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muscle weakness

Etiology: (also see immobility) 1) brain disease a) multiple sclerosis b) transient ischemic attack (TIA) c) cataplexy & sleep paralysis associated with narcolepsy 2) spinal cord disease a) transverse myelitis b) epidural abscess c) extradural tumor d) epidural hematoma e) herniated intervertebral disk f) spinal cord tumor g) amyotrophic lateral sclerosis 3) peripheral nerve disease a) Guillain-Barre syndrome b) acute intermittent porphyria c) arsenic poisoning d) toxic neuropathies e) tick paralysis f) POEMS syndrome 4) myoneural junction disease a) myasthenia gravis b) Lambert-Eaton syndrome c) botulism d) organophosphate poisoning 5) muscle disease a) polymyositis b) rhabdomyolysis-myoglobinuria c) acute alcoholic myopathy d) electrolyte imbalances e) endocrine disease 6) electrolyte disturbances a) hypokalemia b) hyperkalemia c) hypercalcemia d) hypocalcemic tetany e) hyponatremia f) hypophosphatemia g) hypermagnesemia 7) disorders with only subjective weakness a) hyperventilation b) hypoglycemia 8) generalized weakness in the elderly [5] a) severe systemic illness (widespread malignancy) b) severe congestive heart failure -> possibly via deconditioning c) deconditioning (prolonged bedrest) d) malnutrition 9) intensive care unit-acquired weakness a) systemic inflammation b) prolonged immobilization c) systemic glucocorticoids d) neuromuscular blockers Clinical manifestations: 1) bilateral distal weakness suggests polyneuropathy 2) bilateral proximal muscle weakness suggests myopathy 3) weakness made worse with repeated effort suggests myasthenia gravis or related syndromes 4) see signs that distinguish patterns of muscle weakness Differential diagnosis: (3 most likely) 1) Guillain Barre syndrome 2) myasthenia gravis 3) botulism Diphtheria may produce a demyelinating neuropathy.

Related

muscular disease; myopathy myalgia (muscle pain) signs that distinguish patterns of muscle weakness

Specific

asthenia generalized muscle weakness proximal muscle weakness

General

weakness

References

  1. Guide to Physical Examination & History Taking, 6th edition, Bates B, JB Lippincott, Philadelphia, 1995, pg 59
  2. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 641-42
  3. Harrison's Principles of Internal Medicine, 13th ed. Isselbacher et al (eds), McGraw-Hill Inc. NY, 1994, pg 132
  4. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 121
  5. Essentials of Clinical Geriatrics, 4th ed, Kane RL et al (eds) McGraw Hill, NY, 1999