Overview
Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder that affects the connection between nerves and muscles, specifically at the neuromuscular junction.
Causes
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Autoimmune Response: The body's immune system attacks calcium channels in nerve endings
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Associated Conditions:
- Often linked with small cell lung cancer (50-60% of cases)
- Can occur independently as an autoimmune condition
Common Symptoms
Primary Symptoms
- Muscle weakness, particularly in legs and hips
- Fatigue
- Difficulty climbing stairs or standing from a seated position
Other Symptoms
- Dry mouth
- Impaired sweating
- Vision changes
- Speech difficulties
Unique Characteristics
- Weakness typically improves with repeated use of muscles
- Symptoms often worse in morning and improve during day
- Reflexes may be diminished or absent
Diagnosis
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Clinical Examination
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Electrodiagnostic Testing:
- Repetitive nerve stimulation
- EMG studies
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Blood Tests:
- Voltage-gated calcium channel antibodies
- Cancer screening
Treatment Options
Medications
- 3,4-Diaminopyridine (3,4-DAP)
- Guanidine hydrochloride
- Pyridostigmine
- Immunosuppressive medications
Other Treatments
- Treatment of underlying cancer if present
- Plasmapheresis
- Intravenous immunoglobulin (IVIG)
Living with LEMS
- Regular exercise as tolerated
- Physical therapy
- Occupational therapy
- Regular medical monitoring
- Support group participation
When to Seek Medical Care
- Increasing weakness
- Difficulty breathing
- New symptoms
- Worsening of existing symptoms