myotonia congenita Flashcards
what type of disease is this?
congenital
which bodily system does it effect?
neuromuscular
how do skeletal muscles behave in this condition?
-i.e. give the main feature
contract but then can not relax
which gene is implicated?
what does this gene code for?
CLCN1
Cl- channels
symptoms?
-5
Stiffness Hypertrophy Spasm Cramp Legs worse
what happens to muscle size?
Hypertrophy
which is worse, arms or legs?
Legs worse
which “effect” is seen with myotonia congenita?
what is this effect?
warm up effect
Relief through repetitive movements
what happens to handgrip?
Inability to quickly release hand grip
after initial Ix what test is used to confirm diagnosis?
gene testing
pt has myotonia congenita disease.
what feature is seen on blood tests that helps with recognising this is a muscle problem?
Serum CK – slightly elevated
pt has suspected myotonia congenita disease.
what Ix can be used to see nerve behaviour?
positive result on this test?
Electromyography
repetitive discharge of action potential seen
list all potential Ix? and the positive result for each.
-5
Electromyography – repetitive discharge of action potential seen
Muscle biopsy – usually normal, but can reveals minimal abnormal changes (e.g. hypertrophied muscle)
Direct muscle percussion – percussion myotonia
Serum CK – slightly elevated
gene testing - CLCN1 mutated
