Hello! :)
8. APPEARNACE OF MUSCLE :-
- Hypertrophy of Calf muscles =
Dytrophinopathies or Limb girdle muscular dystrophy.
-Pseudohypertrophy= Duchene's
muscular dystrophy, infiltration by sarcoid granulomas,amyloid deposit,
bacterial and parasitic infections.
-Atrophy of gastrocnemius muscles
in medial aspect = Dysferlinooathies
- Atrophy of humeral muscles= FSHD
9. REFLEXES PRESERVED
10. LAB INVESTIGATIONS:-
1. ENZYMES: - I have already
discussed its role in metabolic myopathies.
- ALT, AST, LDH,aldolase :- Found
in both skeletal muscle and liver.Elevated GGT help to establish its liver
origin.
-CK (MM) help to evaluate
myopathies.
2. ELECTRODIAGNOSTIC STUDIES:
-EMG: - diagnose myopathy and help
to choose right muscle for biopsy.
-NCS (nerve conduction
studies):-Help to differentiate myopathies from neuropathy and NMJ disorders.
Diagnostic test for specific type
of myopathies:-
1. FOREARM EXERCISE TEST:-
- Place an indwelling catheter in
to an antecubital vein and obtain baseline blood sample for lactic acid and
ammonia.
-The forearm muscles are exercised.
Vigorously squeeze the sphygmomanometer bulb for 1 min.
-Blood is then obtained at the
intervals of 1,2,4,6 and 10 min for comparison with baseline.
Normally, Both glucose and ammonia
increases with exercise.
Interpretation:-
-Glycolytic defects: - Lactic acid
rise is absent or below normal while rise in ammonia will reach the control
values.
-Myoadenylate deaminase deficiency:
- there occur a selective failure to increase ammonia.
2. DNA ANALYSIS: - Some muscle
disorder are associated with gene defects like deletions and mutations. (In
Duchene muscular dystrophy, we will see it.)
3. MUSCLE BIOPSY:-
-Safe diagnostic procedure in
establishing the final diagnosis of suspected myopathy.
-Different techniques of
microscopic evaluation: - Histology, immunohistochemistry with antibodies,
electron microscopy.
-SITE: - muscle selected may have
mild to moderate muscle weakness.
-NOT PERFORMED ON: - Muscle injured
by previous trauma,injections and EMG needles
-COMMON MUSCLES USED FOR BIOPSY:-
PROXIMAL: biceps, triceps,
quadriceps
DISTAL: - Extensor carpi radialis,
Anterior tibialis.
*Claps*
We are done with the basic for
myopathy.
Now I will go through individual
myopathy. :D
I remember age and progression of myopathy part. :) I will discuss it in next part.
Take care.
-Upasana Y.
