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FOCAL MUSCLE INVOLVEMENT

Bulbar Focal enlargement Focal fibrosing myopathy Focal myositis Hamstring Quadriceps Scapular winging

MRI: Fatty atrophy of Quadriceps

Quadriceps Quadriceps: Selective Weakness Hereditary myopathies Becker LGMD: 1B; 2B; 2H; 2L Emery-Dreifuss: Lamin A/C HIBM3 Inflammatory Myopathies Inclusion Body Myositis Polymyositis with mitochondrial pathology Focal myositis Myopathy with ringed fibers Nerve disorders Spinal muscular atrophy 5q: Type III & IV Lower extremity Dominant GM2 gangliosidosis, Late onset Femoral neuropathy Diabetic amyotrophy L3-L4 radiculopathy Lumbo-Sacral plexopathies: Especially neoplastic

Quadriceps atrophy Inclusion body myositis

Quadriceps: Atrophy with normal strength

• Tear (partial) of rectus femoris
  • Causes
    • Trauma: Usually 2° with muscle stretch
    • Spontaneous: Middle or late age
    • Systemic disease
      • Endocrine: Hyperparathyroidism; Diabetes; Anabolic steroids
      • Renal failure
      • Gout; Rheumatoid arthritis
      • Infection: Tuberculosis; Syphilis
  • Diagnosis: MRI scan
  • Treatment: ? Surgical repair within 1^st months

Quadriceps: Strength selectively spared

• Nonaka distal myopathy/Hereditary inclusion body myopathy 2 (HIBM2): GNE
• McLeod syndrome: XK
• Becker Muscular Dystrophy: Dystrophin; Occasional patients
• LGMD
  • 1D: DNAJB6
  • 2A: Calpain-3
  • 2C: γ-Sarcoglycan
• Congenital fiber type size disproportion: TPM3 mutations

Hamstring weakness

• Myopathies: Hereditary
  • HIBM 2 (Nonaka)
  • Bethlem myopathy
  • Multiple epiphyseal dysplasia with mild myopathy (EDM3)
  • Congenital muscular dystrophy with muscle hypertrophy (MDC1C)
  • Dystrophy
    • LGD: 1D; 2A; 2B (Miyoshi myopathy): 2C; 2I; 2L (Asymmetric)
    • FSHD
    • Becker MD: Occasional patients
• Nerve
  • Radiculopathy: Sacral
  • Lumbosacral plexopathy
  • Sciatic nerve lesion
• Orthopedic
  • Avulsion
  • Surgical: After muscle harvesting for ACL repair
  • Athletic injury: Strain of long head of biceps femoris
  • Also see: Hamstring injury

Scapular winging

Myopathies, Hereditary FSH Dystrophy: Often asymmetric LGMD 1F: TNPO3 1G: HNRNPDL 2A: Calpain 3 2D: α-Sarcoglycan 2E: β-Sarcoglycan 2I: FKRP 2N: POMT2 2S: TRAPPC11 2Z: POGLUT1 Emery-Dreifuss Myopathies ± Paget's disease of bone IBMPFD1: VCP IBMPFD2: HNRNPA2B1 MSP6: ANXA11 Desmin myopathy Early onset, Recessive Kaeser, Dominant Scapuloperoneal syndromes ACTA1 Centronuclear myopathy (MYF6): Adult-onset; Dominant Davidenkow's syndrome (SCPNK): Desmin FSH phenotype with ragged red fibers & cardiomyopathy Glycogen storage Acid maltase deficiency with scapuloperoneal weakness Phosphorylase deficiency (McArdle) Mitochondrial Reducing body myopathy (FHL1): Adult onset Scapuloperoneal muscular dystrophy (SPMD): 1 (FHL1); 2 (MYH7) SPMD with Retardation + Cardiomyopathy: LAMP2 Scapuloperoneal neuronopathy (SPSMA): TRPV4 Other neuromuscular disorders CHD7 CMT 2Z: MORC2 Ehlers-Danlos + Myopathy HIBM2 Holt-Oram Inclusion body myositis Immune myopathy with Mitochondrial antibodies Myopathy + PEO (MYH2) OAT deficiency PEO + Mitochondrial myopathy (MGME1) RYR1 mutations: King-Denborough; Axial myopathy Skeletal dysplasia, Weakness, Intellectual Disability, Ovary &Delta:: SOX8 Spinal muscular atrophy: Distal, type 4 Congenital myasthenia gravis Slow-channel syndrome COLQ SMA with contractures Syndromes with severe muscle wasting Congenital fiber type size disproportion: TPM3 mutations Other congenital myopathies AR-CMT2A: Later in disease course Focal muscle weakness General: Winging caused by weakness of Scapulo-thoracic muscles Nerves Spinal accessory: Trapezius Long thoracic: Serratus anterior Dorsal scapular: Rhomboid C7 radiculopathy Trapezius: Lateral winging Etiologies Nerve lesion: Spinal accessory Cervical segmental origin: C1-C4 Causes Surgical: Common Neck Procedures, posterior triangle (Lymph node bx) Proximal spinal accessory lesion also produces Sternocleidomastoid weakness Prognosis: Poorer outcome Scapular winging Dominant side Arm elevation: Impaired Absent muscle Clinical: Trapezius weakness Examination Winging most evoked by: Lateral abduction of arms Lateral & Upward displacement of scapula Weakness of middle or lower trapezius Associated with drooping shoulder Shoulder shrug: Asymmetric Shoulder droop may be associated with Neurovascular thoracic outlet syndrome External link: Trapezius Serratus anterior: Medial winging Anatomy Roots: C5, C6, C7 Innervation: Long thoracic Etiologies Myopathies: FSH; VCP; Scapuloperoneal Nerve lesion: Long thoracic Anatomy: Nerve formed directly from C5, C6 & C7 roots Causes Neuralgic amyotrophy Injury: Compression & Stretch Blunt trauma to chest wall Sports Volleyball, Weightlift,   Archery, Ballet Surgical 1st rib resection, Heart,   Radical mastectomy, Other: SLE; Immunization; Viral Examination Winging evoked by: Anterior abduction of arms Posterior & Medial displacement of scapula Shoulder shrug: Symmetric External link: Case report Rhomboids: Lateral winging Dorsal scapular nerve Anatomy Nerve formed from C5 proximal to brachial plexus Rare C4 to T1 contributions May share common trunk with long thoracic nerve Examination Weakness: Rhomboids major & minor; Levator scapulae Winging most evoked by: Lateral abduction of arms Medial rotation of lower scapular border Causes Thoracolumbar orthosis bracing for idiopathic scoliosis Entrapment: Hypertrophy of middle scalene muscle Sports injury: Volleyball C7 radiculopathy Orthopedic disorders Rotator cuff Fracture Scapular osteochondroma R/O Sprengel deformity Scoliosis

Scapular winging   Gowers Trapezius wasting From: M Al-Lozi Lateral Winging: Spinal Accessory Nerve lesion Medial Winging: Long Thoracic Nerve lesion

Finger Extension Weakness

• Myopathy
  • Welander: 5th finger
  • Gowers-Laing (MYH7): Thumb & Index finger
  • Nebulin
  • Oculpharyngodistal (OPD) Myopathy
• Neuromuscular junction: Congenital MG
  • Agrin
  • Slow channel syndromes
• Neuropathy
  • NMAN: HINT1
  • Radial nerve
    • Focal lesions
    • Multifocal neuropathy: MMN
    • Systemic disorders
      • Porphyria
      • Lead toxicity

Finger Flexion Weakness ⁵

• Common: Selective & Severe
  • Inclusion-Body Myositis (IM-VAMP)
  • Myotonic Dystrophy 1
• Other
  • Acquired
    • Sarcoid
  • Hereditary
    • Myotonic Dystrophy 2
    • Dystrophy: Dystrophin; Dysferlin; LAMA2
    • Storage: αB-Crystallin; Filamin; MYH7; VCP
    • Metabolic: Pompe (Acid Maltase); GNE
  • Contractures: HNRNPDL

Triceps (or Elbow Extension) Weakness

• Myopathy
  • Bethlem
• Neuropathy
  • Radial nerve
  • Brachial plexopathy
• NMJ
  • Myasthenia gravis
• Motor neuron disorders
  • GM2 gangliosidosis, Late onset
  • HMN 2D
  • ALS 16

Adductors: Leg & Arm

• Acid maltase deficiency
• Duchenne MD
• LGMD 1A: Myotilin
• LGMD 1D: DNAJB6
• LGMD 2A: Calpain-3
• LGMD 2B: Dysferlin
• LGMD 2G: TCAP
• LGMD 2L: ANO5
• HIBM2: GNE
• Multisystem Selenoprotein Deficiency: SECISBP2

FOCAL MYOSITIS 2 Epidemiology Onset Age Range: Childhood to 70's Common: Adulthood; Most in 30's to 50's Sex: Male = Female Identical twins: 1 set both with disease Local pain Clinical features Muscle mass Solitary (Asymmetric) Pain: 14% to 81% Enlarging (Days to Months) Size: 1 to 20 cm Quality: Firm; Dense; Tender Muscles involved General Distribution: Legs (70%); Arms (22%); Head & Neck (8%) 1 (62%) to 3 contiguous muscles Leg: Quadriceps; Gastrocnemius Also: Abdomen; Arm; Forearm; Neck 1; Paraspinous; Tongue; Perioral May involve: Whole, or region, of one muscle or several adjacent muscles Erythema (40%) Associated disorders Immune syndromes (32%); Behcet (5%) Neoplasms (24%) No generalized weakness No joint involvement Natural history Self limited course: Months; < 4 years Eventual spontaneous regression Recurrence 4: 1% to 41%; May occur in other muscles Reported prior events: Campylobacter; Borrellia burgdorferi; BCG vaccination Differential diagnosis: Nodular fasciitis; Sarcoma; Proliferative myositis Treatment Control pain & inflammation: Analgesics & NSAIDS Corticosteroids: 0.75mg/day for 3 to 12 weeks Physical therapy to reduce contracture ? Surgery Laboratory Serum CK Normal (80%) If high: Increased frequency of developing more diffuse involvement Dysglobulinemia (50%): Polyclonal gammopathy Inflammatory markers: Some patients; ESR high, CRP high, ANA+ EMG: Myopathy + Spontaneous activity in affected muscle CT: Poorly defined enlargement; Fatty infiltration; No discrete mass MRI: Muscle enlargement; Edema (High T2 signal; Low T1 signal); Circumscribed mass Ultrasound: Normal orientation of muscle fibers Muscle pathology Perimysial & Endomysial connective tissue: Thickened Myopathic changes: Varied muscle fiber size; Internal nuclei; MHC1 up Inflammation: T-cell predominant Distribution: Varied within muscle HLA types: A2, B62, Cw3 & DQ3 common to small series of Japanese patients Differential diagnosis Benign tumors Rhabdomyoma, Fibromatosis, Intramuscular lipoma Malignant tumors Not restricted to single muscle Rhabdomyosarcoma, Liposarcoma, Leiomyosarcoma, Metastasis Vascular intra-muscular tumor Inflammatory myofibroblastic tumors Lymphoma Proliferative myositis Myositis ossificans

From M. Al-Lozi MRI: T2 weighted image Focal myositis Brachialis (Arrow)

Periodic Fever, Familial, Autosomal Dominant (FPF)

• Nosology
  • TNF Receptor-Associated Periodic Syndrome (TRAPS)
  • Recurrent Fever with Localized Myositis or Fasciitis
• Epidemiology
  • Nothern European families
  • Families not of Mediterranean origin
• Genetics
  • Mutations: Missense or In-Frame deletion
  • Mutation locations: Most in extracellular cysteine-rich domains
  • Allelic disorder: Multiple sclerosis 5 susceptibility
• TNFRSF1A protein
  • Tumor necrosis factor α (TNFα) receptor
  • Expression: All cells
  • Location: Surface membrane
  • TRIM proteins regulate intrinsic & extrinsic apoptosis via TNFRSF1A & other receptors
  • Carfilzomib resistance in multiple myeloma treatment
  • Mutation effects
    • Defective shedding of TNFRSF1A protein from cell membranes
• Clinical features
  • Fever
    • High, with chills
    • Onset: Infancy or Childhood
    • Attack duration: Mean 2 to 3 weeks; Range 3 to 75 days
  • Abdominal pain
    • Diffuse
    • Nausea & Vomiting
    • Bowel obstruction: Appendicitis-like
    • Diarrhea: Occasional
  • Pseudocellulitis
    • Subcutaneous inflammation
    • Warm
    • Pitting edema
  • Skin rash
    • Macular; Erysipelas-like; Erythematous
    • Onset after myalgias
    • Overlies ares of myalgia
  • Myalgia
    • Trunk or Limbs
    • Focal
    • Starts Proximally & Moves Distally
    • Deep cramping sensation
  • Ocular
    • Conjunctivitis
    • Periorbital edema: Unilateral
  • Other pain: Chest; Testicular
  • Course: Chronic recurrences over many years
  • Treatment
    • Some benefit: Corticosteroids, Etanercept, Analgesics & Non-steroidal anti-inflammatory drugs
    • Canakinumab
    • No effect: Colchicine
• Laboratory
  • MRI: Inflammation involves muscle & subcutaneous tissue, spares fascia & joints
  • Muscle biopsy ³
    • Perivascular lymphocytic inflammation
    • Interstitial edema of muscle
    • Monocytic fasciitis: CD16 & CD68 positive cells
    • Perivascular T-cell inflammation
    • Muscle fibers: May remain normal
  • Amyloidosis: Renal