神经病学英文课件：03 Myasthenia Gravis
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Ocular muscles ------- >50% Extraocular muscle weakness or ptosis is present initially in 50% of patients and occurs during the course of illness in 90%.
Bulbar symptoms
Dysphagia : difficulty in swallowing Dysarthria: slurred speech, sounds nasal, of low
intensity (hypophonic) prolonged chewing (fatigable chewing), frequently
Fluctuation ------ cardinal feBaidu Nhomakorabeature of MG
Fluctuation of symptoms
Weakness is increased by exertion and alleviated by rest, at least partially.
The weakness may fluctuate throughout the day, but most commonly worse later in the day or evening.
occurs half-way through a meal
Ptosis
Strabismus
Neck weakness
The weight of the head may overcome the extensors, producing a "dropped head syndrome" ------ unable to support the head.
Fluctuation of disease course
Early in the disorder, the symptoms are often transient in many patients (with hours, days, or even weeks free of symptoms), which may even remit spontaneously for weeks or longer.
Myasthenia Gravis
重症肌无力
What is Myasthenia Gravis?
Myasthenia gravis (MG) is a chronic autoimmune disorder of neuromuscular transmission, which characterized by fluctuating weakness and fatigability of striated skeletal muscles.
Limb weakness
difficulty in lifting arms difficulty in running and climbing, unstable or
waddling gait
Involvement of the respiration muscles
difficulty in breathing
Onset of the Disease
The onset is insidious, sometimes initiated by fatigue, an emotional upset, infection or pregnancy etc.
Once the disease has began, a slow progression follows.
Etiology and Pathogenesis
Neuromuscular Junction (NMJ) in MG
Thymus Gland and MG
In patients with MG, the thymus gland is abnormal.
10-15% developed thymoma 60-70% with thymic hyperplasia
Later, the manifestations typically worsen and are more persistent.
It is believed that the thymus gland may give incorrect instructions about the production of AChR-Ab.
Clinical Manifestations
Prevalence: 10-20/100,000 Annual incidence: 1.5/100,000
MG can occur at any age.
< 50 years prevalence and incidence remained stable and with a constant female preponderance
there has been an increase of MG in the elderly population, especially in males
Presenting Symptoms
Patients typically have fluctuating weakness and fatigue of the specific muscle groups affected. The initial involved muscle as following:
Bulbar muscles ------- 15% Proximal limb muscles ------- <10%
The noticeable symptoms including: Ocular manifestations
Ptosis: drooping of one or both eyelids Diplopia: blurred or double vision
Bulbar symptoms
Dysphagia : difficulty in swallowing Dysarthria: slurred speech, sounds nasal, of low
intensity (hypophonic) prolonged chewing (fatigable chewing), frequently
Fluctuation ------ cardinal feBaidu Nhomakorabeature of MG
Fluctuation of symptoms
Weakness is increased by exertion and alleviated by rest, at least partially.
The weakness may fluctuate throughout the day, but most commonly worse later in the day or evening.
occurs half-way through a meal
Ptosis
Strabismus
Neck weakness
The weight of the head may overcome the extensors, producing a "dropped head syndrome" ------ unable to support the head.
Fluctuation of disease course
Early in the disorder, the symptoms are often transient in many patients (with hours, days, or even weeks free of symptoms), which may even remit spontaneously for weeks or longer.
Myasthenia Gravis
重症肌无力
What is Myasthenia Gravis?
Myasthenia gravis (MG) is a chronic autoimmune disorder of neuromuscular transmission, which characterized by fluctuating weakness and fatigability of striated skeletal muscles.
Limb weakness
difficulty in lifting arms difficulty in running and climbing, unstable or
waddling gait
Involvement of the respiration muscles
difficulty in breathing
Onset of the Disease
The onset is insidious, sometimes initiated by fatigue, an emotional upset, infection or pregnancy etc.
Once the disease has began, a slow progression follows.
Etiology and Pathogenesis
Neuromuscular Junction (NMJ) in MG
Thymus Gland and MG
In patients with MG, the thymus gland is abnormal.
10-15% developed thymoma 60-70% with thymic hyperplasia
Later, the manifestations typically worsen and are more persistent.
It is believed that the thymus gland may give incorrect instructions about the production of AChR-Ab.
Clinical Manifestations
Prevalence: 10-20/100,000 Annual incidence: 1.5/100,000
MG can occur at any age.
< 50 years prevalence and incidence remained stable and with a constant female preponderance
there has been an increase of MG in the elderly population, especially in males
Presenting Symptoms
Patients typically have fluctuating weakness and fatigue of the specific muscle groups affected. The initial involved muscle as following:
Bulbar muscles ------- 15% Proximal limb muscles ------- <10%
The noticeable symptoms including: Ocular manifestations
Ptosis: drooping of one or both eyelids Diplopia: blurred or double vision