Index
Muscle Conditions with Myotonia or Myotonia-like Symptoms
Clinical and Electrical Myotonia
Conditions where both clinical symptoms of myotonia (delayed muscle relaxation after contraction) and electrical myotonia (diagnosed via EMG) are present:
- Dystrophic Muscle Conditions:
- Myotonic Dystrophy Type 1 (DM1)
- Myotonic Dystrophy Type 2 (DM2)
- Non-Dystrophic Muscle Conditions (Channelopathies):
- Chloride Channel (CLCN1) Disorders:
- Myotonia Congenita:
- Thomsen Disease (AD)
- Becker Disease (AR)
- Myotonia Congenita:
- Sodium Channel (SCN4A) Disorders:
- Paramyotonia Congenita
- Hyperkalemic Periodic Paralysis with Myotonia
- Myotonia Fluctuans
- Myotonia Permanens
- Acetazolamide-Responsive Myotonia
- Chloride Channel (CLCN1) Disorders:
Electrical but Not Clinical Myotonia
Conditions where electrical myotonia is evident on EMG but without observable clinical symptoms:
- Myopathies:
- Myotubular Myopathy
- Centronuclear Myopathy
- Acid Maltase Disease (GSD II, Pompe Disease)
- Other Conditions:
- Rippling Muscle Disease
- Hypothyroidism
- Schwartz-Jampel Syndrome
- Episodic Ataxia Type 1
Symptoms Mimicking Myotonia (No Clinical or Electrical Evidence of Myotonia)
Conditions with symptoms resembling myotonia but lacking clinical or electrical features:
- Neuromuscular and Systemic Disorders:
- Stiff-Person Syndrome
- Brody Disease
- Isaacs’ Syndrome
- Periodic Paralysis Syndromes:
- Hypokalemic Periodic Paralysis
- Normokalemic Periodic Paralysis
- Calcium Channel (CACNA1S) Disorders:
- Hypokalemic Periodic Paralysis
Medication-Induced Symptoms Mimicking Myotonia
- Drugs Implicated:
- Colchicine
- HMG-CoA Reductase Inhibitors (Statins)
- Propranolol
- Terbutaline
- Penicillamine
- Cyclosporine
Genetic Patterns and Inheritance:
- Autosomal Dominant (AD):
- Thomsen Disease (Myotonia Congenita)
- SCN4A Disorders (Paramyotonia Congenita, etc.)
- Calcium Channel (CACNA1S) Disorders
- Autosomal Recessive (AR):
- Becker Disease (Myotonia Congenita)
