Myasthenia Gravis Clinical Manifestations

Written by Tang Bo
Neurology
Updated on September 01, 2024
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The clinical manifestations of myasthenia gravis include fluctuating weakness of specific striated muscles that is fatigue-prone. Symptoms are generally milder in the morning and worsen by night, increasing after sustained activity and alleviating after rest. Additionally, some patients may experience ocular muscle weakness, presenting with ptosis and diplopia, which could be among the earliest symptoms. Eye movement disorders may occur, preventing the eyes from looking to one side, and pupil abnormalities may be present. Facial muscle weakness can lead to cheek puffing and air leakage, inability to close the eyes, or asymmetry of the mouth, resembling a forced smile. There may also be weakness in the masticatory muscles, leading to difficulties in chewing and swallowing, potential speech impairments, and coughing when drinking water. Neck muscle weakness may manifest as difficulty in lifting the head. Muscle weakness can affect various limbs, primarily proximally, and respiratory muscle weakness can lead to breathing difficulties and dryness.

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Written by Zhang Hui
Neurology
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Myasthenia gravis belongs to which department?

Myasthenia gravis is an autoimmune disease of the nervous system, primarily affecting the neuromuscular junction where synaptic function is significantly impaired. This disease falls under the purview of neurology, and most neurologists are quite familiar with myasthenia gravis, considering it a common and frequently occurring neurological condition. Patients with myasthenia gravis typically exhibit symptoms such as drooping eyelids, double vision, and general fatigue. They experience a pathological tiredness, feeling extremely exhausted after minor activities, although rest can alleviate symptoms. These symptoms are also commonly associated with the nervous system, so it is appropriate to consult the neurology department. Treatment for patients with myasthenia gravis may involve administering immunoglobulins or corticosteroids, depending on the situation, while also taking precautions to prevent potential complications.

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Written by Tang Bo
Neurology
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Types of myasthenia gravis crisis

Myasthenic crises are categorized into three types, all resulting from worsening conditions or improper treatment, leading to respiratory muscle weakness or paralysis and subsequent difficulty in breathing. The first type occurs due to various triggers or reduction in medication, or after the application of acetylcholinesterase inhibitors which temporarily alleviate the crisis, known as the cholinergic crisis. The second type is a result of excessive use of acetylcholinesterase inhibitors during a cholinergic crisis. Beyond respiratory difficulties, symptoms may also include signs of toxicity such as vomiting, abdominal pain, diarrhea, pupil constriction, excessive sweating, drooling, increased tracheal secretions, and potential muscle tremors, spasms, as well as anxiety, insomnia, confusion, seizures, and coma. The third type is the paradoxical crisis, where neither ceasing nor increasing medication doses alleviates the symptoms, typically occurring after long-term, high-dose medication use.

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Written by Tang Li Li
Neurology
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Is myasthenia gravis an autoimmune disease?

Myasthenia gravis is an autoimmune disease that primarily affects the neuromuscular junction. It is an acquired autoimmune disorder in which acetylcholine receptors at the postsynaptic membrane are present. These receptors bind with acetylcholine released from the presynaptic membrane, promoting the transmission of neuromuscular excitability, enabling muscle contraction and movement. When the acetylcholine receptors are damaged, symptoms of muscle weakness occur. The most common causes of this acquired autoimmune disease are thymoma, thymic hyperplasia, or incomplete thymic involution, leading to the production of antibodies by the body that damage the acetylcholine receptors on the postsynaptic membrane. This damage results in a significant reduction of receptors, insufficient production of endplate potentials, and a disruption in transmission function, triggering myasthenia gravis.

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Written by Tang Bo
Neurology
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Myasthenia gravis initial symptoms

Myasthenia gravis is characterized by fluctuating and fatigue-prone muscle weakness in certain specific striated muscles. Symptoms are generally milder in the morning and more severe in the evening, worsening with continued activity and alleviating after rest. The most common initial symptom is weakness of the external eye muscles, primarily presenting as asymmetrical ptosis (drooping of the upper eyelid) or narrowing of the eye slit, along with diplopia, which refers to seeing double images. These are the most frequent initial symptoms, seen in over 50% of patients with myasthenia gravis. Additionally, some patients may experience disturbances in eye movement, facial muscle weakness, air leakage when puffing cheeks, incomplete eyelid closure, shallower nasolabial folds, as well as difficulty swallowing, speech articulation issues, choking while drinking, and potentially severe respiratory weakness.

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Written by Zhang Hui
Neurology
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Myasthenia Gravis should be seen by which department?

Myasthenia gravis is considered a neurological disease, so if myasthenia gravis is suspected, it is advisable to consult a neurologist. Neurologists are quite familiar with myasthenia gravis, especially those who specialize in its research. They are particularly knowledgeable about diagnosing and treating this disease. Myasthenia gravis is an autoimmune disease of the nervous system that primarily affects the neuromuscular junction, causing muscle weakness in the body. The symptoms typically worsen towards the evening and include pathological fatigue. Muscle weakness usually improves after rest. Clinical manifestations also include ptosis, double vision, difficulty swallowing, and coughing while drinking. Neurologists may prescribe various diagnostic tests such as electromyography, chest CT scans, and tests for acetylcholine receptor antibodies.