A cholinergic crisis is not accompanied by an overdose of proserin. How does myasthenic crisis manifest? Treatment
This disease is of a neuromuscular nature. It occurs chronically with a relapsing or progressive course. The main feature pathology is increased weakness muscles of the striated group. The progression of symptoms usually occurs slowly. And they get sick in childhood.
With myasthenia gravis, any muscle can be involved in the process. However, the most often affected group is the neck, face, eyes, and pharynx. The progression of the disease can reach a state similar to paralysis. The pathology was first described in the 16th century. Data accumulated over such a long period of time indicate that women are three times more likely to suffer from myasthenia gravis.
The incidence is increasing from year to year. On average, it is detected in 6-7 cases per 100,000. The largest proportion of patients with myasthenia gravis is in the age group from 20 to 40 years. However pathological condition has no preferences at the beginning of development and can start at any time, and even be innate.
Causes
Depending on the type of myasthenia gravis, there are several factors that can trigger it. Pathology is classified into two main types:
- Congenital;
- Acquired.
The first appears due to genetic defect. It is predominantly hereditary. Such a failure creates conditions for the formation of muscle weakness at the cellular level. Pathogenesis consists of disruptions in the functioning of synapses - intermediaries between nerves and muscles. Neuroscience studies disorders of synaptic transmission.
Acquired myasthenia is registered more often than the first. However, it is much better treated. It may be due to several factors:
- Oncological. Thus, a number of myasthenia gravis are formed against the background of tumors. These can be neoplasms of the thymus, genital organs (ovaries, prostate gland), less commonly lungs and liver;
- The autoimmune nature of the pathology in Lately becomes one of the most common reasons myasthenia gravis. This means that the disease often occurs against the background of diseases associated with immune failure. In which your own cells attack your body. This can occur with dermatomyositis or scleroderma. With the autoimmune nature of the disease, antibodies are produced to the receptors of synapses - adapters between muscle and nerve. As a result, the delivery of substances necessary for muscle contraction - mediators - is blocked. A failure occurs that leads to myasthenia gravis.
Symptoms
The main symptom that will manifest the disease is pathological muscle weakness. The muscles become tired quickly and cannot work for a long time. This is especially obvious when performing repetitive movements. Rest has a beneficial effect on muscle recovery. Waking up in the morning, the patient may not feel any signs of illness. But, after a few hours, it becomes noticeable again.
Depending on the clinical course pathology, there are 3 of its forms:
- Bulbar;
- Ophthalmic;
- Generalized.
The first is responsible for damage to the muscles - chewing, swallowing and voice-forming muscles. In patients with this form, speech changes - it becomes hoarse, quiet, even silent. The act of passing food is disrupted. Patients have difficulty swallowing and chewing. Due to insufficient food intake, patients lose a lot of weight.
The second type affects eye muscles– outer, round, levating the eyelid. As a result, it becomes difficult for patients to blink and open their eyes. This reduces vision function. And is reflected on social life of people. They prefer to stay at home and not go out. Another clinical form of the disease is generalized.
It sequentially captures the oculomotor, facial, and cervical muscles. This affects not only the functions, but also the appearance patient. The face becomes unplastic and looks prematurely aged. The smile becomes strained, and weak neck muscles make it difficult to hold the head upright.
Progression leads to pathology of the limbs, which impairs walking and free movements. Lack of stress leads to atrophy. This makes the muscles sluggish, flabby and weak. It decreases in volume. Patients look exhausted and emaciated. Therefore, the generalized form is considered the most dangerous - it immediately affects a large number of muscles.
However, this type is more common than others. Other heavy and acute condition Myasthenia gravis is a crisis. This is an instant attack of weakness, which will be accompanied by cessation of muscle function, including vital ones - swallowing and breathing. This condition is deadly due to a decrease in oxygen supply to the body.
Cholinergic crisis
This attack rarely develops in 3% of cases. He progresses more slowly. If we compare an attack with a myasthenic crisis. The cause of such conditions is often an overdose of anticholinesterase drugs. This looks like an increasing deterioration in well-being followed by signs of intoxication. After which a seizure develops.
It is quite difficult to distinguish between cholinergic and myasthenic crises. Both conditions have a pronounced muscle weakness, which involves the bulbar and respiratory group. However, it is still possible to distinguish them. The cholinergic crisis develops against the background of an increased dose of anticholinesterase drugs, which is accompanied by a paradoxical decrease in muscle strength.
Diagnosis of the condition
The proserine test has proven itself well as a research method. This substance is capable of creating a block to the breakdown of mediators that cause muscle contractions. Proserine test passes in the following way– preliminary examination of the patient. This is necessary to assess the condition of the muscular system before diagnosis.
Then the drug is injected subcutaneously. After 30 minutes, the doctor examines the patient again. Revealing changes after taking proserin. Another study necessary if myasthenia gravis is suspected is electromyography. It is based on recording the electrical activity of muscles. It is carried out twice - before the proserine test and after. This method can help in determining the origin of the pathology.
Is it associated with a disorder of neuromuscular transmission or occurs in isolation. Another test used in myasthenia gravis is electroneurography. CT is considered a valuable method ( CT scan). It is aimed at identifying neoplasms, possible reasons development of myasthenia. Among laboratory methods Blood tests deserve attention. They are necessary for the detection of specific antibodies.
Crisis treatment
This pathological condition requires emergency care. Due to an attack of sudden weakness of the breathing and swallowing muscles, a person can die. Therefore, patients in this condition need urgent hospitalization into intensive care. These patients have their own algorithm and treatment protocol. The first activity that is carried out is the formation of cross-country ability respiratory tract with oxygen supply.
Doctors perform tracheal intubation or perform mechanical ventilation. After this, breathing function is constantly monitored and patency is assessed. respiratory tract. If there are no signs of an overdose of proserin, then this particular drug is administered. Side effects eliminated by administering Atropine.
According to indications, glucocorticoids are prescribed at a dosage of 100 mg per day or higher. Such remedies are not indicated for everyone because of their possible negative effect in the form of renewed weakness of breathing. If a secondary infection occurs, antibiotics are prescribed. Laboratory values are constantly monitored to exclude electrolyte disturbances. In some cases, plasmapheresis and immunoglobulin administration are indicated.
Forecast
The course of myasthenia gravis depends on many factors:
- Forms of the disease;
- Start of the process;
- Rate of symptom progression;
- The patient's living conditions;
- Gender and age;
- Timeliness and quality of treatment provided.
It is considered the most favorable ocular type myasthenia gravis. The worst course is generalized. Currently, the arsenal of medications and diagnostic procedures allows us to give a large number patients have a favorable prognosis. This does not mean that they will recover; the goal of therapy is to stop the progression of myasthenia gravis.
Attribution of pathology to chronic process gives the likelihood of lifelong drug use. This is carried out in courses or continuously. Timely diagnosis allows you to provide patients good prognosis. These research methods manage to detect pathology before it affects all muscles and causes irreversible changes.
Prevention
Avoiding the disease is not easy. Due to the fact that the main causes of myasthenia gravis are genetic mutation, tumor formations and autoimmune pathology, preventing the disease is not easy. Preliminary medical and genetic consultation before pregnancy can serve as prevention. And also maintaining healthy image life, which increases the chances of avoiding myasthenia gravis.
Any crisis is a human condition in which the course of the disease suddenly, sharply worsens, and life-threatening symptoms increase very quickly. Myasthenic and cholinergic crises, which are companions of myasthenia gravis, are dangerous because the patient’s breathing may disappear and the heart may stop. Sometimes a person’s life is calculated literally in minutes, during which doctors or people nearby must manage to provide the right help. Why does the exacerbation occur, it would seem not fatal? dangerous disease myasthenia gravis? We invite you to talk in simple language that anyone can understand about what everyone should know: the causes of myasthenic and cholinergic crises, the clinic, emergency care for those who have experienced such a disaster. Perhaps someone near us, if suddenly in transport or just on the street he becomes ill, the information in this article will help save a life.
Myasthenia gravis
Let's start the story about the crisis by explaining the concept of myasthenia gravis. It happens that others mistake this disease for a simulation, since those suffering from myasthenia gravis constantly complain of fatigue, lethargy, and are unable to perform any task. physical work, only the easiest.
In fact, myasthenia gravis is neuromuscular disease, classified as autoimmune, that is, caused by a failure in the body to produce the right antibodies or the production of killer cells that attack healthy tissues and cells, which becomes a big disaster.
Myasthenic crisis develops against the background general disease and has similar symptoms, only to a much greater extent, which previously led to death in approximately 40% of patients. Now, if treatment is started without delay, it can be avoided. I would like to note that 10 people out of every 100 thousand citizens of the Earth suffer from myasthenia, and women suffer from it 3 times more often than men. Myasthenia gravis can manifest itself already in childhood, but such cases are rare. It is mainly observed in people from 20 years of age to very old age.
Symptoms of myasthenia gravis
Without myasthenia, if a person has it, a myasthenic crisis cannot occur. However, some other diseases are sometimes mistaken for it. similar symptoms, for example, such as the above-mentioned lethargy, weakness, increased fatigue. Additional symptoms for myasthenia gravis:
Drooping of the eyelids, most noticeable in the evening and decreasing in the morning after a night's rest;
Double vision;
Exhaustion, high fatigue after normal exercise for other people, for example, climbing stairs;
Initial bulbar signs (the appearance of a nasal voice after eating and a long conversation, difficulty in pronouncing individual letters);
Dynamics of bulbar signs (difficulty swallowing, frequent choking);
Autonomic disorders tachycardia);
Facial signs (very deep wrinkles on the forehead, characteristic facial expression);
Salivation;
Difficulty holding your head up;
Difficulty walking.
A distinctive feature of myasthenia gravis is that all of the above manifestations intensify after physical activity and in the evening, and after good rest decrease or disappear completely.
Symptoms of myasthenic crisis
If a person suffers from myasthenia gravis, under certain circumstances they may experience a myasthenic crisis. Symptoms of the underlying disease, especially such as tachycardia, high fatigue, vital important muscles(respiratory, cardiac), salivation increases. The following manifestations are also characteristic of a crisis:
Paralysis of the swallowing muscles and tongue, as a result of which mucus, saliva, and food can enter the respiratory tract;
Severe agitation and panic due to lack of air;
Cold sweat;
Sometimes spontaneous urination and/or defecation;
Loss of consciousness;
Dry skin;
Blood pressure surges;
Pupil dilation;
Acute heart failure, that is, disturbances in the functioning of the heart.
Myasthenic crisis comes in several degrees:
Average;
Heavy;
Lightning fast.
The differences lie in the strength of the manifestation of the above symptoms. Particularly dangerous are severe and lightning crises, in which a person very quickly, literally in a couple of minutes, develops weakness of the respiratory and swallowing muscles. At first, breathing becomes rapid, the face turns red, blood pressure jumps up, and the pulse reaches about 160 beats per minute. Then breathing begins to become interrupted and may even disappear completely, the face turns blue (in medicine this is called cyanosis), the pressure drops, and the pulse is almost not palpable.
Causes of myasthenic crisis
Myasthenia gravis can be either congenital or acquired. The first occurs due to mutations in genes. The second develops if a person has:
Problems with the thymus gland;
Some forms of cancer (particularly breast, lung, ovarian);
Thyrotoxicosis;
Encephalitis lethargic.
Against the background of these diseases, myasthenic crisis can develop in the following cases:
Acute infectious diseases, including ARVI, influenza, bronchitis;
Operations;
Severe psychological stress;
Taking certain medications (in particular, tranquilizers);
Hormonal disorders;
Patients with myasthenia gravis skipping pills, violating the course of treatment.
Cholinergic crisis
Myasthenic crisis and cholinergic crisis often manifest themselves in parallel, which is why there are errors in differentiation and, as a consequence, in treatment. However, these two are somewhat similar external manifestations states are caused for various reasons and have different etiologies.
Thus, during myasthenic crisis, the density of cholinergic receptors in the membrane decreases due to their destruction, and the remaining ones change their functions. And during a cholinergic crisis, excessive activation of cholinergic receptors (nicotinic and/or muscarinic) occurs. This process is triggered by taking drugs for the treatment of myasthenia gravis in high doses, as well as drugs prohibited for this disease.
It is not easy to diagnose this crisis, since its main symptoms coincide with myasthenic crisis. The following feature in his condition, characteristic of a cholinergic crisis, can help to correctly determine what is happening to a person: the patient begins to show signs of intoxication: a stomach ache, vomiting, and diarrhea begins. Myasthenic crisis is characterized by everything except these symptoms.
The second feature of a cholinergic crisis is that the symptoms of myasthenia gravis worsen without physical activity, but after taking anticholinesterase drugs.
Mixed crisis
This is the best for health and life dangerous look pathology. It combines myasthenic and cholinergic crises, presenting at once all the symptoms noted in both conditions. This complicates correct diagnosis, but even more so - treatment, because those medications that save from myasthenic crisis aggravate the cholinergic crisis even more. In mixed crises, two phases of the flow are distinguished:
1. Myasthenic. Patients have pronounced bulbar disorders, breathing problems, physical activity causes fatigue, but taking medications (Klamin, Proserin) negative reactions doesn't call.
2. Cholinergic characterized by symptoms of intoxication.
Practice has shown that mixed crises most often occur in people who have already suffered one or another crisis with myasthenia gravis.
Suspect mixed crisis possible based on the following features of manifestation:
In patients, bulbar impairment is clearly observed, and motor function limbs are little changed;
Taking medications unequally reduces pathological symptoms, for example improves motor activity and does little to help stabilize breathing.
Diagnostics
In order not to make a mistake and quickly provide effective assistance In case of myasthenic crisis, it is important to correctly diagnose the patient. As noted above, some symptoms of myasthenic crisis may be present in diseases that have nothing to do with myasthenia gravis (for example, difficulty breathing, abnormal heart rhythms). The symptoms of a cholinergic crisis are similar to those that occur with intoxication and some problems with the gastrointestinal tract. If the patient has an accompanying person who can provide information about the presence of myasthenia gravis and the medications he is taking, the diagnosis is greatly simplified. To differentiate the type of crisis, doctors perform
Particular difficulties in diagnosing are observed when mixed crisis. In order to accurately determine its first phase, clinical analysis the patient’s condition, as well as an electrophysiological assessment of the effect obtained from taking anticholinesterase drugs.
The very presence of myasthenia gravis in a person (before the onset of a crisis) is detected using electromyography, pharmacological and immunological tests.
Emergency care for myasthenic and cholinergic crisis
If a patient with myasthenia gravis suddenly has a sharp deterioration in his condition (a crisis ensues), his life counts in minutes. The main thing that others should do is to immediately call an ambulance. Unfortunately, in our reality there are situations when specialized assistance is late. How can you help a dying person in this case? First, try to provide him with breathing, remove mucus from his throat. According to the rules, people suffering from myasthenia gravis must have with them a note stating that they have of this disease, as well as medications (for example, Proserin) and a syringe. If it is not possible for an ambulance to arrive quickly, a person with a myasthenic crisis must receive an injection according to the information in the note.
Doctors who arrive in time are obliged to urgently hospitalize the patient, and in intensive care, where intensive emergency therapy is carried out:
Ensuring airway patency;
Oxygen supply;
If the patient does not have symptoms of cholinergic crisis (vomiting, diarrhea), the following medications: “Prozerin”, “Atropine”. If there are symptoms of intoxication, emergency therapy consists only of artificial ventilation of the lungs and injections of the following drugs: Atropine, Immunoglobulin, as well as some others medical supplies according to indications.
Treatment
If a person has a myasthenic crisis, post-acute care treatment is based on clinical and laboratory tests, analyzes and dynamics of disease development. Mechanical ventilation (i.e. artificial ventilation of the lungs) depending on clinical picture the patient’s condition, as well as the indications of the presence of oxygen in the blood, can be carried out for up to six days, but if the patient has a positive reaction to Proserin after 16 or a little more hours, mechanical ventilation is canceled. In general, the mechanical ventilation procedure is very serious and responsible, requiring constant monitoring of respirators, the % composition of gases in the blood, blood circulation, temperature, balance of fluids in the body, and other things.
An excellent method for coping with all types of crises in myasthenia gravis is exchange plasmapheresis. In this case, blood is taken from the central (or ulnar) vein, it is centrifuged, and the plasma is exchanged for donor or artificial. This method gives excellent results - within a couple of hours the patient’s condition improves significantly. Plasmapheresis is performed over a course of 7 to 14 days.
One of the stages of treatment is drug therapy. According to indications, patients are prescribed immunoglobulins, antioxidants, anticholinesterase drugs, and if available inflammatory processes- antibiotics.
Prognosis and prevention
Thirty to forty years ago deaths in patients with myasthenia gravis during exacerbation of the disease occurred quite often. Now the mortality rate has been reduced by 12 times. You need to understand that sometimes the life of a person who has had a myasthenic crisis depends on our actions. Emergency assistance must be provided very quickly. Therefore, if suddenly on the street, in transport, anywhere we see a person beginning to choke, we need to call an ambulance immediately.
Patients with myasthenia gravis themselves must also follow a number of measures to prevent a crisis:
Be under the supervision of a doctor and strictly follow the prescribed treatment;
Avoid overwork and nervous breakdowns;
If possible, protect yourself from infectious diseases;
Do not expose your body to intoxication;
Include foods rich in potassium in your diet (for example, potato dishes, raisins).
Myasthenia gravis is an acquired autoimmune disease. It is characterized by a pronounced phenomenon of pathological muscle fatigue and muscle weakness due to insufficiency of acetylcholine receptors on the motor end plate of the nerve.
Pathological muscle fatigue- a unique and specific sign of this disease. The muscle weakness that develops in this case differs from ordinary paresis in that when movements are repeated (especially in a rapid rhythm), it increases sharply and can reach the degree of complete paralysis. When muscles work at a slow pace, especially after sleep and rest, muscle strength is maintained for a relatively long time.
In typical cases, the first to appear are oculomotor disorders - double vision of objects, especially during prolonged reading, drooping eyelids. The lesion is asymmetrical and symptoms are dynamic: in the morning the condition is better, in the evening ptosis and double vision increase significantly. Later, weakness and fatigue of the facial muscles and masticatory muscles. When weakness spreads to the muscles of the extremities, the proximal muscles suffer more, first in the arms. In generalized forms, one of the most severe symptoms is weakness of the respiratory muscles.
Modern classification based on clinical features highlights:
Generalized myasthenia gravis without vital impairment important functions and with violations of vital functions;
Local forms without impairment of vital functions and with impairment of vital functions.
Diff. d - h:
Myasthenia gravis, which begins in old age, requires differentiation from cerebrovascular accidents.
Myasthenic crisis is a sudden deterioration in the condition of a patient with myasthenia, which poses an immediate danger to life, since due to the weakness of the respiratory and bulbar muscles, failure may occur. external respiration or severe bulbar abnormalities. Provoking factors are violation of the treatment regimen with anticholinesterase drugs, as well as acute respiratory viral infections, various infectious diseases, physical and psycho-emotional stress, 1-2 days of the menstrual period.
When the first signs of respiratory failure or dysphagia appear, tracheal intubation, auxiliary or artificial ventilation lungs;
Prozerin 0.05% solution - 2-3 ml IM or IV, if there is no effect, then after 30-40 minutes the dose is repeated IM;
Prednisolone 90-120 mg IV (1.5-2 mg/kg).
Cholinergic crises: occur with excessive dosages of anticholinesterase drugs as a result of patients independently increasing the doses recommended by the doctor. Myasthenic crisis with excessive therapy can turn into cholinergic. Symptoms of excessive cholinergic action develop. In this case, signs of both nicotine and muscarinic intoxication appear - fibrillary twitching, miosis, drooling, abdominal pain, agitation, often respiratory problems, pallor, coldness, marbling skin. There is a dissociation in the increased need for anticholinesterase drugs and a decrease in muscle strength after their administration.
There are no specific means for getting out of a crisis.
Use atropine 0.1% solution - 1 ml IV or SC, repeat the dose if necessary.
For respiratory disorders and bronchial hypersecretion - mechanical ventilation, toilet of the upper respiratory tract.
Temporary withdrawal of anticholinesterase drugs.
Tactics:
Patients with myasthenic and cholinergic crises should be emergency hospitalization to hospitals with intensive care and neurological departments.
Dangers and complications:
Development of acute respiratory failure.
Myasthenic crisis (hereinafter - MK) is a life-threatening condition that is characterized by impaired breathing and swallowing to the extent that compensation is impossible without a set of measures intensive care and resuscitation (including intensive ventilation). According to the literature, crisis courses are observed in 30 - 40% of patients with myasthenia gravis and are more common in women.
Molecular basis MK is probably a sharp decrease in the number of functioning acetylcholine receptors (hereinafter referred to as AChRs) due to a massive attack by their autoantibodies.
Differentiate MK from others severe conditions accompanied by respiratory disorders, it is possible according to the presence bulbar syndrome, hypomimia, ptosis, asymmetric external ophthalmoparesis, weakness and fatigue of the muscles of the limbs and neck, decreasing in response to the administration of acetylcholinesterase inhibitors (hereinafter referred to as AChE).
There is an idea that the highest incidence of myasthenia gravis occurs in the first 2 years from the onset of the disease, while there is a group of patients in whom the manifestation of myasthenia gravis debuts. In the literature, there are cases of the development of urticaria accompanied by severe respiratory failure, as the first manifestation of myasthenia gravis (most often with “late” onset of the disease). The trend towards acute development myasthenia in old age was described by K. Osserman, who identified these patients as a separate group in his classification as acute “fulminant” malignant form with late onset of the disease and early atrophy. Currently, many authors note the clinical evolution of myasthenia gravis and the tendency towards significant “aging” of the disease. Thus, researchers note that since approximately the mid-80s of the 20th century, the incidence of diseases in at a young age and increased 3 times in old age. This circumstance underlies one of the current problems diagnosis of myasthenia gravis in the elderly: currently, according to statistics, 4 out of 5 patients with acute onset of myasthenia are late age a diagnosis of stroke, botulism (or polymyositis) is made. In most cases it is possible to determine trigger factor or a combination of several factors leading to the development of crises, however, there is also a “sudden” onset of crises for no apparent reason.
Many authors point to the polyetiological nature of the development of MC, on the one hand, and the absence of any visible reasons crises in some patients with myasthenia gravis, on the other. The literature describes whole line factors (exogenous and endogenous) that can provoke the development of exacerbation and MK. Among the most common causes of the development of urticaria, according to domestic and foreign authors: upper respiratory tract infection (10 - 27% of cases), aspiration (bacterial) pneumonia (10 - 16%), surgery– thymectomy (5 - 17%), initiation of treatment high doses steroids or their withdrawal (2 - 5%), pregnancy and childbirth (4 - 7%); in 35 - 42% of cases they are not found etiological factor crisis.
In most cases, MK occurs suddenly and develops rapidly, leaving no time to change treatment tactics and prevent them, therefore it is important to assess the significance clinical symptoms, immunological, electrophysiological and pharmacological characteristics, which could serve as criteria for predicting the development of MC.
The crisis nature of myasthenia gravis can be predicted already at the onset of the disease. Reliable predictors of a malignant course are facial weakness, bulbar and respiratory disorders, weakness of the muscles of the neck and hands (a symptom of “sagging” of the 3rd to 5th fingers of the hands) and the absence of “classical” oculomotor disorders (double vision) and proximal weakness of the limbs in the clinical pattern of the debut of myasthenia gravis (moreover, such a selective pattern, having formed early, persists throughout throughout the course of the disease and is observed in patients with the most severe course diseases resistant to the main species pathogenetic therapy- GCS, thymectomy (often during the development emergency patients retain the characteristic selectivity of damage to individual muscle groups, having the so-called “partial” type of crisis).
According to the results of the study (from 1997 to 2012) N.I. Shcherbakova et al. (FGBU " Science Center Neurology" RAMS, Moscow):
Crises in patients with myasthenia gravis often develop in the first year from the onset of the disease, which is primarily due to late diagnosis and lack of adequate pathogenetic therapy. Development of the crisis into more late dates The disease is significantly more often associated with the abolition or reduction of the dose of basic GCS therapy, which reflects the objective difficulties of selecting the minimum maintenance dose of steroids.
MK predominates in women at a young age, in men over 60 years of age. With a “late” onset of the disease, the likelihood of developing crises in women and men is the same.
A feature of myasthenia gravis in the elderly is the tendency towards an acute fulminant onset of the disease, up to the manifestation with MK, which, as shown clinical practice, often causes misdiagnosis.
Important predictors of a malignant “crisis” course of the disease should be considered the presence of a selective craniobulbar clinical pattern, a combination of myasthenia gravis with thymoma, and the lack of effect on thymectomy in young people. age groups(up to 40 years), the presence of antibodies (AT) to MTC (specific muscle tyrosine kinase), poor sensitivity of patients to acetylcholinesterase inhibitors.
The titer (concentration) of AT to AChR does not have prognostic value in determining the severity of the disease. The detection of antibodies to MTC in the serum of patients indicates high risk development of a malignant crisis course of the disease.
An electrophysiological criterion for a high risk of MC is a decrease in the amplitude of the M-response to the first electrical stimulus in the clinically affected muscle in combination with to a small extent decrement (block of neuromuscular transmission), not corresponding to the severity of paresis.
