FAQs About IVIG for LEMS
Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disorder that results in progressive muscle weakness. One treatment that doctors can use for patients who do not respond to immunosuppressive drugs is intravenous immunoglobulin (IVIG) infusions.
What is IVIG?
IVIG is a treatment that involves giving patients intravenous — IV, or into-the-vein — infusions of human antibodies. Antibodies or immunoglobulins are molecules that the body uses to detect and fight off infectious diseases. In IVIG, antibodies from 1,000 to 15,000 blood donors per batch are used. The antibodies are extracted from the donor’s blood and then purified to make sure there aren’t any contaminants.
How does IVIG work?
LEMS occurs when a patient’s antibodies mistakenly target the body’s own nervous system. These autoantibodies specifically attack a receptor protein at the ends of nerve cells that are important for sending signals to muscles. When this happens, the nerve cells can’t activate muscle contractions as well as they should, resulting in muscle weakness.
Researchers think that IVIG helps relieve symptoms of LEMS through several related mechanisms. The high amount of non-specific immunoglobulins may reduce the body’s own production of autoantibodies. IVIG antibodies also may block the binding of the autoantibodies to their targets on the nerve cell endings. Finally, IVIG infusions may help dilute the concentrations of the autoantibodies and other products of the immune system that can damage the nerve cells.
How will I receive IVIG?
Clinicians administer IVIG as an IV infusion. The IV is usually inserted into the patient’s arm or hand, and the rate of the inusion is slowly increased every 30 minutes until the maximum rate is reached. Infusions can take two to five hours, or more, depending on the prescribed dosage and maximum rate of infusion. You will receive these infusions at a hospital, specialty infusion center, or at home in the presence of a nurse who monitors you during the process for signs of any reactions or side effects.
How often do I need treatment?
The antibodies delivered through IVIG start to degrade slowly over time so you will typically need infusions every three to four weeks. Guidance specific to LEMS, provided by the Australian government, recommends an initial induction of 2 g/kg of body weight divided into two to five separate doses. After that, patients should receive lower doses every two to six weeks but not exceed a total dosage of 2 g/kg in a four-week period. Your doctor will provide more specific guidance for you.
Is IVIG safe?
There are strict guidelines that companies that manufacture the immunoglobulin products used in IVIG have to follow. They have to screen blood donors carefully and test their blood for a number of known viruses such as hepatitis and HIV. The blood samples then must be purified to remove toxins and then tested again for infectious diseases. There is always a risk of blood-borne pathogens that might not be detected. However, the risk is low and there have been no known infections from IVIG since the 1980s.
What are the side effects?
Most side effects of IVIG are mild. They include headache, nausea, vomiting, and stomach and back pain. These side effects are usually due to the rate of infusion being too high.
Allergic reactions such as trouble breathing, low blood pressure, rapid heart rate, chest pain, and hives also are possible but are rare.
More serious side effects also may occur, including worsening kidney function and blood clots, especially in patients with other illnesses such as kidney disease. Side effects are most likely to occur within the first few infusions. Thus, these infusions should be performed in a medical setting where aid is available immediately.
Are there instances where I should not have IVIG?
Patients with an active infection may be more likely to have a reaction to IVIG. You should check with your physician before treatment if you are not feeling well. In such cases, it may be better to wait a day or two before receiving treatment. If you have any other underlying medical conditions besides LEMS, be sure to tell your physician before starting IVIG so you can discuss the risks versus benefits of the treatment.
Last updated: Nov. 9, 2020
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