Pathogenesis
Causes of Myotonia
Myotonic Dystrophy
- Dystrophia myotonia
- Myotonia congenita
Non-Dystrophic Myotonia
- Paramyotonia congenita
- Acid maltase deficiency
Manifestations
Manifestations of Myotonic Dystrophy
- Myotonia
- Cognitive impairment
- Cataracts
- Hearing impairment
- Endocrine - diabetes, hypogonadism, secondary hyperparathyroidism
- Cardiovascular - arrhythmia, cardiomyopathy, sudden cardiac death
- Respiratory - obstructive sleep apnoea
- Gastrointestinal - transaminase elevation, constipation / diarrhoea
- Hypogammaglobulinaemia
Diagnosis
Clinical Signs
- Myopathic facies - temporalis wasting, mandibular wasting, frontal baldness
- Flaccid dysarthria - nasal speech, breathiness, monotony, impaired articulation
- Warm-up phenomenon - grip myotonia, repeated eye closure
- Percussion myotonia - muscle contraction with percussion of the thenar eminence
- Wasting of the forearm and small muscles of the hand
- Distal muscle weakness
- Hyporeflexia
Next Page
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------