Lambert-Eaton myasthenic syndrome: Difference between revisions

No edit summary
Line 36: Line 36:


[[Category:Neuro]]
[[Category:Neuro]]
==Background==
*Disease of the neuromuscular junction leading to primary presentation of weakness
*Caused by auto-antibodies against the voltage-gated calcium channels at the NMJ
==Clinical Features==
*Often presents with alteration in gait or difficulty rising from a chair
*Symmetrical muscle weakness and fatiguability often beginning in lower extremities
*Autonomic dysfunction (dry mouth, erectile dysfunction)
*Compared with myastenia gravis, ELS begins with lower extremities weakness and rarely begins with extraocular muscle weakness
*Respiratory failure can occur in late stages of the disease
*Paraneoplastic and autoimmune form of LEMS have similar signs and symptoms
==Differential Diagnosis==
*Myasthenia Gravis
*Myositis
*Dermatomyositis
*Amyotrophic Lateral Sclerosis
*Limb-Girdle Muscle Dystrophy
*Inclusion Body Myositis
==Diagnosis==
*Diagnosis is generally a clinical diagnosis
*Confirmation testing for VGCC antibodies
*Neurophysiologic testing
==Management==
*Guanidine
*Aminopyridines
*Acetylcholinesterase inhibitors
*IVIG
*Glucocorticoids
*Plasma exchange
==Disposition==
*Referral to rheumatology
*Any patients with risk factors for small cell lung cancer will need to be referred for evaluation of underlying malignancy
==See Also==
==External Links==
==References==
<UpToDate>

Revision as of 12:50, 7 February 2016

Background

  • Autoantibodies against Ca channels of axon nerve terminals responsible for ACh release
  • Epidemiology
    • Predominantly a disease a/w older men w/ history of cigarette smoking and lung cancer
      • 50% of pts have concurrent small-cell lung cancer
    • Syndrome can precede detection of malignancy by several years

Clinical Features

  • Fluctuating symmetric weakness and fatigue, esp of proximal leg muscles
  • Improvement in strength with sustained or repeated exercise (in contrast to MG)
    • Lambert sign: handshake strength increases over several seconds
  • Myalgias
  • Muscle stiffness (especially in hip and shoulders)
  • Paresthesias
  • Metallic taste
  • Autonomic symptoms (dry mouth, impotence)
  • Eye movements are unaffected
  • Sensory examination normal

Differential Diagnosis

Weakness

Diagnosis

Treatment

  • Supportive (progression to respiratory or bulbar failure is rare)
  • Acetylcholinesterase inhibitors (e.g. pyridostigmine) can improve symptoms

Disposition

  • Admission required when infectious complications occur or when severe disability requires inpatient immunotherapy

See Also

References

Background

  • Disease of the neuromuscular junction leading to primary presentation of weakness
  • Caused by auto-antibodies against the voltage-gated calcium channels at the NMJ

Clinical Features

  • Often presents with alteration in gait or difficulty rising from a chair
  • Symmetrical muscle weakness and fatiguability often beginning in lower extremities
  • Autonomic dysfunction (dry mouth, erectile dysfunction)
  • Compared with myastenia gravis, ELS begins with lower extremities weakness and rarely begins with extraocular muscle weakness
  • Respiratory failure can occur in late stages of the disease
  • Paraneoplastic and autoimmune form of LEMS have similar signs and symptoms

Differential Diagnosis

  • Myasthenia Gravis
  • Myositis
  • Dermatomyositis
  • Amyotrophic Lateral Sclerosis
  • Limb-Girdle Muscle Dystrophy
  • Inclusion Body Myositis

Diagnosis

  • Diagnosis is generally a clinical diagnosis
  • Confirmation testing for VGCC antibodies
  • Neurophysiologic testing

Management

  • Guanidine
  • Aminopyridines
  • Acetylcholinesterase inhibitors
  • IVIG
  • Glucocorticoids
  • Plasma exchange

Disposition

  • Referral to rheumatology
  • Any patients with risk factors for small cell lung cancer will need to be referred for evaluation of underlying malignancy

See Also

External Links

References

<UpToDate>