Anaesthesia challenges of a parturient with paramyotonia congenita and terminal filum lipoma presenting for labour and caesarean section under epidural anaesthesia - a case report.

BACKGROUND: Paramyotonia congenita is a rare autosomal dominant myopathy which presents with periodic weakness due to cold and exercise. It is caused by mutations of the SCN4 gene which encodes the sodium channel in skeletal muscles. CASE PRESENTATION: We report a full term obstetric patient with both paramyotonia congenita and terminal filum lipoma who presents for induction of labour followed by an emergency caesarean section performed under epidural anesthesia. Her recovery is subsequently complicated by a 3-day history of postpartum paraparesis attributed to hypokalemic periodic paralysis. CONCLUSION: We describe the perioperative anesthesia considerations and challenges in this case with a review of the current literature. This case report highlights the importance of early proactive and collaborative multidisciplinary approach, maintaining normal temperature and electrolytes with a heightened vigilance for muscle-related perioperative complications.

Paramyotonia Congenita with Persistent Distal and Facial Muscle Weakness: A Case Report with Literature Review.

BACKGROUND: Paramyotonia congenita (PC; OMIM 168300) is a non-dystrophic myotonia caused by mutations in the SCN4A gene. Transient muscle stiffness, usually induced by exposure to cold and aggravated by exercise, is the predominant clinical symptom, and interictal persistent weakness is uncommon. CASE REPORT: We report a family with a history of PC accompanied by persistent hand muscle weakness with masticatory muscle involvement. Persistent weakness was exacerbated with age, and MR analysis showed marked atrophy of temporal, masseter, and finger flexor muscles with fatty replacement. The PC causative mutation T1313M in the SCN4A gene was prevalent in the family. Administration of acetazolamide chloride improved clinical symptoms and the results of cold and short exercise tests. Phenotypic variation within the family was remarkable, as the two younger affected patients did not present with persistent weakness or muscle atrophy. CONCLUSIONS: PC associated with the T1313M mutation is a possible cause of persistent distal hand weakness.

Clinico-Genotypic Correlation: Recurrent Attacks of Paralysis and Skeletal Muscle SCN4A Mutation (p.Ile693Thr).

Skeletal sodium channel mutations have been known to demonstrate a multitude of clinical manifestations of which one such commonly known entity is paramyotonia congenita. We describe the clinical features of proband in our case report and the various phenotypic manifestations described with the mentioned mutation from different centres. Our case serves to highlight the heterogeneity that exists in SCN4A mutations and the possible effect of other genetic/environmental factors in determining the final phenotype.

Trouble at the junction: When myopathy and myasthenia overlap.

Although myopathies and neuromuscular junction disorders are typically distinct, their coexistence has been reported in several inherited and acquired conditions. Affected individuals have variable clinical phenotypes but typically display both a decrement on repetitive nerve stimulation and myopathic findings on muscle biopsy. Inherited causes include myopathies related to mutations in BIN1, DES, DNM2, GMPPB, MTM1, or PLEC and congenital myasthenic syndromes due to mutations in ALG2, ALG14, COL13A1, DOK7, DPAGT1, or GFPT1. Additionally, a decrement due to muscle fiber inexcitability is observed in certain myotonic disorders. The identification of a defect of neuromuscular transmission in an inherited myopathy may assist in establishing a molecular diagnosis and in selecting patients who would benefit from pharmacological correction of this defect. Acquired cases meanwhile stem from the co-occurrence of myasthenia gravis or Lambert-Eaton myasthenic syndrome with an immune-mediated myopathy, which may be due to paraneoplastic disorders or exposure to immune checkpoint inhibitors.

A unique presentation and etiology of neonatal paradoxical vocal fold motion.

We present a unique case of intermittent paradoxical vocal fold motion (PVFM) as the presenting symptom of a rare underlying neuromuscular disorder in a neonate. Paramyotonia congenita (PC) is an autosomal dominant condition that typically presents in infancy with myotonic episodes affecting the skeletal muscles. Our patient developed intermittent episodes of stridor quickly progressing to apnea shortly after birth that were marked by PVFM on laryngoscopy, ultimately leading to the diagnosis of a previously unrecognized mutation in SCN4A, the gene responsible for PC.

Open-label trial of ranolazine for the treatment of paramyotonia congenita.

INTRODUCTION: Paramyotonia congenita (PMC) is a nondystrophic myotonic disorder that is believed to be caused by a defect in Nav 1.4 sodium channel inactivation. Ranolazine, which acts by enhancing slow inactivation of sodium channels, has been proposed as a therapeutic option, but in vivo studies are lacking. METHODS: We conducted an open-label, single-center trial of ranolazine to evaluate efficacy and tolerability in patients with PMC. Subjective symptoms of stiffness, weakness, and pain as well as clinical and electrical myotonia were evaluated. Baseline measures were compared with those after 4 weeks of treatment with ranolazine. RESULTS: Ranolazine was tolerated well without any serious adverse events. Both subjective symptoms and clinical myotonia were significantly improved. Duration of myotonia was reduced according to electromyography, but this change was not statistically significant in all tested muscles. DISCUSSION: Our findings support the use of ranolazine as a treatment for myotonia in PMC and suggest that a randomized, placebo-controlled trial is warranted. Muscle Nerve 59:240-243, 2019.

Síndrome de Sjögren con presentación atípica / Unusual presentation of Sjögren syndrome

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Narcolepsia y olor: resultados preliminares / Narcolepsy and odour: preliminary report

Objetivo. El propósito de este estudio es probar la hipótesis de un olor corporal característico en narcolépticos como indicador de diagnóstico. Métodos. Se testan muestras de sudor de 12 narcolépticos y 22 controles sanos de forma independiente por 2 perros entrenados. Su detección, positiva o negativa, se compara con el diagnostico gold standard de narcolepsia. Ni adiestrador ni perros conocían el tipo de muestra seleccionada o su emplazamiento en el dispositivo de búsqueda. Doce pacientes con narcolepsia, de ambos sexos y distintas edades, reclutados entre abril de 2011 y junio de 2012 y diagnosticados según criterios estándar mediante su historia clínica y la polisomnografía nocturna seguida de test de latencia múltiple del sueño, conforman el grupo de pacientes. El grupo control está formado por 22 voluntarios sanos, de ambos sexos y distintas edades, sin trastorno del sueño. Las muestras de sudor, tanto de pacientes como de controles, se recogieron siguiendo el mismo protocolo para evitar contaminación y fueron testadas de forma independiente por 2 perros entrenados. Resultados. Once narcolépticos son detectados positivamente por los perros frente a solo 3 controles sanos. Conclusión. Parece que los pacientes con narcolepsia tienen un olor corporal típico que los perros entrenados pueden detectar. El desarrollo de un test de olfato para el diagnóstico de narcolepsia abre nuevas áreas de investigación (AU)

Objectives: This study has been carried out to test the clinical hypothesis of personal smell as a hint to the diagnosis of narcoleptic patients. Methods: Sweat samples from narcoleptic and healthy controls were tested independently by two trained dogs and their positive or negative detection compared to the gold standard diagnosis for narcolepsy. Neither trainer nor dog knew the source of the sample selected or its placement in the search device. Twelve narcoleptic patient, both sexes and various ages, recruited from April 2011 to June 2012 and diagnosed according to standard criteria, through their clinical records and nocturnal polysomnography plus multiple sleep latency test, made up the patient group. The control group was made up of 22 healthy volunteer without sleep disorders, both sexes and various ages. Sweat samples from both patients and controls were collected following the same protocol to avoid contamination, and tested independently for two trained dogs. Results: Eleven narcoleptic were detected positive by the dogs while only three controls. Conclusion: It seems that narcoleptic patients have a distinct typical odour that trained dogs can detect. The development of olfactory test could be a useful method in the screening of narcolepsy while opens a new research area (AU)

Narcolepsy and odor: preliminary report / Narcolepsia y olor: resultados preliminares

Objetivo: El propósito de este estudio es probar la hipótesis de un olor corporal característico en narcolepticos como indicador de diagnóstico. Métodos: Se testan muestras de sudor de 12 narcolepticos y 22 controles sanos de forma independiente por dos perros entrenados y su detección, positiva o negativa, se compara con el diagnostico ‘‘gold standard’’ de narcolepsia. Ni adiestrador ni perros conocían el tipo de muestra seleccionada o su emplazamiento en el dispositivo de búsqueda. 12 pacientes con narcolepsia, de ambos sexos y distintas edades, reclutados entre abril de 2011 y junio de 2012, y diagnosticados de acuerdo a criterios estándar, a través de su historia clínica y polisomnografía nocturna seguida de test de latencia múltiple del sue˜no, conforman el grupo de pacientes. El grupo control está formado por 22 voluntarios sanos, de ambos sexos y distintas edades, sin trastorno del sue˜no. Las muestras de sudor, tanto de pacientes como de controles, se recogieron siguiendo el mismo protocolo para evitar contaminación y fueron testadas de forma independiente por dos perros entrenados. Resultados: 11 narcolepticos son detectados positivamente por los perros frente a solo 3 controles sanos. Conclusión: Parece que los pacientes con narcolepsia tienen un olor corporal típico que perros entrenados pueden detector. El desarrollo de un test de olfato para el diagnostico de narcolepsia abre nuevas áreas de investigación (AU)

Objectives. This study has been carried out to test the clinical hypothesis of personal smell as a hint to the diagnosis of narcoleptic patients. Methods. Sweat samples from narcoleptic and healthy controls were tested independently by two trained dogs and their positive or negative detection compared to the gold standard diagnosis for narcolepsy. Neither trainer nor dog knew the source of the sample selected or its placement in the search device. Twelve narcoleptic patients, both sexes and various ages, recruited from April 2011 to June 2012 and diagnosed according to standard criteria, through their clinical records and nocturnal polysomnography plus multiple sleep latency test, made up the patient group. The control group was made up of 22 healthy volunteer without sleep disorders, both sexes and various ages. Sweat samples from both patients and controls were collected following the same protocol to avoid contamination, and tested independently by two trained dogs. Results. Eleven narcoleptic were detected positive by the dogs while only three controls. Conclusion. It seems that narcoleptic patients have a distinct typical odor that trained dogs can detect. The development of olfactory test could be a useful method in the screening of narcolepsy while opens a new research area (AU)

Restless legs syndrome and daytime sleepiness are prominent in myotonic dystrophy type 2.

OBJECTIVES: Although sleep disturbances are common in myotonic dystrophy type 1 (DM1), sleep disturbances in myotonic dystrophy type 2 (DM2) have not been well-characterized. We aimed to determine the frequency of sleep disturbances in DM2. METHODS: We conducted a case-control study of 54 genetically confirmed DM2 subjects and 104 medical controls without DM1 or DM2, and surveyed common sleep disturbances, including symptoms of probable restless legs syndrome (RLS), excessive daytime sleepiness (EDS), sleep quality, fatigue, obstructive sleep apnea (OSA), probable REM sleep behavior disorder (pRBD), and pain. Thirty patients with DM2 and 43 controls responded to the survey. Group comparisons with parametric statistical tests and multiple linear and logistic regression analyses were conducted for the dependent variables of EDS and poor sleep quality. RESULTS: The mean ages of patients with DM2 and controls were 63.8 and 64.5 years, respectively. Significant sleep disturbances in patients with DM2 compared to controls included probable RLS (60.0% vs 14.0%, p < 0.0001), EDS (p < 0.001), sleep quality (p = 0.02), and fatigue (p < 0.0001). EDS and fatigue symptoms were independently associated with DM2 diagnosis (p < 0.01) after controlling for age, sex, RLS, and pain scores. There were no group differences in OSA (p = 0.87) or pRBD (p = 0.12) scores. CONCLUSIONS: RLS, EDS, and fatigue are frequent sleep disturbances in patients with DM2, while OSA and pRBD symptoms are not. EDS was independently associated with DM2 diagnosis, suggesting possible primary CNS hypersomnia mechanisms. Further studies utilizing objective sleep measures are needed to better characterize sleep comorbidities in DM2.

Manifestaciones cardiacas en los pacientes con distrofia miotónica tipo 1 seguidos de forma protocolizada en una consulta monográfica / Cardiac manifestations in myotonic dystrophy type 1 patients followed using a standard protocol in a specialized unit

Introducción y objetivos. La distrofia miotónica tipo 1 se caracteriza por afección muscular y manifestaciones sistémicas, entre ellas las cardiacas. Nuestro objetivo es documentar la frecuencia y la gravedad de la afección cardiovascular (aparición de disfunción ventricular izquierda y trastornos del ritmo o conducción), la necesidad de implantar marcapasos o desfibrilador o de realizar estudio electrofisiológico y la aparición de muerte súbita durante el seguimiento. Métodos. Estudio observacional retrospectivo de los pacientes con distrofia miotónica tipo 1 remitidos a una consulta monográfica de cardiología y sometidos a seguimiento clínico, electrocardiográfico (con registro Holter) y ecocardiográfico. Resultados. Se incluyó a 81 pacientes (el 51,9% varones; media de edad, 29,9 ± 14,8 años). El seguimiento medio fue de 5,7 ± 3,9 (1-20) años y se documentó bradicardia sinusal en el 48,8%, disfunción sinusal en el 13,8%, arritmias supraventriculares en el 10%, intervalo PR ≥ 220 ms en el 31,3%, taquicardia ventricular el 5%, intervalo QT corregido largo en el 5%, bloqueo auriculoventricular de segundo o tercer grado en el 8,8% e intervalo QRS ≥ 120 ms en el 7,5%. Sólo 1 paciente presentó disfunción ventricular grave. Durante el seguimiento se implantaron 15 marcapasos y 2 desfibribladores y se realizaron 5 estudios electrofisiológicos, la mayoría por taquicardia ventricular. Sólo se produjo 1 muerte súbita. Conclusiones. Los trastornos de conducción y del ritmo son frecuentes durante la evolución de dichos pacientes, y un porcentaje considerable requiere estudio electrofisiológico e implante de dispositivos (marcapasos o desfibrilador). La disfunción sistólica y la muerte súbita son excepcionales en nuestra experiencia (AU)

Introduction and objectives. Myotonic dystrophy type 1 is characterized by muscle damage and systemic manifestations, including cardiac involvement. Our aim was to document the frequency and severity of cardiac involvement (left ventricular dysfunction and arrhythmia or conduction disorders), the need for a pacemaker, implantable cardioverter-defibrillator, or electrophysiological study, and the development of sudden death during follow-up. Methods. Retrospective observational study of myotonic dystrophy type 1 patients referred to a specialized cardiac unit. Patients received clinical, electrocardiographic (Holter monitoring), and echocardiographic follow-up. Results. We included 81 patients (51.9% men; mean age, 29.9 [14.8] years). The mean follow-up was 5.7 (3.9) years (range: 1-20 years). During this period sinus bradycardia was documented in 48.8%, PR interval≥220 ms in 31.3%, long corrected QT interval in 5%, and QRS interval≥120 ms in 7.5%. A total of 13.8% of patients developed sinus node dysfunction, 10% of patients had supraventricular arrhythmias, 5% had ventricular tachycardia, and 8.8% developed second- or third- degree atrioventricular block. Only 1 patient had severe ventricular dysfunction. During the follow-up, 15 pacemakers and 2 implantable cardioverter-defibrillators were implanted and 5 electrophysiological studies were performed (mainly due to ventricular tachycardia). There was only 1 sudden death. Conclusions. Arrhythmia or conduction disorders are frequent during the course of myotonic dystrophy type 1 patients. A significant percentage of patients require electrophysiological study and the use of a device (pacemaker or implantable cardioverter-defibrillator). In our experience, systolic dysfunction and sudden death are rare (AU)

Three family members with elevated plasma cobalamin, transcobalamin and soluble transcobalamin receptor (sCD320).

BACKGROUND: Plasma cobalamin is requested in order to diagnose cobalamin deficiency and low levels confirm a deficient state. Here, we present three family members with unexpected high levels of cobalamin. METHODS: We included a patient referred for cobalamin measurement due to neurological symptoms, her son and her daughter. Mother and son both suffered from myotonic dystrophy type II, while the daughter tested negative for this disease. Blood samples were analyzed for cobalamin, haptocorrin, transcobalamin, holoTC, and sCD320. We employed gel filtration and antibody precipitation for further characterization. The protein coding region of the TCN2 gene, encoding transcobalamin, was sequenced. RESULTS: The patient, her {son} and [daughter] all had cobalamin levels above the measurement range of the routine method employed (>1476 pmol/L). Total transcobalamin and (holoTC) were 5980 (1500), {5260 (2410)} and [5630 (1340)] pmol/L, which is well above the upper reference limits of 1500 (160) pmol/L. The sCD320 concentration was also well above the upper reference limit of 97 arb.u.: 1340, {1510} and [1090] arb.u. Haptocorrin levels were within the reference range and no signs of cobalamin deficiency were found. DNA sequencing of the TCN2 gene revealed several known polymorphisms not associated with highly elevated transcobalamin levels. Upon gel filtration, sCD320 eluted as a larger molecule than previously reported. By incubation with anti-transcobalamin antibodies, we precipitated both transcobalamin and part of sCD320. CONCLUSIONS: The high cobalamin levels were mainly explained by high levels of holoTC, possibly caused by complex formation with its soluble receptor, sCD320. The family occurrence points to a genetic explanation.

Sleep disturbances in myotonic dystrophy type 2.

Sleep disorders in myotonic dystrophy type 1 (DM1) are common and include sleep-disordered breathing, hypersomnia, and fatigue. Little is known regarding the occurrence of sleep disturbance in myotonic dystrophy type 2 (DM2). We hypothesized that DM2 patients may frequently harbor sleep disorders. We reviewed medical records of all genetically confirmed cases of DM2 seen at our sleep center between 1997 and 2010 for demographic, laboratory, overnight oximetry, and polysomnography (PSG) data. Eight patients (5 women, 3 men) with DM2 were identified. Excessive daytime sleepiness was seen in 6 patients (75%), insomnia in 5 (62.5%), and excessive fatigue in 4 (50%). Obstructive sleep apnea was diagnosed in 3 of 5 patients (60%) studied with PSG. Respiratory muscle weakness was present in all 6 patients (100%) who received pulmonary function testing. Four of 8 (50%) met criteria for diagnosis of restless legs syndrome. The clinical spectrum of DM2 may include a wide range of sleep disturbances. Although respiratory muscle weakness was frequent, sustained sleep-related hypoxia suggestive of hypoventilation was not seen in our patients. Further prospective studies are needed to examine the frequency and scope of sleep disturbances in DM2.