Paramyotonia congenita


A rare inherited muscle condition where muscles are difficult to relax following contraction. The main muscles affected are in the face, neck, arms and hands. Repetition of movements makes the muscle stiffness become progressively worse. The condition is not progressive and exposure to cold can trigger symptoms.


* Flaccid muscle paralysis * Reduced reflexes * Difficulty relaxing muscles following contraction * Muscle stiffness


Diagnosis of paramyotonia congenita is made upon evaluation of patient symptoms and case history. Myotonia must increase with exercise/movement and usually must worsen in cold temperatures. Patients that present with permanent weakness are normally not characterized as having PC. Electromyography may be used to distinguish between paramyotonia congenita and myotonia congenita.[4],[5] Clinicians may also attempt to provoke episodes or myotonia and weakness/paralysis in patients in order to determine whether the patient has PC, hyperkalemic periodic paralysis, or one of the potassium-aggravated myotonias. Genomic sequencing of the SCN4A gene is the definitive diagnostic determinant.


The 'prognosis' of Paramyotonia congenita usually refers to the likely outcome of Paramyotonia congenita. The prognosis of Paramyotonia congenita may include the duration of Paramyotonia congenita, chances of complications of Paramyotonia congenita, probable outcomes, prospects for recovery, recovery period for Paramyotonia congenita, survival rates, death rates, and other outcome possibilities in the overall prognosis of Paramyotonia congenita. Naturally, such forecast issues are by their nature unpredictable.


Some patients do not require treatment to manage the symptoms of paramyotonia congenita. Others, however, require treatment for their muscle stiffness and often find mexiletine to be helpful. Others have found acetazolamide to be helpful as well. Avoidance of myotonia triggering events is also an effective method of mytonia prevention.