Myasthenia gravis is a long-term autoimmune disease and it attacks the neuromuscular functions of body that leads to weakness of skeletal muscles. The muscles that are mostly affected are the muscles of the eyes. This disease occurs suddenly most of the times. Some patients may also develop thymoma where the thymus gland enlarges. Initially, the main symptom of the disease is weakness of the skeletal muscles and it is painless. Fatigue is generally absent at the beginning of the course of disease. The muscles show weakness on doing physical activities and the weakness tends to decrease as the patient takes rest and reduces the muscular activity.(1)
Can You Donate Blood With Myasthenia Gravis?
Myasthenia gravis is an autoimmune disease where the immune system of body produces antibodies against acetylcholine receptors (AChR). Acetylcholine receptors are present at the nerve endings and help in transmission of nerve impulses to the muscles. When the antibodies are produced, they attach to these acetylcholine receptors and hence the transmission of nerve impulses is blocked. Due to this blockage of nerve impulse transmission, there is weakness and fatigue of the muscles and improper functioning of muscles.
Actually the patients with myasthenia gravis are not allowed to donate blood. According to the policies of the American Red Cross for blood donation, people who suffer from autoimmune diseases along with myasthenia gravis and other diseases are not allowed to donate blood.
An experiment was done where an animal was injected with the antibodies against acetylcholine receptor (AChR) and due this the animal was found to be suffering from myasthenia gravis. So, this shows that myasthenia gravis can be transmitted through blood transfusion in animals, although there is no evidence that the same thing happens in humans too. There is no evidence yet that says that people who receive the blood of patients with myasthenia gravis were found to have the disease transmitted. But on the other hand there is no strong report that suggests that transfusion of blood of a patient with myasthenia gravis to a healthy person is totally harmless.
Another aspect of the reason why people with myasthenia gravis are not allowed to donate blood is that, after blood transfusion, the patient becomes very weak because of loss of blood volume from the body. People with myasthenia gravis feel fatigued as it is and due to blood donation, the weakness increases and this might lead to serious complications.
Even though people with myasthenia gravis are not allowed to make a blood donation, they are however allowed to donate small quantity of their blood for research purposes.(2)
How Is Myasthenia Gravis Diagnosed?
Physical Examination- The doctor checks the activity of muscles by asking the patient to perform certain repetitive movements.
For example, there is a test where patient’s one eye is held open and this will lead to automatic closing of other eye of the patient, this is called “curtain sign”. If the test is positive, it points towards possibility of myasthenia gravis.
Blood Tests- Serological tests are performed to diagnose myasthenia gravis and they are-
Checking for antibodies against acetylcholine receptor, it has 80-90% sensitivity
Also, antibodies against muscle specific kinase (MuSK) protein are also checked because some patients may not possess antibodies against acetylcholine receptors.
Edrophonium Test (Also Known As Tensilon Test)- In this test, neostigmine or Edrophonium chloride (these drugs act as acetylcholinesterase inhibitors thereby, preventing breakdown of acetylcholine) is injected intravenously. After injecting these drugs if the patient has myasthenia gravis, he will experience sudden improvement of muscle strength and will be able to perform actions appropriately. On the other hand if there is no improvement of the muscle strength; it means that the person has some other disease excluding myasthenia gravis.
Electrodiagnostics- A method called electromyography is used. In this test, a needle electrode is used to trigger the muscle fiber and record the action potentials. If a jitter is seen then the test is positive. Jitters are said to be present if the action potentials show abnormal variations. If blocking is present, even then it the test is said to be positive. Blocking is when there is no elicitation of action potentials in the muscle fiber.(3)
According to the policies of the American Red Cross, it is not allowed to donate blood for the patients who have myasthenia gravis. There is no evidence that myasthenia gravis have been transmitted to a healthy person who received blood from a diseased person. But the main reason because of which blood donation is avoided in patients with myasthenia gravis is because such patients already experience muscle fatigue and weakness and after blood donation the weakness and fatigue worsens due to loss of blood volume from the body. So, blood transfusion is better avoided in patients who suffer from myasthenia gravis.
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- Recovery Period For Myasthenia Gravis
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- Is There Any Pain With Myasthenia Gravis?
- What Is The Best Treatment For Myasthenia Gravis?