Myasthenia gravis – causes, symptoms, treatment and prognosis

Proven content

Myasthenia gravis is an autoimmune disease characterized by increased muscle fatigue. Patients cannot cope with, inter alia, with impaired speech, drooping eyelids or sudden falls. Myasthenia gravis is much more common in women than in men.

What is myasthenia gravis?

Myasthenia gravis, also known as myasthenia gravis, is an autoimmune disorder of the nervous system. It is characterized by excessive weariness of skeletal muscles. People suffering from this ailment usually have problems with proper speech, sudden falls or drooping eyelids. In Poland, about five thousand people suffer from myasthenia gravis, and the disease itself affects more women than men. Myasthenia gravis can occur at any age, even in children, but the highest incidence is noted in women over 30 and men over 50. Importantly, this disease is not genetically inherited.

If you want to know more about autoimmune diseases, read on: Autoimmune diseases

Myasthenia — history

The first records and medical descriptions of myasthenia gravis appeared in the XNUMXth century. Myasthenia gravis has been described by Thomas Willis, a British physician and anatomist, and Samuel Wilks, a well-known physician and historian of medicine.

It is worth mentioning that at the end of the XNUMXth century the symptomatology of myasthenia gravis was discovered. It was possible thanks to the scientific achievements of Wilhelm Erb, Samuel Goldflam and Hermann Oppenheim.

In 1895 the term “Myasthenia gravis pseudoparalytica” was introduced by Friedrich Jolly, a German psychiatrist and neurologist. In turn, the relationship between myasthenia gravis and thymic insufficiency was noticed and described by Carl Weigert, a German physician and pathologist.

The first thymectomy in the treatment of myasthenia gravis was performed by the German surgeon Ferdinand Sauerbruch in 1912. In turn, the first attempts at pharmacotherapy were undertaken in the 30s. century. An interesting fact is that these attempts were made by Mary Walker, who herself suffered from myasthenia gravis.

What is the thymus and what functions does it perform? Check: Thymus (myasthenia gravis) – what is it and what are its functions?

The causes of myasthenia gravis

Myasthenia gravis is an autoimmune disease. This means that myasthenia gravis is caused by the targeting of antibodies produced by our immune system towards our own tissues, i.e. against muscle fiber receptors. Acetylcholine is a neurotransmitter that is released from the nerve endings that supply the muscle fibers.

If the muscle is functioning properly, the presence of acetylcholine in it is a signal to start a series of reactions, the consequence of which is contraction. For these reactions to happen, it must bind to a receptor on a muscle cell. In people with myasthenia gravis, the receptors are blocked by antibodies, effectively preventing this combination. It is worth mentioning that about 85% of patients diagnosed with myasthenia gravis also have IgG antibodies against the acetylcholine receptor. The remaining 15% of the sick are patients with the so-called seronegative form of the disease.

Antibodies are produced by the thymus, an organ that should disappear soon after puberty (however, the role of the thymus in myasthenia gravis is not fully understood). It is known to be a gland in the mediastinum that helps build our immunity. The connection of the thymus with the genesis of the disease results from the fact that more than 65% of patients with myasthenia gravis have thymic hyperplasia, moreover, after gland excision, the health of patients with myasthenia gravis improves significantly. In addition, 15% of patients with myasthenia gravis are diagnosed with thymic neoplasm.

When is it worth performing an ultrasound of the thymus? Check: Ultrasound of the thymus – what diseases can it detect?

Symptoms of myasthenia gravis

The general symptoms of myasthenia gravis consist of weakening of the body’s muscles, which fatigue frequently and rapidly. Patients have no influence on e.g. for drooping eyelids (myasthenia gravis), muscles of the palate, pharynx and larynx (speech and swallowing disorders), head drooping and weakness in the hands, and even sudden and uncontrolled falls. Symptoms of myasthenia gravis progress over time – it usually takes several years to get worse.

The first symptoms of myasthenia gravis they usually concern the weakness of the levator eyelid and oculomotor muscles. Patients (as mentioned above) complain of drooping eyelids and sometimes even indicate double vision. In some people, the ocular symptoms are the only features, while in others the disease process generates and over time begins to attack other parts of the muscles as well.

The disease may gradually involve:

1. bulb muscles – they affect the work of the throat, mouth and larynx. After being attacked by myasthenia gravis, patients begin to have trouble speaking, swallowing and chewing food (frequent choking). In addition, the lower jaw may drop, which the patient has to support with his hand;
2. facial muscles – their occupation by myasthenia gravis leads to impairment of the patient’s facial expressions. Difficulties in smiling appear (circular muscle of the mouth), the smile becomes flat, the corners of the mouth do not rise, the patient seems depressed or tired;
3. muscles of the upper and lower limbs – there are difficulties in everyday life and activities. Patients have trouble writing, washing or even prosaic combing their hair. The longer an activity is performed, the weaker the muscles become. When the myasthenia gravis affects the lower limbs, walking difficulties appear, and a regular walk begins to require rest every few steps;
4. intercostal muscles and diaphragm – their involvement by myasthenia gravis is particularly dangerous because the patient begins to have breathing problems and increasing shortness of breath. Very often, such patients undergo intubation and artificial respiration;

Symptoms of myasthenia gravis are also triggered or intensified due to factors such as: pregnancy, menstruation, bacterial and viral infections, stress, excessive emotions, anxiety, temperature fluctuations in the environment, insecurity or narcosis.

Do you know what myopathy is? Check: Myopathy

Myasthenia gravis – clinical classification

Symptoms that occur in patients with myasthenia gravis also serve as criteria for the clinical classification of this disease. Osserman’s modified division assumes the following distinction:

1. Group I of myasthenia gravis – ocular myasthenia gravis;
2. Group IIA of myasthenia gravis – mild generalized myasthenia gravis;
3. Group IIB of myasthenia gravis – moderate to severe generalized myasthenia gravis;
4. Group III of myasthenia gravis – acute (sudden) or severe generalized myasthenia gravis with respiratory failure;
5. Group IV – late, severe myasthenia gravis with significant bulbar symptomatology.

It is worth mentioning that the previously described symptom of ptosis or double vision occurs in the initial phase of myasthenia gravis. In the next phase, there is a dysfunction of the muscles of the pharynx and larynx. In the next stage, the myasthenia gravis begins to affect the muscles of the trunk and limbs.

A clinical symptom scoring system has also been introduced to help determine the severity of myasthenia gravis. This system includes 8 symptoms, which are scored on a scale from 0 to 3, where the maximum score represents the greatest severity of a given symptom.

In the following years, this scale was extended to 13 symptoms, creating the Quantitative Myasthenia Gravis Test scale, or QMG for short. This scale is currently used and according to it, the most severe clinical form of myasthenia gravis is estimated at 39 points.

What is Muscle Atrophy? What are the reasons? Check: Muscle atrophy – Causes and Symptoms

Myasthenia gravis – diagnosis

The diagnosis of myasthenia gravis is mainly based on the physical examination of the patient, additional tests and, as a standard, medical history.

The patient can also make the initial suspicion of the disease on his own with testu apokamnozy. This test consists in repeating the same activities several times and observing whether muscle weakness increases with effort. The test is considered positive when the patient observes muscle fatigue with the constant blink of the eyelid, which over time begins to refuse and droop.

Another diagnostic method is a pharmacological test, which uses agents that increase the amount of acetylcholine in the neuromuscular disc, i.e. intravenous edrophonium chloride, intramuscular neostigmine and cholinesterase inhibitors. If a patient has myasthenia gravis – after administration of the preparations, muscle weakness subsides quickly.

In addition, it is used in the diagnosis of myasthenia gravis electrophysiological studies, the most important of them are:

1. EMG — electromyography;
2. electrostimulation test of muscle fatigue;
3. immunological test – aimed at assessing the histocompatibility system and confirming or excluding the presence of AChR p / k antibodies;
4. assessment of the thymus.

During the differential diagnosis of myasthenia gravis, it is also important to take into account the presence of diseases or disorders such as:

1. Lambert-Eaton myasthenic syndrome;
2. botulism;
3. poisoning with pesticides;
4. multiple sclerosis;
5. brain stem tumor;
6. damage to the oculomotor nerves;
7. oropharyngeal myopathy;
8. mitochondrial myopathy;
9. neurosis.

How is an EMG test done and when is it worth doing? Read: EMG tests – indications, course, price [EXPLAINED]

Myasthenia gravis – treatment

The treatment of myasthenia gravis is a very long process that involves good contact and understanding between the patient and the doctor. It is important to support loved ones, avoid stress, infections or other factors that may aggravate the symptoms of the disease. Patients’ treatment should be individualized according to their state of health, as muscle fatigue tends to develop over a period of days to weeks or remain at the same stage for many years. Treatment of myasthenia gravis is carried out with the aim of:

1. Removal of active antibodies against acetylcholine receptors by plasmapheresis: this method is based on the purification of blood plasma with redundant molecules. A certain amount of blood is taken, and then it is separated into plasma and cellular elements, which are then put back into the human body.
2. Facilitate neuromuscular transmission: cholinergic drugs are helpful for this. They inhibit the enzyme that breaks down acetylcholine at the ends of the neuromuscular junction, which in turn causes more ACh and better transmission of impulses to the muscle. In Poland, the means used for this purpose are: pyridostigmine, ambenonium and neostigmine.
3. Inhibition of autoantibody production: in this case, two methods are used. One of them is a surgical procedure in which the thymus is removed. This procedure causes the disease to go into remission in approximately 30% of patients. The second method is pharmacological treatment, which is based on taking immunosuppressants (suppressing the immune system), e.g. prednisone, or modifying the work of the human immune system (immunomodulating), e.g. cyclophosphamide, methotrexate or azathioprine. Immunosuppressants are used mainly in severe myasthenia gravis, in pregnant women or in patients with diplopia.

What exercises should you do if you have myasthenia gravis? Check: Exercise for patients with myasthenia gravis – expert advice

Myasthenia gravis – possible complications

Complications may occur in the course of myasthenia gravis. Specialists point to the two most common complications of myasthenia gravis: myasthenic crisis and cholinergic breakthrough.

The myasthenic crisis is the moment in the course of the disease, when respiratory failure occurs. A myasthenic crisis is caused by a sudden worsening of the symptoms of the disease. The causes of this exacerbation are infection, use of contraindicated drugs, pregnancy or electrolyte disturbances.

In the event of a myasthenic crisis, the patient usually goes to the hospital. Treatment consists of plasma exchange, administration of glucocorticosteroids, discontinuation of cholinesterase blockers, but also connection to a ventilator.

A cholinergic crisis occurs in patients who misuse cholinesterase blockers, resulting in drug overdose. In the event of a cholinergic crisis, breathing problems, muscle twitching, slow heartbeat, constriction of the pupils, diarrhea and stomach pain may occur.

The treatment is similar to that in the case of a myasthenic crisis.

What might dyspnea indicate? Check: When is breathlessness a serious illness? [WE EXPLAIN]

Myasthenia gravis – what should patients avoid?

The course of the disease and complications can be minimized by taking certain precautions. First of all, patients with myasthenia gravis should avoid any situation that is stressful or disturbing for them. A sense of security and psychological comfort is very important for a patient with myasthenia gravis.

In addition, it is extremely important to care for the physical health of the patient. Symptoms of myasthenia gravis significantly worsen in the event of infection, so the patient cannot be exposed to people with an infection. Therefore, patients with myasthenia gravis should avoid traveling by public transport, frequent visits to public places or locations where larger groups of people gather. Patients with myasthenia gravis should therefore avoid cinemas, swimming pools or crowded waiting rooms.

People diagnosed with myasthenia gravis should take special care of their surroundings. In order for the symptoms of myasthenia gravis not to intensify, fatigue, overheating or sudden cooling of the body should be avoided. A patient suffering from myasthenia gravis is very sensitive to any temperature changes in his environment.

How sudden changes in weather affect our health? Check: Sudden warming is ahead of us. How do sudden changes in the weather affect our health and well-being?

Myasthenia gravis – patient care

Caring for a person suffering from myasthenia gravis requires commitment from the caregiver and extraordinary care for the patient’s comfort.

1. patients with myasthenia gravis have a problem with swallowing – improper administration of food can weaken the body and even lead to malnutrition. Remember to give the patient food in small amounts, but more frequently, e.g. 6-7 times a day
2. taking care of the patient’s diet is very important – the diet should be balanced and provide the patient with all the necessary nutrients. Food should be given in a semi-liquid form, preferably food for special medical purposes;
3. care for patients with myasthenia gravis must be comprehensive, but also tailored to the individual needs and health of the patient;
4. it is important to help with simple activities such as washing, brushing the hair or dressing;
5. monitoring the regular intake of medications;
6. taking care of the appropriate conditions of the patient with myasthenia gravis, with particular emphasis on the room temperature.   

What are the rules and guidelines for a liquid diet? Read: Liquid diet – when is it worth using?

Myasthenia gravis – prognosis and life expectancy

Myasthenia gravis is a chronic and autoimmune disease. Unfortunately, it is also impossible to heal completely. However, it should be noted that the correct treatment of this disease gives a good prognosis.

Myasthenia gravis is characterized by exacerbations in which symptoms worsen, but also periods of remission when symptoms may completely disappear. The frequency of exacerbations and remissions of the disease is an individual matter. However, it is worth remembering that this frequency can be influenced by infection, stress or hormonal disorders.

Anyone diagnosed with myasthenia gravis may develop the so-called myasthenic crisis, which is a medical emergency. A myasthenic crisis is a significant impairment of the breathing muscles and a swallowing disorder. In such cases, hospitalization and intensive treatment are usually required.

Myasthenia gravis does not particularly affect the patient’s life expectancy. If the patient is well cared for and takes medication regularly, he or she may even reach old age. Many people with myasthenia gravis live up to 90-100 years.

What are the secrets of longevity? Check: How to live to be a hundred years old? Seven ways. Including … less friends

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