eMedicine Specialties > Neurology > Neuromuscular Diseases

Lambert-Eaton Myasthenic Syndrome: Follow-up

Author: David E Stickler, MD, Assistant Professor, Department of Neurosciences, Director of Electromyography Laboratory, Director of MDA Clinic, Director of Neuromuscular Service, Director of ALS Clinic, Medical University of South Carolina
Coauthor(s): Donald B Sanders, MD, EMG Laboratory Director, Professor of Medicine (Neurology), Division of Neurology, Duke University Medical Center
Contributor Information and Disclosures

Updated: Jan 29, 2009

Follow-up

Prognosis

  • Prognosis is largely determined by the presence and type of any underlying cancer, the presence and severity of any associated autoimmune disease, and the severity and distribution of weakness. In addition, patients with rapidly progressive symptoms usually have more severe disease.
  • Because Lambert-Eaton myasthenic syndrome (LEMS) may lead to early detection of small cell lung cancer (SCLC), prognosis of SCLC in patients with SCLC-LEMS is better than in SCLC without LEMS. Patients with SCLC who develop LEMS possibly have a more effective immunologic response to the cancer, which results in improved survival.
  • When LEMS has been symptomatic for at least 2 years and no underlying cancer has been demonstrated, the LEMS was probably caused by an autoimmune process. At that point, prognosis is determined by severity of dysfunction and the presence and severity of other autoimmune conditions.
  • A more rapid clinical course is more frequent in patients with SCLC-LEMS.
    • In most patients, weakness does not severely affect vital muscles.
    • Maximum severity usually becomes established within several months of symptom onset.
    • Without treatment, weakness and dysfunction do not usually vary. Exceptions are during periods of exacerbation induced by intercurrent illness or by medications that impair neuromuscular transmission.

Patient Education

For excellent patient education resources, visit eMedicine's Cancer and Tumors Center. For information specific to lung cancer see Lung Cancer.

Miscellaneous

Medicolegal Pitfalls

To avoid possible medicolegal problems, a thorough search for an underlying SCLC should be performed. In addition, drugs that can exacerbate the condition should be avoided if possible.

Special Concerns

  • Drugs that may exacerbate weakness in LEMS
    • Drugs that compromise neuromuscular transmission frequently exacerbate weakness in LEMS. Competitive neuromuscular blocking agents, such as d-tubocurarine and pancuronium, have an exaggerated and prolonged effect in patients with LEMS.
    • Initial signs of possible LEMS include prolonged weakness or apnea following administration of neuromuscular blocking agents during anesthesia.
    • Some antibiotics, particularly aminoglycosides, fluoroquinolones (eg, ciprofloxacin), and erythromycin, have significant neuromuscular blocking effects. Some antiarrhythmics (eg, quinine, quinidine, procainamide) and beta-adrenergic blocking drugs also worsen myasthenic weakness.
    • Exacerbation of LEMS after administration of any of several other agents, including magnesium and intravenous iodinated radiographic contrast agents, has been reported in isolated cases. In general, patients with LEMS should be observed for clinical worsening after initiating any new medication.
    • Unless absolutely necessary, avoid drugs that are known to impair neuromuscular transmission. In such cases, a thorough knowledge of their potential deleterious effects is required.
  • Elevated temperature
    • Weakness of LEMS may be worse when the ambient temperature increases or when the patient is febrile.
    • Patients should avoid hot showers or baths.
    • Systemic illness of any sort may cause transient worsening of weakness.
 


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
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References

  1. Sabater L, Titulaer M, Saiz A, Verschuuren J, Güre AO, Graus F. SOX1 antibodies are markers of paraneoplastic Lambert-Eaton myasthenic syndrome. Neurology. March 2008;70:924-928. [Medline].

  2. Chalk CH, Murray NM, Newsom-Davis J, et al. Response of the Lambert-Eaton myasthenic syndrome to treatment of associated small-cell lung carcinoma. Neurology. Oct 1990;40(10):1552-6. [Medline].

  3. Elmqvist D, Lambert EH. Detailed analysis of neuromuscular transmission in a patient with the myasthenic syndrome sometimes associated with bronchogenic carcinoma. Mayo Clin Proc. Oct 1968;43(10):689-713. [Medline].

  4. Lambert EH, Eaton LM, Rooke ED. Defect of neuromuscular conduction associated with malignant neoplasms. Am J Physiol. 1956;187:612-613. [Medline].

  5. Lennon VA. Serological profile of myasthenia gravis and distinction from the Lambert-Eaton myasthenic syndrome. Neurology. 1997;48 (Suppl 5):S23-S27. [Medline].

  6. Lennon VA, Kryzer TJ, Griesmann GE, et al. Calcium-channel antibodies in the Lambert-Eaton syndrome and other paraneoplastic syndromes. N Engl J Med. Jun 1 1995;332(22):1467-74. [Medline].

  7. Lundh H, Nilsson O, Rosen I. Novel drug of choice in Eaton-Lambert syndrome. J Neurol Neurosurg Psychiatry. Jul 1983;46(7):684-5. [Medline].

  8. Lundh H, Nilsson O, Rosen I, Johansson S. Practical aspects of 3,4-diaminopyridine treatment of the Lambert-Eaton myasthenic syndrome. Acta Neurol Scand. Aug 1993;88(2):136-40. [Medline].

  9. McEvoy KM, Windebank AJ, Daube JR, Low PA. 3,4-Diaminopyridine in the treatment of Lambert-Eaton myasthenic syndrome. N Engl J Med. Dec 7 1989;321(23):1567-71. [Medline].

  10. 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].

  11. Pellkofer HL, Armbruster L, Krumbholz M, Titulaer MJ, Verschuuren JJ, Schumm F, et al. Lambert-Eaton myasthenic syndrome differential reactivity of tumor versus non-tumor patients to subunits of the voltage-gated calcium channel. Journal of Neuroimmunology. 2008;epub ahead of print:[Medline].

  12. 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].

  13. Sanders DB, Massey JM, Sanders LL, Edwards LJ. A randomized trial of 3,4-diaminopyridine in Lambert-Eaton myasthenic syndrome. Neurology. Feb 8 2000;54(3):603-7. [Medline].

  14. Tim RW, Massey JM, Sanders DB. Lambert-Eaton myasthenic syndrome (LEMS). Clinical and electrodiagnostic features and response to therapy in 59 patients. Ann N Y Acad Sci. May 13 1998;841:823-6. [Medline].

  15. Tim RW, Sanders DB. Repetitive nerve stimulation studies in the Lambert-Eaton myasthenic syndrome. Muscle Nerve. Sep 1994;17(9):995-1001. [Medline].

  16. Wirtz PW, Bradshaw J, Wintzen AR, Verschuuren JJ. Associated autoimmune diseases in patients with the Lambert-Eaton myasthenic syndrome and their families. J Neurol. Oct 2004;251(10):1255-9. [Medline].

  17. Wirtz PW, Wintzen AR, Verschuuren JJ. Lambert-Eaton myasthenic syndrome has a more progressive course in patients with lung cancer. Muscle Nerve. Aug 2005;32(2):226-9. [Medline].

  18. Zambelis T, Foutsitzi A, Giannakopoulou A, et al. Lambert-Eaton myasthenic syndrome. Clinical and electrophysiological findings in seven cases. Electromyogr Clin Neurophysiol. Jul-Aug 2004;44(5):289-92. [Medline].

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Further Reading

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Keywords

Lambert-Eaton myasthenic syndrome, LEMS, acetylcholine release, ACh release, neuromuscular transmission, small cell lung cancer, SCLC, non-SCLC lung cancer, non–small cell lung cancer, lymphosarcoma, malignant thymoma, carcinoma of the breast, carcinoma of the stomach, carcinoma of the colon, carcinoma of the prostate, carcinoma of the bladder, carcinoma of the kidney, carcinoma of the gallbladder

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Contributor Information and Disclosures

Author

David E Stickler, MD, Assistant Professor, Department of Neurosciences, Director of Electromyography Laboratory, Director of MDA Clinic, Director of Neuromuscular Service, Director of ALS Clinic, Medical University of South Carolina
David E Stickler, MD is a member of the following medical societies: American Academy of Neurology and American Association of Neuromuscular and Electrodiagnostic Medicine
Disclosure: Nothing to disclose.

Coauthor(s)

Donald B Sanders, MD, EMG Laboratory Director, Professor of Medicine (Neurology), Division of Neurology, Duke University Medical Center
Donald B Sanders, MD is a member of the following medical societies: American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, American Neurological Association, and New York Academy of Sciences
Disclosure: Nothing to disclose.

Medical Editor

Paul E Barkhaus, MD, Professor, Department of Neurology, Medical College of Wisconsin; Director of Neuromuscular Diseases, Milwaukee Veterans Administration Medical Center
Paul E Barkhaus, MD is a member of the following medical societies: American Academy of Neurology, American Association of Neuromuscular and Electrodiagnostic Medicine, and American Neurological Association
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Neil A Busis, MD, Chief, Division of Neurology, Department of Medicine, Head, Clinical Neurophysiology Laboratory, University of Pittsburgh Medical Center-Shadyside
Neil A Busis, MD is a member of the following medical societies: American Academy of Neurology and American Association of Neuromuscular and Electrodiagnostic Medicine
Disclosure: Nothing to disclose.

CME Editor

Selim R Benbadis, MD, Professor, Director of Comprehensive Epilepsy Program, Departments of Neurology and Neurosurgery, University of South Florida School of Medicine, Tampa General Hospital
Selim R Benbadis, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Sleep Medicine, American Clinical Neurophysiology Society, American Epilepsy Society, and American Medical Association
Disclosure: Nothing to disclose.

Chief Editor

Nicholas Y Lorenzo, MD, Chief Editor, eMedicine Neurology; Consulting Staff, Neurology Specialists and Consultants
Nicholas Y Lorenzo, MD is a member of the following medical societies: Alpha Omega Alpha and American Academy of Neurology
Disclosure: Nothing to disclose.

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