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Long-term observation of incremental response and antibodies to voltage-gated calcium channels in patients with Lambert-Eaton myasthenic syndrome: two case reports.
- Source :
-
Journal of medical case reports [J Med Case Rep] 2015 Mar 14; Vol. 9, pp. 59. Date of Electronic Publication: 2015 Mar 14. - Publication Year :
- 2015
-
Abstract
- Introduction: Lambert-Eaton myasthenic syndrome is a rare autoimmune disorder of neuromuscular transmission due to the presence of antibodies to presynaptic P/Q-type voltage-gated calcium channels. The gold standard of therapy is the potassium channel blocker 3,4-diaminopyridine. To the best of our knowledge, no clinical reports have been published to date about long-term follow-up outcomes in patients who discontinued 3,4-diaminopyridine therapy. In addition, we know of no recent articles in which the natural history in patients with autoimmune-mediated Lambert-Eaton myasthenic syndrome has been addressed. In this report, we describe the cases of two such patients.<br />Case Presentation: Patient 1 was a Caucasian man who had been diagnosed at age 15 years with Lambert-Eaton myasthenic syndrome with symptoms of fluctuating muscle weakness and easy fatigability. These symptoms stabilized, and his electrophysiological parameters normalized, during treatment with a maintenance dose of 50mg/day of 3,4-diaminopyridine. After 5.5 years, however, he wished to discontinue the treatment. After that point, his electrophysiological parameters and presynaptic P/Q-type voltage-gated calcium-channel antibody titer remained stable. During the 15-year follow-up period, patient 1 reported mild exertion-induced complaints but did not feel restricted in his occupation and most daily activities. Patient 2 was a Caucasian man diagnosed at 32 years of age with a moderate limb girdle syndrome. He was treated with up to 80 mg/day of 3,4-diaminopyridine. Because of the drug's very short-lasting effect (<1 hour), however, he took it mostly irregularly (≤ 1 × 20 mg/day). During the 14- year period of observation, his repetitive nerve stimulation responses and presynaptic P/Q-type voltage-gated calcium-channel antibody titer remained stable, his compound muscle action potential amplitudes were decreasing and his clinical symptoms did not deteriorate. At his last follow-up examination, patient 2 was independent in all of his daily activities.<br />Conclusion: Some patients with autoimmune-mediated Lambert-Eaton myasthenic syndrome show a stable clinical long-term course without treatment. The benefit of each long-term therapy should be critically assessed during follow-up, and possible side effects should be balanced against the quality of life in these patients.
- Subjects :
- 4-Aminopyridine administration & dosage
Adult
Amifampridine
Calcium Channels immunology
Follow-Up Studies
Humans
Immunoglobulins, Intravenous therapeutic use
Lambert-Eaton Myasthenic Syndrome physiopathology
Male
Middle Aged
4-Aminopyridine analogs & derivatives
Lambert-Eaton Myasthenic Syndrome drug therapy
Potassium Channel Blockers administration & dosage
Subjects
Details
- Language :
- English
- ISSN :
- 1752-1947
- Volume :
- 9
- Database :
- MEDLINE
- Journal :
- Journal of medical case reports
- Publication Type :
- Academic Journal
- Accession number :
- 25885033
- Full Text :
- https://doi.org/10.1186/s13256-015-0524-9