1. Muscle Dystrophy Jon Durrani, DO Attending Neurologist
Dayton Center for Neurologic Disorders

2. What is Muscle Dystrophy?
Essentially a group of muscle wasting disorders that cause a breakdown and subsequent of skeletal muscle over time. 
There is great variability among the various dystrophies, including the muscle groups effected, the degree of weakness, the rate of decline, and the when the symptoms first appear. 
Despite all the technology of today, there is no known cure yet discovered.  

3. Types of Muscle Dystrophy
There are nine main categories of muscle dystrophy, within those categories there are more than thirty types of specific muscle dystrophies that can be diagnosed. 
This discussion today will focus on the three main ones likely to be seen in practice: Duchenne Muscle Dystrophy (DMD), Becker Muscle Dystrophy, and Myotonic Dystrophy. 

4. General Symptoms of Muscle Dystrophy
Poor Balance
Scoliosis
Progressive inability to walk

5. General Symptoms of Muscle Dystrophy
Progressive muscle wasting of skeletal muscles

6. General Symptoms of Muscle Dystrophy
Waddling gait

7. General Symptoms of Muscle Dystrophy
Calf deformation
Limited range of movement
Respiratory difficulty
Cardiomyopathy
Muscle Spasms

8. General Symptoms of Muscle Dystrophy
Gower's sign

9. Causes of Muscle Dystrophy
Generally speaking, these are inherited genetic disorders. 
There are many patterns of inheritance and very from each subtype of muscle dystrophy, and can be X-linked, recessive, or dominant. 
There are rare instances where there is de novo mutations within the individual with on family history of muscle dystrophy. 

10. Diagnosis of Muscle Dystrophy
History of the patient and family members that may have been affected.
Initial testing of muscle testing includes a physical examination, look for the aforementioned signs and symptoms. 
Additionally, further investigation includes muscle biopsy, CK testing, EMG, and genetic testing. 

11. Diagnosis of Muscle Dystrophy
Additionally, Chest X-rays, Echocardiogram can be performed as well. 

12. Treatment of Muscle Dystrophy
Even in 2018, unfortunately we do not have a cure for muscle dystrophy.
The main stays of treatment today are:
Physical therapy
Occupational Therapy
Orthortic Intervention (AFO, etc.)
Speech Therapy
Respiratory Therapy
Steroids (Prednisone)

13. Duchenne Muscular Dystrophy

14. Duchenne Muscular Dystrophy
X-linked recessive, 1:3300 males
Xp21, dystrophin gene mutation (2/3 familial, 1/3 new mutations)
Females with a single copy of the gene may show mild symtpoms
Typically presents at 5 years old
difficulty running
abnormal gait (waddling)
historic motor delay

15. Duchenne Muscular Dystrophy
Physical Exam:
Musculoskeletal
Lumbar lordosis
Pseudohypertrophy (enlarging) of tongue and calf muscles. The muscle tissue is eventually replaced by fat and connective tissue, hence the term pseudohypertrophy.

16. Duchenne Muscular Dystrophy
Neurologic Exam:
Neck flexor weakness
Symmetric and proximal UE and LE weakness, LE > UE
Diffuse hypotonia, DTRs 1+ diffusely

17. Duchenne Muscular Dystrophy
Other system involvement
Dystrophin is found in skeletal muscle, smooth muscle, cardiac muscle and brain
May have cognitive impairment
All develop cardiomyopathy
Cardiac involvement may require a pacemaker
May develop intestinal pseudo-obstruction
Higher risk of neurobehavioral disorders (e.g., ADHD), learning disorders (dyslexia), and non-progressive weaknesses in specific cognitive skills (in particular short-term verbal memory), which are believed to be the result of absent or dysfunctional dystrophin in the brain.

18. Duchenne Muscular Dystrophy
Diagnosis
CK elevated (10x upper limit normal)
Muscle biopsy (absent dystrophin)
Genetic/DNA testing
+/- EMG/NCV

19. Duchenne Muscular Dystrophy
Prognosis
Supportive care
+/- steroids
Wheelchair bound by 13 years old
Death in 20s from respiratory or cardiac failure

20. Becker Muscle Dystrophy

21. Becker Muscle Dystrophy
Same pathogenesis as DMD
Except for inframe mutations for BMD, out of frame for DMD

22. Becker Muscle Dystrophy
Slower course
Present between 5-15 years old
Wheelchair bound after 16 years old
Live through their 30s-40s

23. Becker Muscle Dystrophy
Less severe course, less likely to have
Cognitive impairment
Cardiac disease
Contractures
Scoliosis
GI issues

24. Becker Muscle Dystrophy
CK elevated (5x upper limit of normal)
Muscle biopsy with decreased dystrophin

25. Congenital Myotonic Dystrophy

26. Congenital Myotonic Dystrophy
Autosomal Dominant
> 1000 CTG repeats in the DMPK gene, 19q13.3 (anticipation)
Mom is typically the affected parent (check her grip!)

27. Congenital Myotonic Dystrophy
Poor fetal movement, polyhydramnios
Feeding and respiratory difficulties, cognitive
impairment, developmental delay

28. Congenital Myotonic Dystrophy
There are two kinds of Myotonic Dystrophy
DM1 and DM2
DM1 has an error in the DMPK gene.
DM2 has an error in CNBP gene.

29. Congenital Myotonic Dystrophy
Neurologic Exam:
Facial diplegia
Hypotonia
Decreased DTRs
Intellectual disability

30. Congenital Myotonic Dystrophy
Other Physical Exam findings:
Joint deformities, from clubfoot to arthrogryposis
Cataracts
Heart Conduction problems

31. Congenital Myotonic Dystrophy
No clinical or EMG myotonia until 2 years of age
Genetic testing

32. Congenital Myotonic Dystrophy
Treatment
There is no treatment for myotonic dystrophy
Pain can be treated with tricyclic antidepressants (Amitryptiline, Nortyptiline) or NSAIDs
Associated Sleep Apnea – OSA, CSA treated with appropriate devices.
Orthotics
Physical Therapy

33. Muscle Dystrophy The future:
Research Currently in the United States and the UK with gene research and neuromuscular regeneration.