Journal of Acuherb in Medicine


Myasthenia Gravis

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By Dr. Ken. Wang

Myasthenia gravis is a chronic disorder of neuromuscular junction function that causes muscles to become weak and to tire easily. The specific pattern of muscle involvement is often important to diagnosis. 

The Brain and Nervous System
The central nervous system comprises the brain and spinal cord. Nerves are attached to the spinal cord and branch out to the entire body forming the peripheral nervous system. Nerve impulses can travel along each nerve in one direction only. One type of nerve (motor) carries signals from the brain to the legs, for example, and another (sensory) sends signals back from the legs to the brain.

 

Myasthenia gravis is an autoimmune disease that results in chronic defective transmission of nerve impulses to the muscles. The disease produces weakness and abnormally rapid fatigue of voluntary muscles. Symptoms improve after rest or medication. The disease usually presents between the ages of 10 and 50 years and women are affected more often than men in 200,000. It is an uncommon disease occurring in approximately one in 200,000 people.

Depending on the symptoms it produces, myasthenia gravis is placed in different traditional Chinese medicine (TCM) syndrome categories:

When weakness of the limbs predominates, it is classified as flacciditysyndrome. In TCM, this refers to a syndrome marked by weakness, limited movement and muscular atrophy (wasting) of the limbs, especially the lower limbs and results from lack of nourishment reaching the muscle tissue. This can be caused by consumption of body fluid by lung-heat, an overwhelming effect of dampness-heat evil, or weakness of the liver and kidneys leading to insufficiency of essence and blood.
If the main symptom is drooping of one or both eyelids, the syndrome is classified as ptosis.
In individuals presenting with weakness of the eye muscles and suffering from double vision, the syndrome is classified as vision changes.
Others classifications include drooping head or respiratory collapse and relate to corresponding manifestations of the disease.

Causes

Myasthenia gravis has an overall incidence of about four cases per million. There is no racial or geographic predilection, and the disorder can occur at any age. However, there is an increased incidence in young women, especially in the third decade, and in older men in the seventh decade.

The disease is caused by the autoimmune destruction of the acetylcholine receptors on the post-synaptic membrane of the muscle fiber. Immune complexes are deposited at the post-synaptic membranes causing interference with and later destruction of the acetylcholine receptor. The communication between the nerve impulses and muscle fibers is impaired or lost and muscle weakness results.

Click here to see structure of the Neuromuscular Junction

The process that initiates the immune response is unknown, but the thymus gland appears to be critical for both the autoimmune activation and the maintenance of the activated autoimmune state. Overgrowth of the thymus gland is found in 70 per cent of myasthenic patients below the age of 40 years. In 10 per cent of patients there is a tumor of the thymus gland and the incidence of this increases with age.

There is an association between myasthenia gravis and thyroid diseaserheumatoid diseasepernicious anemia and systemic lupus erythematosus. Myasthenia gravis is sometimes caused by D-penicillamine treatment in rheumatoid disease.

In TCM, myasthenia gravis is considered to be a complex disease. Many organs or systems of the body are involved and progress of the disease varies. Manifestations of the disease do not necessarily follow a prescribed order, but depend on the pathogenic factors involved and the mechanisms affected. The causes can be classified as follows:

Exogenous causes 
Invasion by exogenous pathogens leads to impaired functioning of organs and depletion of blood and vital energy (qi), contributing to the disease. TCM considers that blood belongs to yin-fluid, which is mainly responsible for providing moisture and nourishment to the tissues. The role of qi is to promote and consolidate all body functions. Deficiency in blood and qi result in inadequate supply of these essentials to the muscles, tendons and meridians and flaccidity syndrome results.

Endogenous causes
These can occur when an individual encounters emotional problems or damage by the seven modes of emotions (for example, anger damaging the liver, fear damaging the kidneys or melancholia damaging the spleen). The understanding in TCM is that the liver stores the blood that supports the tendons, and the kidneys store essence for the production of bone marrow. Both blood and essence are part of yin. If an individual’s liver-yin and kidney-yin are depleted, a virtual fire is created internally causing the supply of blood and essence to become exhausted. The tendons and muscles then lose their nutrient supply and become weak and numb.

Non-exogenous/endogenous cause
This is mainly the result of an imbalanced lifestyle and includes the eating of an improper diet (too much greasy or sweet food) or excess consumption of alcohol and leads to spleen and stomach injury. Stress and chronic disease can also result in a decline in qi and body fluid and cause spleen and stomach damage. The spleen and stomach are the primary organs for digestion and absorption; they extract nutritive essence from food and use it for the production of qi, blood and body fluids. If they do not function properly, muscle weakness, drooping eyelids or breathing difficulties can develop.

Congenital factors
Inborn defects, such as weakness of the spleen and stomach, yang-deficiency of the spleen and kidneys or yin-deficiency of the liver and kidneys, can cause failure in different organs and lead to the disease.

Symptoms

Weakness is the defining symptom of myasthenia gravis. Patients may not recognize it as such and complain to their doctor of double vision, difficulty swallowing, slurring of speech, or even a change in gait. Five areas of motor function are commonly affected and involve the muscles that control the following:

the eye
the face, nose and throat
respiration
the torso (pectoral and pelvic muscles), and
the arms and legs.

The symptoms may fluctuate from hour to hour, from day to day, or over longer periods. They are provoked or worsened by exertion, exposure to extremes of temperature, viral or other infections, menses and excitement. 

The symptoms experienced are commonly these: 

 

Eye muscle involvement often results in drooping of the upper eyelid and double vision. It usually affects both eyes and is asymmetrical.
Weakness of other muscles innervated by cranial nerves results in loss of facial expression, everted (pouting) lips, a smile that resembles a snarl, jaw drop, nasal regurgitation of liquids, choking on foods and secretions, and a slurred, nasal speech with a reduced volume.
Depending on the severity of the disease, difficulty breathing can appear on moderate or mild exertion or be present even at rest.
Abnormal tiredness of the limb muscles causes difficulty in combing the hair, lifting objects repeatedly, climbing stairs, walking and running.


Initially, the symptoms affect only the eyes in 40 per cent of patients; are generalized in 40 per cent; involve only the extremities in 10 per cent; and affect only the nose, mouth or throat, or these muscles and the eye muscles in another 10 per cent. Subsequently, the weakness can spread from the eye to the facial, salivary, swallowing and respiratory muscles and then to the torso and limb muscles, but the sequence may vary. Arm and leg muscles are affected more than hands and feet. In the most advanced cases the weakness is general throughout the body.

By the end of the first year, the eye muscles are affected in nearly all patients. The symptoms remain ocular (involving the eye) in only 16 per cent. In nearly 90 per cent of those in whom the disease becomes generalized, this occurs within the first year after the onset. Progression is most rapid within the first three years, and more than half of the deaths caused by myasthenia gravis occur in that period.

Spontaneous remissions lasting from weeks to years can occur. Long remissions are uncommon, and most remissions occur during the first three years.

TCM practitioners will examine a sufferer and categorize symptoms under special syndrome groups known as “disharmony patterns.” Certain disharmony patterns are present at different stages of a disorder. In myasthenia gravis, these can be classified into the following types:

Qi-deficiency in the spleen and stomach
Individuals present with drooping eyelids, weakness of the limbs, and difficulty in holding the head up and chewing food. Symptoms are worse towards the end of the day. Others symptoms include poor appetite, diarrhea, a reluctance to speak and shortness of breath.

Yang-deficiency in the spleen and kidneys
This often presents with drooping eyelids, limitation in muscular control of the eye, and limb weakness. Other accompanying symptoms are soreness in the loin region, spontaneous sweating, aversion to cold temperatures, cold limbs, a pale complexion, difficulty in swallowing, poor appetite and diarrhea, and the excretion of large volumes of dilute urine.

Yin-deficiency in the liver and kidneys
The main symptoms include drooping eyelids, difficulty in swallowing and chewing food, and limb weakness. Symptoms worsen towards the end of the day. Other accompanying symptoms are soreness and weakness in the lumbar (lower back) region and knees, dizziness, ringing in the ears, insomnia and nightmares. A feeling of dryness in both eyes and a hot sensation in the chest, palms of the hands and soles of the feet can develop.

Deficiency in both qi and blood
Individuals present with fatigue and weakness, palpitation, shortness of breath, a reluctance to speak, pale complexion, drooping eyelids, difficulty in swallowing and chewing food, muscle wasting and fatigue, and spontaneous sweating. 

Diagnosis

The presence of weakness (usually worse at the end of the day or after vigorous exercise), but without loss of sensation is necessary although not sufficient on its own to make the diagnosis of myasthenia gravis. Diagnosis is based on the clinical history, physical examination and results of specific tests and laboratory studies. 

Tensilon (edrophonium) test
Edrophonium chloride (an anticholinesterase) is given intravenously. If improvement in weakness occurs within seconds and lasts for two to three minutes the test is considered positive. Occasionally the test itself can cause respiratory constriction and fainting and is always carried out in a proper clinical setting.

Serum acetylcholine receptor antibodies
These disease-specific antibodies are present in 90 per cent of cases of generalized myasthenia gravis. The antibodies are found in no other condition.

Nerve stimulation
Stimulation of the motor nerve results in a characteristic decrease in muscle response.

Other tests
Chest X-ray may show a mass (enlarged gland) in the area of the thymus that can be confirmed by computed tomography scanning. Nothing unusual can be detected from peripheral blood samples.

Diagnosis in TCM places importance on determining the circumstances and manifestations of a disease through inquiry and symptom observation. Diagnosis is based on the traditional four examination techniques:

1. Questioning The TCM practitioner will establish the medical history of both the patient and his family.
2. Observation Examination of the physical features of the body, such as the face, tongue, hair, nails, sputum (mucus that is coughed up), and location of pain, all offer clues to the problem. The tongue is a particularly useful indicator of the functioning of the internal organs.
3. Listening and smelling The smelling of sputum and breath and listening to the sounds produced by the chest offer additional clues to the patient’s health.
4. Touching Feeling the pulse is a cornerstone of TCM diagnosis and gives the practitioner much information about any bodily imbalance.

In myasthenia gravis, the procedures used in TCM to differentiate between disharmony patterns can be explained as follows: 

Qi-deficiency in the spleen and stomach
Impaired functioning of the spleen and stomach causes an insufficiency in qi and blood production. This reduces the supply of nutrients available to the muscles and tendons and results in weakness in muscular contractions. A reluctance to speak and shortness of breath also result from qi and blood insufficiency. Poor appetite and diarrhea are symptoms of spleen weakness.

On examination, the tongue is swollen, pink in color, indented on the margins and coated with a thin, white fur. The pulse is weak and fine.

Yang-deficiency in the spleen and kidneys

Yang-deficiency implies under-functioning of these two organs. This leads to a decline in the storage of essence and muscle weakness results. Kidney-yang deficiency also causes soreness in the loin area, production of copious amounts of dilute urine and an aversion to cold temperatures.

On examination, the tongue is swollen, pink in color and covered with a thin, white fur. The pulse is deep and fine.

Yin-deficiency in the liver and kidneys
Yin-deficiency of these organs leads to essence and blood depletion and results in loss of nourishment and moisture to the body. Body structures, such as the muscles, bones and tendons, become weak. Liver-yin deficiency can also cause insomnia, nightmares and dryness of the eyes. Kidney problems cause dizziness, ringing in the ears, soreness and weakness in the loin area and the knees.

On examination, the tongue is red with a scanty fur covering. The pulse is fine and rapid.

Deficiency in both qi and blood

Deficiency in qi and blood not only affects the supply of nutrients to muscles and tendons, but also leads to general impairment of the whole body. In addition to symptoms of muscle weakness, individuals present with fatigue, palpitation, shortness of breath, pallor and spontaneous sweating.

On examination, the tongue is pale, swollen and indented on the margins. The tongue fur is white and thin. The pulse is deep and fine.

Treatment

There are three therapeutic options in the TCM treatment of myasthenia gravis: the regularization of disharmony patterns, use of Chinese patent medicines and acupuncture therapy.

Therapeutic regimens for disharmony patterns

Qi-deficiency in the spleen and stomach


Therapeutic aim: 
To Tonify the spleen and benefit the qi

Prescription:
 Buzhong yiqi decoction (modified)

dang shen pilose asiabell root
huang qi milk-vetch root
bai zhi large head atractylodes root
sheng ma cimicifuga rhizome
chai hu Chinese thorowax root
chen pi dried tangerine peel
dang gui Chinese angelica
sheng jiang fresh ginger
da zao Chinese date
yi yi ren coix seed
fu ling Indian bread

In this prescription, pilose asiabell, milk-vetch and large head atractylodes roots are used to tonify the spleen and benefit the qi. Cimicifuga rhizome and Chinese thorowax root improve the transformation and transportation functions in the spleen. Dried tangerine peel regulates the qi movement; Chinese angelica aids the blood; and fresh ginger and Chinese date improve the communication between the interior and exterior of the body. Coix seed and Indian bread invigorate the spleen and expel dampness evil. Used in combination, these ingredients invigorate the spleen and stomach, increasing production of nutrient essence and relieving symptoms.

Yang-deficiency in the spleen and kidneys

Therapeutic aim: To warm and tonify the spleen and kidneys

Prescription: Yougui bolus (modified)

fu zi monkshood
rou gui cassia bark
lu jiao jiao deerhorn glue
shu di processed rehmannia root
shan yu rou Asiatic cornelian cherry
tu si zi dodder seed
gou qi chi Chinese wolfberry fruit
du zhong eucommia
dang gui Chinese angelica
dang shen pilose asiabell root
huang qi milk-vetch root
shan yao common yam root
bai zhi large head atractylodes root

In this prescription, monkshood, cassia bark and deerhorn glue warm and invigorate the spleen and kidneys. Rehmannia root, Asiatic cornelian cherry, dodder seed, wolfberry and eucommia are used for nourishing the spleen-yin and kidney-yin. Chinese angelica replenishes the blood; and pilose asiabell, milk-vetch, common yam and large head atractylodes roots replenish the qi and tonify the spleen.

 

Yin-deficiency in the liver and kidneys

Therapeutic aim: To nourish and invigorate the liver and kidneys

Prescription:
 Zuogui bolus (modified)

sheng di fresh rehmannia rhizome
gou qi chi Chinese wolfberry fruit
shan yu rou Asiatic cornelian cherry
lu jiao jiao deerhorn glue
gui jiao tortoise shell glue
tu si zi dodder seed
niu xi achyranthes root
shan yao common yam root

In this prescription, fresh rehmannia rhizome is used in quantity for effective nourishment of the kidney-yin. Wolfberry replenishes the essence and improves visual acuity; and Asiatic cornelian reduces depletion of essence and calms the liver. Deerhorn glue invigorates the yang; and tortoise shell glue nourishes the yin. A combination of these two glues can replenish essence and bone marrow. Dodder seed and achyranthes root reinforce the lumbar (lower back) region and knees, and strengthen the tendons and bones. Common yam root tonifies the spleen and aids the kidneys.

 

Deficiency in both qi and blood

Therapeutic aim: To invigorate and replenish the qi and blood 

Prescription:
 Bazhen decoction (modified)

ren shen ginseng
fu ling Indian bread
bai zhi large head atractylodes root
gan cao liquorice root
dang shen pilose asiabell root
bai shao white peony root
shu di processed rehmannia root
chuan xiong Szechwan lovage root
sheng jiang fresh ginger
da zao Chinese date

In this prescription, ginseng, Indian bread, large head atractylodes root and liquorice root invigorate the spleen and benefit the qi. Pilose asiabell, white peony and rehmannia roots nourish the heart and blood. Szechwan lovage root improves the blood circulation; when combined with pilose asiabell root and rehmannia root, it increases blood production without causing an increase in viscosity (thickening). Fresh ginger and Chinese date help the ginseng and Indian bread to regulate the spleen and kidneys.

Chinese patent drugs
These drugs are available in small dosages and are readily absorbed on ingestion. They are more convenient to use because they are not bulky to carry about and are therefore more appropriate to a busy lifestyle. Taking a pill or a bolus is often easier for those who do not wish to consume large volumes of liquid or who do not like the bitter taste of decoctions. Examples of patent medicines used in the treatment of myasthenia gravis are:

Qi-deficiency in the spleen and stomach:Buzhong yiqi bolus
Yang-deficiency in the spleen and kidneys:Ginseng yangrong bolus
Yin-deficiency in the liver and kidneys:Liuwei dihuang bolus 
Deficiency in both qi and blood
Jinkui shenqi bolus

Acupuncture therapies
Use of acupuncture stimulates the meridians. These connect the internal organs with the limbs and their stimulation results in: 

activation of qi and blood
regulation of yin and yang
strengthening of the tendons and bones, and
lubrication of the joints.

Acupuncture can be used therefore as the main or an adjuvant therapy. 
Treatment is given daily over 10 days; four to five acupoints are selected each time and the needle retained for 20 to 30 minutes.

For drooping eyelids, acupoints are selected on the face: zan-zhu, yang-bai, yu-yao, si-bai and jing-ming.
For limb weakness: he-gu, nei-guan, wai-guan, san-yin-jiao, tai-chong, da-zhui, pi-yu, shen-yu and zu-san-li are used.

Otopuncture therapy 
This therapy is used weekly and applied to each ear alternately. The method involves acupoint embedding of the needle under the skin.

The acupoints used are spleen, kidney, liver and points for endocrine functions. 

 

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