Lamber Eaton myasthenic Syndrome

Question 1

Which condition is Lambert Eaton Myasthenic Syndrome associated with

Answer 1

Small cell lung cancer

Question 2

Pathophysiology of Lambert Eaton Myasthenic syndrome

Answer 2

Antibodies produced against the voltage gated calcium channels in the presynaptic terminals of the neuromuscular junction

Question 3

Features of Lambert Eaton Myasthenic syndrome

Answer 3

Slowly progressive muscle weakness

Affects the proximal muscles - notably proximal leg weakness

Question 4

Presentation of Lambert Eaton Myasthenic syndrome

Answer 4

Proximal muscle weakness
Diplopia - affecting intraocular muscles
Slurred speech - affecting the oropharyngeal muscles
Ptosis - affecting the levator muscles

Autonomic dysfunction:
Dry mouth
Blurred vision
Impotence

Hyporeflexia
Post tetanic potentiation
Dizziness

Question 5

Post tetanic potentiation

Answer 5

Reflexes become temporarily normal for a short period of time following a period of strong muscle contraction

Question 6

Treatment of Lambert Eaton Myasthenic Syndrome

Answer 6

Amifampridine - allows more acetylcholine to be released in the neuromuscular junction space by blocking voltage gated potassium channels in the presynaptic cell, prolonging depolarisation

Immunosuppression - Prednisolone or azathioprine
IV immunoglobulins
Plasmapheresis

Question 7

Investigations for Lambert Eaton Myasthenic syndrome

Answer 7

Investigate for SCLC

• CXR
• lung biopsy

Antibody test