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Lambert-Eaton Myasthenic Syndrome: Differential Diagnoses & Workup
Updated: Sep 2, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Differential Diagnoses
Other Problems to Be Considered
Botulism
Paraneoplastic syndrome
Tick paralysis
Workup
Laboratory Studies
- Very few tests are of importance to the ED physician in regard to LEMS since the diagnosis is not made in the ED. It would be reasonable, however, to consider basic tests in any patient with cancer who reports weakness and dry mouth. These basic tests would include the following:
- CBC
- Basic chemistry
- Pulse oximetry
Imaging Studies
- Chest radiography
- Chest CT if chest malignancy is suspected: Screening strategies may help to detect SCLC in patients with newly diagnosed LEMS and therefore offer a better approach to treatment. In a large cohort study, Titulaer et al screened for tumors using various methods (CT, radiography, [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET), bronchoscopy, and/or mediastinoscopy) and found that CT of the thorax detected 93% of the tumors in this study.2
Procedures
- Tensilon test
- This test may be used to help differentiate LEMS and myasthenia gravis. However, the test is highly subjective, and it is of little value in the diagnosis of LEMS in the ED.
- The test may produce an improvement in strength but rarely is the response in patients with LEMS as noticeable as the typical response in patients with myasthenia gravis.
- The only true methods of differentiating myasthenia gravis and LEMS are the detection of ACh receptor antibodies and the presence of underlying malignancy.
- Electrodiagnostic studies are critical to the clinical diagnosis. Criteria that are characteristic of LEMS include the following:
- Low-amplitude CMAP after a single, supramaximal stimulus
- Postexercise potentiation of CMAP
- Rapid disappearance of postexercise increment
- Decremental response at lower rates of stimulation after repetitive nerve stimulation and incremental response at higher rates of stimulation
More on Lambert-Eaton Myasthenic Syndrome |
| Overview: Lambert-Eaton Myasthenic Syndrome |
 Differential Diagnoses & Workup: Lambert-Eaton Myasthenic Syndrome |
| Treatment & Medication: Lambert-Eaton Myasthenic Syndrome |
| Follow-up: Lambert-Eaton Myasthenic Syndrome |
| Multimedia: Lambert-Eaton Myasthenic Syndrome |
| References |
| « Previous Page | Next Page » |
References
Wirtz PW, Sotodeh M, Nijnuis M, et al. Difference in distribution of muscle weakness between myasthenia gravis and the Lambert-Eaton myasthenic syndrome. J Neurol Neurosurg Psychiatry. Dec 2002;73(6):766-8. [Medline].
Titulaer MJ, Wirtz PW, Willems LN, van Kralingen KW, Smitt PA, Verschuuren JJ. Screening for small-cell lung cancer: a follow-up study of patients with Lambert-Eaton myasthenic syndrome. J Clin Oncol. Sep 10 2008;26(26):4276-81. [Medline].
Illa I. IVIg in myasthenia gravis, Lambert Eaton myasthenic syndrome and inflammatory myopathies: current status. J Neurol. May 2005;252 Suppl 1:I14-8. [Medline].
[Best Evidence] Maddison P, Newsom-Davis J. Treatment for Lambert-Eaton myasthenic syndrome. Cochrane Database Syst Rev. 2005;CD003279. [Medline].
Argov Z, Shapira Y, Averbuch-Heller L, Wirguin I. Lambert-Eaton myasthenic syndrome (LEMS) in association with lymphoproliferative disorders. Muscle Nerve. Jul 1995;18(7):715-9. [Medline].
Buchwald B, Ahangari R, Weishaupt A, Toyka KV. Presynaptic effects of immunoglobulin G from patients with Lambert-Eaton myasthenic syndrome: their neutralization by intravenous immunoglobulins. Muscle Nerve. Apr 2005;31(4):487-94. [Medline].
Collins DR, Connolly S, Burns M, et al. Lambert-eaton myasthenic syndrome in association with transitional cell carcinoma: a previously unrecognized association. Urology. Jul 1999;54(1):162. [Medline].
Lang B, Newsom-Davis J. Immunopathology of the Lambert-Eaton myasthenic syndrome. Springer Semin Immunopathol. 1995;17(1):3-15. [Medline].
Lee JH, Shin JH, Kim DS, et al. A case of Lambert-Eaton myasthenic syndrome associated with atypical bronchopulmonary carcinoid tumor. J Korean Med Sci. Oct 2004;19(5):753-5. [Medline].
Lin JT, Lachmann E. Lambert-eaton myasthenic syndrome: a case report and review of the literature. J Womens Health (Larchmt). Dec 2002;11(10):849-55. [Medline].
Maddison P, Lang B, Mills K, Newsom-Davis J. Long term outcome in Lambert-Eaton myasthenic syndrome without lung cancer. J Neurol Neurosurg Psychiatry. Feb 2001;70(2):212-7. [Medline].
O'Neill JH, Murray NM, Newsom-Davis J. The Lambert-Eaton myasthenic syndrome. A review of 50 cases. Brain. Jun 1988;111 ( Pt 3):577-96. [Medline].
Peterlin BL, Flood W, Kothari MJ. Use of intravenous immunoglobulin in Lambert-Eaton myasthenic syndrome. J Am Osteopath Assoc. Dec 2002;102(12):682-4. [Medline].
Posner JB, Dalmau JO. Paraneoplastic syndromes affecting the central nervous system. Annu Rev Med. 1997;48:157-66. [Medline].
Rosen P, Barkin RM. Emergency Medicine: Concepts and Clinical Practice. Vol 2. 3rd ed. 1992:1820-1821. [Medline].
Sanders DB. Lambert-Eaton myasthenic syndrome: clinical diagnosis, immune-mediated mechanisms, and update on therapies. Ann Neurol. May 1995;37 Suppl 1:S63-73. [Medline].
Sanders DB. Lambert-Eaton myasthenic syndrome: pathogenesis and treatment. Semin Neurol. Jun 1994;14(2):111-7. [Medline].
Smith AG, Wald J. Acute ventilatory failure in Lambert-Eaton myasthenic syndrome and its response to 3,4-diaminopyridine. Neurology. Apr 1996;46(4):1143-5. [Medline].
Verschuuren JJ, Wirtz PW, Titulaer MJ, et al. Available treatment options for the management of Lambert-Eaton myasthenic syndrome. Expert Opin Pharmacother. Jul 2006;7(10):1323-36. [Medline].
Further Reading
Keywords
LEMS, neuromuscular transmission, voltage-gated calcium channels, presynaptic motor nerve terminal, Lambert-Eaton myasthenic syndrome, muscle weakness, acetylcholine, ACh, myasthenia gravis
