Myasthenia gravis is a chronic neuromuscular disease that leads to fluctuating muscle weakness and fatigue. The disease is characterized by variable degrees of weakness of the skeletal muscles. The name myasthenia gravis is derived from a Latin word, meaning “grave muscle weakness.”
The muscle weakness happens mainly due to the circulation of antibodies which block nicotinic acetylcholine receptors at the postsynaptic neuromuscular junction. By blocking the ability of the neurotransmitter acetylcholine to bind to these receptors in the muscle, these antibodies deter motor neurons from signalling the muscle to contract.
Alternatively, in a much rarer form, muscle weakness is the result of a genetic defect in some portion of the neuromuscular junction that is inherited at birth as compared to the development through passive transmission from the mother’s immune system at birth or through autoimmunity later in life.
Explore more: Immunity and its Types
Myasthenia Gravis Symptoms
The major symptom of myasthenia gravis is in the form of weakness in the voluntary skeletal muscles, that are the muscles which control the area. The muscles fail to contract as they are unable to respond to nerve impulses. Without proper transmission of the impulse, the communication is blocked between nerves and muscles.
Symptoms of myasthenia gravis include:
- Hoarse voice.
- Double vision.
- Drooping of eyelids.
- Difficulty in talking.
- Difficulty in swallowing or chewing.
- Problems in lifting objects and walking upstairs.
- Difficulty in breathing due to muscular weakness.
Although myasthenia gravis could affect any of the muscles that you control voluntarily, certain muscle groups are more commonly affected than others, some of them are:
- Eye Muscles
- Double vision.
- Drooping of one or both eyelids.
- Face and Throat Muscles
- Altered speaking.
- Difficulty swallowing.
- Problems in chewing.
- Limited facial expressions.
Myasthenia Gravis Causes
Myasthenia gravis is resulted by a defect in the transmission of nerve impulses to muscles. It occurs when normal communication between the nerve and muscle is interrupted at the neuromuscular junction—the place where nerve cells connect with the muscles they control.
This neuromuscular disease is caused by transmission defects in nerve impulses to muscles. The neuromuscular junction is apparently affected: acetylcholine, which produces muscle contraction under normal conditions no longer produces the contractions necessary to muscle movement.
Also Read: Conduction of Nerve Impulse
Myasthenia Gravis Diagnosis
Myasthenia Gravis is a long-term and autoimmune condition, which results in muscle weakness. It is very difficult to diagnosis Myasthenia gravis as its symptoms tend to get worse with the severity of the weakness and varies from person to person.
Based on the symptoms, infectious diseases and other past medical histories, an individual is allowed to undergo certain physical examinations and several other tests to confirm the exact cause of the disease. These tests include – blood tests, electromyography, CT scan or MRI scan, few neurological tests, nerve stimulation, edrophonium tests, etc.
Myasthenia Gravis Treatment
Myasthenia gravis is believed to be caused by variations in certain genes. The disorder occurs when the immune system malfunctions and attacks the body’s tissues. There is no cure for myasthenia gravis. The goal of treatment is to manage symptoms and control the activity of your immune system through the below-mentioned ways:
- Plasma Exchange.
- Lifestyle Changes.
- Thymus Gland Removal.
- Intravenous Immune Globulin.
- Avoid stress and heat exposure.
- Rest to help minimize muscle weakness.
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