Lambert-Eaton Syndrome Flashcards
Primary manifestation of Lambert-Eaton Syndrome is what? What is it/what is it a/w?
muscular weakness
autoimmune disorder
50% a/w malignancy (paraneoplastic syndrome)
Risk factors of Lambert-Eaton Syndrome
- malignancy
- personal or family hx of autoimmune dz
Pathophys of Lambert-Eaton Syndrome
- antibodies bind to voltage gated calcium channels
- interfere w/ calcium influx
- reduced acetylcholine release from presynaptic membrane
- impaired muscle fxn
What are the 2 types of LEMS?
Paraneoplastic
non-paraneoplastic
MC malignancy a/w Paraneoplastic LEMS?
small cell lung CA
Presentation of both types of LEMS?
Slowly progressive symmetric proximal limb/muscle weakness
(-alteration in gait, difficulty arising from chair or managing stairs
-assoc. depressed or absent DTRs)
muscle fatiguability or cramping after prolonged exercise
Post-exercise facilitation
Autonomic dysfunction (dry mouth, ptosis, sluggish pupillary light reflex)
How is it differentiated from MG?
Post exercise facilitation
-recovery of DTRs or improvement in muscle strength w/ brief vigorous muscle activation=
Unique to LEMS
(In MG, the more they do the weaker they get)
MC autonomic sx a/w LEMS? What other one is important?
dry mouth due to reduced salivation = #1
Sluggish pupillary response
What would nerve conduction studies show in LEMS?
100% or more improvement in measurements post-exercise
Tx of Paraneoplastic LEMS
tumor resection
For patients w/ moderate-severe weakness in LEMS, what do you give?
Pyridostigmine-> ACh-esterase inhibitor
3,4-DAP (3,4-diaminopyridine)–> enhances calcium entry at the presynaptic terminal
Pt with mild weakness w/o significant impairment tx?
Nothinnn, just monitor
What can you give for immunosuppression in LEMS pts?
Prednisone and azathioprine (DMARD)
