Use the difference between myotonia and paramyotonia, you clinically test for myotonia and paramyotonia, and cramp-fasciculation syndrome to frame the working diagnosis and next step; anchor the next clinical decision to it rather than restating it. Make you clinically test for myotonia and paramyotonia the checkpoint that determines whether you escalate testing, narrow the differential, or change treatment.

Classic myotonia improves with repetition, while paramyotonia worsens with repeated use; Cold exposure aggravates both disorders; Cramp-fasciculation syndrome causes fasciculations, myalgias, and myokymia, often with EMG confirmation; Isaacs syndrome can cause continuous neuromyotonia even during sleep; Carbamazepine is a common symptomatic treatment for peripheral nerve hyperexcitability syndromes