The key difference between myasthenia gravis and Lambert Eaton myasthenic syndrome is that myasthenia gravis is an autoimmune condition that occurs due to the attack of autoantibodies on the acetylcholine receptors of nerves, while Lambert Eaton myasthenic syndrome is an autoimmune condition that occurs due to the attack of autoantibodies on the voltage-gated calcium channels of the nerves.
Myasthenia gravis and Lambert Eaton myasthenic syndrome are two different types of autoimmune neurological diseases. These diseases occur due to autoantibodies attacking different parts of their own nervous system.
CONTENTS
1. Overview and Key Difference
2. What is Myasthenia Gravis
3. What is Lambert Eaton Myasthenic Syndrome
4. Similarities – Myasthenia Gravis and Lambert Eaton Myasthenic Syndrome
5. Myasthenia Gravis vs Lambert Eaton Myasthenic Syndrome in Tabular Form
6. Summary – Myasthenia Gravis vs Lambert Eaton Myasthenic Syndrome
What is Myasthenia Gravis?
Myasthenia gravis is an autoimmune neurological condition discovered by the Oxford physician Thomas Willis in the 17th century. The first modern description of myasthenia gravis was made by Samuel Wilks in 1877. Myasthenia gravis is an autoimmune condition due to autoantibodies attacking the acetylcholine receptors of nerves. This disease is characterized by weakness and rapid fatigue of the muscle under voluntary control, drooping of one or both eyelids, double vision that is horizontal or vertical, impaired speaking, difficulty in swallowing, affected chewing, changes in facial expression, walking difficulties, and difficulty holding up the head.
Figure 01: Myasthenia Gravis
In addition to acetylcholine receptor problems, autoantibodies in this condition can also disrupt the function of two proteins as muscle-specific receptor tyrosine kinase (MUSK) and lipoprotein-related protein 4 (LRP4), which can also lead to myasthenia gravis. Other causes of myasthenia gravis include an abnormal thymus gland that suppresses acetylcholine and hereditary genetic changes. Myasthenia gravis can be diagnosed through neurological examination, ice pack test, blood analysis, repetitive nerve stimulation, single-fiber electromyography (EMG), imaging tests (CT scan, MRI), and pulmonary function tests. Furthermore, treatment options for myasthenia gravis may include medications (cholinesterase inhibitors, corticosteroids, and immunosuppressants), intravenous therapy (plasmapheresis, intravenous immunoglobulin (IVIg), and monoclonal antibody), and surgery (video-assisted thymectomy and robot-assisted thymectomy).
What is Lambert Eaton Myasthenic Syndrome?
Lambert Eaton myasthenic syndrome is an autoimmune neurological disorder first described by neurologists Edward Lambert and Lee Eaton at the Mayo Clinic in Rochester, Minn., in the 1950s and 1960s. It is due to the attack of autoantibodies on the voltage-gated calcium channels of the nerves. The signs and symptoms of Lambert Eaton myasthenic syndrome may include aching muscles, difficulty in walking and climbing stairs, difficulty in lifting objects, difficulty in raising arms, drooping eyelids, dry eyes, blurred vision, swallowing problems, dizziness when standing, dry mouth, constipation, erectile dysfunction, and physical strength that normally improves when exercising and reduces when exercises continue.
Lambert Eaton myasthenic syndrome can be diagnosed through physical examination, testing reflexes, blood tests, nerve studies, and scans (CT scan and PET scan). Furthermore, treatment options for Lambert Eaton myasthenic syndrome include treatment for lung cancer that improves the symptoms of Lambert Eaton myasthenic syndrome, medicine to help nerve signals reach the muscles (3, 4 diaminopyridine and pyridostigmine), medicine to reduce the activity of immune system called immunosuppressants (steroid tablets such as prednisolone, azathioprine, and methotrexate), immunoglobulin therapy (injections of antibodies from donated blood), and plasmapheresis.
What are the Similarities Between Myasthenia Gravis and Lambert Eaton Myasthenic Syndrome?
- Myasthenia gravis and Lambert Eaton myasthenic syndrome are two different types of autoimmune neurological diseases.
- Both disorders are due to the reduction of the release of acetylcholine neurotransmitters.
- They may have similar symptoms, such as weakness in muscles, drooping eyelids, blurred vision, and swallowing difficulties.
- Both disorders can be diagnosed through blood tests and imaging tests such as CT scans and MRIs.
- They are treated through specific medicines such as immunosuppressants and therapies such as immunotherapy.
What is the Difference Between Myasthenia Gravis and Lambert Eaton Myasthenic Syndrome?
Myasthenia gravis is an autoimmune condition caused by the attacking of autoantibodies on the acetylcholine receptors of nerves, while Lambert Eaton myasthenic syndrome is an autoimmune condition caused by the attacking of autoantibodies on the voltage-gated calcium channels of the nerves. Thus, this is the key difference between myasthenia gravis and Lambert Eaton myasthenic syndrome. Furthermore, myasthenia gravis can be inherited, while Lambert Eaton myasthenic syndrome is not inherited.
The below infographic presents the differences between myasthenia gravis and Lambert Eaton myasthenic syndrome in tabular form for side-by-side comparison.
Summary – Myasthenia Gravis vs Lambert Eaton Myasthenic Syndrome
Myasthenia gravis and Lambert Eaton myasthenic syndrome are two different types of autoimmune neurological diseases that arise from the reduction of releasing acetylcholine neurotransmitters. Myasthenia gravis occurs due to the attacking of autoantibodies on the acetylcholine receptors of nerves. Lambert Eaton myasthenic syndrome occurs due to the attacking of autoantibodies on the voltage-gated calcium channels of the nerves. So, this summarizes the difference between myasthenia gravis and Lambert Eaton myasthenic syndrome.
Reference:
1. “Myasthenia Gravis.” Mayo Clinic, Mayo Foundation for Medical Education and Research.
2. “Lambert-Eaton Myasthenic Syndrome (LEMS): Symptoms & Causes.” Cleveland Clinic.
Image Courtesy:
1. “Ptosis myasthenia gravis” By Mohankumar Kurukumbi, Roger L Weir, Janaki Kalyanam, Mansoor Nasim, Annapurni Jayam-Trouth. – Rare association of thymoma, myasthenia gravis and sarcoidosis : a case report. Journal of Medical Case Reports. 2008;2:245. doi:10.1186/1752-1947-2-245 (CC BY 2.0) via Commons Wikimedia