1
Fifth stage
Medicine
Lec-13
د.بشار
17/4/2016
DISEASES OF THE MUSCLES
MUSCLE DYSTROPHY
CONG. MYOPATHY
MYOTONIC DYSTROPHY
INFLAMMATORY MYOPATHY
METABOLIC MYO.
ENDOCRINE MYO.
ALCOHOLIC MYO.
DRUG-INDUCED MYO.
MUSCLE DYSTROPHIES:
• INHERITED DISORDERS
• PROGRESSIVE MUS. WEAKNESS&WASTING
• SUBDIVIDED BY:-MODE OF INHERITANCE
AGE OF ONSET
DISTRIBUTION OF INVOLVED MUSC.
RATE OF PROGRESSION
DUCHENNES MUS. DYSTROPHY:
• THE MOST COMMON
• BEGIN AT FIVE,SEVERE DISABILITY BY ADOLESCENCE,DEATH IN THIRD DECADE
• TOE WALK.,WADDLING GAIT,INABILITY TO RUN
• LOW. LIMBS >UPP. LIMBS
• GOWER SIGN IS POSITIVE
• PSEUDOHYPERTROPHY OF CALVES
• CARDIOMYOPATHY&MENTAL RETARDATION
• CPK IS VERY HIGH
• NO DEFINITE THERAPY
• STEROIDS 1.5mg/Kg/day
• DYSTROPHIN IS ABSENT OR REDUCED
2
BECKER DYSTROPHY:
• SIMILAR TO DUCHENNE
• ONSET AT 11 –DEATH AT 40s
• CARDIAC &COGNITIVE FUNCTION IS NORMAL
• CPK IS LESS ELEVATED
• DYSTROPHIN STRUCTURE IS ABNORMAL
LIMB GIRDLE MUS. DYSTROPHY:
• AUT. RECESSIVE/CHROM 15
• LATE CHILD. TO EARLY ADULTHOOD
• SHOULDER&PELVIC GIRDLE MUSCLES
• NO PSEUDOHYPERTROPHY
• CPK IS LESS ELEVATED
FACIOSCAPULOHUMERAL DYSTRO.:
• AUT. DOMINANT
• ONSET AT ADOLESCENCE/// NORMAL LIFE SPAN
• WEAKNESS IN FACE, NECK, SHOULDER MUSCLES
• WINGING OF SCAPULAE
• HEART IS NORMAL
• CPK IS NORMAL
DISTAL MYOPATHY:
• AD
• ONSET AFTER 40/// SLOW PROGRESSION
• SMALL MUS. OF HANDS &FEET,,WRIST EXT.&FOOT DORSIFLEXORS
• MAY BE AR OR SPORADIC
OCULAR DYSTROPHY:
• AUTO. DOMINANT COULD BE RECESSIVE
• ONSET < 40
• SLOWLY PROGRESSIVE
3
• PTOSIS , OPHTHALMOPLEGIA,FACIAL WEAKNESS
OCULOPHARYNGEAL DYSTROPHY:
• AUTO.DOMINANT
• ONSET: 3
rd
-5
th
DECADE
• PTOSIS, OPHTHALMOPLEGIA, DYSPHAGIA, FACIAL WEAKNESS &PROX. MUSCLE
WEAKNESS
• MILD ELEVATION OF CPK
PARASPINAL DYSTROPHY:
• ONSET >40
• BACK PAIN &KYPHOSIS
MYOTONIA:
• ABNORMALITY OF MUSCLE FIBRE MEMBRANE LEADING TO MARKED DELAY OF
RELAXATION AFTER CONTRACTION CAUSING APPARENT MUSCLE STIFFNESS.
• PERCUSSION MYOTONIA ------- THENAR MUSCLES AND
TONGUE
•
MYOTONIC DYSTROPHY:
• AUTO. DOMINANT
• MANIFEST IN 3
rd
OR 4
th
DECADE
• MAY APPEAR IN EARLY CHILDHOOD
• MYOTONIA, WEAKNESS&WASTING OF FACIAL, STERNOCLIEDOMASTOID&DISTAL
LIMB MUSCLES WITH PTOSIS.
• CATARACT, DM,FRONTAL BALDNESS,TESTICULAR ATROPHY,CARDIAC&INTELLECTUAL
DEFECT
• MYOTONIA IS TREATED WITH QUININE SULPHATE300-400mg tds OR PROCAINAMIDE
0.5-1 gm qds OR PHENYTOIN 100mg tds
MYOTONIA CONGENITA:
4
• AUTO. DOMINANT ,MUTATION IN CHRO.7
• GENERALIZED MYOTONIA , NO WEAKNESS
• PRESENT FROM BIRTH BUT SYMPTOMS MAY NOT DEVELOP UNTIL EARLY CHILDHOOD
• MUS. STIFFNESS IS ENHANCED BY COLD &INACTIVITY RELIEVED BY EXERCISE
• MUSCLE HYPERTROPHY SOMETIMES PRONOUNCED
• AUTO. RECESSIVE FORM:-
• LATER ONSET, SLIGHT WEAKNESS, ATROPHY OF DISTAL MUSCLES
• TREATMENT OF MYOTONIA
METABOLIC MYOPATHY:
• PROXIMAL MUSCLE WEAKNESS
• CHRONIC HYPOKALEMIA
• ACUTE HYPOKALEMIA OR HYPERKALEMIA
• OSTEOMALACIA WITH BONE PAIN &TENDERNESS,MILD DECREASE IN
SERUM Ca , INCREASE ALK. PHOSPHATASE. TREATMENT WITH VIT. D
• PERIODIC PARALYSIS SYNDROMES
• MAY BE FAMILIAL, AUTO. DOMINANT
• EPISODES OF FLACCID WEAKNESS OR PARALYSIS
• STRENGTH IS NORMAL BETWEEN THE ATTACKS
• HYPOKALEMIC, HYPERKALEMIC, NORMOKALEMIC
FPP:
HYPOKALEMIC:
• ASSOCIATED WITH THYROTOXICOSIS
• ATTACKS ON AWAKENING,
• AFTER EXERCISE OR HEAVY MEAL
• MAY LAST FOR SEVERAL DAYS
• ACETAZOLAMIDE OR ORAL POTTASIUM FOR PREVENTION
• ORAL OR I.V.POTTASIUM FOR TREATMENT
• THYROTOXICOSIS SHOULD BE TREATED
HYPERKALEMIC:
• ATTACKS AFTER EXERCISE
• BRIEFER < 1 hr
• SOMETIMES ASSOCIATED WITH MYOTONIA
• Rx WITH Ca GLUCONATE, I.V. DIURETICS LIKE LASIX OR GLUCOSE
• ACETAZOLAMIDE OR CHLOROTHIAZIDE FOR PREVENTION
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NORMOKALEMIC
• UNRESPONSIVE TO TREATMENT
ENDOCRINE MYOPATHY:
• HYPER. OR HYPOTHYROIDISM
• HYPER. OR HYPOPARATHYROIDISM
• HYPER. OR HYPOADRENALISM
• HYPOPITUITARISM
• ACROMEGALY
DRUG- INDUCED:
• STEROIDS
• CHLOROQUINE
• CLOFIBRATE
• B-BLOCKERS
• COLCHICINE
• EMETINE ZIDOVUDINE
INFLAMMATORY MYOPATHY
POLYMYOSITIS &DERMATOMYOSITIS
لالطالع
• DESTRUCTION OF MUSCLE FIBERS&INFLAMMATORY CELL INFILTRATION
• OCCUR AT ANY AGE
• FEVER, MUSCLE PAIN, TENDERNESS&WASTING OF PROXIMAL LIMB &GIRDLE
MUSCLES
• ARTHRALGIA ,MALAISE ,WEIGHT LOSS ,DYSPHAGIA ,RESP.DIFFICULTIES ,RAYNAUD
PHENOMENA
• VARIABLE PROGRESSION
• IN DERMATOMYOSITIS THERE IS ERYTHEMATOUS RASH AROUND THE EYES &EYELIDS
• MAY BE ASSOCIAT. AUTOIMMUNE DISEASES
• IN ADULTS WITH CANCER
CPK IS ELEVATED, IF NORMAL DOESN’T EXCLUDE DIAGNOSIS
EMG SHOWS MYOPATHIC CHANGES
TREATMENT WITH STEROIDS, PREDNISOLONE 60- 80 mg / day for ? 2-3 YEARS
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POLYMYALGIA RHEUMATICA
لالطالع
• MORE IN WOMEN ABOVE 60 YEARS
• MUSCLE PAIN &STIFFNESS ABOUT THE NECK &GIRDLE MUSCLES
• HEADACHE, ANOREXIA , Wt LOSS, LOW GRADE FEVER,
• RAISED ESR
• ENZYMES, EMG, MUS. BIOPSY ARE NORMAL
• Rx PREDNISOLONE 10- 15 mg/ day for ? One year
• GIANT CELL ARTERITIS
DISEASES OF NEUROMUSCULAR JUNCTION
MYASTHENIA GRAVIS
• OCCUR AT ANY AGE
• MORE IN FEMALES
• FLUCTUATING WEAKNESS&EASY FATIGUABILITY OF VOLUNTARY MUSCLES
• WEAKNESS IS DUE TO IMMUNE- MEDIATED DECREASE IN THE NUMBER OF AchR
LEADING TO BLOCK OF N-M. TRANSMISSION
• MAY BE ASSO. WITH THYMIC TUMOR, THYROTOXICOSIS, SLE, Rh. Arthritis
CLINICALLY
INSIDIOUS ONSET
PTOSIS, DIPLOPIA , DIFFICULTY IN CHEWING OR SWALLOWING,
NASAL SPEECH
RESP. DIFFICULTY &LIMB WEAKNESS
SYMPTOMS ARE FLUCTUATING IN SEVERITY ( DIURNAL VARIATION)
SPONTANEOUS RELAPSES &REMISSIONS
EXACERBATIONS ---- infection, pregnancy, premenstrual &drugs
EXAMINATION ----NO ATROPHY, NO REFLEX CHANGES, NO SENSORY SIGNS,
CONFIRM WEAKNESS& FATIGUABILITY, SUSTAINED UPGAZE,
REPEATED KNEE BENDING
DIAGNOSIS-----CLINICAL, TENSILON TEST, EMG, AchR ANTIBODIES
CXR & CT CHEST
TREATMENT----- ANTICHOLINESTRASE
THYMECTOMY
STEROIDS
AZATHIOPRINE
PLASMAPHERESIS
I. V. IMMUNOGLOBULIN