Citations

Abstract Background and purpose Elevation of serum creatine kinase (CK) or hyperCKemia is considered a biological marker of myopathies. However, selective elevation of serum aldolase with normal CK has been reported in a few myopathies, including dermatomyositis, immune‐mediated myopathy with perimysial pathology and fasciitis with associated myopathy. The aim was to investigate the disease spectrum of myopathies with isolated aldolase elevation. Methods Medical records were reviewed to identify patients >18 years old seen between December 1994 and June 2020 who had pathologically proven myopathies with elevated aldolase and normal CK level. Patients with alternative causes of aldolase elevation were excluded. Results Thirty‐four patients with various types of myopathies were identified. Myopathies were treatable in 27 patients. The three most common etiologies were dermatomyositis ( n = 8), overlap myositis ( n = 4) and nonspecific myopathy ( n = 4). Perimysial pathology comprising inflammation, fragmentation, vasculitis, calcified perimysial vessels or extracellular amyloid deposition was found in 17/34 patients (50%). Eight dermatomyositis patients with selective elevated aldolase were compared to 24 sex‐ and age‐matched patients with dermatomyositis and hyperCKemia. Dermatomyositis patients with normal CK significantly ( p < 0.05) had less frequent cutaneous involvement (50.0% vs. 100.0%) and fibrillation potentials (50.0% vs. 90.5%) but higher median erythrocyte sedimentation rate (33.5 vs. 13.5 mm/h) and more common perifascicular mitochondrial pathology (37.5% vs. 4.2%). Conclusion Isolated aldolase elevation can be found in a greater variety of myopathies than initially thought and most were treatable. Dermatomyositis is the most common myopathy with selective elevation of aldolase in our cohort, which features some unique characteristics compared to dermatomyositis with hyperCKemia.

Background: The normal limits of nerve conduction studies are commonly determined by testing healthy subjects. However, in comprehensive real-life nerve conduction electrodiagnostic (EDX) evaluations, multiple nerves are tested, including normal nerves, for purposes of comparison with abnormal ones. Objective: This study aims to evaluate the average values of normal nerve conduction studies in a large population and examined the influence of age and sex. Methods: EDX parameters were extracted from an electronic database of studies performed from May 2016 to February 2022. Established normal values were used to determine the classification of a nerve study as normal. Results: We identified 10,648 EDX reports with 5077 normally interpreted nerve conduction studies (47.6%) of which 57% ( n = 2890) were for females. The median age of studies with no abnormalities was 45.1 years (range < 1 to 92) overall and 42.5 years (range: 0.16 –89.5 years) for males and 47.5 years (range:<1 –91.7) for females. Correlations between age and amplitude, latency, and velocity ( p < 0.001) were observed in most nerves. Amplitude correlated negatively with age in adults in all nerves with a mean of –0.44 (range: –0.24 to –0.62). However, in the pediatric population (age < 18 years), amplitude as well as velocity increased significantly with age. In the adult cohort, sex differences were noted, where females had higher mean sensory nerve action potentials in ulnar, median, and radial evaluations ( p < 0.001). In older patients (aged > 70 years) with normally interpreted EDX studies (845 records of 528 patients), sural responses were present in 97%. Conclusions: This real-life study confirms that advanced aging is associated with decreased nerve conduction amplitudes, increased latency, and the slowing of conduction velocity. The findings also indicate higher sensory amplitudes and conduction velocities in females. Sural nerve responses were identified in most adults over age 70.

AbstractBackground and AimsComprehensive study of sural nerve biopsy utility based on individual histopathologic preparations is lacking. We aimed to quantify the value of different histologic preparations in diagnosis.MethodsOne hundred consecutive sural nerves were studied by standard histological preparations plus graded teased nerve fibers (GTNF), immunohistochemistry, and epoxy‐semithin morphometry. Three examiners scored the individual preparations separately by a questionnaire of neuropathic and interstitial abnormalities, masked to the biopsy number, versus a gold‐standard of all preparations. Multivariate modeling was utilized to determine best approach versus the gold‐standard.ResultsHighest confidence (range 8–9 of 10) and inter‐rater reliability (99%) for fiber abnormalities came from GTNF, and interstitial abnormalities from paraffin stains (range 7–8, 99%). Vasculitic neuropathy associated with GTNF axonal degeneration (moderate to severe 79%) with OR 3.8, 95% CI (1.001–14.7), p = .04, but not significantly with the other preparations. Clinicopathologic diagnoses associated with teased fiber abnormalities in chronic inflammatory demyelinating polyradiculoneuropathy, 80% (8/10); amyloidosis, 50% (1/2); adult‐onset polyglucosan disease 100% (1/1). GTNF and paraffin stains significantly correlated with fiber density determined by morphometric analysis (GTNF: OR 9.9, p < .0001, paraffin: OR 3.8, p = .03). GTNF combined with paraffin sections had highest accuracy for clinicopathologic diagnoses and fiber density with 0.86 C‐stat prediction versus morphometric analysis. Pathological results lead to initiation or changes of immunotherapy in 70% (35/50; initiation n = 22, reduction n = 9, escalation n = 4) with the remaining having alternative intervention or no change.InterpretationNerve biopsy paraffin stains combined with GTNF have highest diagnostic utility, confidence, inter‐rater reliability, improving accuracy for a pathologic diagnosis aiding treatment recommendations. Immunostains and epoxy preparations are also demonstrated useful supporting consensus guidelines. This study provides class II evidence for individual nerve preparation utility.

Abstract Background: Vasculitic neuropathies usually present acutely to subacutely, with an asymmetric pattern, involving multiple peripheral nerve territories. Drug-induced vasculitis is an often overlooked etiology of vasculitic neuropathy. Methods: We present the first reported case of nitrofurantoin-associated and an illustrative case of minocycline-associated vasculitic neuropathy, with a review of the literature. Results: The first patient is a 60-year-old woman who developed axonal sensorimotor peripheral neuropathy after nitrofurantoin use, with a superficial radial nerve biopsy confirming vasculitis. The second patient is a 23-year-old woman, with a history of acne vulgaris treated with minocycline, who presented with a subacute right common peroneal mononeuropathy followed by a left deep peroneal mononeuropathy, with elevated antinuclear, perinuclear-antineutrophil cytoplasmic, and myleoperoxidase antibodies, and MPO titers, and a sural nerve biopsy showing large arteriole vasculitis. Finally, we provide a comprehensive review of previously published cases. Conclusions: Medications should be considered as a trigger for medication-induced vasculitic neuropathy. Accurate diagnosis would ensure timely treatment.