Myasthenia gravis (MG) is a rare, chronic autoimmune disorder characterized by impaired communication between nerves and muscles. The name “Myasthenia gravis” comes from Greek and Latin, meaning “severe muscle weakness.” Typically, MG causes weakness of the skeletal muscles, which worsens with physical activity and improves with rest. Although rare, it affects thousands of people worldwide, with women generally being more frequently affected than men. The disease can occur at any age but is often diagnosed in women between the ages of 20 and 30 and in men over the age of 50.

Causes of Myasthenia Gravis

MG is an autoimmune disorder in which the body’s immune system mistakenly produces antibodies against specific receptors on muscle cells. In most cases, these antibodies target the **acetylcholine receptor** (AChR), which is responsible for transmitting nerve impulses to the muscles. By blocking or destroying these receptors, the normal transmission of nerve impulses is disrupted, leading to insufficient muscle contraction. In some cases, other structures, such as the protein MuSK (muscle-specific kinase), may be affected.

The exact reason why the immune system starts producing these antibodies is not fully understood. A connection is often found with the thymus, a gland that plays an important role in the immune system. In many patients, the thymus is either enlarged or has tumors (thymomas) that stimulate the production of the misguided antibodies.

Symptoms

The main symptom of Myasthenia gravis is muscle weakness or fatigue, which typically worsens as the day progresses or after exertion. Commonly affected muscle groups include:

  • Eye muscles (ocular myasthenia): This leads to drooping eyelids (ptosis) and double vision (diplopia).
  • Facial muscles: Patients may have difficulty speaking (dysarthria), chewing, or swallowing (dysphagia).
  • Arms and legs: Muscle weakness in the limbs can lead to problems with daily activities like walking, climbing stairs, or holding objects.
  • Respiratory muscles: In severe cases, weakness of the respiratory muscles can occur, which can be life-threatening (myasthenic crisis).

Symptoms vary greatly from person to person and depend on the severity and spread of the disease.

Forms and Progression of Myasthenia Gravis

There are different forms of Myasthenia gravis:

  • Generalized Myasthenia gravis: Affects multiple muscle groups, including the face, neck, arms, legs, and respiratory muscles.
  • Ocular Myasthenia gravis: This form primarily affects the eye muscles, causing ptosis and diplopia. Sometimes the disease remains limited to the eye muscles.
  • Neonatal Myasthenia gravis: Newborns of mothers with MG may temporarily acquire MG due to the transmission of antibodies from the mother.
  • Congenital Myasthenia: This rare form of MG is not autoimmune but genetic and manifests in infants.

The course of the disease can vary significantly. Some patients experience a gradual worsening over months or years, while others have acute exacerbations. A dangerous complication is the myasthenic crisis, where respiratory muscle weakness becomes so severe that mechanical ventilation is required.

Medical Treatment Options

Treatment for Myasthenia gravis focuses on alleviating symptoms, modulating the immune system, and improving nerve-muscle transmission. Common therapeutic approaches include:

  • Acetylcholinesterase inhibitors: These medications, such as Pyridostigmine, inhibit the enzyme acetylcholinesterase, which breaks down acetylcholine. This allows the neurotransmitter to remain active in the synaptic cleft longer, enhancing muscle contraction.
  • Immunosuppressants: Drugs like Prednisone, Azathioprine, or Mycophenolate mofetil suppress immune system activity and reduce antibody production.
  • Plasmapheresis and intravenous immunoglobulin (IVIG): These therapies are used in acute exacerbations. Plasmapheresis cleanses the blood of antibodies, while IVIG modulates the immune system.
  • Thymectomy: Surgical removal of the thymus can lead to improvement or even remission in many patients.

Physiotherapy in Myasthenia Gravis

Physiotherapy plays an important role in the treatment of Myasthenia gravis, especially in long-term care and rehabilitation. It aims to improve muscle strength, maintain mobility, and enhance daily functional abilities without overstraining the muscles. Physiotherapeutic approaches must be carefully tailored, as excessive physical activity can worsen the symptoms.

Goals of Physiotherapy for Myasthenia Gravis:

  • Improve muscle strength: Targeted exercises help maintain or improve overall muscle strength without risking overexertion. Patients learn to recognize their limits and take breaks when necessary.
  • Support respiratory muscles: Breathing exercises and respiratory therapy are crucial, especially in patients with impaired respiratory muscles. Techniques like diaphragmatic breathing or using respiratory training devices can help support respiratory function.
  • Improve endurance: Light, aerobic exercises like walking or swimming can improve general endurance. Moderate intensity is key to avoiding overexertion.
  • Maintain joint mobility and movement coordination: Passive and active stretching exercises, as well as coordination training, are essential to promote joint mobility and improve movement coordination.

Physiotherapy Methods:

  • Individual exercise programs: Since symptoms vary from patient to patient, a customized program is developed, considering the current muscle deficits and overall fitness of the patient.
  • Electrical muscle stimulation (EMS): For severely weakened muscles, electrical muscle stimulation can activate and strengthen muscles without overburdening joints and muscles.
  • Hydrotherapy: Water-based exercises, as used in hydrotherapy, provide a low-impact way to improve muscle strength and endurance, as water supports the body while offering gentle resistance.
  • Postural training: Many MG patients suffer from postural disorders due to muscle weakness, so specific postural training is conducted to improve body posture and avoid incorrect loading.

Role of the Physiotherapist:

The physiotherapist works closely with the patient to find a balance between physical activity and rest periods. Close monitoring of progress is essential to continuously adjust the therapy program and optimize the level of exertion. Patients are also trained in coping with daily challenges, such as energy-saving techniques for tasks like climbing stairs, walking, or lifting objects.

Conclusion

Myasthenia gravis is a complex but treatable disease that requires an interdisciplinary approach. While medications play a central role in controlling symptoms, physiotherapy is a vital component of comprehensive care. It enables patients to maintain their muscle function, improve their quality of life, and actively participate in everyday life. With tailored exercise programs and the right balance between activity and rest, patients can learn to manage the disease and optimize their physical abilities.