Cholinergic crisis with an overdose of prozerin is not accompanied. How does myasthenic crisis manifest itself? Treatment
This disease is neuromuscular in nature. It proceeds chronically with a relapsing or progressive course. main feature pathology is increased weakness muscles of the striated group. The onset of symptoms is usually slow. And get sick in childhood.
With myasthenia, any muscle can be involved in the process. However, the group of the neck, face, eyes, and pharynx is most often affected. The progression of the disease can reach a state similar to paralysis. For the first time, pathology was described in the 16th century. The 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. Most of the patients with myasthenia gravis account for 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 congenital.
Causes
Depending on the type of myasthenia, 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 the conditions for the formation of muscle weakness at the cellular level. The pathogenesis consists of disturbances in the functioning of synapses - mediators between nerves and muscles. Neurology deals with the study of disorders of synaptic transmission.
Acquired myasthenia is recorded more often than the first. However, it is much better treated. It may be due to several factors:
- Oncological. So, a number of myasthenia gravis is formed against the background of tumors. These may be neoplasms of the thymus, genital organs (ovaries, prostate), less often lungs and liver;
- The autoimmune nature of pathology in Lately becomes one of the most common causes myasthenia. 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 the muscle and the nerve. As a result, the delivery of substances necessary for muscle contraction - mediators - is blocked. There is a failure that leads to myasthenia gravis.
Symptoms
The main symptom that will manifest the disease is pathological weakness of the muscles. Muscles become tired quickly, they cannot work for a long time. This is especially evident when performing repetitive movements. Rest has a beneficial effect on muscle recovery. Waking up in the morning, the patient may not feel signs of illness. But after a few hours, it becomes noticeable again.
Depending on the clinical course pathology, there are 3 forms:
- bulbar;
- Eye;
- Generalized.
The first is responsible for damage to the muscles - chewers, swallowers and voice-forming. In patients with this form, speech changes - it becomes hoarse, quiet, up to soundlessness. The act of passing food is disturbed. Patients have difficulty swallowing and chewing. Due to insufficient food intake, patients become very thin.
The second type affects eye muscles- external, round, raising the eyelid. As a result, it becomes difficult for patients to blink and open their eyes. This reduces the function of vision. And reflects on social life of people. They prefer to stay at home and not go out. Another form of the disease in the clinic is generalized.
It successively captures the oculomotor, mimic, and cervical muscles. This affects not only functions, but also appearance patient. The face becomes non-plastic, looks prematurely aged. The smile is strained, and the weakness of the neck muscles makes it difficult to keep the head upright.
Progression leads to limb pathology, which disrupts walking and free movements. Lack of exercise leads to atrophy. This makes the muscles sluggish, flabby and weak. It decreases in volume. Patients look emaciated and emaciated. Therefore, the generalized form is considered the most dangerous - it immediately strikes a large number of muscles.
However, this type is more common than others. Other heavy and acute condition with myasthenia gravis is a crisis. This is an instant attack of weakness, which will be accompanied by a cessation of muscle work, including vital ones - swallowing and breathing. This condition is deadly for due to a decrease in the supply of oxygen to the body.
Cholinergic crisis
This seizure rarely develops in 3% of cases. It progresses more slowly. If we compare an attack with a myasthenic crisis. The cause of such conditions is often an overdose of anticholinesterase agents. It looks like a growing deterioration in well-being, followed by signs of intoxication. After which a seizure develops.
It is quite difficult to distinguish between cholinergic and myasthenic crisis. Both states have a pronounced muscle weakness, which captures the bulbar and respiratory group. However, they can still be distinguished. The cholinergic crisis develops against the background of an increased dose of anticholinesterase drugs, which is accompanied by a paradoxical decrease in muscle strength.
Condition Diagnostics
As a research method, the prozerin test has proven itself well. This substance is able to block the breakdown of mediators that cause muscle contractions. Prozerin test passes in the following way- Preliminary examination of the patient. This is necessary to assess the state of the muscular apparatus before diagnosis.
Then the drug is injected subcutaneously. After 30 minutes, the doctor examines the patient again. Revealing changes after taking prozerin. Electromyography is another study necessary if myasthenia gravis is suspected. It is based on fixing the electrical activity of the muscles. It is carried out twice - before the prozerin test and after. This method can help in determining the origin of pathology.
Whether it is associated with a violation of neuromuscular transmission or occurs in isolation. Another study used in myasthenia gravis is electroneurography. CT is considered a valuable method ( CT scan). It is aimed at detecting neoplasms, possible causes development of myasthenia gravis. Among laboratory methods blood tests deserve attention. They are necessary for the determination of specific antibodies.
Crisis treatment
This pathological condition requires urgent care. Due to an attack of sudden weakness of the respiratory 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 being carried out is the formation of patency respiratory tract with oxygen supply.
Doctors intubate the trachea or perform mechanical ventilation. After that, the respiratory function is constantly monitored and the patency is assessed. respiratory tract. If there are no signs of an overdose of prozerin, then this particular drug is administered. Side effects eliminated by the introduction of "Atropine".
According to indications, glucocorticoids are prescribed at a dosage of 100 mg per day and above. Such funds are not shown to everyone because of their possible negative effect in the form of a new onset of weakness of breathing. In case of secondary infection, antibiotics are prescribed. Constantly monitor laboratory parameters to rule out electrolyte disorders. In some cases, plasmapheresis and the introduction of immunoglobulin are indicated.
Forecast
The course of myasthenia gravis depends on many factors:
- Forms of the disease;
- The beginning of the process;
- The rate of progression of symptoms;
- Conditions of existence of the patient;
- Gender and age;
- Timeliness and quality of treatment.
The most favorable is eye type myasthenia. Worst of all proceeds generalized. Currently, the arsenal of medicines and diagnostic manipulations allows you 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.
The assignment of pathology to chronic process gives the possibility of lifelong use of drugs. This is done in courses or continuously. Timely diagnosis allows patients to good forecast. These research methods have time to fix the pathology before it captures all the muscles and comes to 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, it is not easy to prevent the disease. Prevention can be a preliminary medical genetic consultation before pregnancy. As well as maintaining healthy lifestyle life, which increases the chances of avoiding myasthenia gravis.
Any crisis is a state of a person in which the course of the disease suddenly worsens, and life threatening symptoms develop very quickly. Myasthenic and cholinergic crisis, which are satellites of myasthenia gravis, are dangerous in that the patient may stop breathing and stop the heart. Sometimes a person's life is measured in literally minutes, during which doctors or people nearby must have time to provide the right help. Why is there an aggravation, it would seem, not fatal dangerous disease myasthenia gravis We offer a 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 had such a misfortune. Perhaps someone close to us, if he suddenly becomes ill in transport or just on the street, the information in this article will help save a life.
myasthenia gravis
Let's start the story about the crisis with an explanation of the concept of myasthenia gravis. It happens that others take this disease as a simulation, as those suffering from myasthenia gravis constantly complain of fatigue, lethargy, unable to perform any physical work, only the lightest.
In fact, myasthenia gravis is neuromuscular disease belonging to the category of 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.
The myasthenic crisis develops against the background common disease and has symptoms similar to it, only manifested to a much greater extent, which previously led to the death of about 40% of patients. Now, if the treatment is started without delay, it can be avoided. I would like to note that 10 people suffer from myasthenia gravis for every 100 thousand citizens of the Earth, and women suffer from it 3 times more often than men. Myasthenia can manifest itself already in childhood, but such cases are rare. It is mainly observed in people from 20 years old to extreme 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 such as the aforementioned lethargy, weakness, fatigue. Additional symptoms with myasthenia gravis:
Drooping of the eyelids, most marked in the evening, and better in the morning after a night's rest;
double vision;
Weakness, high fatigue after the usual activities 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 in swallowing, frequent choking);
Vegetative disorders tachycardia);
Mimic signs (very deep wrinkles on the forehead, a characteristic facial expression);
Salivation;
Difficulty holding the head;
Difficulty walking.
A distinctive feature of myasthenia is that all of the above manifestations increase after physical activity and in the evening, and after good rest decrease or disappear altogether.
Symptoms of myasthenic crisis
If a person suffers from myasthenia gravis, under certain circumstances, he may experience a myasthenic crisis. Symptoms of the underlying disease, especially such as tachycardia, high fatigue are vital important muscles(respiratory, cardiac), salivation, while increasing. Also, the crisis is characterized by the following manifestations:
Paralysis of the swallowing muscles and tongue, as a result of which mucus, saliva, food can enter the respiratory tract;
Strong excitement and panic due to lack of air;
Cold sweat;
Sometimes spontaneous urination and/or defecation;
Loss of consciousness;
Dry skin;
Jumps in blood pressure;
Pupil dilation;
Acute heart failure, that is, disorders in the work of the heart.
Myasthenic crisis is of several degrees:
Middle;
heavy;
Lightning fast.
The differences lie in the strength of the manifestation of the above symptoms. A severe and lightning-fast crisis is especially dangerous, in which a person develops weakness of the respiratory and swallowing muscles very quickly, literally in a couple of minutes. Breathing at first becomes rapid, the face turns red, the pressure jumps up, the pulse reaches about 160 beats per minute. Then breathing begins to interrupt, it may disappear altogether, the face turns blue (in medicine this is called cyanosis), the pressure drops, the pulse is almost not felt.
Causes of myasthenic crisis
Myasthenia can be both congenital and acquired. The first occurs due to mutations in genes. The second develops if a person has:
Problems with the thymus;
Some forms of cancer (particularly breast, lung, ovarian);
thyrotoxicosis;
Encephalitis lethargic.
Against the background of these diseases, myasthenic crisis can develop in such cases:
Acute infectious diseases, including SARS, influenza, bronchitis;
Operations;
Severe psychological stress;
Taking certain medications (in particular, tranquilizers);
Hormonal disorders;
Skipping patients with myasthenia taking pills, violation of the course of treatment.
Cholinergic crisis
Myasthenic crisis and cholinergic crisis often occur in parallel, which is why there are errors in differentiation and, as a result, in treatment. However, these two are somewhat similar external manifestations states are called different reasons and have different etiologies.
Thus, during myasthenic crisis, the density of cholinergic receptors of the membrane decreases due to their destruction, and the remaining ones change their functions. And with a cholinergic crisis, excessive activation of cholinergic receptors (nicotinic and / or muscarinic) occurs. This process starts by taking drugs for the treatment of myasthenia gravis in high doses, as well as drugs that are prohibited in this disease.
It is not easy to diagnose this crisis, since its main symptoms coincide with myasthenic. To help correctly determine what is happening to a person, such a feature in his condition, characteristic of a cholinergic crisis, can help: the patient has signs of intoxication: the stomach hurts, vomiting opens, diarrhea begins. Myasthenic crisis is characterized by everything except these symptoms.
The second feature of the cholinergic crisis is that the symptoms of myasthenia worsen without performed physical exertion, but after taking anticholinesterase drugs.
mixed crisis
This is the most for health and life dangerous view pathology. It combines a myasthenic and cholinergic crisis, presenting at once all the symptoms noted in both conditions. This makes it difficult to diagnose correctly, but even more so - treatment, because those drugs that save from a 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 drugs (Klamin, Prozerin) negative reactions does not 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 according to the following manifestations:
In patients, bulbar disturbance is also clearly observed, and motor function limbs changed a little;
The use of drugs does not equally reduce 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 myasthenic crisis, it is important to correctly diagnose the patient. As noted above, some symptoms of a myasthenic crisis may be present in diseases that have nothing to do with myasthenia gravis (for example, shortness of breath, failure of heart rhythms). The symptoms of a cholinergic crisis are similar to those that occur with intoxication and some problems with the digestive tract. If there is an accompanying person with the patient who can give 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 worsens (a crisis occurs), the life count goes on for minutes. The main thing that others should do is to immediately call an ambulance. Unfortunately, in our reality there are situations when specialized care is late. How can you help a dying person in such a case? First, try to get him breathing, remove the mucus from his throat. According to the rules, those suffering from myasthenia gravis should have a note with them stating that they have this disease, as well as medicines (for example, "Prozerin") and a syringe. If there is no possibility of a quick arrival of an ambulance, a person with a myasthenic crisis must be given an injection according to the information in the note.
Arriving physicians are obliged to urgently hospitalize the patient, and in intensive care, where intensive emergency therapy is carried out:
Ensuring the patency of the respiratory tract;
supply of oxygen;
If the patient does not have symptoms of a cholinergic crisis (vomiting, diarrhea), the following medicines: "Prozerin", "Atropine". If there are symptoms of intoxication, emergency therapy consists only in artificial ventilation of the lungs and in injections of such drugs: Atropine, Immunoglobulin, and some others. medical supplies according to indications.
Treatment
If a person has a myasthenic crisis, treatment after emergency care is carried out based on clinical and laboratory tests, analyzes and dynamics of the development of the disease. IVL (that is, artificial ventilation of the lungs), depending on clinical picture the patient's condition, as well as from indications of the presence of oxygen in the blood, up to six days can be carried out, but if the patient has a positive reaction to Prozerin after 16 or a little more hours, mechanical ventilation is canceled. In general, the ventilator procedure is very serious and responsible, requiring ongoing monitoring of respirators, % of gases in the blood, blood circulation, temperature, fluid balance in the body, and other things.
An excellent method for coping with all types of crises in myasthenia gravis is exchange plasmapheresis. At the same time, blood is taken from the central (or ulnar) vein, it is centrifuged, and the plasma is changed to donor or artificial. This method gives excellent results - in a couple of hours the patient's condition improves significantly. Plasmapheresis is performed in 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 in the presence of inflammatory processes- antibiotics.
Forecast and prevention
Thirty or forty years ago deaths in patients with myasthenia during exacerbation of the disease occurred quite often. Now mortality 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 care must be provided very quickly. Therefore, if suddenly on the street, in transport, anywhere we see a person starting to choke, an ambulance must be called immediately.
Patients with myasthenia gravis themselves must also observe a number of measures to prevent a crisis:
Be under the supervision of a doctor and strictly follow the prescribed treatment;
Avoid overwork, nervous breakdowns;
Avoid infectious diseases as far as possible;
Do not expose your body to intoxication;
Include foods rich in potassium in the diet (for example, potato dishes, raisins).
Myasthenia 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 muscular weakness that develops at the same time differs from ordinary paresis in that with the repetition of movements (especially in a frequent 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, oculomotor disorders are the first to appear - doubling of objects, especially during prolonged reading, drooping of the eyelids. The asymmetry of the lesion and the dynamism of symptoms are characteristic: in the morning the condition is better, in the evening ptosis and doubling increase significantly. Later, weakness and fatigue of mimic muscles and chewing muscles. With the spread of weakness to the muscles of the limbs, the muscles of the proximal sections suffer more, first in the hands. With generalized forms, one of the most severe symptoms is respiratory muscle weakness.
Modern classification based on clinical features highlights:
Generalized myasthenia gravis without violation of vital important functions and with violations of vital functions;
Local forms without violation of vital functions and with violations of vital functions.
Dif. e - h:
Myasthenia gravis, which begins in old age, requires differentiation from cerebrovascular accidents.
A myasthenic crisis is a sudden deterioration in the condition of a patient with myasthenia gravis, which poses an immediate danger to life, since due to weakness of the respiratory and bulbar muscles, insufficiency may occur. external respiration or severe bulbar disturbances. The provocative moments are the 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.
At the first signs of respiratory failure or dysphagia - tracheal intubation, auxiliary or artificial ventilation lungs;
Prozerin 0.05% solution - 2-3 ml intramuscularly or intravenously, if there is no effect, then after 30-40 minutes the dose is repeated intramuscularly;
Prednisolone 90-120 mg IV (1.5-2 mg/kg).
Cholinergic crises: occur with excessive dosages of anticholinesterase drugs due to the patient's self-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, there are signs of both nicotine and muscarinic intoxication - fibrillar twitching, miosis, salivation, abdominal pain, agitation, often respiratory disorders, pallor, coldness, marbling skin. There is a dissociation in an increase in the need for anticholinesterase drugs and a decrease in muscle strength after their administration.
There are no specific means to get out of the crisis.
Apply atropine 0.1% solution - 1 ml IV or s / c, if necessary, repeat the dose.
With 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 are subject to emergency hospitalization in hospitals with intensive care and neurological departments.
Dangers and complications:
Development of acute respiratory failure.
Myasthenic crisis (hereinafter - MK) is a life-threatening condition, which 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 of the lungs). According to the literature, a crisis course is observed in 30-40% of patients with myasthenia gravis and is more common in women.
Molecular basis MK is probably a sharp decrease in the number of functioning acetylcholine receptors (hereinafter referred to as AChR) due to a massive attack by their autoantibodies.
Differentiate MK from others severe conditions accompanied by respiratory disorders, it is possible by 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 introduction of acetylcholinesterase inhibitors (hereinafter referred to as AChE).
There is an idea that the highest incidence of MC 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 MC debuts. In the literature, there are cases of the development of MC, accompanied by severe respiratory failure, as the first manifestation of myasthenia gravis (most often with a "late" onset of the disease). trend towards acute development myasthenia gravis in the elderly was described by K. Osserman, who identified these patients in 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 a tendency to a significant "aging" of the disease. Thus, the researchers note that approximately since the mid-80s of the XX century, the incidence in young age and 3 times increased in old age. This fact underlies one of the actual problems diagnosis of myasthenia gravis in the elderly: currently, according to statistics, 4 out of 5 patients with acute onset of myasthenia in 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 polyetiology of MC development, 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 MC, according to domestic and foreign authors: upper respiratory tract infection (10-27% of cases), aspiration (bacterial) pneumonia (10-16%), surgical intervention– thymectomy (5 - 17%), start of treatment high doses steroids or their cancellation (2 - 5%), pregnancy and childbirth (4 - 7%); in 35 - 42% of cases they do not find etiological factor crisis.
In most cases, MC comes on suddenly and develops rapidly, leaving no time to change treatment tactics and prevent them, so 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 in the onset of the disease. Reliable predictors of a malignant course are mimic weakness, bulbar and respiratory disorders, weakness of the muscles of the neck and hands (a symptom of "sagging" 3-5 fingers of the hands) and the absence of "classic" oculomotor disorders (double vision) and proximal weakness of the limbs in the clinical pattern of myasthenia gravis onset (moreover, a similar 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 the defeat of individual muscle groups, having the so-called "partial" type of crisis).
According to the result of the study (from 1997 to 2012) N.I. Shcherbakov et al. (FGBU " Science Center neurology" RAMS, Moscow):
Crises in patients with myasthenia often develop in the first year from the onset of the disease, which is primarily due to late diagnosis and the lack of adequate pathogenetic therapy. The development of the crisis in more late dates diseases are significantly more often associated with the abolition or reduction of the dose of basic corticosteroid therapy, which reflects the objective difficulties in selecting the minimum maintenance dose of steroids.
MC predominate 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 a tendency to an acute fulminant debut of the disease, up to manifestation with MC, which, as shown clinical practice often leads to misdiagnosis.
Important predictors of a malignant "crisis" course of the disease should be considered the presence of a selective craniobulbar clinical pattern, the 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 MTK (specific muscle tyrosine kinase), poor sensitivity of patients to acetylcholinesterase inhibitors.
Titer (concentration) of AT to AChR has no predictive value in determining the severity of the disease. Detection in the serum of patients with antibodies to MTK 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 a clinically affected muscle in combination with small degree decrement (block of neuromuscular transmission) that does not correspond to the severity of paresis.
