clincial heredity biochem MYOPATHY biopsy Erik Stålberg Uppsala, Sweden imaging genetics Electrodes A B C MU D E Conc EMG signals from 2-15 muscle fibres CNEMG At rest denervation and spec spontaneous activity (myotonia, CRD, neuromyotonia) MUP number of fibres in recorded area fibre diameters n-m transmission IP recruitment pattern total number of MUs at full effort 1
Spontaneous activity from the muscle Spontaneous activity from the nerve FINDING fibrillation potentials, psw myotonic discharges CRD myokymic discharges myogenic extra discharges Stålberg QUANTIFY AS #/ 10 recording sites or +, ++, +++, ++++ few moderate abundant or spontaneous or after provocation FINDING neuromyotonic discharges myokymic discharges muscle cramps fasciculations neurogenic extra discharges Stålberg QUANTIFY AS #/ 10 recording sites or +, ++, +++, ++++ Few (per time unit) moderate abundant or spontaneous or after provocation Spontaneous acitivity generated in the muscle fibre (Stålberg,Daube 2003) Fibrillation potentials Positive waves Myotonic discharges Complex repetitive discharge 50 ms 100 ms 500 ms 100 uv 100 uv 50 uv 100 uv 5 ms 5 ms 5 ms Muscular dystrophies IBM Debrancher Glycogenosis. Acid Maltase Deficiency Hyperkalemic per paralysis Nemaline myop Myotubular myopathy Mitochondrial myopathy Carnitine Def Hypothyroid myopathy Myositis Rhabdomyolysis Toxic; chloroquine alcoholic 100 ms 5 ms Acid Maltase Deficiency Hyperkalemic per paralysis Myotubular myopathy Acid Maltase Deficiency Hyperkalemic per paralysis LGMD 1A Acid Maltase Deficiency Acid Maltase Deficiency Acid Maltase Deficiency Hypothyroid myopathy Myositis Hypothyroid myopathy Myositis Hypothyroid myopathy Hypothyroid myopathy Hypothyroid myopathy Myositis Myositis Myositis Toxic; chloroquine Chloroquine 2
Muscular dystr Muscular dystr IBM IBM Debrancher Glycogen. Debrancher Glycogen. Myotonic conditions LGMD 1A Colchicine Chlorophenoxy Lipid lowering agent Myotonic discharge Myotonic discharge Avi wma Myotonia; warm up after 1 minute of activity Myotonia; warm up after 1 minute of activity wma avi 3
MUP, normal TA CNEMG At rest MUP IP denervation and spec spontaneous activity (myotonia, CRD, neuromyotonia) number of fibres in recorded area fibre diameters n-m transmission recruitment pattern total number of MUs at full effort MUP, myopathy TA Emery-Dreifuss muscular dystrophy, X-linked type 1 (EDMD; emerinopathy) Mild to moderate dystrophic changes: Fiber size variation, a few necrotic fibers, central nuclei, increase of fibrous connective tissue and fat between myofibers. Courtesy Kallimo, 2010 4
CNEMG Myopathy EMG - interference pattern At rest MUP IP denervation and spec spontaneous activity (myotonia, CRD, neuromyotonia) number of fibres in recorded area fibre diameters n-m transmission recruitment pattern total number of MUs at full effort Normal Neuropathy Interference pattern analysis in normal, neuropathic and myopathic conditions IP MUP Myopathy Tib ant 18446 CRD in Pompe s disease (CN rec) avi 5
CRD in Pompe s disease (CN rec) Complex repetitive discharge, CRD pacemaker wma Complex repetitive discharge, CRD co-pacemaker 2 1 3 4 Myopathy, EDB Hereditary distal myopathy (CN rec) 3741 Lat vastus m 6
Duchenne muscular dystrophy (dystrophinopathy, Duchenne phenotype, WMS 1.1) An advanced stage: Many fibers are necrotized ( ) with phagocytes removing cell debris. Some fibers are hypercontracted ( * ) Courtesy Kallimo, 2010 * * H&E staining Muscle fibres in myopathy normal hypertrophy atrophy splitting Recording from 2 or more still synchronous AP.s from branches of a split muscle fibre may produce high ampl Stålberg Split muscle fibers Scanning EMG Scan in a normal muscle (simulation) Scan in a myopathic muscle (simulation) 7
Scanning EMG Normal MND Normal Scanning EMG Muscular dystr TA muscle 2 ms Stålberg 0 1 mv Scanning EMG Sensitivity/specificity of EMG in Myopathies Sensitivity (abnormal vs normal): depends on type of myopathy: Duchenne, myositis.. 90-99% Metabolic myopathy.may be very low Specificity (classification): EMG usually not specific in separating subgroups EMG combined with other findings gives a clue Myopathy +Neuropathy; think of mitochondrial dysfunction, malignancy Normal EMG in clinical myopathy; think of metabolic myopathy Performance/EMG discrepancy; Weakness + full EMG pattern Weakness + normal EMG myopathy central Weakness/fatigue central motor neurone peripheral nerve; pnp, focal muscle (nm-j, myopathy, periodic weakness) Numbness Cramps myotonia, ben. fasc. syn., neurotonia, stiff p. syn Pain ICU Critical illness 8
Weakness/fatigue central motor neurone peripheral nerve; pnp, focal muscle (nm-j, myopathy, periodic weakness) Cramps myotonia, ben. fasc. syn., neurotonia, stiff p. syn Pain ICU Critical illness 9