Myopathy II

Question 1

Limb-Girdle MD

Answer 1

Age of onset: teens to early adulthood (up to late 40’s)
•Inheritance/gender: AR (chromosome 5 = calpain 3 protein), AD (chromosomes 2, 13, 15, 17 = adhalin protein) / males and females
•Muscles first affected: proximal muscles; hip/shoulder girdle – scapular winging, lumbar lordosis, abdominal protrusion, poor balance, inability to raise arms; face muscles not affected
•Progression: usually slow; starts in hips and moves to shoulders; often milder impairments; walking difficult within 20 years of age; often spontaneous mutation

Question 2

Emery-Dreifuss MD (humeroperoneal)

shoulders upper arms/ lower legs

Answer 2

Age of onset: childhood to early teens
•Inheritance/gender: X-linked (protein = emerin) /males
•Muscles first affected: shoulders, upper arms, lower legs; contractures often appear before significant muscle weakness is experienced
•Progression: slow with less severe muscle weakness; life-threatening heart problems (conduction defects) can occur (in females as well); life expectancy variable

Question 3

Type I cells affected

Type 1 smaller than type II

Answer 3

Muscle types

Question 4

Facioscapulohumeral MD (aka Landouzy-Dejerine MD)

Answer 4

Age of onset: variable, usually teens to early adulthood (may be infancy to 30s or 40s)
•Inheritance/gender: AD (chromosome 4 = ? Protein) / males and females
•Muscles first affected: face, shoulders (latissimus dorsi spared), upper arms; may have hearing or vision problems; forward sloping of shoulders, difficulty raising arms over head and closing eyes, expressionless face
•Progression: slow proximal to distal (sometimes with rapid spurts); life expectancy variable

Question 5

More than 1/2 of MD is

Answer 5

Duchanes

Question 6

Scapuloperoneal MD

Answer 6

A variation of FSH (without face involvement)
•Age of onset: any age, from early childhood to adult
•Inheritance/gender: AD (chromosome 12 = ? Protein) or AR / males and females
•Muscles affected first: distal muscles of LE, then proximal shoulder girdle muscles; often present with foot drop first; shoulder weakness develops later
•Progression: ?

Question 7

Myotonic Dystrophy (MTD)

Answer 7

•Age of onset: adolescent most common
–Severe form is Congenital MD
•with onset at birth, associated with hypotonia, severe MR, spinal deformities, and frequently early death
•Inheritance/gender: AD (chromosome 19 = DMPK gene) / males and females
•Muscles affected first: distal wasting then proximal; myotonia, delay in muscle relaxation time, muscle weakness; complaints of weakness and stiffness
•Progression: generalized and variable; foot drop and intrinsic muscle wasting first signs; Long thin “hatchet” face, frontal balding, SCM weak and wasted; skeletal, cardiac and smooth muscle may be affected; life expectancy depends on onset

Question 8

Myotonic Dystrophy (MTD)

Answer 8

•Congenital severe
•Adult progression
Hatchet face
temporalis wasting
balding
wasting of scm

Question 9

Congenital Muscular Dystrophy

Answer 9

Age of onset: at birth
•Inheritance/gender: AR / males and females
•Muscles first affected: generalized, small muscle weakness, poor muscle tone; joint contractures common
•Progression: slow, short life span; brain abnormalities common with MR, seizures, speech problems

Question 10

Oculopharyngeal MD

Answer 10

Age of onset: 40s, 50s
•Inheritance/gender: AD or AR (chromosome 14 = protein poly(A) binding protein 2) / males and females
•Muscles first affected: drooping eyelids, throat muscles (difficulty swallowing); progresses to weak pelvic/ shoulder muscles
•Progression: slow; swallowing problems can lead to choking and recurrent pneumonia
•Ophthalmoplegic

Question 11

Distal MD

Answer 11

Age of onset: childhood to adulthood

–
•Muscles first affected: a rare group with common weaknesses and wasting of distal muscles of forearm, hands, lower legs and feet
•Progression: variable, usually slow; generally less severe; walking improved with orthopedic foot/ankle devices

Question 12

Muscles Affected and severity

Answer 12

Study Chart

Question 13

With most dystrophies do what exercises

Answer 13

Eccentric Exercises

Question 14

Inflammatory Myopathies

Answer 14

•A sporadic, hereditary factor implicated with an abnormal immune system
–However, these are not familial diseases
•Direct invasion of microorganisms secondary to systemic infections
–Exception: primary with Trichinosis
•Voluntary muscles undergo degenerative changes
(Prevent)
–Weakness and wasting
–Inflammation
•Cardinal symptom is muscle weakness
–Usually progressive and may be severely disabling
•Patient has difficulty rising from chair, climbing stairs,
holding arms upright
–Excessive fatigue with prolonged standing or walking
–Clumsy, waddling gait with tendency to fall
–In some cases, may spread to throat and respiratory muscles

Question 15

Inflammatory Myopathies

Answer 15

•Polymyositis and Dermatomyositis most common
•Occur at all ages with bimodal incidence
–5-15 yo incidence
–40-60 yo incidence
•Females > males
•Varies in severity, rate of progression, symptoms, and complications, but usually muscle weakness develops within weeks or months (not years like with MD)
–Typically symmetrical
–First noticed in proximal muscles of pelvic and shoulder girdles
•Treatment
–Prednisone
–Immunosuppressive medication
–Plasmapheresis

Question 16

Dermatomyositis

Answer 16

Boy of 9.5 years. Sudden onset of muscle pains followed by weakness, symmetric, scaly, erythematous papules over the metacarpophalangeal and proximal interphalangeal joints of the hands (Gottron’s sign), and reddish purple facial rash

Question 17

Tests for Polymyositis

Answer 17

•MRI
•EMG
•Muscle biopsy
•Blood levels of muscle enzymes
–Creatine kinase (CK) and aldolase

Question 18

Treatments for Polymyositis

Answer 18

Drugs
–Corticosteroids
–Corticosteroid sparing-immunosuppressants
•Methotrexate, Azathioprine
•Antibody therapy (IV Ig)
•Biological
–Enbrel and Remicade not effective
•TNF inhibitors
•Physical Therapy

Question 19

How Do Inflammatory Myopathies Differ?

Answer 19

Polymyositis
–More clinically diverse and more difficult to define
–Less likely to involve pronounced pain with movement
–More slowly progressive (rule out late onset MD with muscle biopsy)
–Frequently associated with autoimmune collagen diseases (SLE, RA, scleroderma, Sjogren’s syndrome, MCTD)

Dermatomyositis
–Muscle weakness associated with a patchy, erythematous skin rash over cheeks, eyes, neck, shoulders, or upper chest
–Gottron’s sign: scaly, patchy redness over MCPs
–When acute, movement painful with tender, swollen muscles
–Higher incidence of associated malignancy (lymphoma, breast, lung, ovarian, colon)