of the cases. This activity was focal in all but one case. Conversely, in most cases of absence seizures, epileptiform activity intermixed with occipital intermittent rhythmic delta activity. Furthermore, the frequency of the occipital rhythmic discharges in studies of children with absences was generally faster (3-4 Hz) than in localization-related epilepsy (2-3 Hz). Most patients were awake when occipital intermittent rhythmic delta activity occurred. Chronic encephalopathy was seen in one child only. Analysis of neuroimaging studies in eight cases revealed no structural pathology associated with occipital intermittent rhythmic delta activity.

CONCLUSIONS

Occipital intermittent rhythmic delta activity is probably an epileptiform pattern, although it is noted occasionally in encephalopathic children. Its electrographic characteristics appear to differ between localization-related epilepsy and primary generalized epilepsy, particularly absence seizures.

Cervical paraspinal electromyography: normal values in 100 control subjects

The normal electromyographic values and the significance of spontaneous activity, when examining the cervical paraspinal muscles, has been studied rarely, and there are very few studies concerning this issue. To obtain muscle unit potential (MUP) reference values for cervical paraspinal muscles, we examined 100 volunteers. Spontaneous activity and the analysis of 20 MUPs in every individual were checked by the automated MUP analysis program. In those individuals ages 20 to 40 years, no spontaneous activity was observed, and in the ones ages 40 to 60 years and 60 years or older, fibrillations and/or positive sharp waves were seen in 8% and 92%, respectively. MUP values were found to be close to those of upper limb muscles. Age has no significant effect on MUP values, except for mean amplitude that was increased in individuals ages 60 to 80 years.Our findings suggest that fibrillations and positive sharp waves do not have much electrodiagnostic value in the study of cervical paraspinal muscles of middle-aged and elderly subjects, when it is an isolated finding, and there is a need for an extended electromyographic examination, including other muscles, to exclude radiculopathy. Automated MUP analysis is easily performed, and our results may serve as reference values.

Acute heroin-related neuropathy

Heroin-related peripheral nervous injury has scarcely been reported, mostly as compressive neuropathy. Rarely, other types of peripheral nervous system (PNS) injury have been recognized, such as plexopathy, polyradiculopathy, mononeuropathy, and rhabdomyolysis. These complications are usually not related to local trauma, but the nature of nerve injury remains unknown. Immunologic mechanisms have been proposed, although generally there is no laboratory evidence of inflammation and usually there is no improvement following steroid therapy. We describe six patients who developed acute PNS injury following intravenous or intranasal heroin self-administration with no evidence of compression injury or inflammation. Four patients had plexopathy (two lumbosacral and two brachial), and two had symmetric distal axonal sensorimotor neuropathy affecting the lower extremities. Of the six patients, five had concomitant rhabdomyolysis (creatine kinase, CK: 5,000-100,000 U/l) and one patient with brachial plexopathy had normal CK levels. The neurological deficit was noticed 3-36 h after heroin administration. Electromyography in five patients was consistent with sensorimotor axonal loss either confined to the affected plexus or with a diffuse distribution in the legs in the two patients with neuropathy. We propose that a toxic mechanism may be responsible for non-compression cases of acute neuropathy following heroin abuse.

Skin biopsy for assessment of autonomic denervation in Parkinson's disease

Autonomic dysfunction in Parkinson's disease (PD) is considered a late complication of the disease or an adverse effect of anti-parkinsonian medications. Morphological changes are demonstrated only by postmortem examination. The study objective was to evaluate peripheral autonomic neural involvement in PD using punch skin biopsy. The study sample included 22 patients (mean age 50 +/- 7.7 years, mean disease duration 5.3 +/- 3.8 years) and 19 controls. Four-millimeter skin biopsies were immunohistochemically stained with anti-PGP 9.5 antibody. Autonomic innervation of the blood vessels, sweat glands, and erector pili muscles was assessed and rated from 0 (normal) to 2 (severe). Cutaneous autonomic innervation was decreased in patients compared to controls. Semi quantitative analysis demonstrated reduced autonomic innervation of the blood vessels (1.0 +/- 0.8 vs. 0.42 +/- 0.8 in controls; p < 0.02), of sweat glands (0.95 +/- 0.67 vs. 0.47 +/- 0.61; p < 0.02) and of the erector pili muscles (1.06 +/- 0.55 vs 0.21 +/- 0.42; p < 0.001). This method demonstrates that the peripheral autonomic system is affected in PD at early stage of the disease and that autonomic involvement in PD may be more prevalent than previously thought.

A benign congenital myopathy in an inbred Samaritan family

We describe a novel form of myopathy in a mother and her two daughters from an inbred Samaritan family. The patients displayed severe neonatal hypotonia, lethargy and dysmorphic features. Motor milestones were delayed; however, the hypotonia and muscle weakness gradually improved during the first 2 years of life and independent walking was achieved by 18 months. The mother at the age of 23 years shows myopathic facies and minimal proximal weakness. Her intelligence is normal. Her muscle biopsy revealed central nuclei and disruption of the intermyofibrillary network with moth eaten and spiral fibers. Mutations in SMN, MTM1 and the myotonic dystrophy genes were excluded. We suggest this is a new benign form of congenital myopathy. Inheritance is probably autosomal recessive.

Acute steroid responsive small-fiber sensory neuropathy: a new entity?

Small-fiber neuropathy is often idiopathic and commonly follows a chronic course. Treatment is often effective in treating the core symptom of pain, but it has no effect on the pathologic process. We describe four patients with acute small-fiber neuropathy who responded dramatically to steroid therapy. All patients had acute onset neuropathic pain, normal nerve conduction studies, and evidence of small-fiber dysfunction in quantitative sensory testing and skin biopsy. Symptoms were distal and symmetrical in three patients and generalized in one patient. In two cases, the neuropathy presented as an erythromelalgia-like syndrome. Marked clinical improvement occurred 1-2 weeks after oral prednisone therapy was initiated. Three patients remained symptom free, and one patient experienced recurrence of neuropathy after prednisone was tapered.

Asymptomatic or minimally symptomatic hyperCKemia: histopathologic correlates

BACKGROUND

Persistent creatine kinase elevation is occasionally encountered in subjects without any clinical manifestation of a neuromuscular disorder or any condition known to be associated with increased serum CK levels. It is still unresolved whether extensive investigations and specifically a muscle biopsy should be performed in clinically normal individuals with elevated CK levels.

OBJECTIVE

To study the muscle pathology of patients with asymptomatic or minimally symptomatic hyperCKemia.

METHODS

The clinical and laboratory data of patients with persistent hyperCKemia and normal neurologic examination were reviewed and their muscle biopsies evaluated.

RESULTS

The study group included 40 patients aged 7-67 years; the male to female ratio was 3:1. Nineteen patients were completely asymptomatic, 20 had mild non-specific myalgia, and 1 had muscle cramps. Electromyography was performed in 27 patients and showed myopathic changes in 7 (26%). Abnormal muscle biopsy findings (e.g., increased variation in fiber size, increased number of central nuclei, and occasional degenerating fibers) were detected in 22 of the 40 patients (55%). No fat or glycogen accumulation was detected. Immunohistochemistry demonstrated abnormal dystrophin staining in 3 patients (8%), resembling the pathologic changes of Becker muscular dystrophy. No abnormal findings were detected on immunohistochemical staining for merosin, dysferlin, caveolin 3, or alpha and gamma sarcoglycans. The EMG findings did not correlate with the pathologic findings.

CONCLUSIONS

Abnormal muscle biopsies were found in 55% of patients with asymptomatic or minimally symptomatic hyperCKemia. Specific diagnosis of muscular dystrophy, however, was possible in only 8% of the patients.