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January 1966

Picture of the Month

Am J Dis Child. 1966;111(1):81-82. doi:10.1001/archpedi.1966.02090040117016

Denouement and Discussion 

MYOTONIA CONGENITA  (Thomsen's Disease)

MAJOR MANIFESTATIONS  Myotonia—or increased tone—of all voluntary muscles may be present, decreasing with repeated movement. The muscles, especially those of the extremities, become hypertrophied, giving the patient a herculean appearance. There is impaired release of grip, stiffness of gait on first attempts at walking, and slowness at starting any activity involving voluntary musculature. Following the relaxation of the muscles in use, a new activity involving another muscle group will again cause myotonia. Any sudden movement such as a sneeze may cause the involved muscles to go into spasm. Spasm of the extraocular muscles may cause a convergent strabismus and occasionally there may be some respiratory difficulties. Percussion of a muscle group will cause marked myotonia due to spasm of the affected fasciculus. This is well demonstrated by percussion of the thenar eminence or the deltoid muscle. Cold, fatigue, and excitement will increase the