Myotonic disorders

Myotonic disorders

1. myotonia= delayed relaxation after sustained mm contraction

   • IDed clinically and on EMG

2. dystrophia myotonica

   • dominantly inherited
   • caused by nucleotide triplet expansion
     • so there can be anticipation through the generations
       • esp when maternally transmitted
   • presentation
     • newborns
       • hypotonia
       • resp & feeding difficulties
         • due to mm weakness
       • good to examine mum for myotonia
         • manifestation
           • slow release of handshake
           • difficulty releasing tightly clasped fist
     • older kids
       • myopathic facies
       • LD
       • myotonia
   • diagnosis
     • imp to be sensitive while giving diag in the neonate
   • adults
     • cataracts
     • males
       • baldness
       • testicular atrophy
   • death usually due to cardiomyopathy