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Please enter at least one feature (symptom, sign or investigation result) before performing the calculation.
For example, if chest pain and low oxygen saturations were present, but haemoptysis was absent, the features section should look as follows:
To add a feature that is present, start typing and then click the green arrow.
To add the absence of a feature (i.e. a 'negative' finding), start typing then click the red cross.
If you want to remove a feature from the list simply click the grey cross in the box to the right of the feature.
Lambert-Eaton myasthenic syndrome is seen in association with small cell lung cancer and to a lesser extent breast and ovarian cancer. It may also occur independently as an autoimmune disorder. Lambert-Eaton myasthenic syndrome is caused by an antibody directed against presynaptic voltage-gated calcium channel in the peripheral nervous system.
Incidence: 0.50 cases per 100,000 person-years
Peak incidence: 70+ years
Sex ratio: 1:1
repeated muscle contractions lead to increased muscle strength (in contrast to myasthenia gravis)
in reality, this is seen in only 50% of patients and following prolonged muscle use muscle strength will eventually decrease
ophthalmoplegia and ptosis not commonly a feature (unlike in myasthenia gravis)
incremental response to repetitive electrical stimulation
treatment of underlying cancer
immunosuppression, for example with prednisolone and/or azathioprine
3,4-diaminopyridine is currently being trialled
works by blocking potassium channel efflux in the nerve terminal so that the action potential duration is increased. Calcium channels can then be open for a longer time and allow greater acetylcholine release to the stimulate muscle at the end plate
intravenous immunoglobulin therapy and plasma exchange may be beneficial