The document provides a comprehensive overview of myopathies, including their definitions, symptoms, classifications, and laboratory investigations. It details various types of muscular dystrophies, their clinical features, inheritance patterns, and diagnostic methods, along with treatment options for conditions like Duchenne and Becker muscular dystrophies. Additionally, it addresses associated disorders of muscle energy metabolism and mitochondrial myopathies.

1. MYOPATHY
DR BIPUL BORTHAKUR
PROF & HEAD
DEPT. OF ORTHOPAEDICS
SILCHAR MEDICAL COLLEGE

2. LEARNING OBJECTIVES
 INTRODUCTION
 SYMPTOMS
 CLASSIFICATION
 LABORATORY INVESTIGATIONS.
 INDIVIDUAL MYOPATHY.
 TREATMENT

3. MYOPATHY
 These are disorders with structural changes or
functional impairment of muscle.

4. INTRODUCTION
 Skeletal muscle is made up of large number of multinucleated
muscle fibres with outer membrane and cytoplasm
(sarcoplasm).
 The fibres are separated by connective
tissue(endomysium) and arranged in bundles(fasciculi).
 Each fasciculus has a connective tissue sheath(perimysium).

5. STRUCTURE OF SKELETAL MUSCLE

6. HISTOLOGY

7. GROUP OF SYMPTOMS
 Motor manifestations-
1)weakness- bilateral ,symmetrical affecting certain
group of muscles (proximal).
2) Hypotonia .
3) Change in muscle bulk(pseudohypertrophy).

8.  Pain- It is rare complaint in primary muscle disease.
 No sensory manifestations.
 No sphincter dysfunction.

9. CLASSIFICATION
 Primary - Progressive muscle dystrophy.
 Secondary –
1)Inflammatory.
2)Metabolic, periodic familial paralysis.
3)Endocrinal, thyrotoxic, cushing.
4)Drug induced- corticosteroid, statin.
5) Miscellaneous, carcinomatous.

10. CLASSIFICATION OF PROGRESSIVE
MUSCLE DYSTROPHY
1) X-LINKED DISORDERS
A) Duchenne’s muscular dystrophy.
B) Becker’s muscular dystrophy.
2) AUTOSOMAL RECESSIVE DISORDERS
A) Limb- Girdle muscular dystrophy.

11. AUTOSOMAL DOMINANT DISORDERS
 Fascio-scapulo- humeral muscular dystrophy.
 Distal myopathy.
 Ocular myopathy.
 Oculo-pharyngeal myopathy.

12. MYOPATHY BASED ON
WEAKNESS/MUSCLE INVOLVEMENT
PROXIMAL WEAKNESS(LIMB GIRDLE)
 Limb girdle , myotonic dystrophy type 2,rare FSHD.
 Congenital myopathies.
 Metabolic myopathies(glycogen and lipid storage)
 Mitochondrial myopathies.
 Inflammatory myopathies.
 Toxic myopathy.
 Neuromuscular junction disorders(myasthenia gravis, LEMS
etc).

13. BASED ON DISTAL WEAKNESS
 Distal muscular dystrophies/Myofibrillar dystrophy.
 Late onset centronuclear and nemaline rod
myopathy.
 Metabolic like Glycogen storage (McArdle disease)
Lipid storage disease(neutral lipid storage myopathy)
 NMJ disorders (myasthenia gravis etc).

14. SCAPULOPERONEAL/HUMEROPERONEAL
WEAKNESS
 Facioscapulohumeral muscular dystrophy(FSHD).
 Emery-Dreifuss muscular dystrophy(EMMD).
 Bethlem myopathy.

15. DISTALARM/PROXIMAL LEG WEAKNESS
 Inclusion body myositis.
 Myotonic dystrophy.

16. AXIAL MUSCLE WEAKNESS
 Inflammatory(cervico-brachial).
 Isolated neck extensor myopathy/Bent spine syndrome.
 FSHD
 Late onset central core(RYR 1 MUTATION).
 Late onset pompe disease.

17. EYE MUSCLE WEAKNESS
 PTOSIS WITHOUT OPHTHALMOPARESIS
A) Myotonic dystrophy.
b) Congenital myopathies.
 PTOSIS WITH OPTHALMOPARESIS
A) Oculopharyngeal dystrophy.
b) Mitochondrial myopathy.

18. MUSCLE STIFFNESS
 Myotonia congenital.
 Paramyotonia congenital.
 Hyperkalemic periodic paralysis with myotonia.
 Schwartz –jampel syndrome.
 Brody disease.

19. SYMPTOMS
 Muscle weakness –
A) Intermittent weakness.
B)Persistent weakness
 Myalgia ,cramps and stiffness.

20. LABORATORY EVALUATION
 Serum enzymes
1)CREATINE KINASE- most sensitive.
2) CK-MB
3)AST,ALT and LDH
4)ALDOLASE
5)GAMMA GLUTAMYL TRANSFERASE

21. ELECTRODIAGNOSTIC STUDIES
 EMG(ELECTROMYOGRAPHY)
 NCS(NERVE CONDUCTION STUDIES)
 REPETITIVE NERVE STIMULATION .

22. EMG AND NCS

23.  GENETIC TESTING IS THE GOLD STANDARD.
 FOREARM EXERCISE TEST.
 MUSCLE BIOPSY- mainly from most affected
muscle is taken.

24. DUCHENNE MUSCULAR DYSTROPHY
 It is the most common muscular
dystrophy affecting 1 in 3500 males
born worldwide.
 Females are carriers.
 Son of carrier mother has 50% chance
of inheriting mutated gene.

25. PATHOGENESIS
 Disorder is caused by mutation in DYSTROPHIN
gene,the largest gene on human x chromosome.
 Muscles undergo repeated cycles of necrosis and
regeneration.
 Mitochondrial dysfunction occurs due to excess
calcium penetration in sarcolemma.

26. PATHOGENESIS

27. CLINICAL FEATURES
 Age of onset – 2 to 6 yrs.
 Difficulty in climbing upstairs .
 Difficulties in running.
 Hypertrrophy of muscles particularly in calves.
 Mental Retardation and cardiomyopathy occurs.
 Cardiomyopathy usually occurs by 2nd or 3rd decade.

28. GOWERS SIGN
 S

29. LABORATORY EVALUATION
 Serum ck levels are elevated(50 to 100 times).
 Western blot analysis of muscle biopsy samples .
demonstrate absent dystrophin.
 Deletions within or duplications of the dystrophin .

30. HISTOLOGY

31. TREATMENT
 Glucocorticoids slows progression in DMD.
 There is NO CURE yet for DMD.
 Positional Aids.
 Nutritional counselling .
 Psychological counselling.

32. BECKER MUSCULAR DYSTROPHY
 X LINKED recessive muscular dystrophy.
 Muscle weakness due to DYSTROPHIN.
 Age of onset(10 to 13) yrs.
 Subtle form of DMD.
 Cardiopathy starts around 4th or 5th decade.
 Physical and occupational therapy are helpful.

33. LIMB GIRDLE MUSCULAR DYSTROPHY
 Males =Females
 Pelvic and Shoulder girdle musculature are affected.
 Immunohistochemistry differentes diff.
types(sarcoglycans,dysferlin,alpha dystroglycans).
 LGMD2L,the most common cause of LGMD is associated
with marked scapular winging,lack of calf muscle
hypertrophy.

34. EMERY-DREIFUSS MUSCULAR DYSTROPHY
 EMERIN and FHL1 mutations are due to X LINKED
inheritance.
 AUTOSOMAL dominant type associated with LAMIN A/C
gene.
 Muscle weakness affects humeral and peroneal
muscles>limb girdle .
 Atrial fibrillation and atrioventricular heart block can occur.

35.  Serum ck increased.
 Muscle biopsy- Myofibrillar myopathy.
 Supportive care and stretching of contractures.
 Use of defibrillators or cardiac pacemakers for
cardiomyopathy and arrhythmias .

36. MYOTONIC DYSTROPHY
 Two types myotonic dystrophy type 1 and 2 (known as
proximal myotonic myopathy).
 Type 1 have hatched faced appearance.
 Complete heart block and sudden cardiac death can occur.
 DM2 affects proximal muscle.
 CK inc,muscle biopsy shows internalised nuclei combined
with many atrophic fibres with pyknotic nuclear clamps.

37.  Cardiac pacemaker or implantable cardioverter
defibrillator should be considered.
 Molded ankle foot orthoses used in foot drop.
 BiPAP and modafinil may be beneficial.

38. FACIOSCAPULOHUMERAL MUSCULAR
DYSTROPHY
 Type 1 and type 2(95 and 5%) respectively.
 Presents in childhood,facial weakness is initial
manifestation.
 Loss of scapular stabilizers .
 COATS disease with telangiectasia,exudation and
retinal detachment occurs.
 NO specific treatment ,ankle foot orthosis are
helpful.

39. OCULOPHARYNGEAL DYSTROPHY
 Includes progressive external ophthalmoplegia.
 Pupil is spared,has late onset.
 Presents with ptosis or dysphagia.
 On electron microscope,feature of OPMD is presence
of 8.5nm tubular filament in muscle cell nuclei.
 Autosomal dominant,affects (French-Canadian and
Ashkenazi jews)
 Cricopharyngeal myotomy improves swallowing.

40. DISTAL MYOPATHIES
 Welander,Udd and Merkesbery-Griggs type distal
myopathies are late onset usually begins after 40
yrs.
 Laig distal myopathy and myofibrillar myopathies
presents with diatal weakness.
 In Miyoshi myopathy Gastrocnemius Muscles are
affected.

41.  Laing and Miyoshi myopathy,rimmed vacuoles can
be seen .
 Occupational therapy for loss of hand function,ankle
foot orthoses for lower limb support.

42. DISORDERS OF MUSCLE ENERGY
METABOLISM
 GLYCOGEN STORAGE AND GLYCOLYTIC DEFECTS
1)Pompe disease-alpha glucosidase or acid maltase
deficiency(type 2 glycogenosis)
- usually infants are affected,childhood form resembles
DMD.
-DEATH by 1.5 yrs.
2) Debranching enzyme deficiency(type 3 glycogenesis)

43.  Branching Enzyme deficiency(type 4 glycogenosis).

44. DISORDERS OF GLYCOLYSIS CAUSING
EXERCISE INTOLERANCE
 McArdle disease caused by myophosphorylase
deficiency.
 Carnitine Palmitoyltransferase 2 deficiency is the
most common cause of recurrent myoglobinuria.

45. MITOCHONDRIAL MYOPATHY
 Kearn-Sayre syndrome.
 Progressive external ophthalmoplegia.
 Myoclonic Epilepsy with Ragged Red
fibres(MERRF).
 Mitochondrial Myopathy,Encephalopathy,Lactic
acidosis and stroke like episodes.(MELAS)
 Mitochondrial DNA depletion Syndromes.

46. THANK YOU