Effect of newly proposed CK reference limits on neuromuscular diagnosis

Late-Onset Pompe Disease with Normal Creatine Kinase Levels: The Importance of Rheumatological Suspicion

Pompe disease (PD), also defined as acid maltase deficiency, is a rare autosomal recessive disease that causes glycogen accumulation due to a deficiency of the lysosomal enzyme acid α-glucosidase. An excessive amount of undisposed glycogen causes progressive muscle weakness throughout the body. It particularly affects skeletal muscles and the nervous system, especially in the late-onset phase. Here, we present a clinical case of late-onset PD (LOPD) with normal CK (creatinine kinase) values treated after a misdiagnosis of demyelinating motor polyneuropathy and chronic inflammatory neuropathy. The suspicion of possible fibromyalgia induced the patient to seek a rheumatology consultation, and the investigations performed led to the diagnosis of PD. The patient was investigated for genetic and enzymatic studies. PD was diagnosed using the α-glucosidase assay on DBS. In LOPD, clinical manifestations, such as muscle weakness, exercise intolerance, myalgia, or even high hyperCKemia, often appear as nonspecific and may mimic a wide variety of other muscle disorders, such as limb muscle dystrophies, congenital, metabolic, or inflammatory myopathies. In our case, the patient had CK values in the normal range but with continued complaints typical of PD. An analysis of enzyme activity revealed a pathologic value, and genetic analysis identified the c.-32-13T>G mutation in homozygosis. The association of the pathological enzyme value and mutation in homozygosity with LOPD led to a familial segregation study. Our results contribute to the characterization of PD in Italy and support the importance of rheumatologic attention. This suggests further studies are needed to define the broad clinical and pathological spectrum observed in this disease.

Causes of HyperCKemia in Children: A Retrospective Cohort Study

Background and Objectives: Creatine kinase (CK) is a commonly used screening test for neuromuscular disorders (NMDs). However, hyperCKemia can result from several pathologic and physiologic causes. We analyzed neuromuscular disorders in noninfant children with hyperCKemia including those with no weakness and mild CK elevations (<5 times the upper limit of normal). We hypothesized that children with mild CK elevation and no weakness would be unlikely to have neuromuscular disorders and require additional evaluation. Methods: We retrospectively evaluated patients between 1 and 18 years of age seen at a single children's hospital over a 3-calendar-year period with initial total CK values greater than the upper limit of normal with at least 2 years of follow-up data. Final diagnoses were analyzed and associations with possible risk factors assessed. Receiver operating characteristic curves were generated to assess altering CK cutoff values. Results: Of 260 subjects with hyperCKemia, 18 had a neuromuscular disorder (6.9%, 95% confidence interval [CI] 4.2%-10.9%). Of 166 subjects with CK <5 times the upper limit of normal and no weakness, 8 had a neuromuscular disorder (4.8%, 95% CI 2.3%-9.6%). Weakness (odds ratio [OR] 32.5, 95% CI 4-385, P = .0002), and family history of neuromuscular disorders (OR not calculable, P = .0003) were associated with neuromuscular disorders. An optimal CK threshold of 777 was identified on receiver operating characteristic curve analysis (sensitivity of 72% and specificity of 64%). The most commonly identified neuromuscular disorders were muscular dystrophies, inflammatory myopathies, and metabolic myopathies. Conclusion: Most children with hyperCKemia will not be diagnosed with a neuromuscular disorder, but a significant minority even with mild hyperCKemia and without weakness may warrant additional evaluation.

Creatine Kinase Is Associated With Recurrent Stroke and Functional Outcomes of Ischemic Stroke or Transient Ischemic Attack

Background

Many patients after stroke are found to have elevated serum creatine kinase (CK). This study aimed to investigate the associations between serum CK levels and clinical outcomes in patients with acute ischemic stroke or transient ischemic attack.

Methods and Results

The study included 8910 patients with acute ischemic stroke or transient ischemic attack from the CNSR‐III (Third China National Stroke Registry). Baseline serum CK levels after admission were measured. The associations between CK and clinical outcomes (stroke recurrence, death, and disability, defined as modified Rankin scale score 3–6 or 2–6) were analyzed. Patients with elevated CK levels had higher risks of recurrent stroke (hazard ratio [HR], 1.53; 95% CI, 1.21–1.93), death (HR, 1.68; 95% CI, 1.10–2.58), and disability (modified Rankin scale score, 3–6; odds ratio, 1.57; 95% CI, 1.29–1.90) at 3 months after adjusting confounding factors. Similar results were found at 1 year. The effects of CK on death and disability were more significant in male patients than female patients (P value for interaction <0.05). Elevated CK‐MB levels were not associated with clinical outcomes in this study.

Conclusions

Elevated serum CK after ischemic stroke or transient ischemic attack is associated with higher risks of recurrent stroke, death, and disability at 3 months and 1 year. Serum CK may act as a useful predictor for recurrent stroke and poor functional outcomes in patients with acute ischemic stroke or transient ischemic attack. Sex modifies the relationship between elevated CK and disability or death.

HyperCKemia associated with acupuncture: a case report and review of the literature

Background

Acupuncture therapy has been widely used as an alternative therapy to treat multiple diseases, such as sequelae of stroke, pain, facial paralysis and so on. In recent years, few adverse events related to acupuncture treatment have been reported, among which hematoma, bleeding and dizziness are the main manifestations. However, to date, there have been no existing cases reported the association between acupuncture therapy and asymptomatic/pauci-symptomatic hyperCKemia.

Case presentation

We report a patient who developed hyperCKemia during 5 sessions of acupuncture at different frequencies. After stopping acupuncture treatment for 1 month, follow-up showed a significant downward trend in serum creatine kinase (sCK). However, after that this patient started to get acupuncture treatment again in order to improve the sequelae of stroke. Meantime, the sCK rose again.

Conclusion

HyperCKemia may associated with acupuncture therapy. All kinds of adverse events of acupuncture should be recorded comprehensively and objectively so as to improve the safety standard system of acupuncture therapy.

European Federation of Neurological Societies cutoff values significantly reduce creatine kinase sensitivity for diagnosing neuromuscular disorders

INTRODUCTION

Elevated creatine kinase (CK) level was redefined by the European Federation of Neurological Societies)EFNS(as 1.5 times the upper limit of normal. In the current study we sought to determine the sensitivity and specificity of CK testing for the diagnosis of neuromuscular disorders.

METHODS

Demographics and CK levels were retrospectively extracted from an electronic database for 234 patients with neuromuscular disorders. Sensitivity, specificity, and likelihood ratios and the area under curve were determined for each diagnosis and different cutoff CK values.

RESULTS

Using the EFNS cutoff values significantly reduced CK test sensitivity. Creatine kinase values >1000 IU/L showed a high likelihood (11.04) for myopathies and a low likelihood for polyneuropathies (0).

DISCUSSION

European Federation of Neurological Societies cutoff values significantly reduce CK sensitivity for diagnosing neuromuscular disorders. While low CK values cannot exclude a neuromuscular disease, values >1000 IU/L are associated with a high likelihood of myopathy.

Elevated Creatine Kinase in a 6-Year-Old Boy

Paucisymptomatic or asymptomatic but persistently elevated serum creatine kinase is not an uncommon pediatric neurology referral question. The challenge is in promptly identifying etiologies with specific treatments, even if they are rare. The presenting features for a child or adolescent with juvenile-onset Pompe disease (JOPD) can be nonspecific and heterogeneous. Clinical manifestations can appear at any age after 2 years and before adulthood, with insidious onset of symptoms related to slowly progressive skeletal or respiratory muscle weakness. This reported case highlights the importance of screening for JOPD in children with "hyper-CK-emia." Dried blood spot measuring acid α-glucosidase enzyme activity is reliable, rapid, noninvasive, and inexpensive, allowing early diagnosis. Diagnosis of JOPD is important as enzyme replacement therapy with alglucosidase alpha, an intravenous recombinant α-glucosidase, is available, and early treatment improves muscle function, quality of life, and long-term survival.

Spectrum of Neuromuscular Disorders With HyperCKemia From a Tertiary Care Pediatric Neuromuscular Center

Elevated creatine kinase is a useful screening test in the diagnostic workup of patients with neuromuscular disorders. We did a retrospective study of children with hyperCKemia (>175 IU/L) who were followed in the neuromuscular program of a tertiary care pediatric center from 2005 to 2016. Patients with hyperCKemia were divided into 2 groups: myopathic and nonmyopathic. Within the myopathic group, there were 3 arbitrary subgroups based on creatine kinase values: A (creatine kinase >10 times normal), B (creatine kinase 5-10 times normal), and C (creatine kinase 1-5 times normal). The 3 major categories of myopathies across all the subgroups were muscular dystrophies (commonest) followed by metabolic myopathies and inflammatory myopathies. Among the nonmyopathic causes of hyperCKemia, spinal muscular atrophy was the commonest. Muscular dystrophies should be considered in children with hyperCKemia, muscle weakness, or calf hypertrophy, and metabolic myopathies to be considered in children with recurrent rhabdomyolysis.

Exertional rhabdomyolysis: a clinical review with a focus on genetic influences

In this review, the clinical and laboratory features of exertional rhabdomyolysis (ER) are discussed in detail, emphasizing the full clinical spectrum from physiological elevations of serum creatine kinase after exertion to life-threatening rhabdomyolysis with acute kidney injury and associated systemic complications. Laboratory markers used to diagnose both ER and rhabdomyolysis are very sensitive, but not very specific, and imperfectly distinguish "subclinical" or asymptomatic from severe, life-threatening illness. However, genetic factors, both recognized and yet to be discovered, likely influence this diverse clinical spectrum of disease and response to exercise. Genetic mutations causative for McArdle disease, carnitine palmitoyl transferase deficiency 2, myoadenylate deaminase deficiency, and malignant hyperthermia have all been associated with ER. Polymorphic variations in the myosin light chain kinase, α-actin 3, creatine kinase-muscle isoform, angiotensin I-converting enzyme, heat shock protein, and interleukin-6 genes have also been associated with either ER or exercise-induced serum creatine kinase elevations typical of ER. The prognosis for ER is significantly better than that for other etiologies of rhabdomyolysis, but the risk of recurrence after an initial episode is unknown. Guidelines for management are provided.

Are the currently used reference intervals for creatine kinase (CK) reflecting the general population? The Tromsø Study

Laboratory reference intervals are not necessarily reflecting the range in the background population. This study compared creatine kinase (CK) reference intervals calculated from a large sample from a Norwegian population with those elaborated by the Nordic Reference Interval Project (NORIP). It also assessed the pattern of CK-normalization after standardized control analyses.

New upper reference limits (URL) CK values were calculated after exclusion of individuals with risk of hyperCKemia and including individuals with incidentally detected hyperCKemia after they had completed a standardized control analysis. After exclusion of 5924 individuals with possible causes of hyperCKemia, CK samples were analyzed in 6904 individuals participating in the 6th survey of The Tromsø Study. URL was defined as the 97.5 percentile.

New URL in women was 207 U/L. In men <50 years it was 395 U/L and in men ≥50 years 340 U/L. In individuals with elevated CK, normalization grade after control analysis was inversely correlated to the CK level (p<0.04).

URL CK values in women and in men <50 years of age were in accordance with URL CK values given by the NORIP. In men ≥50 years, a higher URL was found and the findings suggest an upward adjustment of URL in this age group.

Electrodiagnostic approach to the patient with suspected myopathy

Electrodiagnostic testing is a useful component of the approach to a patient with suspected myopathy. It follows the history and is guided by the neurologic examination findings. Uncovering various electrodiagnostic patterns (eg, fibrillation potentials with short-duration motor unit potentials, short-duration motor unit potentials without fibrillation potentials, myotonic discharges, and short-duration motor unit potentials with complex repetitive discharges) can lead to more targeted laboratory testing and a refined differential diagnosis. Electromyography may also be used to detect subclinical myopathy, assess disease activity, and help select a suitable muscle for biopsy.