Meningitis: symptoms, treatment, consequences of meningitis
- Causes of meningitis
- The mechanism of meningitis
- Symptoms of meningitis
- Treatment of meningitis
Meningitis is a clinical form of the course of meningococcal infection in the human body, which is a serious infectious disease caused by meningococci with airborne droplet transmission of the pathogen. The incidence of meningococcal infection is low, but cases of infection in different countries are recorded every year. Children and young people are more sensitive to meningococcus.
Cases of meningitis are found in all countries. The incidence is higher in African countries, since a warm climate promotes the spread of infection. The incidence is higher in the spring-winter period, which is associated with the weakening of the human body against a background of reduced intake of vitamins into it. More sensitive children, young and elderly people, because they have an immune system that is weaker against meningococci. The source of infection is only a person (anthroponous infection), the way of transmission of meningococcus is airborne, in the environment they are excreted with the smallest droplets of mucus (aerosol) during sneezing and talking. Then, when the aerosol is inhaled by a healthy person, infection occurs. In epidemiological terms, the most dangerous are people with asymptomatic meningococcal disease and bacterial carriers, which actively excrete the pathogen in the environment.
Causes of meningitis
The causative agent of meningococcal infection is the bacterium meningococcus, belonging to the genus Neisseria, which contains 2 kinds of bacteria - meningococci and gonococci (cause the development of gonorrhea). Meningococci are spherical bacteria, which in the human body are grouped in pairs and covered with a thin capsule. They are not stable in the external environment and quickly die out of the human body. Solutions of antiseptics and boiling destroy them instantly. Meningococci contain a number of pathogenicity factors that lead to the development of the disease in the human body, including:
- Small villi on the surface of a bacterial cell - promote its attachment (adhesion) to the cells of the mucosa of the upper respiratory tract and nasopharynx.
- Endotoxin is a lipopolysaccharide complex contained in the cell wall of meningococci and released when they die. This is the main factor of the pathogenicity of the causative agent of meningococcal infection, which causes a number of effects - a violation of blood coagulability, a decrease in vascular tone (decrease in systemic blood pressure), sensitizing effect with the development of an allergic reaction, an increase in body temperature (pyrogenic properties). The endotoxin of meningococcus is several times stronger than the analogous substance of other bacterial species.
- Capsule - covers bacteria cells, prevents their phagocytosis (devouring) by cells of the immune system (macrophages), and it also has the ability to suppress the body's immune response in response to infection.
- The enzyme hyaluronidase is produced by the cells of the meningococcal bacteria, splits the molecules of the intercellular space of the tissues of the human body and promotes the spread of infection.
By the presence of certain antigens on the cell wall, meningococci are divided into several serological groups - A, B and C. The most pathogenic group is A, which, when infected, leads to the development of a severe course of meningococcal infection.
The mechanism of meningitis
The entrance gate for meningococci is the mucosa of the upper respiratory tract, namely the nasopharynx. With the help of villi, bacteria attach to epitheliocytes, which triggers the activation of a local nonspecific immune response. In weakened people and children, meningococci easily overcome local defense factors and penetrate the submucosal layer. In the future, depending on the nature of the pathogen (the presence of pathogenicity factors) and the state of the human body (primarily the functional activity of the immune system), the mechanism of the development of the disease can go along several paths:
- Meningococcal nasopharyngitis - bacteria are localized in the submucosal layer of the nose and pharynx, causing local inflammatory reactions in it. At the same time, bacteria are actively captured by macrophages, but thanks to the presence of the capsule, they are not destroyed, but remain viable.
- Meningitis (meningoencephalitis) - the pathogen through the holes of the lattice bone or perineural way (through the nerve shells) penetrates into the membranes of the brain with the development of purulent inflammation in them.
- Meningococcemia is the ingress of meningococcus into the blood from the site of its primary (nasopharynx) or secondary (cerebral cortex) localization, with the development of severe general intoxication, disseminated intravascular coagulation syndrome (DVS), and severe multi-organ failure. This variant of the flow in the mechanism of infection development is called generalization of the process and can lead to serious complications and even death.
In general, the pathogenesis of meningococcal infection is determined by the properties of the pathogen, the serological group of meningococcus (group A leads to a severe course of pathology more often) and the protective capabilities of the infected organism. In adults with sufficient functional activity of the immune system, meningococcal infection occurs more often in the form of nasopharyngitis or bacteriocarrier. In childhood and in weakened people, meningitis or meningococcemia often develops.
Symptoms of meningitis
The duration of the incubation period of meningococcal infection is 5-6 days (less often up to 10 days). Manifestations of the disease depend on the pathogenetic type of the course of meningococcal infection, identify several forms of the infectious process - bacteriocarrier and asymptomatic course, meningococcal nasopharyngitis, meningitis, meningococcemia and combined form.
Asymptomatic current and bacteriocarrierism
This clinical form is characterized by the presence of meningococcus in the human body (in the mucosa and submucosal layer of the nasopharynx) without any clinical manifestations. Sometimes at the moment of ingestion of meningococci in the nasal cavity and pharynx, small discomfort in the form of perspiration in them can develop, which pass independently.
Symptoms of this clinical form are characterized by the prevalence of local manifestations in the form of a runny nose, mucous or purulent discharge from the nose, and perspiration in the throat. With a more severe course of nasopharyngitis, an increase in body temperature to 38 ° C and a general weakness and a slight aching in the muscles and joints that last about 3 days are associated. In general, nasopharyngitis can last up to a week, then a recovery or a transition to bacterial carry-over occurs. In the case of weakened human immunity, the transition of infection into more severe clinical forms develops.
It is a severe clinical form of meningococcal infection, in which the pathogen spreads with its settling on the membranes of the brain and its substance (meningoencephalitis). Characterized by a violent onset of the disease with the development of several major symptoms:
- A sharp onset of the disease with an increase in body temperature to 39-40 ° C.
- Persistent headache from the first days of the disease, which is intensified when exposed to various stimuli - a loud sound, light.
- Hyperesthesia - increased skin sensitivity.
- Multiple vomiting, which is the result of irritation of the emetic center of the medulla oblongata.
- Symptoms of brain shell irritation (meningeal signs) are stiff neck muscles, which are determined by their resistance when trying to tilt the head forward, increasing the headache when lifting and bending the leg up in a supine position (a symptom of the tension of the spinal cord membranes).
- Disorders of consciousness, up to its loss and development of coma - can develop rapidly, within a few days from the onset of the disease.
In general, the duration of this clinical form of meningococcal infection is different, on average it is about a week, subject to the implementation of active therapeutic measures.
Combined clinical form
This is a more severe variant of the course of the disease, in which joint development of meningitis and meningococcemia occurs most often.
The clinical form, characterized by the ingress of meningococcus into the blood with the development of severe disease, distinguishes a typical and atypical course of meningococcemia. A typical course is characterized by the appearance of a number of symptoms, which include:
- Rapid onset of the disease with high body temperature, chills and severe signs of general intoxication (general weakness, lack of appetite, aching muscles and joints).
- The appearance of a diffuse (diffuse) headache with periodic vomiting (symptoms of irritation of the brain membranes with meningococcemia are absent).
- The increase in the heart rate, which may be accompanied by a decrease in blood pressure.
- The appearance of a characteristic meningococcal rash on the skin - it has the appearance of small, dark points of a stellate shape, characterized by the appearance of the first elements on the skin of the flexural surface of the joints and natural folds. This symptom is characteristic of meningococcemia and is a signal to the beginning of urgent therapeutic measures.
- Psychomotor agitation against a background of general intoxication of the body, can sometimes be accompanied by the development of tonic-clonic seizures.
Atypical form of meningococcemia proceeds without an eruption, which complicates its diagnosis. There is a lightning-fast form of meningococcemia, in which all of its symptoms develop very quickly and within a short period of time develops an internal combustion engine with internal hemorrhage and an infectious-toxic shock with severe multiple organ dysfunction, a progressive decrease in systemic arterial pressure. With the development of a fulminant form, a high risk of a fatal outcome of the disease, especially in childhood. Therefore, a very important measure is the early diagnosis and treatment of meningococcal infection.
Meningococcal infection due to its severe course, depending on the clinical form, can lead to various complications that can remain in a person throughout life. These include:
- Infectious-toxic shock (ITSH) and DIC-syndrome - develop due to the circulation of large amounts of endotoxin in the blood, can lead to bleeding in various organs, impairment of their functional activity up to a lethal outcome.
- Waterhouse-Frideriksen syndrome - acute failure of adrenal function, which produce a number of hormones, is accompanied by a progressive decrease in blood pressure.
- Myocardial infarction - necrosis of a part of the muscle layer of the heart, this complication develops mainly in the elderly.
- The cerebral edema against the background of intoxication, with the subsequent wedging of the medulla oblongata into the canal of the spine.
- Decreased intelligence is a fairly common complication, which is a consequence of meningitis with purulent inflammation of the membranes and brain substance.
- Deafness due to toxic damage to the auditory nerve by endotoxins of meningococci.
In accordance with the presence or absence of complications, early treatment, meningococcal infection can occur with several outcomes:
- In the absence of treatment, the lethality from the disease reaches 100%.
- Complete clinical recovery without complications is possible with timely and adequate start of treatment for meningococcal infection.
- Residual effects and complications in the form of deafness, loss of intelligence, blindness, hydrocephalus, periodic epileptic seizures - a frequent outcome, which can be even with the timely start of treatment.
Specific diagnostics, in addition to identifying characteristic clinical symptoms, include laboratory research methods aimed at identifying the causative agent in the human body:
- Direct bacterioscopy (examination under a microscope) of stained smears taken from the nasopharyngeal mucosa or cerebrospinal fluid (cerebrospinal fluid) - thus revealing spherical bacteria that are grouped in pairs.
- Bacteriological study - biological material (blood, cerebrospinal fluid, nasopharyngeal mucus) is sowed on special nutrient media in order to obtain a culture of microorganisms, which are then identified.
- A serological study of blood to detect specific antibodies to meningococcus is carried out in dynamics, increasing the antibody titer indicates an ongoing infectious process in the human body.
To determine the degree of intoxication, structural changes in internal organs and the central nervous system, an additional study is carried out:
- Clinical analysis of blood and urine.
- Hemogram for determining the extent of disorders in the blood coagulation system.
- Clinical analysis of cerebrospinal fluid - puncture (puncture) of the brain membranes at the level of the lumbar spine is performed to take the cerebrospinal fluid. Taken liquor is examined under a microscope, it can directly identify meningococci, count the number of leukocytes (their high content indicates a purulent process), determine the presence of protein and its concentration.
- Instrumental examination (electrocardiogram, ultrasound examination, lung and head x-ray) allow to identify and determine the degree of structural changes in the relevant organs.
Treatment of meningitis
Given the severity of the course, the frequent development of complications and the possible adverse outcome of meningococcal infection, its treatment is carried out only in the conditions of a medical hospital. With the development of meningitis or meningokceemia, a person is transferred to the intensive care unit or resuscitation department, where there is the possibility of constant monitoring of all vital indicators of the functioning of the cardiovascular and respiratory system. Therapeutic measures for meningococcal infection include etiotropic, pathogenetic and symptomatic therapy.
Meningococci are sensitive to almost all antibacterial agents that cause their death. For their destruction, antibiotics of the penicillin group or their semisynthetic analogues ( amoxicillin ) are most often used. Antibiotics are carried out with caution, the drug is used in a dosage that does not cause the death of bacteria (bactericidal action), but stops their growth and development (bacteriostatic action). This is due to the fact that when mass death of meningococci in the body, a large amount of endotoxin is released, which can lead to the development of an infectious-toxic shock. The duration of antibiotic therapy is determined by the clinical condition of the patient, on average it is 10 days, if necessary or the continued development of symptoms of meningococcal infection, the use of antibiotics continues.
The main purpose of this type of therapy for meningococcal infection is to detoxify the body, it consists in binding and excretion of endotoxins. To this end, solutions for intravenous administration are used - physiological saline, Reosorbilact (a sorbent capable of binding endotoxin), glucose. These activities are conducted against the background of therapy of functional changes in the internal organs and brain. In the case of developing cerebral edema, dehydration with diuretics (diuretics) is carried out. Dehydration is performed cautiously, since a sharp reduction in cerebral edema can lead to a subsequent wedging of the medulla oblongata in the canal of the spine. To normalize the hemostasis (blood clotting system), under the laboratory control (hemogram), hemostatics are used (means to improve blood coagulation).
This treatment is performed to reduce the severity of the main symptoms of meningococcal infection. Anti-inflammatory, analgesic, antihistamine (anti-allergic) drugs are used. By itself, symptomatic therapy does not lead to an improvement in the state of internal organs and the central system, but only allows to improve the subjective well-being of a person.
The main method of preventing the development of the disease is nonspecific prevention, including measures to identify, isolate and treat patients. Also, sanation (release of the organism from pathogens) of people with asymptomatic course of meningococcal infection or bacterial carriers is carried out. Specific prevention consists in emergency vaccination against meningococcus groups A and C in the case of a significant increase in the incidence or epidemic.
The urgency of meningococcal infection has not lost its significance for today. Despite the use of modern diagnostic techniques, timely treatment with antibiotics, the level of development of complications and mortality from this infection remains high, especially in cases of childhood disease.