Understanding Tremors as a Myasthenia Gravis Symptom

Understanding Tremors as a Symptom of Myasthenia Gravis

Myasthenia gravis is an autoimmune disease that affects the connection between nerves and muscles. It causes weakness and rapid fatigue in various muscle groups, most commonly those that control eye movements, facial expressions, chewing, swallowing, and limb movements.

One of the characteristic symptoms of myasthenia gravis is tremors or uncontrollable shaking. Tremors can affect different parts of the body and have varying severity between individuals. Understanding more about tremors in myasthenia gravis can help patients identify when to seek medical care and how to best manage this challenging symptom.

What Causes Tremors in Myasthenia Gravis?

The muscle weakness that defines myasthenia gravis is caused by autoantibodies interfering with acetylcholine receptors. Acetylcholine is a neurotransmitter that motor neurons release to activate muscles. The acetylcholine receptors allow this signal to be received by the muscles. When autoantibodies block these receptors, the signal gets disrupted, leading to impaired muscle activation and contraction.

Experts believe tremors associated with myasthenia gravis also stem from dysfunctional signaling between motor neurons and muscles. When muscles rapidly alternate between contraction and relaxation, tremors result. The fluctuation in weakness caused by autoantibodies leads to this imbalanced muscle activation.

What Muscles are Most Affected?

In individuals with myasthenia gravis, tremors can occur in various muscle groups, most commonly:

• Facial muscles - causing lip, jaw, cheek, or tongue tremors
• Vocal cords - leading to a tremulous voice
• Eye muscles - resulting in oscillopsia or shaky vision
• Limbs and extremities - causing shakiness of the arms, legs, hands, or fingers
• Neck/head - resulting in yes-yes or no-no tremors

Typically, the muscles that experience the most significant weakness due to myasthenia gravis are also most prone to tremors. The distribution and type of tremors can help healthcare providers determine which muscle groups are most affected.

When Do Tremors Worsen?

One of the unique aspects of myasthenia gravis is that symptoms worsen with sustained activity but improve after periods of rest. The same goes for tremors associated with the condition.

Factors that can exacerbate myasthenia gravis related tremors include:

• Repetitive movement
• Holding a posture against gravity
• Later in the day when fatigue sets in
• During or after physical activity
• Exposure to heat, humidity, or stress
• Illnesses like infections

Patients may notice their tremors are minimal when resting but worsen if they try to hold their arms outstretched or keep their neck extended. Tremors also tend to progress as myasthenia gravis symptoms amplify later in the day.

How Are Myasthenia Gravis Tremors Diagnosed?

To diagnose tremors related to myasthenia gravis, doctors take a full medical history and conduct a neurological exam. They will ask about the onset, duration, location, aggravating factors, and severity of tremors.

The exam evaluates muscle strength throughout the body, looking for asymmetry or changes during sustained activity. Doctors may ask patients to perform repetitive movements to elicit tremors.

If myasthenia gravis is suspected, doctors can order blood tests that measure acetylcholine receptor autoantibodies. They may also conduct tests that evaluate nerve-muscle transmission:

• Edrophonium test - This test uses an injection of edrophonium chloride to temporarily improve neuromuscular transmission and muscle strength.
• Electromyography - EMG measures electrical activity in muscles. Abnormal results can indicate impaired nerve-muscle communication.
• Nerve conduction studies - These studies measure how well signals travel through peripheral nerves.

Based on the clinical evaluation, blood work, and nerve studies, doctors can confirm if tremors are a manifestation of myasthenia gravis or caused by another neurological condition.

How Are Tremors Managed?

While tremors may not be completely eliminated in myasthenia gravis, various treatments can help reduce symptoms. Management options include:

• Acetylcholinesterase inhibitors - Medications like pyridostigmine help lengthen the effect of acetylcholine at the neuromuscular junction.
• Immunosuppressants - Drugs like prednisone, azathioprine, and rituximab suppress the autoimmune attack on acetylcholine receptors.
• Plasmapheresis - This blood filtering treatment removes autoantibodies from the circulation.
• IVIG - Intravenous immunoglobulin provides healthy antibodies to block autoantibody activity.
• Thymectomy - Removing the thymus gland limits autoantibody production.
• Physical therapy - Strengthening unaffected muscles can compensate for weakness.
• Assistive devices - Items like braces or weights can aid limb tremors.

Treatment aims to improve patients' baseline muscle strength and endurance to minimize fatigue-induced tremors. Lifestyle changes like adequate rest, stress reduction, and activity pacing help as well.

When to Seek Emergency Care

For most myasthenia gravis patients, tremors are manageable with standard treatments. However, prompt medical attention is required if:

• Tremors affect breathing and become severe
• Swallowing problems develop and increase choking risk
• Tremors greatly limit ability to perform daily activities
• New tremors arise in body parts not previously affected
• Existing tremors worsen despite standard treatment

Worsening tremors can signal a myasthenia gravis crisis or flare-up requiring emergency intervention. Intravenous immunoglobulin or plasmapheresis may be needed to stabilize symptoms.

Coping with the Impact of Tremors

Maintaining quality of life is an important concern for those experiencing myasthenia gravis related tremors. While the physical impact can be challenging, there are ways to enhance daily function and emotional well-being.

Recommended tips include:

• Use tremor-resistant products like spill-proof mugs, weighted utensils, and touchscreen devices.
• Modify activities by bracing limbs on stable surfaces to enhance control.
• Schedule demanding tasks for times of day when energy levels are highest.
• Allow extra time to complete tasks at a safe, reasonable pace.
• Set up your environment to minimize lifting and reaching.
• Find peer support groups to exchange advice and coping strategies.
• Focus on remaining abilities and independence rather than limitations.

Occupational therapy evaluation can also help identify useful aids and techniques for managing tremors at home, work, or school.

The Bottom Line

Tremors are a common manifestation of the muscle weakness caused by myasthenia gravis. They stem from dysfunctional communication at the neuromuscular junction. Tremors often worsen with activity and in involved muscle groups. While treatment focuses on the underlying disease, lifestyle changes and assistive devices can help patients manage tremors safely and effectively.

Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult with a healthcare professional before starting any new treatment regimen.