Although less severe, DM2 closely resembles adult-onset DM1 with common features, including progressive weakness, myotonia, cardiac arrhythmias, cataract, male hypogonadism, insulin insensitivity, and hypogammaglo-bulinemia. The most frequent manifestations are muscle pain, muscle stiffness, myotonia, and weakness. Muscle pain is frequently fluctuating or episodic. Weakness characteristically affects the neck flexors, elbow extensors, deep finger flexors, hip flexors, and hip extensors. Facial and ankle dorsiflexion weakness is uncommon. Mild muscle wasting occurs in —10% of the cases. Creatine kinase is typically mildly elevated. Muscle biopsy shows similar features as in DM1, but preferentially type 2 fiber atrophy. Cataracts of the posterior, subcapsular, and iridescent type develop between age 30 and 50 years. Cardiac manifestations comprise palpitations, intermittent tachycardia, and episodic syncope, which frequently increase with age. Frequent ECG abnormalities are atrioventricular or intraventricular block. Some patients develop fatal arrhythmias. Idiopathic car-diomyopathy is rare. Cerebral MRI may demonstrate atrophy but less severe than in DM1. g-Glutamyltransferase may be elevated.
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The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.