Myasthenia gravis

Myasthenia gravis
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■ Outline:
Muscle is easily fatigued due to stimulation transmission disorder at the neuromuscular junction of the skeletal muscle (carpal tunnel).

■ Definitions:
Myasthenia gravis is a disease in which myocardial strength is reduced, easily fatigued, restored by rest, and symptoms change during the day. The acetylcholine receptors (Ach R) in the nerve-muscle junction are damaged by autoimmune antibodies (Ach R antibodies), and the autoimmune antibodies Disease.
[frequency]
It occurs in 5-10 people per 100,000 population, and women are four times more than men. The age of onset is most prevalent around 0-5 years and around 20-30 years. About one-third of all patients develop in children.
■ Symptom:
Clinical symptoms vary and are classified according to the location of symptoms and the degree of symptoms. Myocardial infarction is defined as the omental type, and the myasthenia gravis, the respiratory muscle, and the swollen gyrus are called myasthenia gravis myasthenia gravis.
Symptoms are characterized by a certain degree of recovery from any type of breakdown, which can be seen in the morning during the day, with mild symptoms during the day, and during the afternoon to nighttime symptoms. In addition, depending on the temperature, the disturbance of neurotransmission is different and the temperature is getting worse in summer.
Depending on the time of onset, adult types occurring after puberty and those that occurred before are classified as child malformations.
Classification of childhood malformations is as follows.

1. Congenital Bottle

A. Neonatal transient form
It is caused by anti-AHR antibodies transmitted through maternal placenta in newborns born to mothers with severe myasthenia. Most of them are transient. If my mother has myasthenia gravis, the incidence is about 12%. Symptoms include dystocia, decreased mating power, weak crying, and respiratory problems. Symptoms do not exceed a maximum of 12 weeks and are cured spontaneously, but in the case of respiratory and dysphagia, the cholinesterase (ChE) pyridostigmine (1-2 mg / kg) is administered every 4 hours.
B. Congenital persistent form
I was born from a mother with no myasthenia gravis, but I can see the cases that occurred in the neonatal period and occurred in my family. Symptoms include not only symptoms but also all new symptoms. Anti-ChE agents are not responsive and often have sequelae.
C. Familial infantile form (familial infantile form)
As an example reported in 1960, my mother has no myastigm, but she has an outbreak of siblings and can see respiratory depression at birth. Obstructive sleep apnea occurs frequently during the first two years of life and should be observed with caution. It will improve with the increase in age. The reaction to the anti-ChE agent is good.

2. Juvenile form

This is all except for the three congenital formations that occurred in childhood, and the type of this category actually corresponds to the adult type. The most common type is oculomotor type, and about half of the cases that occur before and after 3 years of age are type 2.

A. Observer
The onset age is 2-3 years, and there are many in girls. The eyelid is getting harder and harder to get down, and when you have eye movement disorder, you see a diplopia that looks like two objects. Symptoms can be worse in the evening than in the morning. Symptoms can be worse in the case of sleep deprivation, menstruation, and pregnancy. Ptosis usually occurs on one side, but it also comes on both sides. If the pupil is blocked by more than half due to high ptosis, it will cause a decrease in visual acuity.
B. Bulbar type
When you speak, the pronunciation is strange, it is difficult to swallow food, and it becomes difficult to sput the sputum. It usually appears with a new type of symptoms
C. New type
Skeletal muscle of the whole body is invaded and muscle weakness appears. Tired easily and muscle weakness is the first symptom. If the symptoms are mild, you feel tired easily after climbing the stairs, walking for a long time, running, or writing. If the symptoms continue, you may also see muscle atrophy.
Symptoms are mild in the morning, severe in the evening and restored by rest. It is mainly grown in adults but can also occur in childhood. Intercostal muscles cause respiratory paralysis when they are injured, which is called a muscular crisis.

■ Causes / Pathophysiology:
It is caused by an autoimmune mechanism for the acetylcholine receptor (Ach R) in the posterior junctional membrane as a barrier to chemical neurotransmission at the nerve junction.
■ Diagnosis:
Diagnosis of severe myasthenia is made when the symptoms of characteristic intradiscal fluctuation, symptoms of tensilon test are improved, and other central, peripheral nerve and muscle disorders are excluded. The following diagnostic guidelines are used.

1. Intra-day variability of symptoms
By repetitive motion, muscular strength of some muscles such as the underarms and swallowing muscles, or muscle strength of the whole body is lowered and restored temporarily by rest.
2. No pyramidal symptoms or sensory disturbances.
3. Symptoms such as muscle weakness are improved by the administration of ChE agent.
4. M-wave abnormalities can be seen in EMG.
5. Immunological examination

Detection of anti-AchR antibodies
80% of all newborns are detected as benign, but in the intramuscular type, the positive rate is low and the antibody level is low. There is no correlation between changes in antibody titers even after treatment.
T-wave: The reduction of Suppressor T-lymphocyte can be seen early on.

6. Pneumomediastinography, chest CT
Thymoma, and thymoma are often accompanied by complications.
7. Miscellaneous The following symptoms often occur.

Ptosis
Eye movement disorder or diplopia
Swallowing and speech disorders
Gait disorder
Difficulty in breathing

■ Treatment:
As the pathogenic mechanism is found to be an autoimmune disease, it is recommended that the treatment is based on anti-ChE treatment centered therapy and recently relatively early immunotherapy.

Significant ptosis (upper) recovered to normal with the administration of anticholinesterase.
Although the role of antibody is important, plasma exchange therapy has been introduced, but it is not generalized due to the diversity of anti-AchR antibody to complex AchR structure, but we believe that the mechanism of action will be improved in the future

1. Pharmacotherapy: Anti-ChE agent and steroid agent
In pediatric intramuscular form, this drug is completely cured in 1/3.
2. Surgery: As an adult, you may have a thymoma.
3. Plasma Exchange: Removal of antibodies to the acetylcholine receptor in the blood is effective or has a short duration of effect.
4. Crisis (Crisis) Treatment: sudden symptoms of severe paralysis and symptoms of paralysis and respiratory muscle paralysis, such as when the pupil is small, and then you see the pupil and then bring it to the hospital should be done with artificial respiration and appropriate treatment.

■ Prevention:
In patients with myasthenia gravis, the following medications can worsen symptoms and should be avoided. Antibiotics used for colds, urinary tract infections, sinusitis, anti-arrhythmic drugs, narcotics, nervous stabilizers, and anticonvulsants.