In grip myotonia, the patient has difficulty letting go of an object after gripping it strongly. Percussion myotonia is elicited by tapping on the muscle. Eyelid myotonia may cause transient difficulty opening the eyes after a forceful contraction or transient lid retraction after looking up.
Myotonia occurs in myotonic dystrophy types 1 and 2, the sodium channelopathies (hyperkalemic periodic paralysis and paramyotonia congenita), chloride channelopathies (myotonia congenita) and other conditions. The various conditions causing myotonia that are not DM1 or DM2 are sometimes referred to as the nondystrophic myotonias.
Testing in the patient shown in the video showed a mutation in the SCN4A gene diagnostic of a sodium channelopathy, one of the nondystrophic myotonias.(3) Examination showed grip myotonia and prominent delayed relaxation of the eyelids after forced eye closure (eyelid myotonia).
Video legend. Patient with eyelid myotonia showing delayed relaxation of the eyelids after forced eye closure. Also note the full beard that the patient cited as helpful for mitigating facial muscle stiffening and pain in cold weather.
Video courtesy of Constantine Farmakidis MD and Srijan Adhikari MD, University of Kansas Medical Center.
1. Campbell WW. Clinical signs in neurology: a compendium. Philadelphia: Wolters Kluwer Health, 2016.
2. Roberts K, Kentris M. Myotonia. 2022 May 8. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 32644698.
3. Adhikari S, Statland J, Farmakidis C. Eyelid myotonia and face stiffness in skeletal muscle sodium channelopathy. RRNMF Neuromuscular Journal 2021:2;71-72.