Myasthenia Gravis: Understanding Symptoms and Diagnostic Methods

Myasthenia Gravis (MG) is a chronic autoimmune disorder that affects the communication between nerves and muscles, leading to muscle weakness and rapid fatigue. This condition primarily impacts voluntary muscles, with symptoms often worsening during periods of activity and improving after rest. One of the most notable characteristics of MG is that symptoms tend to be less severe in the morning and progressively worsen throughout the day.

Common Signs and Symptoms

Patients may experience drooping eyelids (ptosis), blurred or double vision (diplopia), difficulty chewing or swallowing, and weakness in the limbs that makes tasks like climbing stairs or rising from a seated position challenging. These symptoms can vary in severity and may appear suddenly, making early recognition crucial for timely diagnosis.

Preliminary Diagnostic Tests

Clinicians often use simple physical tests to assess for MG. For example, the "eye blink test" involves asking the patient to open and close their eyes repeatedly—typically 30 to 50 times. A noticeable decline in the ability to keep the eyes open toward the end of the test may indicate muscle fatigue consistent with MG. Similarly, a squat test, where the patient performs 30 squats, can reveal increased fatigue and weakness post-exercise compared to their initial state.

Confirmatory Diagnostic Procedures

To confirm a diagnosis, doctors may perform a neostigmine test. This involves administering a small dose of neostigmine (1 mg or 1.5 mg intramuscularly), a medication that improves nerve signal transmission. If symptoms significantly improve within 10–15 minutes and the effect lasts for 2–3 hours, it strongly supports the diagnosis of MG.

Additional Diagnostic Tools

• Repetitive Nerve Stimulation (RNS): This test measures the electrical response of muscles to repeated nerve stimulation and often reveals a decremental response in MG patients.
• Imaging Scans: While not directly related to the disease itself, imaging techniques such as CT scans may be used to check for abnormalities in the thymus gland, including thymoma, which is associated with MG in some cases.
• Antibody Testing: Blood tests to detect antibodies against the acetylcholine receptor (AChR) are highly specific for MG and help confirm the diagnosis.

Early detection and proper diagnosis of Myasthenia Gravis are essential for effective management. If you or someone you know experiences unexplained muscle weakness or fatigue, especially with a pattern of worsening symptoms throughout the day, it's important to consult a healthcare professional for a comprehensive evaluation.