Meningitis: symptoms, treatment, effects of meningitis
- Causes of meningitis
- The mechanism of development of meningitis
- Symptoms of Meningitis
- Meningitis treatment
Meningitis is a clinical form of the course of meningococcal infection in the human body, which is a serious infectious disease caused by meningococcal disease with airborne transmission of the pathogen. The incidence of meningococcal disease is low, but every year there are cases of infection in various countries. 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 contributes to the spread of infection. The incidence is higher in the spring-winter period, which is associated with a weakening of the human body against the background of reduced intake of vitamins into it. Children, young and old, are more susceptible to infection, as their immune system is weaker against meningococci. The source of infection is only human (anthroponotic infection), the transmission route of meningococci is airborne, and they are released into the environment with the smallest droplets of mucus (aerosol) when sneezing and talking. Then, at the moment of inhalation of the aerosol by a healthy person, its infection occurs. In epidemiological terms, the greatest danger is people with asymptomatic meningococcal infection and bacteria that actively excrete the pathogen into the environment.
Causes of meningitis
The causative agent of meningococcal infection is a meningococcus bacterium belonging to the genus Neisseria, which contains 2 types 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 outside the human body. Antiseptic solutions and boiling destroy them instantly. Meningococci contain a number of pathogenicity factors that lead to the development of the disease in the human body, these include:
- Small villi on the surface of the bacterial cell - contribute to its attachment (adhesion) to the cells of the mucous membrane of the upper respiratory tract and nasopharynx.
- Endotoxin is a lipopolysaccharide complex contained in the cell wall of meningococci and released during their death. This is the main pathogenic factor of the causative agent of meningococcal infection, which causes a number of effects - a violation of blood clotting, a decrease in vascular tone (a decrease in systemic arterial pressure), a sensitizing effect with the development of an allergic reaction, an increase in body temperature (pyrogenic properties). Endotoxin of meningococci is several times stronger than the similar substance of other types of bacteria.
- Capsule - covers the cells of bacteria, prevents their phagocytosis (devouring) cells of the immune system (macrophages), it also has the ability to suppress the body's immune response in response to infection.
- The enzyme hyaluronidase, produced by the bacteria cells of meningococcus, breaks down the intercellular space molecules of human tissues and promotes the spread of infection.
According to the presence of certain antigens on the cell wall, meningococci are divided into several serological groups - A, B and C. The most pathogenic is group A, which, when infected, leads to the development of a severe course of meningococcal infection.
The mechanism of development 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 epithelial cells, which causes an activation of a local nonspecific immune response. In weakened people and children, meningococci easily overcome local protection factors and penetrate into the submucosal layer. In the future, depending on the properties of the pathogen (presence of pathogenicity factors) and the state of the human body (primarily the functional activity of the immune system), the mechanism of the disease can go in several ways:
- 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 due to the presence of a capsule, they are not destroyed, but retain their viability.
- Meningitis (meningoencephalitis) - the pathogen through the holes of the ethmoid bone or perineural (through the sheaths of the nerves) penetrates into the sheaths of the brain with the development of purulent inflammation in them.
- Meningococcemia - getting meningococcus into the blood from the place of its primary (nasopharynx) or secondary (brain membrane) localization, with the development of severe general intoxication, disseminated intravascular coagulation syndrome (DIC) and severe multiorgan failure. Such a variant of the course in the mechanism of infection 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 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 children and weakened people, meningitis or meningococcemia is more common.
Symptoms of Meningitis
The duration of the incubation period for 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, there are several forms of the infectious process - bacteriocarrier and asymptomatic, meningococcal nasopharyngitis, meningitis, meningococcemia and the combined form.
Asymptomatic and bacteriocarrier
This clinical form is characterized by the presence of meningococcus in the human body (in the mucous and submucosal layer of the nasopharynx) without any clinical manifestations. Sometimes at the time of meningococcal contact with the nasal cavity and pharynx, a slight discomfort may develop in the form of tickling in them, which pass independently.
The symptoms of this clinical form are characterized by a predominance of local manifestations in the form of a runny nose, mucous or purulent discharge from the nose, and tickling in the throat. With a more severe course of nasopharyngitis, an increase in body temperature of up to 38 ° C and general weakness and slight aches in the muscles and joints, which last for about 3 days, join. In general, nasopharyngitis can last up to a week, then recovery or transition to a bacteriocarrier occurs. In the case of a weakened human immunity, a transition of infection to more severe clinical forms develops.
It is a severe clinical form of meningococcal infection, in which the pathogen spreads with its sedimentation on the membranes of the brain and its substance (meningoencephalitis). It is characterized by a rapid onset of the disease with the development of several main symptoms:
- Abrupt onset of the disease with fever up to 39-40º C.
- Persistent severe headache from the first days of the disease, which is aggravated by various stimuli - a loud sound, light.
- Hyperesthesia - increased skin sensitivity.
- Repeated vomiting, which is the result of irritation of the vomiting center of the medulla oblongata.
- Symptoms of irritation of the membranes of the brain (meningeal signs) - stiffness of the muscles of the neck, which is determined by their resistance when trying to tilt the head forward, increased headache when lifting and bending the legs up in the supine position (a symptom of tension of the membranes of the spinal cord).
- Disorders of consciousness, up to its loss and the development of coma - can develop rapidly, within a few days of the onset of the disease.
In general, the duration of this clinical form of meningococcal infection varies, 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 the joint development of meningitis and meningococcemia most often occurs.
The clinical form, characterized by the ingress of meningococcus into the bloodstream with the development of a severe disease course, is characterized by a typical and atypical course of meningococcemia. A typical course is characterized by the appearance of a number of symptoms, which include:
- The 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 lining of the brain during meningoccemia are absent).
- Increased heart rate, which can be accompanied by a decrease in blood pressure.
- The appearance of the characteristic meningococcal rash on the skin - it has the appearance of small dark points of a star-shaped form, characterized by the appearance of the first elements on the skin of the flexor surface of the joints and natural folds. This symptom is characteristic of meningococcemia and is a signal for the commencement of urgent therapeutic interventions.
- Psychomotor agitation against the background of general intoxication of the body, can sometimes be accompanied by the development of tonic-clonic seizures.
Atypical form of meningococcemia occurs without a rash, which complicates its diagnosis. There is a fulminant form of meningococcemia, in which all its symptoms develop very quickly and for a short amount of time DIC syndrome develops with hemorrhages in the internal organs and infectious-toxic shock with severe polyorgan failure, a progressive decrease in systemic arterial pressure. With the development of fulminant (fulminant) forms a high risk of a lethal outcome of the disease, especially in childhood. Therefore, a very important event 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 persist in a person throughout life. These include:
- Infectious-toxic shock (ITSH) and DIC-syndrome - develop due to the circulation of a large amount of endotoxin in the blood, can lead to bleeding in various organs, violations of their functional activity, or even death.
- Waterhouse-Frideriksen syndrome - acute adrenal insufficiency, which produce a number of hormones, is accompanied by a progressive decrease in blood pressure.
- Myocardial infarction - necrosis of the muscular layer of the heart, such a complication develops mainly in the elderly.
- Cerebral edema due to intoxication, followed by wedging of the medulla oblongata into the spinal canal.
- A decrease in intelligence is a fairly frequent complication, which is a consequence of the transferred meningitis with purulent inflammation of the membranes and the substance of the brain.
- Deafness due to toxic damage to the auditory nerve by meningococcal endotoxins.
In accordance with the presence or absence of a complication, early initiation of treatment, meningococcal infection can occur with several outcomes:
- In the absence of treatment, the mortality rate of the disease reaches 100%.
- A complete clinical recovery without the development of complications is possible with the timely and adequate start of treatment of meningococcal infection.
- Residual effects and complications in the form of deafness, reduced 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 methods of research aimed at identifying the pathogen in humans:
- Direct bacterioscopy (microscopic examination) of stained smears taken from the nasopharyngeal mucosa or cerebrospinal fluid (cerebrospinal fluid) - spherical bacteria are detected, which are grouped in pairs.
- Bacteriological examination - biological material (blood, cerebrospinal fluid, mucus from the nasopharynx) is seeded on special nutrient media in order to obtain a culture of microorganisms, which are then identified.
- Serological examination of blood for the detection of specific antibodies to meningococci is carried out in dynamics, an increase in antibody titer indicates a continuing infection process in the human body.
To determine the degree of intoxication, structural changes in the internal organs and the central nervous system, additional research is carried out:
- Clinical analysis of blood and urine.
- Hemogram to determine the extent of violations in the blood coagulation system.
- Clinical analysis of the cerebrospinal fluid - a puncture (puncture) of the brain membranes at the level of the lumbar spine is performed to take cerebrospinal fluid Taken liquor is examined under a microscope, it is possible to identify meningococci directly, 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 techniques, radiographs of the lungs and head) allow us to identify and determine the degree of structural changes in the corresponding organs.
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 a medical hospital. With the development of meningitis or meningoccemia, a person is transferred to the intensive care unit or intensive care unit, where it is possible to continuously monitor all vital indicators of the functioning of the cardiovascular and respiratory systems. Therapeutic measures for meningococcal infections include etiotropic, pathogenetic and symptomatic therapy.
Meningococci are sensitive to almost all antibacterial agents that cause their death. To destroy them, antibiotics of the penicillin group or their semi-synthetic analogues ( amoxicillin ) are most often used. Antibiotic therapy is 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 during the 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 infections is to detoxify the body, it is to bind and eliminate endotoxins. For this purpose, solutions for intravenous administration are used - saline, Reosorbilact (is a sorbent capable of binding endotoxin), glucose. These activities are carried out against the background of therapy of functional changes in the internal organs and the brain. In the case of the development of cerebral edema, dehydration is carried out using diuretics (diuretics). Dehydration is carried out carefully, as a sharp decrease in cerebral edema can lead to the subsequent insertion of the medulla oblongata into the spinal canal. To normalize hemostasis (blood coagulation system), under laboratory control (hemogram), hemostatic agents (blood clotting agents) are used.
This treatment is carried out to reduce the severity of the main symptoms of meningococcal infection. Anti-inflammatory, analgesic, antihistamine (antiallergic) drugs are used. By itself, symptomatic therapy does not lead to an improvement in the state of the 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 non-specific prophylaxis, including measures to identify, isolate and treat patients. Sanitation (release of the organism from pathogens) of people with asymptomatic meningococcal infection or bacteria carriers is also carried out. Specific prevention consists of emergency vaccination against meningococcal groups A and C in the event of a significant increase in the incidence or epidemic rate.
The relevance of meningococcal infection has not lost its meaning to date. 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 when the disease is in childhood.