Diseases of the neuromuscular junction
Lambert Eaton Myasthenic Syndrome (LEMS)
Rare Disease Classifications:
IMPORTANT INFORMATION
The information on the Rare Awareness Rare Education (RARE) Portal is intended for educational purposes only and does not replace professional advice.
Rare diseases typically display a high level of symptom complexity and variability. Individuals diagnosed with the same rare disease may be impacted differently and each person’s experience is unique. Please seek support from qualified healthcare professionals to learn more about the most suitable care and support options for you.
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Contributors
This page has been co-developed with RVA Partner, Myasthenia Alliance Australia, which represents Myasthenia Gravis Association of Queensland Inc. and The Australian Myasthenic Association in NSW.
Quick Page Search:
Emergency Management | Clinical Care Guidelines | Synonyms | Summary | Personal Stories | Symptoms | Cause/Inheritance | Diagnosis | Treatment | Clinical Care | Research and Data | Rare Disease Organisation(s) | Support Services/Resources | Mental Health | Other | References
Emergency Management
There may be special considerations for the emergency management of individuals living with Lambert Eaton Myasthenic Syndrome (LEMS) presenting to emergency departments.
There are certain medications that are best to avoid, if possible, when treating individuals with LEMS. This includes antibiotics such as aminoglycosides and other drugs that can impair neuromuscular transmission.1,2
There are very rare cases of respiratory failure reported in LEMS individuals.3,4
Clinical Care Guidelines
We are not aware of any current clinical care guidelines for Lambert Eaton Myasthenic Syndrome (LEMS) in Australia. If you know of any relevant care guidelines, please let us know via the Contribute page.
The following guidance is available from international experts outside Australia; however, there may be information that is not relevant or applicable to the Australian context, and may not be up to date:
- Guidance for the management of myasthenia gravis (MG) and Lambert-Eaton myasthenic syndrome (LEMS) during the COVID-19 pandemic prepared by an international working group of MG experts and endorsed by American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM); please note that this was prepared in 2020.
Synonyms
Eaton Lambert syndrome; Lambert Eaton syndrome; Myasthenic syndrome of Lambert-Eaton; Myasthenic-Myopathic syndrome of Lambert-Eaton
Summary
Lambert Eaton myasthenic syndrome (LEMS) is an autoimmune, neuromuscular condition affecting the neuromuscular junction (NMJ).5,6 In LEMS, the voltage-gate calcium channels (VGCC) at the NMJ do not function properly and this affects the release of signals (neurotransmitters) that allow the nerve and muscle cells to communicate with each other. LEMS affects voluntary muscles (muscles that can be controlled) as well as the autonomic nervous system (organs that control automatic body functions). This leads to muscle weakness, usually in the legs and arms but can also affect the facial muscles, as well as dry mouth and eyes, constipation, decreased tendon reflexes and other symptoms.3-7
LEMS is often associated with small cell lung cancer (SCLC) as well as other types of cancer, with the onset of LEMS symptoms usually observed prior to the cancer diagnosis.4,5
LEMS differ from other myasthenic (muscular weakness) disorders, such as Myasthenia Gravis (MG), which is also an autoimmune condition but affects only skeletal (voluntary) muscles, and Congenital Myasthenic Syndromes (CMS) that are genetic conditions.
Useful Links for Professionals
Orphanet: Lambert-Eaton myasthenic syndrome
Human Phenotype Ontology (HPO): Lambert-Eaton Myasthenic Syndrome
Personal Stories
Lambert Eaton myasthenic syndrome (LEMS) varies between individuals, and each person’s experience is unique.
If you would like to share your personal story with Rare Voices Australia and have it included on the RARE Portal, please visit Rare Voices Australia: Share Your Story.
Symptoms
The most common symptom of Lambert Eaton Myasthenic Syndrome (LEMS) is weakness in the proximal muscles (muscles closest to the core of the body), particularly of the legs and arms.3,4 Other symptoms include muscle pain and stiffness, double vision and slurred speech.4,6 The autonomic nervous system can also be affected, which may lead to dry mouth and eyes, constipation, changes in sweating, drop in blood pressure when moving from sitting or lying down to standing up (orthostatic hypotension) and erectile dysfunction in males.3,4,7 Decreased or absent tendon reflexes may also be observed. There may also be further complications such as gum disease (due to chronic dry mouth) and eye issues including corneal scarring (due to severe dry eyes). Respiratory failure has been reported but is rare in LEMS individuals.3,4
A proportion of individuals with LEMS have also been found to have cancer, such as small cell lung cancer (SCLC).6 Additional complications of LEMS may include cerebellar ataxia,6 a disorder of the nervous system that may result in impaired motor skills and coordination.
Please speak to your medical team to learn more about the symptoms and complications of LEMS.
Cause/Inheritance
Lambert Eaton Myasthenic Syndrome (LEMS) is due to a dysfunction in the P/Q-type (and possibly N-type) voltage-gate calcium channel (VGCC) at the neuromuscular junction, which prevents release of acetylcholine, a neurotransmitter involved in transmission of signals between two cells.4,6 In majority of cases of LEMS, this dysfunction is caused by production of auto-antibodies (anti-VGCC) by one’s own body attacking the VGCC. There are also a low number of individuals who are seronegative, in that they have a defect in their VGCC but anti-VGG auto-antibodies have not been detected.
A proportion of individuals with LEMS also have cancers such as small cell lung cancer (SCLC), which has been thought to contribute to the production of anti-VGCC autoantibodies.4
Diagnosis
Lambert Eaton Myasthenic Syndrome (LEMS) may be diagnosed using a blood test to detect for the presence of anti-VGCC auto-antibodies as well as repetitive nerve stimulation (RNS) test to identify specific patterns of abnormalities in the response to motor nerve stimulation.6 Single fibre electromyography (SFEMG) has also been used to detect impaired neuromuscular transmission in LEMS.4
Treatment
There is no curative treatment for Lambert Eaton Myasthenic Syndrome (LEMS). Treatment of LEMS typically involves treatment of tumour if one is present, and management of the symptoms.4 This may include oral medications to control the condition, such as:2,6
- Potassium channel blockers, such as amifampridine, which increases release of acetylcholine
- Anti-acetylcholinesterase agents
- Immunosuppressive medication, which may be long-term treatments
Additional treatments for LEMS include: 2,6
- Plasmapheresis, in which the liquid portion of blood that contains the auto-antibodies (plasma) is removed and replaced with treated or new plasma
- Intravenous immunoglobulin (IVIg) – infusion of plasma solution from healthy donors
There may also be other strategies to treat specific symptoms and complications associated with LEMS.
It is best to speak with your medical team to learn more about suitable treatments for LEMS and its associated symptoms. Treatment will depend on an individual’s specific symptoms and complications.
Clinical Care
Healthcare professionals involved in the treatment of Lambert Eaton Myasthenic Syndrome (LEMS) may include general practitioners (GP), neurologists, ophthalmologists, dentists, pulmonologists, immunologists, urologists, dermatologists, cardiologists and oncologists. The need for different healthcare professionals may change over a person’s lifetime and extend beyond those listed here.
Clinics
Speciality Clinic for Myasthenia Gravis and Myasthenic Syndromes (NSW)
Department of Neurology
Concord Repatriation and General Hospital, Sydney
Ph: 02 9767 6416 / 02 9767 5623
Website: https://www.slhd.nsw.gov.au/concord/department-neurosciences-services.html
Neuroimmunology clinic provides services for patients with Neurological disorders with an immunologic basis including myasthenia gravis and multiple sclerosis and includes clinical research and access to clinical trials.
Neurology Service, Princess Alexandra Hospital (QLD)
Level 2C, Building 1
Princess Alexandra Hospital
199 Ipswich Rd
Woolloongabba 4102 Qld
Website: https://www.metrosouth.health.qld.gov.au/services/neurology/neurology-princess-alexandra-hospital
Myasthenia gravis is one of the conditions treated at the Princess Alexandra Hospital neurology clinics. The neurology team includes doctors, nurses, occupational therapists, physiotherapists and speech pathologists.
The Neuroimmunology Centre (VIC)
The Royal Melbourne Hospital (RMH) Elizabeth St
Level 7
635 Elizabeth St, Melbourne, Victoria
Email: [email protected]
Phone:(03) 9342 7061
Website:https://www.thermh.org.au/services/neurology-stroke/neurology-stroke-services/multiple-sclerosis-neuroimmunology
The Neuroimmunology clinics are dedicated to the assessment and long-term management of people with a possible or definite diagnosis of MS and other neuroimmunological conditions, including neuromyelitis optica, neurosarcoidosis, autoimmune encephalitis, cerebral vasculitis and myasthenia gravis.
Research and Data
For research updates, please visit Myasthenia Alliance Australia: Research
Please visit Australian Clinical Trials to learn about clinical trials for Lambert Eaton Myasthenic Syndrome (LEMS) in Australia; there may not be any clinical trials currently available.
Information regarding clinical trials for LEMS in other countries can be found at ClinicalTrials.gov; there may not be any clinical trials currently available.
It is best to discuss your interest in any clinical trials with your medical team to determine suitability and eligibility.
Rare Disease Organisation(s)
The Myasthenia Gravis Associations of Australia have come together under a National Myasthenia Alliance to enhance the support already offered to Australians suffering from the neurological auto-immune conditions categorised under the term ‘Myasthenia’, including for Lambert Eaton Myasthenic Syndrome (LEMS).
Myasthenia Alliance Australia (MAA) RVA Partner Australian Organisation
Website: https://myastheniaalliance.org.au/
Phone: 1800 802 568
Email: [email protected]
Below are the organisations that make up MAA; both organisations provide support for all Australians living with myasthenia, including their families and carers, regardless of location:
Myasthenia Gravis Association of Queensland Inc. RVA Partner Australian Organisation
Website: https://www.mgaq.org.au/
Phone: 1800 802 568
Email: [email protected]
Contact form: https://www.mgaq.org.au/contact-us
The Australian Myasthenic Association in NSW Inc. Australian Organisation
Website: https://www.myasthenia.au/
Phone: (02) 4283 2815
Email: [email protected]
Support Services/Resources
Myasthenia Alliance Australia‘s state organisations provide support resources relevant for individuals living with Lambert Eaton Myasthenic Syndrome (LEMS):
- Myasthenia Gravis Association of Queensland Inc.: Resources
- Australian Myasthenic Association in NSW: Patient Support
The Loop – Your Neuromuscular Resource Hub: Funding provides information on available social services that are relevant to the neuromuscular community.
For information on available government and social services that provide support for individuals with a rare disease, please visit the National and State Services pages.
Mental Health
Please visit the ‘Mental Health’ sections listed on the National and State Services pages.
Other
Further information on Lambert Eaton myasthenic syndrome (LEMS), or neuromuscular conditions in general, can be found at:
References
- Lipka AF, Verschuuren JJGM. Chapter 18 – Lambert-Eaton myasthenic syndrome. 2024. In: Giometto B, Pittock SJ. (eds) Handbook of Clinical Neurology, Vol. 200 (3rd series) Paraneoplastic Neurologic Disorders, p 307-325. https://doi.org/10.1016/B978-0-12-823912-4.00012-8
- Harada Y, Guprill JT. Management/Treatment of Lambert-Eaton Myasthenic Syndrome. Curr. Treat. Options Neurol. 2021; 23(34). http://doi.org/10.1007/s11940-021-00690-4
- Jayarangaiah A, Lui F, Kariyanna PT. Lambert-Eaton Myasthenic Syndrome. Updated 23 October 2023. In: StatsPearl [internet]. Treasure Island (FL): StatPearls Publishing. 2024-. Accessed 13 November 2024. https://www.ncbi.nlm.nih.gov/books/NBK507891/
- Kesner VG, Oh SJ, Dimachkie MM, Barohn RJ. Lambert-Eaton Myasthenic Syndrome. Neurol. Clin. 2018; 36(2): 379-394. http://doi.org/10.1016/j.ncl.2018.01.008
- Genetic and Rare Diseases (GARD) Information Center. Lambert Eaton myasthenic syndrome. Accessed March 23, 2023. https://rarediseases.info.nih.gov/diseases/6851/lambert-eaton-myasthenic-syndrome
- Lambert-Eaton myasthenic syndrome. Accessed 23 March 2023. https://www.orpha.net/en/disease/detail/43393
- National Organization for Rare Diseases (NORD). Lambert-Eaton Myasthenic Syndrome. Updated September 2023. Accessed 13 November 2024. https://rarediseases.org/rare-diseases/lambert-eaton-myasthenic-syndrome/
- Myasthenia Gravis Association of Queensland Inc. Myasthenia Gravis – a comprehensive guide to living with and understanding this manageable condition. Queensland; 2022. 36p. https://mgaq.org.au/sites/default/files/2024-09/MGAQ_Brochure_2022.pdf
Page Last Updated
19/11/2024 14:37
