Materiały źródłowe

• #1 Lambert-Eaton Myasthenic syndrome: early diagnosis is key | DNND

  https://www.dovepress.com/lambert-eaton-myasthenic-syndrome-early-diagnosis-is-key-peer-reviewed-fulltext-article-DNND

  Lambert-Eaton myasthenic syndrome (LEMS) is clinically characterized by proximal muscle weakness, autonomic dysfunction and areflexia. […] In clinically suspected cases, diagnoses are confirmed by serological and electrodiagnostic tests. […] Diagnosis requires a high level of awareness and necessitates the initiation of a prompt screening and surveillance process to detect and treat malignant tumors. […] Clinical suspicion is the first and most important step in the diagnostic process. LEMS should be considered in any patient presenting with proximal muscle weakness, especially if it is associated with hypo- or areflexia, dry mouth, constipation or oculobulbar symptoms. […] In cases with a compatible clinical constellation, the diagnosis is confirmed with electrophysiological and serological tests.

• #1 Recognizing LEMS | LEMS Aware HCPLEMS Aware logoLEMS Aware on LinkedInLEMS Aware on TwitterLEMS Aware on FacebookCatalyst Logo

  https://www.lemsawarehcp.com/recognizing-lems/

  The early recognition of LEMS is crucial for improving clinical outcomes but remains a major challenge. […] Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder of the neuromuscular junction. […] It is estimated that about half of these individuals are still undiagnosed. […] They suffer despite the fact there are simple tests available to clinicians that can accurately diagnose the disorder and effective medicines that can mitigate its devastating effects. […] The progressive nature of LEMS and the diagnostic challenges that it presents make early symptom recognition critical for optimal patient care. […] LEMS is often suspected based on a clinical triad of signs and symptoms. […] Because many patients with LEMS spend an average of 4.4 years searching for a correct diagnosis, proximal muscle weakness is reason enough to order a LEMS antibody test for your patients.

• #1 LEMS Testing and Diagnosis | LEMS Aware HCPLEMS Aware logoLEMS Aware on LinkedInLEMS Aware on TwitterLEMS Aware on FacebookCatalyst Logo

  https://www.lemsawarehcp.com/lems-testing-and-diagnosis/

  The discovery of pathogenic autoantibodies to voltage-gated calcium channels (VGCCs) has facilitated diagnosis. […] The discovery that P/Q-type anti-VGCC antibodies are a pathogenic factor in Lambert-Eaton myasthenic syndrome (LEMS) represented a major scientific breakthrough. With an established etiological basis for LEMS, physicians now have confirmatory tests and tools to shorten the diagnostic delay. […] A diagnosis of LEMS may be suspected based on clinical symptomatology, including proximal muscle weakness, autonomic dysfunction, and hyporeflexia or areflexia. However, confirmatory tests are critical for a definitive diagnosis. […] High titers of anti-VGCC antibodies (>30 pmol/L*) indicate a positive diagnosis of LEMS. […] Low titers (<30 pmol/L*) suggest a negative or normal diagnosis. However, EMG testing should be considered to rule out the possibility of seronegative LEMS. Up to 15% of patients with LEMS have undetectable anti-VGCC antibody levels.

• #1 Diagnosis and Treatment of Lambert-Eaton Myasthenic Syndrome

  https://practicalneurology.com/articles/2024-apr/diagnosis-and-treatment-of-lambert-eaton-myasthenic-syndrome

  Recognition of this rare immune-mediated disorder of the neuromuscular junction is critical for treatment, including of potential associated malignancy. Awareness of the clinical features, diagnostic evaluation, malignancy workup, and management of LEMS, as well as a high index of suspicion, are important for timely diagnosis and proper treatment. […] The diagnosis of LEMS is based on the presence of the typical clinical triad, with support from serology and electrodiagnostic testing. Serologic studies are used to confirm a suspected diagnosis of LEMS, with autoantibodies against the P/Q type VGCC being the most sensitive and specific for LEMS. […] Electrodiagnostic studies may be helpful to exclude other diagnoses and provide additional supportive evidence of a presynaptic NMJ defect.

• #1 Lambert-Eaton Myasthenic Syndrome – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK507891/

  Lambert-Eaton myasthenic syndrome (LEMS) is a neuromuscular junction disorder affecting communication between nerves and muscles. […] This activity reviews the pathogenesis, diagnostic procedures, and treatment strategies for LEMS. […] Clinical features such as proximal muscle weakness associated with areflexia and autonomic dysfunction should raise suspicion and prompt an evaluation for LEMS. This diagnosis can be confirmed through P/Q-type VGCC and electrodiagnostic studies (EDS). […] Antibodies directed against P/Q-type VGCC, as detected in a radioimmunoassay, are present in approximately 85% to 95% of individuals with LEMS. […] When clinical suspicion arises regarding LEMS, EDS provides valuable assistance in confirming the diagnosis. […] Due to the strong association with malignancy, a diagnosis of LEMS warrants an immediate and extensive investigation for an underlying malignancy. […] The differential diagnosis of LEMS includes MG. The distinguishing features include areflexia, autonomic dysfunction, and the post-exercise facilitation phenomenon specific to LEMS.

• #1 Lambert-Eaton Disease: Symptoms, Causes and Treatment

  https://lonestarneurology.net/blog/lambert-eaton-disease/

  Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder affecting signals transmitted from the nerves to the muscles. […] The LEMS diagnosis is made by a neurologist based on the examination of the patient, a neurological examination and the results of an electroneuromyography. […] Lambert-Eaton syndrome has a definite increase in muscle strength during movement, which distinguishes it from myasthenia gravis, where muscle weakness increases with movement. […] The treatment of Lambert-Eaton syndrome depends on what caused it: If the origin of Lambert-Eaton syndrome is due to the manifestation of a malignant tumor, therapy is primarily aimed at eliminating it. […] If the origin of the disease is autoimmune, symptomatic treatment is carried out. For this purpose, drugs (most often glucocorticosteroids) that suppress the immune system are used. […] The Lambert Eaton disease can be progressive without proper treatment and care.

• #1 Lambert-Eaton Myasthenic Syndrome (LEMS) Workup: Approach Considerations, Antibody Assays, Imaging Studies and Bronchoscopy

  https://emedicine.medscape.com/article/1170810-workup

  In all adult patients with LEMS, diagnostic imaging (eg, computed tomography [CT] or magnetic resonance imaging [MRI]) of the chest for cancer detection should be performed. […] If imaging findings are negative in a patient with a substantial risk of having lung cancer, bronchoscopy should be performed. […] Repetitive nerve stimulation (RNS) studies confirm the diagnosis of Lambert-Eaton myasthenic syndrome (LEMS) by demonstrating characteristic findings. […] Testing with edrophonium (Tensilon) may be performed to help differentiate Lambert-Eaton myasthenic syndrome (LEMS) from myasthenia gravis (MG). However, such testing is highly subjective, and it is of little value in the diagnosis of LEMS in the ED.

• #1 LEMS Testing and Diagnosis | LEMS Aware HCPLEMS Aware logoLEMS Aware on LinkedInLEMS Aware on TwitterLEMS Aware on FacebookCatalyst Logo

  https://www.lemsawarehcp.com/lems-testing-and-diagnosis/

  Increment on high-frequency nerve stimulation and post-exercise facilitation can provide confirmatory evidence of a diagnosis of LEMS. […] LEMS is a clinically important early indicator of possible cancer; therefore, a LEMS diagnosis should immediately prompt rigorous oncological screening and surveillance.

• #1 Lambert-Eaton Myasthenic syndrome: early diagnosis is key | DNND

  https://www.dovepress.com/lambert-eaton-myasthenic-syndrome-early-diagnosis-is-key-peer-reviewed-fulltext-article-DNND

  The detection of diffusely reduced CMAPs in the absence of an alternative explanation should also raise the alarm. […] Anti-P/Q-type VGCC antibodies are helpful and provide additional diagnostic certainty but are complementary and cannot replace electrodiagnosis. […] We propose a diagnostic algorithm wherein we consider 3 possible electrodiagnostic scenarios for clinically suspected cases: 1. The patient exhibits a typical pattern (a significantly reduced CMAPs, a decremental CMAP response on low-frequency RNS and an incremental response after PET or HFS) that is confirmatory for LEMS. […] In such cases, the detection of specific antibodies differentiates between seropositive and seronegative LEMS. […] 2. The patient has suggestive electrophysiological findings (a normal or mildly reduced CMAPs and an abnormal decremental response without a significant incremental response).

• #1 Lambert-Eaton myasthenic syndrome – Symptoms, diagnosis and treatment | BMJ Best Practice US

  https://bestpractice.bmj.com/topics/en-us/1052?locale=fr

  1st tests to order include nerve conduction studies, low-frequency repetitive nerve stimulation, anti-P/Q voltage-gated calcium-channel serology, chest CT scan, anti-acetylcholine receptor (AChR) serology, and thyroid-stimulating hormone (TSH). […] Emerging tests include alpha-1A P/Q voltage-gated calcium-channel subunit antibodies and anti-SOX1 antibodies.

• #1 Lambert-Eaton Myasthenic Syndrome (LEMS) Workup: Approach Considerations, Antibody Assays, Imaging Studies and Bronchoscopy

  https://emedicine.medscape.com/article/1170810-workup

  In the emergency setting, very few tests are of importance in regard to Lambert-Eaton myasthenic syndrome (LEMS) because 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: Complete blood count, Basic chemistry, Pulse oximetry. […] Other, more specific tests are ordered as indicated. Antibodies to voltage-gated calcium channels (VGCCs) have been reported in 75-100% of Lambert-Eaton myasthenic syndrome (LEMS) patients who have small cell lung cancer (SCLC) and in 50-90% of LEMS patients who do not have underlying cancer. […] The only true methods of differentiating MG from LEMS are the detection of AChR antibodies and the presence of underlying malignancy.

• #1 Review of the Diagnostic Challenges of Lambert–Eaton Syndrome Revealed Through Three Case Reports | Canadian Journal of Neurological Sciences | Cambridge Core

  https://www.cambridge.org/core/journals/canadian-journal-of-neurological-sciences/article/review-of-the-diagnostic-challenges-of-lamberteaton-syndrome-revealed-through-three-case-reports/199C1272374AFEEE24643F5C0F86913B

  Lambert-Eaton syndrome (LES) is a rare immune-mediated disorder characterized by proximal leg weakness, autonomic symptoms and hypoactive tendon reflexes. […] The early recognition of LES is crucial for improving clinical outcomes but remains a major challenge. […] Patients were assessed by image-based screening, serological testing and electrophysiological evaluations, which included respiratory and autonomic testing. […] A better understanding of the common pitfalls in the clinical, serological and neurophysiologic diagnosis of LES through assessment of typical LES dysfunction throughout the nervous system should enable improved recognition and treatment of this syndrome. […] This review highlights the most common diagnostic pitfalls in the clinical approach to LES and focuses on the usefulness of autonomic and respiratory testing.

• #1 LEMS Diagnosis: Patient Presentation and Testing

  https://www.onclive.com/view/lems-diagnosis-patient-presentation-and-testing

  Patients with small cell lung cancer may have low levels of various antibodies, even without a symptomatic or definable neurological condition occurring. […] When we talk about misdiagnosis of Lambert-Eaton syndrome, theres a lack of recognition of the disease and underdiagnosing. […] Its very sensitive, if you have Lambert-Eaton youre likely to have the antibodies, but in our practice, many people who have the antibodies dont have Lambert-Eaton syndrome. […] We must put these things into context: our clinical judgment, the antibody testing, and the ancillary testing, whether it be electrodiagnostic testing or imaging.

• #1 Finding a Specialist | LEMS AwareLEMS Aware on InstagramLEMS Aware on Facebook

  https://www.lemsaware.com/finding-a-specialist/

  Specialists who can diagnose and treat Lambert-Eaton myasthenic syndrome (LEMS) […] Neurologists […] Physicians who specialize in conditions that affect the nervous system, including the brain, the spinal cord, and all the nerves in the body. […] Neuromuscular specialists […] Physicians who specialize in conditions that affect the neuromuscular system, including disorders of the neuromuscular junction. […] Physiatrists […] Physicians who specialize in physical medicine and the rehabilitation of medical conditions affecting the brain, spinal cord, bones, joints, nerves, and muscles. […] Before meeting with the doctor, write down notes that include a brief but thorough description of your current health status. […] Specific information about your symptoms and how they affect your daily activities

• #1 Diagnosis and Treatment of Lambert-Eaton Myasthenic Syndrome

  https://practicalneurology.com/diseases-diagnoses/neuromuscular/diagnosis-and-treatment-of-lambert-eaton-myasthenic-syndrome/32113/

  The most common initial clue for LEMS is diffusely reduced CMAP amplitude. Whenever an individual with proximally predominant muscle weakness is noted to have diffusely low CMAP amplitudes, LEMS must be suspected. […] Single-fiber EMG may also be utilized to support a diagnosis of LEMS and is typically reserved for when there is strong suspicion for LEMS despite negative serology and nerve conduction studies. […] Additional radiologic testing is mandatory in LEMS based on the strong association with malignancy, particularly SCLC. The DELTA-P (Dutch-English LEMS Tumor Association Prediction) score is helpful in predicting risk for future malignancy development and assists in modulating the frequency of imaging studies and other methods to evaluate for SCLC. Repeat screening for cancer every 3 to 6 months is recommended for at least 2 years after the diagnosis of LEMS. […] Diagnosis is based on history and examination findings, and is supported by serology and an electrophysiologic triad.

• #1 Lambert-eaton myasthenic syndrome: diagnosis and treatment – PubMed

  https://pubmed.ncbi.nlm.nih.gov/14592920/

  A high index of suspicion is essential in arriving at the correct diagnosis of Lambert-Eaton myasthenic syndrome (LEMS). LEMS should be considered in the differential in any patient who has proximal weakness, reduced or absent muscle stretch reflexes, and dry mouth. The diagnosis is confirmed by demonstrating characteristic electromyographic findings-low-amplitude muscle responses that increase dramatically after activation. Most patients also have circulating antibodies to the voltage-gated calcium channel. The diagnosis should trigger an intensive search for malignancy, especially in older patients with a history of smoking. Improvement, if any, occurs only after many months and requires chronic administration of immunosuppressive medications at significant doses. […] The long-term prognosis in LEMS is determined by the presence of cancer or other autoimmune disease.

• #2 Diagnosis and Treatment of Lambert-Eaton Myasthenic Syndrome

  https://practicalneurology.com/diseases-diagnoses/neuromuscular/diagnosis-and-treatment-of-lambert-eaton-myasthenic-syndrome/32113/

  Recognition of this rare immune-mediated disorder of the neuromuscular junction is critical for treatment, including of potential associated malignancy. Awareness of the clinical features, diagnostic evaluation, malignancy workup, and management of LEMS, as well as a high index of suspicion, are important for timely diagnosis and proper treatment. […] The diagnosis of LEMS is based on the presence of the typical clinical triad, with support from serology and electrodiagnostic testing. Serologic studies are used to confirm a suspected diagnosis of LEMS, with autoantibodies against the P/Q type VGCC being the most sensitive and specific for LEMS. […] Electrodiagnostic studies may be helpful to exclude other diagnoses and provide additional supportive evidence of a presynaptic NMJ defect.

• #2 Recognizing LEMS | LEMS Aware HCPLEMS Aware logoLEMS Aware on LinkedInLEMS Aware on TwitterLEMS Aware on FacebookCatalyst Logo

  https://www.lemsawarehcp.com/recognizing-lems/

  The presentation of areflexia/hyporeflexia—and autonomic symptoms such as dry mouth, dry eyes, constipation, and impotence—only adds to the urgency to test for LEMS. […] Dr. Dimachkie walks through determining the cause of a patient’s muscle weakness, common clinical symptoms, and diagnostic testing in order to help clinicians diagnose LEMS.

• #2 Lambert-Eaton Myasthenic Syndrome – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK507891/

  Lambert-Eaton myasthenic syndrome (LEMS) is a neuromuscular junction disorder affecting communication between nerves and muscles. […] This activity reviews the pathogenesis, diagnostic procedures, and treatment strategies for LEMS. […] Clinical features such as proximal muscle weakness associated with areflexia and autonomic dysfunction should raise suspicion and prompt an evaluation for LEMS. This diagnosis can be confirmed through P/Q-type VGCC and electrodiagnostic studies (EDS). […] Antibodies directed against P/Q-type VGCC, as detected in a radioimmunoassay, are present in approximately 85% to 95% of individuals with LEMS. […] When clinical suspicion arises regarding LEMS, EDS provides valuable assistance in confirming the diagnosis. […] Due to the strong association with malignancy, a diagnosis of LEMS warrants an immediate and extensive investigation for an underlying malignancy. […] The differential diagnosis of LEMS includes MG. The distinguishing features include areflexia, autonomic dysfunction, and the post-exercise facilitation phenomenon specific to LEMS.

• #2 Lambert–Eaton myasthenic syndrome – Wikipedia

  https://en.wikipedia.org/wiki/Lambert%E2%80%93Eaton_myasthenic_syndrome

  LambertEaton myasthenic syndrome is caused by autoantibodies to the presynaptic membrane. […] The diagnosis is usually confirmed with electromyography and blood tests; these also distinguish it from myasthenia gravis, a related autoimmune neuromuscular disease. […] Along with a medical history and physical examination by a neuromuscular physician, a Voltage-gated calcium channels (VGCCs) antibody test and Electromyography (EMG) test can obtain a diagnosis of LEMs. […] The diagnosis is usually made with nerve conduction study (NCS) and electromyography (EMG), which is one of the standard tests in the investigation of otherwise unexplained muscle weakness. […] Blood tests may be performed to exclude other causes of muscle disease (elevated creatine kinase may indicate a myositis, and abnormal thyroid function tests may indicate thyrotoxic myopathy). Antibodies against voltage-gated calcium channels can be identified in 85% of people with EMG-confirmed LEMS. […] Once LEMS is diagnosed, investigations such as a CT scan of the chest are usually performed to identify any possible underlying lung tumors.

• #2 Myasthenia Gravis vs. Lambert Eaton Syndrome

  https://www.healthline.com/health/myasthenia-gravis/myasthenia-gravis-vs-lambert-eaton

  Myasthenia gravis and Lambert-Eaton syndrome both cause unusual muscle weakness but in different ways. […] In this article, we discuss the similarities and differences between MG and LEMS, including their causes and symptoms, how doctors diagnose and treat them, and the respective outlooks for people with these conditions. […] To diagnose LEMS and MG, a doctor takes your medical history, performs a physical exam, and orders specialized tests. These tests may include: blood tests to check for specific antibodies characteristic of each condition, repetitive nerve stimulation and electromyography to measure muscle and nerve function, a CT scan or other imaging tests to check for underlying or related conditions, such as SCLC. […] In MG, these tests typically show decreased muscle function with repeated stimulation. In LEMS, muscle response measured with electrical testing may improve with exercise.

• #2 Lambert-Eaton Myasthenic Syndrome Versus Myasthenia GravisShare to Facebookprint pageBookmark for latercommentcaret iconcaret iconmore actionsFollow us on facebookFollow us on instagramFollow us on facebookFollow us on linkedincaret icon

  https://myasthenia-gravis.com/clinical/lems-symptom-differences

  Myasthenia gravis (MG) and Lambert-Eaton myasthenic syndrome (LEMS) are autoimmune conditions. This means the immune system attacks your own healthy cells. Both conditions involve the immune system interfering with nerves communicating to muscles. This leads to muscle weakness and fatigue in both conditions. However, they are different conditions with different causes and symptoms. […] Knowing the difference between symptoms can help obtain the correct diagnosis earlier. This can help you get the best treatment. […] Doctors diagnose LEMS based on your health history, a neurological exam, and certain tests. The results of these tests help your doctor tell the difference between LEMS and MG. […] Your doctor may test your blood for antibodies that attack calcium channels. These are different from the antibodies seen in people with MG. A test called electromyography can show your doctor how well your nerves talk to your muscles. This test can differentiate between LEMS and MG. Your doctor may also take CT or MRI scans of your chest to look for SCLC if they suspect LEMS.

• #2

  https://www.alliedacademies.org/articles/understanding-lamberteaton-myasthenic-syndrome-pathophysiology-diagnosis-and-treatment-29408.html

  Diagnosing LEMS involves a combination of clinical evaluation, laboratory tests, and electrophysiological studies. Key diagnostic steps include: Clinical Examination: Assessment of muscle strength, reflexes, and autonomic function. A history of symptoms and any associated malignancies is also crucial. Serological Tests: Detection of anti-VGCC antibodies in the blood, which are present in most LEMS patients. […] Electrophysiological Studies: Repetitive nerve stimulation tests show a characteristic pattern of low baseline compound muscle action potential (CMAP) amplitude, which increases significantly after brief exercise or high-frequency stimulation. Tensilon Test: This test, commonly used for myasthenia gravis, can sometimes help distinguish LEMS. Patients with LEMS may show some improvement with edrophonium, although it is typically less pronounced than in myasthenia gravis.

• #2 Diagnosis – Lambert-Eaton Myasthenic Syndrome (LEMS) – Diseases | Muscular Dystrophy Association

  https://www.mda.org/disease/lambert-eaton-myasthenic-syndrome/diagnosis

  If negative, a PET-CT should be considered. […] If negative, follow-up chest CTs are recommended for up to five years to monitor for an underlying cancer. […] A 2010 taskforce recommended repeating this screening at three to six months, and then every six months for two years in people with LEMS, if testing remains unrevealing. […] Most cancers, if present, are detected in the first year.

• #2 Lambert-Eaton Myasthenic syndrome: early diagnosis is key | DNND

  https://www.dovepress.com/lambert-eaton-myasthenic-syndrome-early-diagnosis-is-key-peer-reviewed-fulltext-article-DNND

  This pattern is a possible scenario during the initial stages of LEMS; therefore, to avoid underdiagnosis, we recommend a repetition of the electrophysiological study. […] 3. In the third and last electrodiagnostic scenario, there are no electrophysiological findings suggestive of LEMS, or the findings do not reach the required values. […] If there is high clinical suspicion, the detection of specific antibodies could warrant the repetition of the test; otherwise, the diagnosis of LEMS is highly improbable.

• #2 Neuro-Ophthalmic Manifestations of Lambert-Eaton Myasthenic Syndrome – EyeWiki

  https://eyewiki.org/Neuro-Ophthalmic_Manifestations_of_Lambert-Eaton_Myasthenic_Syndrome

  Ocular and bulbar symptoms are reported in 49-78% of LEMS and are usually seen late in the disease as it progresses craniocaudal. […] LEMS may manifest before malignancy is detected, so extensive and repeated oncological screening should be considered after LEMS diagnosis. […] Electrodiagnostic testing has high sensitivity and specificity in diagnosing LEMS and ruling out MG. […] Detection of anti-voltage-gated calcium channel antibodies may be achieved with radioimmunoassay. In LEMS patients, anti-P/Q type VGCC antibodies are seen in 85-90% of patients. Anti-N type VGCCs antibodies are seen in 33% of patients. […] SOX antibodies have been used to differentiate LEMS with SCLC and NT-LEMS with 67% sensitivity and 95% specificity, but these antibodies have not been shown to impact the survival of SCLC patients. […] LEMS is often misdiagnosed, and MG is the most common incorrect attribution. This may be due to the rarity of LEMS.

• #2 Lambert Eaton Myasthenic Syndrome (LEMS) – Rare Awareness Rare Education

  https://rareportal.org.au/rare-disease/lambert-eaton-myasthenic-syndrome-lems/

  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. Single fibre electromyography (SFEMG) has also been used to detect impaired neuromuscular transmission in LEMS. […] 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.

• #2 Recognizing LEMS | LEMS Aware HCPLEMS Aware logoLEMS Aware on LinkedInLEMS Aware on TwitterLEMS Aware on FacebookCatalyst Logo

  https://www.lemsawarehcp.com/recognizing-lems/

  The early recognition of LEMS is crucial for improving clinical outcomes but remains a major challenge. […] Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder of the neuromuscular junction. […] It is estimated that about half of these individuals are still undiagnosed. […] They suffer despite the fact there are simple tests available to clinicians that can accurately diagnose the disorder and effective medicines that can mitigate its devastating effects. […] The progressive nature of LEMS and the diagnostic challenges that it presents make early symptom recognition critical for optimal patient care. […] LEMS is often suspected based on a clinical triad of signs and symptoms. […] Because many patients with LEMS spend an average of 4.4 years searching for a correct diagnosis, proximal muscle weakness is reason enough to order a LEMS antibody test for your patients.

• #2 Review of the Diagnostic Challenges of Lambert–Eaton Syndrome Revealed Through Three Case Reports | Canadian Journal of Neurological Sciences | Cambridge Core

  https://www.cambridge.org/core/journals/canadian-journal-of-neurological-sciences/article/review-of-the-diagnostic-challenges-of-lamberteaton-syndrome-revealed-through-three-case-reports/199C1272374AFEEE24643F5C0F86913B

  The diagnosis of LES may be overlooked when symptoms and signs of multiple paraneoplastic disorders coexist, particularly in the setting of subacute cerebellar ataxia or severe peripheral neuropathy. […] The diagnosis of this condition is indicative of locally advanced disease, which is generally not reversible. […] Symptoms or signs of autonomic dysfunction have been found in up to 80% of LES patients and may be the presenting symptom in 6% of patients, preceding muscle weakness onset by years. […] Although the autonomic dysfunction is mostly mild to moderate, and the frequency is similar in P-LES and NP-LES patients, the severity tends to be greater in older patients with cancer. […] In clinical practice, P/Q-type VGCCAb have the highest sensitivity and specificity in LES, rather than the rarer N- or L-type VGCCAb.

• #2 Lambert-Eaton Myasthenic Syndrome (LEMS): Treatment and more

  https://www.verywellhealth.com/lambert-eaton-myasthenic-syndrome-lems-5100988

  However, these tests are not perfect. A minority of people with small-cell lung cancer have high amounts of these antibodies even though they dont have symptoms of LEMS. […] Sometimes electrophysiology tests can help confirm a diagnosis as well. A test like electromyography (EMG) can provide some helpful information. […] Its also critical to investigate whether a cancer, particularly small-cell lung cancer, might be present. For this reason, its usually recommended that people diagnosed with LEMS receive a computed tomography (CT) scan of the chest.

• #2 Finding a Specialist | LEMS AwareLEMS Aware on InstagramLEMS Aware on Facebook

  https://www.lemsaware.com/finding-a-specialist/

  A timeline of your illness: when symptoms first appeared, how they progressed, and whether they’ve fluctuated, gotten better, or gotten worse […] Details about previous treatments you’ve received or used, including prescription drugs, over-the-counter remedies, and any physical therapy or rehab […] Details about your medical history, particularly if you have a history of smoking or using tobacco and/or if you have been diagnosed with an autoimmune disorder, as these things are risk factors sometimes associated with LEMS […] You should also prepare a list of any questions you may have about the tests or treatments that your doctor may recommend.

• #2 Lambert-Eaton myasthenic syndrome (LEMS): Causes, symptoms, and more

  https://www.medicalnewstoday.com/articles/lambert-eaton-syndrome

  Electromyography and repetitive nerve stimulation can detect electrical irregularities in muscle response. […] A CT or MRI scan can help identify any underlying cancer, especially SCLC. […] Diagnosis involves clinical evaluation, electrodiagnostic studies, and blood tests. […] Early detection and a multidisciplinary approach are key to managing LEMS effectively.

• #2 Lambert-Eaton Myasthenic Syndrome (LEMS): Treatment and more

  https://www.verywellhealth.com/lambert-eaton-myasthenic-syndrome-lems-5100988

  Lambert-Eaton myasthenic syndrome (LEMS) is a disorder that can lead to fatigue, significant muscle weakness, and other symptoms like dry mouth. […] Unfortunately, a correct diagnosis of LEMS doesnt always happen right away. Because it is such a rare disease, its important that clinicians think of it as a possibility. […] Neurologists can bring special expertise to the diagnostic process. They must consider not only diseases that can affect the nervous system but also causes that affect the musculoskeletal system. […] Because LEMS is sometimes caused by cancer, it is important to be correctly diagnosed as quickly as possible. An early diagnosis of LEMS can point the way to an earlier cancer diagnosis, leading to more effective cancer treatment. […] Medical history and clinical exam are critical parts of diagnosis. Through these alone, a clinician might suspect LEMS.

• #3 Diagnosis – Lambert-Eaton Myasthenic Syndrome (LEMS) – Diseases | Muscular Dystrophy Association

  https://www.mda.org/disease/lambert-eaton-myasthenic-syndrome/diagnosis

  The diagnosis of LEMS is often difficult if the disease is not suspected, since weakness in the legs with or without arm weakness and fatigue are common complaints in general. […] The diagnosis is more likely to be suspected in people with cancer. […] Often, the initial suspected diagnosis is MG, due to an overlap in symptoms. […] The presence of a dry mouth is also a helpful clue. […] A neurologist will ask many questions and conduct a physical exam to determine the extent of weakness. […] The tendon (muscle stretch) reflexes are usually decreased in LEMS and that is a helpful finding. […] In addition, some patients will have improvement in reflexes after 10 seconds of activating a muscle, and this finding is also a clue that LEMS may be present. […] Often, the diagnosis is made in the electromyography (EMG) laboratory, where patients may undergo testing for various causes of weakness.

• #3 LEMS Testing and Diagnosis | LEMS Aware HCPLEMS Aware logoLEMS Aware on LinkedInLEMS Aware on TwitterLEMS Aware on FacebookCatalyst Logo

  https://www.lemsawarehcp.com/lems-testing-and-diagnosis/

  The discovery of pathogenic autoantibodies to voltage-gated calcium channels (VGCCs) has facilitated diagnosis. […] The discovery that P/Q-type anti-VGCC antibodies are a pathogenic factor in Lambert-Eaton myasthenic syndrome (LEMS) represented a major scientific breakthrough. With an established etiological basis for LEMS, physicians now have confirmatory tests and tools to shorten the diagnostic delay. […] A diagnosis of LEMS may be suspected based on clinical symptomatology, including proximal muscle weakness, autonomic dysfunction, and hyporeflexia or areflexia. However, confirmatory tests are critical for a definitive diagnosis. […] High titers of anti-VGCC antibodies (>30 pmol/L*) indicate a positive diagnosis of LEMS. […] Low titers (<30 pmol/L*) suggest a negative or normal diagnosis. However, EMG testing should be considered to rule out the possibility of seronegative LEMS. Up to 15% of patients with LEMS have undetectable anti-VGCC antibody levels.

• #3 Diagnosis – Lambert-Eaton Myasthenic Syndrome (LEMS) – Diseases | Muscular Dystrophy Association

  https://www.mda.org/disease/lambert-eaton-myasthenic-syndrome/diagnosis

  The nerve responses are usually low, and the examiners should then have the person exercise the muscle for 10 seconds and stimulate it again. […] In LEMS, the response usually increases by more than 60 percent and this is called an increment. […] When positive, especially at 100 percent increment, this test is diagnostic of LEMS. […] In addition, if the physical exam is consistent with LEMS and if the EMG is suggestive of LEMS, the neurologist usually orders a blood test designed to detect antibodies to calcium channels on the nerve side of the nerve-muscle junction. […] Positive test results support a diagnosis of MG, but some individuals lack these antibodies. […] In some instances, the antibody test is performed before the EMG. […] If a diagnosis of LEMS is confirmed, a CT scan of the chest should be obtained to look for a small cell lung cancer.

• #3 Review of the Diagnostic Challenges of Lambert–Eaton Syndrome Revealed Through Three Case Reports | Canadian Journal of Neurological Sciences | Cambridge Core

  https://www.cambridge.org/core/journals/canadian-journal-of-neurological-sciences/article/review-of-the-diagnostic-challenges-of-lamberteaton-syndrome-revealed-through-three-case-reports/199C1272374AFEEE24643F5C0F86913B

  A positive P/Q-type VGCCAb result is useful for distinguishing LES from MG, but results must be interpreted in the context of the clinical and electrophysiological findings in each individual patient. […] The differential diagnosis of LES includes MG, congenital myasthenic syndromes and defects of neuromuscular transmission induced by drugs or toxins. […] The combination of proximal weakness and reduced TR, seen in LES, might suggest an inflammatory neuropathy with minimal sensory involvement or myopathy. […] Facilitation greater than 400% in any muscle or greater than 100% in most tested muscles, as noted in this patient, is almost certainly diagnostic of LES.

• #3 Diagnosis and Treatment of Lambert-Eaton Myasthenic Syndrome

  https://practicalneurology.com/articles/2024-apr/diagnosis-and-treatment-of-lambert-eaton-myasthenic-syndrome

  The most common initial clue for LEMS is diffusely reduced CMAP amplitude. Whenever an individual with proximally predominant muscle weakness is noted to have diffusely low CMAP amplitudes, LEMS must be suspected. […] Single-fiber EMG may also be utilized to support a diagnosis of LEMS and is typically reserved for when there is strong suspicion for LEMS despite negative serology and nerve conduction studies. […] Additional radiologic testing is mandatory in LEMS based on the strong association with malignancy, particularly SCLC. The DELTA-P (Dutch-English LEMS Tumor Association Prediction) score is helpful in predicting risk for future malignancy development and assists in modulating the frequency of imaging studies and other methods to evaluate for SCLC. […] Diagnosis is based on history and examination findings, and is supported by serology and an electrophysiologic triad.

• #3 Lambert-Eaton Myasthenic syndrome: early diagnosis is key | DNND

  https://www.dovepress.com/lambert-eaton-myasthenic-syndrome-early-diagnosis-is-key-peer-reviewed-fulltext-article-DNND

  The detection of diffusely reduced CMAPs in the absence of an alternative explanation should also raise the alarm. […] Anti-P/Q-type VGCC antibodies are helpful and provide additional diagnostic certainty but are complementary and cannot replace electrodiagnosis. […] We propose a diagnostic algorithm wherein we consider 3 possible electrodiagnostic scenarios for clinically suspected cases: 1. The patient exhibits a typical pattern (a significantly reduced CMAPs, a decremental CMAP response on low-frequency RNS and an incremental response after PET or HFS) that is confirmatory for LEMS. […] In such cases, the detection of specific antibodies differentiates between seropositive and seronegative LEMS. […] 2. The patient has suggestive electrophysiological findings (a normal or mildly reduced CMAPs and an abnormal decremental response without a significant incremental response).

• #3 Review of the Diagnostic Challenges of Lambert–Eaton Syndrome Revealed Through Three Case Reports | Canadian Journal of Neurological Sciences | Cambridge Core

  https://www.cambridge.org/core/journals/canadian-journal-of-neurological-sciences/article/review-of-the-diagnostic-challenges-of-lamberteaton-syndrome-revealed-through-three-case-reports/199C1272374AFEEE24643F5C0F86913B

  The diagnosis of LES may be overlooked when symptoms and signs of multiple paraneoplastic disorders coexist, particularly in the setting of subacute cerebellar ataxia or severe peripheral neuropathy. […] The diagnosis of this condition is indicative of locally advanced disease, which is generally not reversible. […] Symptoms or signs of autonomic dysfunction have been found in up to 80% of LES patients and may be the presenting symptom in 6% of patients, preceding muscle weakness onset by years. […] Although the autonomic dysfunction is mostly mild to moderate, and the frequency is similar in P-LES and NP-LES patients, the severity tends to be greater in older patients with cancer. […] In clinical practice, P/Q-type VGCCAb have the highest sensitivity and specificity in LES, rather than the rarer N- or L-type VGCCAb.

• #3 Recognizing LEMS | LEMS Aware HCPLEMS Aware logoLEMS Aware on LinkedInLEMS Aware on TwitterLEMS Aware on FacebookCatalyst Logo

  https://www.lemsawarehcp.com/recognizing-lems/

  The early recognition of LEMS is crucial for improving clinical outcomes but remains a major challenge. […] Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder of the neuromuscular junction. […] It is estimated that about half of these individuals are still undiagnosed. […] They suffer despite the fact there are simple tests available to clinicians that can accurately diagnose the disorder and effective medicines that can mitigate its devastating effects. […] The progressive nature of LEMS and the diagnostic challenges that it presents make early symptom recognition critical for optimal patient care. […] LEMS is often suspected based on a clinical triad of signs and symptoms. […] Because many patients with LEMS spend an average of 4.4 years searching for a correct diagnosis, proximal muscle weakness is reason enough to order a LEMS antibody test for your patients.

• #3 The Challenges Getting a LEMS Diagnosis, A Case Study – Lambert-Eaton News Forums

  https://lamberteatonnews.com/forums/forums/topic/the-challenges-getting-a-lems-diagnosis-a-case-study/

  Recently I did a topic talking about how rare LEMS is, and how incredibly rare it is in children. […] The important takeaway from this article from my perspective is, because of our rarity, doctors looking for a diagnosis, need to widen the search in cases of muscle weakness, to include the possibility of Lambert-Eaton in their differential diagnosis. The more aware they are, the sooner a diagnosis of LEMS can get the patient on a good treatment plan and improved symptoms.

• #3 Clinical, Pathophysiological and Electrodiagnostic Aspects of Lambert-Eaton Myasthenic Syndrome | IntechOpen

  https://www.intechopen.com/online-first/87108

  The first analysis is through EMG that confirms the presence of a presynaptic disorder, which the physiopathology will be explained in Electrophysiology chapter. […] The importance of antibody research is to predict cancer development, due to half of LEMS patients having associated SCLC. […] Nearly 90% of LEMS cases are seropositive for P/Q- type VGCC antibodies, once the disease acts impairing the release of ACh at active zones. […] Because of the high association with malignancy, the diagnosis of the myasthenic syndrome should lead to immediate and extensive search and screening for underlying malignant processes. […] Among them, computed tomography (CT) of the chest or magnetic resonance imaging (MRI) would be the recommended initial imaging study. […] Among the established criteria and the electrophysiology of LEMS, repetitive nerve stimulation (RNS) is the test of choice, making it possible to analyze characteristic findings that are part of the classic triad in the diagnosis.

• #4 Diagnosis – Lambert-Eaton Myasthenic Syndrome (LEMS) – Diseases | Muscular Dystrophy Association

  https://www.mda.org/disease/lambert-eaton-myasthenic-syndrome/diagnosis

  The diagnosis of LEMS is often difficult if the disease is not suspected, since weakness in the legs with or without arm weakness and fatigue are common complaints in general. […] The diagnosis is more likely to be suspected in people with cancer. […] Often, the initial suspected diagnosis is MG, due to an overlap in symptoms. […] The presence of a dry mouth is also a helpful clue. […] A neurologist will ask many questions and conduct a physical exam to determine the extent of weakness. […] The tendon (muscle stretch) reflexes are usually decreased in LEMS and that is a helpful finding. […] In addition, some patients will have improvement in reflexes after 10 seconds of activating a muscle, and this finding is also a clue that LEMS may be present. […] Often, the diagnosis is made in the electromyography (EMG) laboratory, where patients may undergo testing for various causes of weakness.

• #4 MGLE – Overview: Myasthenia Gravis/Lambert-Eaton Myasthenic Syndrome Evaluation, Serum

  https://www.mayocliniclabs.com/test-catalog/overview/608979

  Negative results do not exclude the diagnosis of an autoimmune neuromuscular junction disorder. If clinical suspicion remains and symptoms persistent or worsen consider retesting. […] Specimens should be collected prior to administration of immunosuppressant therapy as this may reduce the diagnostic sensitivity of the assay; the neurological diagnosis is further confounded if steroid myopathy develops. […] These results should only be interpreted in the appropriate clinical and electrophysiological context and are not diagnostic in isolation.

• #4 Testing for LEMS

  https://www.onclive.com/view/testing-for-lems

  David Gerber, MD: Steve, it might be helpful at this point to go over how we diagnose and test for LEMS [Lambert-Eaton myasthenic syndrome]. […] That leads to our techniques in diagnosing and testing for Lambert-Eaton myasthenic syndrome because we’re looking for that characteristic impairment in the communication between the motor nerve and the muscle. […] We can do that many ways, but for the most part it starts with our neurological examination. […] One is electrodiagnostic testing, where we can take the patient to the EMG [electromyography] laboratory. […] In Lambert-Eaton myasthenic syndrome, CMAPs are usually small, maybe 10% of normal, in all muscles, not just in the ones that are clinically weak. […] We see a decremental response on the repetitive stimulation, which is like what we see in the other neuromuscular junction disorder, myasthenia gravis, or in a condition like botulism that causes a poisoning of the neuromuscular junction.

• #4 Lambert-Eaton myasthenic syndrome

  https://www.nhs.uk/conditions/lambert-eaton-myasthenic-syndrome/

  LEMS is caused by the body’s natural defences (the immune system) mistakenly attacking and damaging the nerves. […] The GP will first check your medical history, ask about your symptoms, carry out a physical examination, and test your reflexes. […] If they think you have a problem with your nerves, they may refer you to a specialist called a neurologist for further tests to determine the cause. […] Tests you may have include: […] a blood test can detect substances in the blood (antibodies) resulting from the immune system attacking the nerves […] a needle may be inserted into your skin to check how well signals are reaching the muscles from the nerves […] you may have a CT scan or PET scan to check for lung cancer. […] If initial scans do not find cancer, you may be advised to have regular scans every few months for a few years to check that it does not develop later on.

• #4 Lambert-Eaton Myasthenic syndrome: early diagnosis is key | DNND

  https://www.dovepress.com/lambert-eaton-myasthenic-syndrome-early-diagnosis-is-key-peer-reviewed-fulltext-article-DNND

  This pattern is a possible scenario during the initial stages of LEMS; therefore, to avoid underdiagnosis, we recommend a repetition of the electrophysiological study. […] 3. In the third and last electrodiagnostic scenario, there are no electrophysiological findings suggestive of LEMS, or the findings do not reach the required values. […] If there is high clinical suspicion, the detection of specific antibodies could warrant the repetition of the test; otherwise, the diagnosis of LEMS is highly improbable.

• #4 Diagnosis of LEMS | Lambert-Eaton NewsEnvelope icon

  https://lamberteatonnews.com/diagnosis/

  These self-reactive antibodies target and damage proteins that play a key role in nerve-muscle communication, and are considered the underlying cause of LEMS. […] The presence of these antibodies confirms the diagnosis of LEMS, as they are highly specific to the condition. […] The presence of anti-SOX1 antibodies in the blood in addition to anti-VGCC antibodies also can serve as a diagnostic measure to confirm LEMS in SCLC patients and distinguish LEMS associated with SCLC from non-SCLC LEMS. […] Once the diagnosis of LEMS is confirmed, patients are usually screened for SCLC, a specific type of lung cancer often seen in patients with LEMS.

• #4 Lambert-Eaton Myasthenic Syndrome (LEMS): Treatment and more

  https://www.verywellhealth.com/lambert-eaton-myasthenic-syndrome-lems-5100988

  Lambert-Eaton myasthenic syndrome (LEMS) is a disorder that can lead to fatigue, significant muscle weakness, and other symptoms like dry mouth. […] Unfortunately, a correct diagnosis of LEMS doesnt always happen right away. Because it is such a rare disease, its important that clinicians think of it as a possibility. […] Neurologists can bring special expertise to the diagnostic process. They must consider not only diseases that can affect the nervous system but also causes that affect the musculoskeletal system. […] Because LEMS is sometimes caused by cancer, it is important to be correctly diagnosed as quickly as possible. An early diagnosis of LEMS can point the way to an earlier cancer diagnosis, leading to more effective cancer treatment. […] Medical history and clinical exam are critical parts of diagnosis. Through these alone, a clinician might suspect LEMS.

• #4 Any LEMS (Lambert-Eaton Myasthenic Syndrome) people out there? | Mayo Clinic Connect

  https://connect.mayoclinic.org/discussion/lambert-eaton-mysathenic-syndrome/?pg=3

  Good morning John. I have a great portal called MyChart. I emailed the MS specialist and she replied that the neuromuscular team will decide what happens next. I have my EMG scheduled for tomorrow at OHSU in Portland and should get the feedback I need then. I was wondering how definitive an EMG is for diagnosing LEMS. Thanks for your input! […] „ELECTRODIAGNOSTIC TESTING (EMG) Increment on high-frequency nerve stimulation and post-exercise facilitation can provide confirmatory evidence …” — LEMS Testing and Diagnosis – LEMS Aware HCP: https://www.lemsawarehcp.com/lems-testing-and-diagnosis […] I have just found out I may have LEMS. I had an M/G evaluation w/reflex lab test done at Mayo, with the following comment: „This antibody profile is consistent with Lambert-Eaton Myasthenic Syndrome. A paraneoplastic basis should be considered, small cell lung cancer is the most commonly associated cancer.” Normal readings should be < 0.02 nmol/L and my reading was .62 nmol/L. I am mildly alarmed by this as I have been dealing with a possible MS diagnosis for many years, with never a thought of cancer. [...] EMG testing is another piece of the puzzle and will help complete the picture. Good luck on your journey! [...] Will the EMG results provide a definitive answer as to the LEMS? Thanks!

• #4 Clinical, Pathophysiological and Electrodiagnostic Aspects of Lambert-Eaton Myasthenic Syndrome | IntechOpen

  https://www.intechopen.com/online-first/87108

  Needle EMG shows erratic changes in motor unit action potential such as low and short during voluntary action potential. […] The treatment itself for the onset of the disease is based on the underlying etiology, requiring monitoring and treatment of the cancer, if it has a neoplastic etiology. […] However, there are drugs that can act directly on the synaptic terminal, improving quality of life and reducing symptoms. […] The diagnosis of LEMS should immediately prompt rigorous oncologic screening and surveillance.

• #5 Lambert-Eaton myasthenic syndrome – Symptoms, diagnosis and treatment | BMJ Best Practice US

  https://bestpractice.bmj.com/topics/en-us/1052?locale=fr

  Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder of the neuromuscular junction. […] Symptoms include insidious and gradual onset of fatigue, weakness, and a dry mouth. […] Clinical findings include proximal muscle weakness in hip girdle and thigh muscles; absent or reduced tendon reflexes that may facilitate after brief exercise; and dilated, poorly reactive pupils. […] Serum P/Q-type voltage-gated calcium-channel antibodies are usually present. […] Electrophysiologic studies usually demonstrate decremental responses to low-frequency repetitive nerve stimulation, and may also exhibit postactivation facilitation of 100%. […] Key diagnostic factors include history of small cell lung cancer or other malignancy, history of autoimmune disorder, history of cigarette smoking, family history of autoimmune disease, limb weakness, dry mouth, and weakness.

• #5 MGLE – Overview: Myasthenia Gravis/Lambert-Eaton Myasthenic Syndrome Evaluation, Serum

  https://www.mayocliniclabs.com/test-catalog/overview/608979

  Negative results do not exclude the diagnosis of an autoimmune neuromuscular junction disorder. If clinical suspicion remains and symptoms persistent or worsen consider retesting. […] Specimens should be collected prior to administration of immunosuppressant therapy as this may reduce the diagnostic sensitivity of the assay; the neurological diagnosis is further confounded if steroid myopathy develops. […] These results should only be interpreted in the appropriate clinical and electrophysiological context and are not diagnostic in isolation.

• #5 Diagnosis – Lambert-Eaton Myasthenic Syndrome (LEMS) – Diseases | Muscular Dystrophy Association

  https://www.mda.org/disease/lambert-eaton-myasthenic-syndrome/diagnosis

  The nerve responses are usually low, and the examiners should then have the person exercise the muscle for 10 seconds and stimulate it again. […] In LEMS, the response usually increases by more than 60 percent and this is called an increment. […] When positive, especially at 100 percent increment, this test is diagnostic of LEMS. […] In addition, if the physical exam is consistent with LEMS and if the EMG is suggestive of LEMS, the neurologist usually orders a blood test designed to detect antibodies to calcium channels on the nerve side of the nerve-muscle junction. […] Positive test results support a diagnosis of MG, but some individuals lack these antibodies. […] In some instances, the antibody test is performed before the EMG. […] If a diagnosis of LEMS is confirmed, a CT scan of the chest should be obtained to look for a small cell lung cancer.

• #5 Diagnosis – Lambert-Eaton Myasthenic Syndrome (LEMS) – Diseases | Muscular Dystrophy Association

  https://www.mda.org/disease/lambert-eaton-myasthenic-syndrome/diagnosis

  If negative, a PET-CT should be considered. […] If negative, follow-up chest CTs are recommended for up to five years to monitor for an underlying cancer. […] A 2010 taskforce recommended repeating this screening at three to six months, and then every six months for two years in people with LEMS, if testing remains unrevealing. […] Most cancers, if present, are detected in the first year.

• #6 Myasthenia Gravis/Lambert-Eaton Myasthenic Syndrome Evaluation, Serum – Logan Health Medical Center Laboratory Test Catalog

  https://logan.testcatalog.org/show/MGLE

  The diagnostic sensitivity of these tests depends on the disease severity and duration of symptoms. AChR binding antibodies may be undetectable for 6 to 12 months after MG symptom onset and similarly P/Q-type calcium channel antibody may be undetectable for 6 to 12 months after LEMS onset. Only about 5% of adult patients with generalized MG who are not immunosuppressed remain seronegative for muscle AChR beyond 12 months. […] Positive results in this antibody evaluation are indicative of an autoimmune neuromuscular junction disorder. These results should be interpreted in the appropriate clinical and electrophysiological context. […] Negative results do not exclude the diagnosis of an autoimmune neuromuscular junction disorder. If clinical suspicion remains and symptoms persistent or worsen consider retesting.

• #6 Testing for LEMS

  https://www.onclive.com/view/testing-for-lems

  In Lambert-Eaton syndrome, you can look for this facilitation by having the patient do contractions of the muscle, or by giving a high-frequency stimulation to get some of that calcium mobilized in the neuromuscular junction. […] The decrement on repetitive nerve stimulation and a facilitation after exercise is convincing for Lambert-Eaton myasthenic syndrome, or perhaps some other rare conditions, but it’s suspicious. […] We also have a serological test. […] Antibodies against the P/Q-type voltage-gated calcium channel are commonly found in Lambert-Eaton myasthenic syndrome, regardless of whether it’s autoimmune- or cancer-related. […] That test, in some cases is considered to be 90% to 95% sensitive. […] Those are the 2 tools we use, but you have to suspect the diagnosis to think about order those tests. They are good at confirming the diagnosis of Lambert-Eaton syndrome.

• #6 Lambert-Eaton Myasthenic Syndrome (LEMS): Symptoms & Causes

  https://my.clevelandclinic.org/health/diseases/23202-lambert-eaton-myasthenic-syndrome-lems

  Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder. […] The first step in the diagnosis of LEMS is a thorough evaluation by your healthcare provider, in most cases a general neurologist or a neurologist who specializes in disorders of nerves and muscles. A detailed history of your symptoms, as well as a review of your medical and medication history, is part of this process. A detailed neurological examination is often done to look for patterns of weakness and signs consistent with a diagnosis of LEMS. […] Testing for LEMS includes: A blood test can reveal if you have anti-calcium channel antibodies. About 85% of people with LEMS have these antibodies in their blood. […] This test shows how well your muscles and nerves are working together. LEMS produces very specific findings on electromyography that can help confirm a diagnosis. […] These imaging tests check for signs of lung cancer, as LEMS can happen in people who have small-cell lung cancer. […] LEMS can appear from months to up to six years before the cancer does. […] Your healthcare provider will recommend a screening schedule that’s appropriate for you.

• #7 Diagnosis and Treatment of Lambert-Eaton Myasthenic Syndrome

  https://practicalneurology.com/articles/2024-apr/diagnosis-and-treatment-of-lambert-eaton-myasthenic-syndrome

  The most common initial clue for LEMS is diffusely reduced CMAP amplitude. Whenever an individual with proximally predominant muscle weakness is noted to have diffusely low CMAP amplitudes, LEMS must be suspected. […] Single-fiber EMG may also be utilized to support a diagnosis of LEMS and is typically reserved for when there is strong suspicion for LEMS despite negative serology and nerve conduction studies. […] Additional radiologic testing is mandatory in LEMS based on the strong association with malignancy, particularly SCLC. The DELTA-P (Dutch-English LEMS Tumor Association Prediction) score is helpful in predicting risk for future malignancy development and assists in modulating the frequency of imaging studies and other methods to evaluate for SCLC. […] Diagnosis is based on history and examination findings, and is supported by serology and an electrophysiologic triad.

• #8 Orphanet: Lambert-Eaton myasthenic syndrome

  https://www.orpha.net/en/disease/detail/43393

  Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune, presynaptic disorder of neuromuscular transmission characterized by fluctuating muscle weakness and autonomic dysfunction frequently associated with small-cell lung cancer (SCLC). […] The diagnosis of LEMS is based on the detection of VGCC antibodies by using radioimmunoprecipitation assays and/or typical abnormalities of the repetitive nerve stimulation (RNS) test: a low amplitude compound muscle action potential (CMAP), a decremental response to low rate stimulation, and an incremental response to high rate stimulation or after brief exercise (postexercise facilitation). […] Abnormal single fiber EMG (SFEMG) can confirm a disorder of the neuromuscular junction, but is non-specific. The diagnosis of LEMS almost invariably precedes the discovery of SCLC.

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