II. Evaluation

  1. Distinguish weakness from Fatigue and Asthenia
    1. Asthenia is exhaustion without weakness
    2. Fatigue is inability to perform task repeatedly
    3. Weakness is inability to perform task initially
  2. Determine distribution
    1. Unilateral, focal weakness
      1. Mononeuropathy (focal Peripheral Neuropathy)
      2. Multiple Sclerosis
      3. Cerebrovascular Accident (CVA)
    2. Symmetric proximal weakness
      1. Myopathy
    3. Symmetric distal weakness
      1. Polyneuropathy
      2. Amyotrophic Lateral Sclerosis
      3. Guillain-Barre Syndrome
      4. Myopathy less commonly effects distal muscles
        1. Statins, Alcohol may effect distal and proximal
        2. Inclusion body Myositis
        3. Myotonic dystrophy
  3. Consider specific causes
    1. See Muscle Weakness Causes
    2. See Neuropathy
    3. See Toxic Myopathy

III. Diagnostic evaluation based on category

  1. See Neuropathy
  2. Myopathy (see also Polymyositis)
    1. Creatine Kinase (CPK)
    2. Erythrocyte Sedimentation Rate
    3. Serum chemistry (e.g. Chem 8)
      1. Electrolytes Glucose, calcium, Magnesium, phosphate
    4. Thyroid Stimulating Hormone (TSH)
    5. Other tests as indicated
      1. 24-hour urine cortisol
      2. Growth Hormone
      3. Antinuclear Antibody
    6. Definitive testing
      1. Electromyogram
      2. Muscle Biopsy

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Ontology: Muscle Weakness (C0151786)

Definition (MSHCZE) Neurčitý pocit ochablosti, únavy nebo vyčerpanosti, který může být atributem slabosti různých svalů. Slabost je charakterizována jako subakutní nebo chronická, často jako zhoršující se a je projevem mnoha svalových a neurosvalových nemocí. (In Wyngaarden et al., Cecil Textbook of Medicine, 19th ed, p2251) R
Definition (NCI) A reduction in the strength of one or more muscles.
Definition (MSH) A vague complaint of debility, fatigue, or exhaustion attributable to weakness of various muscles. The weakness can be characterized as subacute or chronic, often progressive, and is a manifestation of many muscle and neuromuscular diseases. (From Wyngaarden et al., Cecil Textbook of Medicine, 19th ed, p2251)
Concepts Sign or Symptom (T184)
MSH D018908
SnomedCT 26544005
English Muscle Weaknesses, Muscular Weakness, Muscular Weaknesses, Weakness, Muscle, Weakness, Muscular, Weaknesses, Muscle, Weaknesses, Muscular, Decreased muscle strength, Diminished muscle strength, Muscle Weakness, muscle weakness (symptom), muscle weakness, Muscle weakness NOS, Weakness muscle, Muscle Weakness [Disease/Finding], decreased muscle strength, muscle weaknesses, muscular weakness, Weakness;muscle(s), WEAKNESS, MUSCULAR, MUSCLE WEAKNESS, Muscular weakness, Muscle weakness, Muscle strength reduced, Muscle weakness (finding), muscle; weakness
Spanish DEBILIDAD MUSCULAR, Debilidad muscular, Debilidad muscular NEOM, debilidad muscular, debilidad muscular (hallazgo), paresia, paresia (hallazgo), fuerza muscular disminuida, Pérdida de fuerza muscular, Debilidad Muscular
Dutch spier zwakte, spierzwakte NAO, zwakte van spier, spier; zwak, spierzwakte, Spierzwakte, Zwakte, spier-
French Faiblesse de muscle, Faiblesse musculaire SAI, FAIBLESSE MUSCULAIRE, Faiblesse musculaire, Faiblesse du muscle
German Muskelschwaechen, Schwaeche Muskel, Muskelschwaeche NNB, MUSKELSCHWAECHE, Muskelschwaeche, Muskelschwäche
Italian Debolezza muscolare NAS, Debolezza muscolare
Portuguese Fraqueza do músculo, Paresia NE, FRAQUEZA MUSCULAR, Fraqueza muscular, Debilidade Muscular
Japanese 筋力低下NOS, キンリョクテイカNOS, キンリョクテイカ, 筋力低下
Swedish Muskelsvaghet
Czech svaly - slabost, Svalová slabost, Slabost svalu, Svalová slabost NOS
Finnish Lihasheikkous
Polish Osłabienie mięśni, Słabość mięśni
Hungarian Izomgyengeség k.m.n., Izomgyengeség
Norwegian Muskelsvakhet