Muscle & Nerve最新文献

Introduction/aims: Corneal confocal microscopy (CCM) detects small nerve fiber loss and correlates with skin biopsy findings in diabetic neuropathy. In chronic idiopathic axonal polyneuropathy (CIAP) this correlation is unknown. Therefore, we compared CCM and skin biopsy in patients with CIAP to healthy controls, patients with painful diabetic neuropathy (PDN) and diabetics without overt neuropathy (DM).

Methods: Participants with CIAP and suspected small fiber neuropathy (n = 15), PDN (n = 16), DM (n = 15), and healthy controls (n = 16) underwent skin biopsy and CCM testing. Inter-center intraclass correlation coefficients (ICC) were calculated for CCM parameters.

Results: Compared with healthy controls, patients with CIAP and PDN had significantly fewer nerve fibers in the skin (IENFD: 5.7 ± 2.3, 3.0 ± 1.8, 3.9 ± 1.5 fibers/mm, all p < .05). Corneal nerve parameters in CIAP (fiber density 23.8 ± 4.9 no./mm², branch density 16.0 ± 8.8 no./mm², fiber length 13.1 ± 2.6 mm/mm²) were not different from healthy controls (24.0 ± 6.8 no./mm², 22.1 ± 9.7 no./mm², 13.5 ± 3.5 mm/mm², all p > .05). In patients with PDN, corneal nerve fiber density (17.8 ± 5.7 no./mm²) and fiber length (10.5 ± 2.7 mm/mm²) were reduced compared with healthy controls (p < .05). CCM results did not correlate with IENFD in CIAP patients. Inter-center ICC was 0.77 for fiber density and 0.87 for fiber length.

Discussion: In contrast to patients with PDN, corneal nerve parameters were not decreased in patients with CIAP and small nerve fiber damage. Therefore, CCM is not a good biomarker for small nerve fiber loss in CIAP patients.

Introduction/aims: Females with generalized myasthenia gravis (gMG) report lower quality of life (QoL) and have more severe disease than males. Sex differences in disease characteristics exist, however whether there are sex differences in the treatment of gMG that may contribute to QoL disparities is unknown. Our objective is to determine whether there are sex differences in the treatment of gMG.

Methods: We performed a single-center retrospective study of people diagnosed with gMG at the University of Calgary between 1997 and 2021. Primary outcome was proportion starting treatment and secondary outcome was time from diagnosis to treatment initiation. Treatments included pyridostigmine, prednisone, steroid sparing therapies (azathioprine, mycophenolate mofetil [MMF], methotrexate [MTX], or tacrolimus), intravenous immunoglobulin (IVIg), plasmapheresis, rituximab, eculizumab, cyclosporine, stem cell transplantation, and thymectomy. Multivariable logistic and Cox proportional hazards regression models were used to examine treatment associations with sex, adjusted for time from onset to diagnosis, age at diagnosis, presence of thymoma, and antibody status.

Results: A total of 179 people with gMG were included (41.9% female). Odds of starting treatment were not statistically associated with sex after adjustment for confounders and correction for multiple testing. Results of the secondary analysis using time to treatment initiation as the outcome were similar.

Discussion: We found no sex differences in odds of starting treatment or time to treatment initiation that might explain previously observed sex-based differences in QoL. Future work should capture physician and patient treatment preferences that may influence disease management.

Introduction/aims: Severe spinal deformities and previous spinal orthopedic instrumentation may result in substantial technical challenges for nusinersen delivery through lumbar puncture in patients with spinal muscular atrophy (SMA). The aim of this paper was to review our experience with ultrasound-guided cervical puncture as an alternative approach for the intrathecal administration of nusinersen.

Methods: This was a retrospective medical record review of transverse interlaminar ultrasound-guided C1-C2 puncture for nusinersen delivery in SMA patients. The details of puncture, complications, and success rate of the procedure were summarized.

Results: There were four patients who received a total of 13 cervical punctures for nusinersen delivery. All procedures were technically successful with no major complications. Full doses of nusinersen were delivered intrathecally.

Discussion: Transverse interlaminar ultrasound-guided C1-C2 puncture is an alternative approach for administering nusinersen if lumbar puncture fails. The success of the technique requires a thorough preprocedural evaluation of cervical spine imaging, sound knowledge of the cervical sonoanatomy and careful manipulation of the needle.

Introduction/aims: Amyotrophic lateral sclerosis (ALS) exhibits selective muscle weakness. The weak shoulder and arm sparing signs, assessed by a single experienced neurologist, have been reported to be superior to previous signs in sensitivity and specificity. However, it is unknown whether the same results are observed when assessed by multiple neurologists.

Methods: Subjects were retrospectively identified from our department's inpatient database from 2014 to 2023. Medical Research Council (MRC) scores of the deltoid (Del), biceps brachii (BB), triceps brachii (TB), and first dorsal interosseous (FDI) muscles were evaluated. The weak shoulder sign was defined as positive when Del was weaker than BB and TB. The arm sparing sign was defined as positive when both Del and FDI were weaker than BB and TB. Sensitivity was analyzed in all ALS patients and in subgroups based on the region of symptom onset, presence or absence of upper motor neuron (UMN) signs, and the Japanese ALS Severity Classification.

Results: Seventy-one patients with ALS were identified. Eight neurologists and three neurology residents evaluated each patient's MRC scores. The weak shoulder and arm sparing signs were observed in 72% and 48% of patients, respectively, with no significant difference in sensitivity across patient subgroups.

Discussion: The weak shoulder and arm sparing signs showed high and moderate sensitivity, respectively, consistent with a previous report, even when evaluated by multiple examiners. This expands the clinical utility and increases the reliability of these signs, potentially contributing to accurate ALS diagnosis when combined with other clinical features and objective assessments.

Introduction/aims: Intercostal nerve injury can occur after rib fractures, resulting in denervation of the abdominal musculature. Loss of innervation to the rectus abdominis and intercostal muscles can cause pain, atrophy, and eventual eventration, which may be an underrecognized and thus undertreated complication of rib fractures. We investigated the clinical utility of intercostal nerve electrodiagnostic testing following rib fractures to diagnose and localize nerve injury at levels T7 and below.

Methods: Five patients with displaced bicortical rib fractures involving the 7th-11th ribs and clinical eventration of the ipsilateral abdominal wall underwent intercostal nerve conduction studies (NCS) and needle electromyography (EMG) on the affected side. EMG of the rectus abdominis and intercostal muscles was performed with ultrasound guidance, and ultrasound measurements of rectus abdominis thickness were obtained to assess for atrophy.

Results: Average patient age was 59.4 years and average body mass index (BMI) was 31.5 kg/m². Intercostal NCS and EMG were able to reliably diagnose and localize intercostal nerve damage after rib fractures. Ultrasound demonstrated an average rectus abdominis transverse cross-sectional thickness of 0.534 cm on the affected side, compared with 1.024 cm on the non-affected side.

Discussion: Intercostal electrodiagnostic studies can diagnose and localize intercostal nerve damage after displaced rib fractures. Musculoskeletal ultrasound can be used to diagnose and quantify rectus abdominis atrophy and to accurately and safely guide needle EMG to the intercostal and rectus abdominis muscles.

Introduction/aims: Ryanodine receptor 1 (RYR1)-related myopathies associated with variants in the RYR1 gene present with a wide range of symptoms and severity. Two of the milder phenotypes associated with dominant pathogenic variants in RYR1 are rhabdomyolysis and myalgia. Only a few studies have investigated the muscle function and structure of individuals with RYR1-related rhabdomyolysis/myalgia objectively, showing inconsistent results. This study aimed to describe structural changes and contractility of muscles in individuals with RYR1-related rhabdomyolysis/myalgia.

Methods: We investigated 15 individuals with dominant variants in the RYR1-gene and compared them with 15 age-, sex-, and body mass index (BMI)-matched controls using MRI, stationary isokinetic dynamometry, and comprehensive clinical evaluation.

Results: No significant differences were found between individuals with RYR1-related rhabdomyolysis/myalgia and healthy controls in peak torque, fat fraction, cross-sectional area, contractile cross-sectional area, or contractility (p > .05) in muscles of the lower back (MRI data only), thigh, or calf. On clinical examination, three individuals exhibited weakness in hip or back extension on the Medical Research Council (MRC) test and eight had muscle hypertrophy. Individuals with weakness were not hypertrophic.

Discussion: Most individuals with RYR1-related rhabdomyolysis/myalgia have close to normal strength, and normal fat fraction and contractility of muscles, and therefore constitute a mild phenotype of RYR1-related myopathies.

Introduction/aims: Oculopharyngodistal myopathy type 4 (OPDM4) arises from a CGG repeat expansion in the 5' UTR of the RILPL1 gene. Reported cases of OPDM4 have been limited. The aim of this study was to investigate the clinical and myopathological characteristics of OPDM4 patients with advanced disease.

Methods: We assessed a total of 8 affected and 12 unaffected individuals in an OPDM4 family with autosomal dominant inheritance. Muscle biopsy tissue from the proband underwent histological, enzyme histochemical, and immunohistochemical stains, and electron microscopy analysis. Whole exome sequencing and repeat primer PCR (RP-PCR) were conducted to investigate underlying variants.

Results: OPDM4 patients displayed a progressive disease course. Most experienced lower limb weakness and diminished walking ability in their 20s and 30s, followed by ptosis, ophthalmoplegia, swallowing difficulties, and dysarthria in their 30s to 50s, By their 50s to 70s, they became non-ambulatory. Muscle magnetic resonance imaging (MRI) of the proband in advanced disease revealed severe fatty infiltration of pelvic girdle and lower limb muscles. Biopsied muscle tissue exhibited advanced changes typified by adipose connective tissue replacement and the presence of multiple eosinophilic and p62-positive intranuclear inclusions. Immunopositivity for the intranuclear inclusions was observed with anti-glycine antibody and laboratory-made polyA-R1 antibody. RP-PCR unveiled an abnormal CGG repeat expansion in the 5' UTR of the RILPL1 gene.

Discussion: The clinical and radiological features in this family broaden the phenotypic spectrum of OPDM4. The presence of intranuclear inclusions in the proliferative adipose connective tissues of muscle biopsy specimens holds diagnostic significance for OPDM4 in advanced disease.

Introduction/aims: There is a lack of studies comparing the accuracy of neuromuscular jitter analysis during voluntary activation (v-jitter study) versus axonal stimulation (s-jitter study). The study aimed to compare these two techniques in the same population of patients with suspected ocular myasthenia gravis (OMG).

Methods: Fourteen control subjects (mean age: 55.5 ± 15.2 years) and 34 patients with suspected OMG (mean age: 59 ± 13.9 years) were prospectively evaluated. Twenty spike pairs and 30 individual spikes were analyzed during v-jitter and s-jitter study, respectively. Two different criteria for abnormal individual jitter values were evaluated: ≥ or > than 10% values exceeding the upper normal limit.

Results: OMG was diagnosed in 19 patients based on clinical and laboratory findings, without considering jitter measurements. In most patients, v-jitter and s-jitter analyses provided comparable results. The maximum sensitivity (89%) was achieved with s-jitter study using the ≥10% criterion, while the maximum specificity (93%) was found with v-jitter study using the >10% criterion.

Discussion: Both v-jitter and s-jitter studies showed good to very good accuracy for the diagnosis of OMG, in the absence of any statistically significant difference. Therefore, the patient's cooperation level and examiner's experience should guide the choice of performing v-jitter or s-jitter analysis in patients with suspected OMG.