Show Summary Details
Page of

Myotonia 

Myotonia
Chapter:
Myotonia
Author(s):

David Hilton-Jones

DOI:
10.1093/med/9780198746690.003.0610
Page of

PRINTED FROM OXFORD MEDICINE ONLINE (www.oxfordmedicine.com). © Oxford University Press, 2021. All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in Oxford Medicine Online for personal use (for details see Privacy Policy and Legal Notice).

date: 26 February 2021

Myotonia is defined at an electrical level as repetitive discharge of the muscle fibre membrane after initial activation, which occurs due to dysfunction of the membrane’s ion channels, most commonly the chloride channel, less commonly the sodium channel. This manifests clinically as stiffness of the muscle and delayed relaxation after voluntary contraction (e.g. difficulty relaxing the grip after clenching the fingers, and stiffness in the thigh muscles and difficulty walking on first moving after rest). Disabling myotonia may respond to carbamazepine, phenytoin or, often most effectively, mexiletine, although supplies are now limited. This chapter takes a closer look at the condition, its symptoms, presentations, diagnosis, and treatment.

Access to the complete content on Oxford Medicine Online requires a subscription or purchase. Public users are able to search the site and view the abstracts for each book and chapter without a subscription.

Please subscribe or login to access full text content.

If you have purchased a print title that contains an access token, please see the token for information about how to register your code.

For questions on access or troubleshooting, please check our FAQs, and if you can't find the answer there, please contact us.