Asymptomatic hyper‐CK‐emia: An electrophysiologic and histopathologic study

Abstract

Since the popularization of routine creatine kinase (CK) measurement, an increasing number of patients with unexplained CK elevation ("asymptomatic hyper-CK-emia") are being identified. We studied 19 patients with persistent CK elevation of unknown etiology with electromyography (EMG) and muscle biopsy. Needle EMG was abnormal in 14 patients. Muscle biopsy was positive in all individuals with abnormal EMG and in one patient with normal EMG. Diagnoses included polymyositis in five patients, morphologically nonspecific myopathy in three, mitochondrial myopathy in two, and sarcoid myopathy, central core disease, multicore disease, inclusion body myopathy, and McArdle's disease in one case, respectively. Five patients with abnormal biopsies developed weakness within 1 year of presentation. We conclude that persistent asymptomatic CK elevation represents mild or early myopathy in a majority of cases.

Muscle biopsy in the evaluation of patients with modestly elevated creatine kinase levels

“…Another series in which a cause of the hyperCKemia was identified in 15 of 19 patients (79%) also included patients with much higher serum CK levels than in our series, many of whom had markedly abnormal electrodiagnostic studies. 3 In agreement with our findings, a low diagnostic yield was found in a recent series of asymptomatic or minimally symptomatic patients with elevated serum CK levels. 4 Detailed histochemical studies were performed on all biopsies, and immunohistochemical, biochemical, molecular genetic, and other studies were undertaken when necessary.…”

“…Electrodiagnostic studies (nerve conduction studies and needle electromyography) may be nondiagnostic. 1,3,4,6 If so, the physician must determine the value of obtaining a muscle biopsy. Elevated serum CK levels may occur in the absence of neuromuscular disease, and may be related to factors such as exercise, muscle trauma, medications, and endocrinopathies, 2 or may be idiopathic ("idiopathic hyperCKemia").…”

Asymptomatic hyperCKemia during a two-year monitoring period: A case report and literature overview

“…According to Dabby et al, even though muscle biopsy is often non-normal in patients with persistent hyperCKemia, the majority of the abnormalities are non-specific, rendering the confirmation of a definite diagnosis relatively low (14). On the other hand, based on a diagnostic approach to pauci-or asymptomatic hyperCKemia guidelines, a normal electromyogram increases the probability of a normal biopsy to ≤74-80% (4,6,15).…”

Duchenne gene carrier as cause of asymptomatic hyperckemia

“…A better term to be used in this context could be "asymptomatic pathologic hyperCKemia". In fact, most patients with persistent asymptomatic elevated CPK levels have an underlying muscle disease 7 , usually with a benign course 1 , although in a minority of cases the abnormality can precede an ominous neuromuscular disease 6 . Our patient had received a diagnosis of myotonic dystrophy in other medical center based on the presence of excessive central nuclei in the muscle biopsy, despite the absence of clinical and electrophysiological myotonia and negative genetic testing for myotonic dystrophy.…”