Meningococcal disease is an infectious disease that combines a whole group of diseases that have a variety of clinical manifestations: from nasopharyngitis to meningococcal sepsis and meningitis. What unites them is that they are all caused by meningococci, which are carried by airborne droplets. Meningococcal disease is dangerous, as it is widespread, transient, can cause severe complications and lead to death.
A39 Meningococcal disease
Meningococcal disease is an infectious disease with typical clinical manifestations in the form of lesions of the nasopharyngeal mucosa. This disease is characterized by the spread of the process, which leads to specific septicemia and purulent leptomeningitis. Meningococcal disease has spread to all countries of the world, in which there are both sporadic cases and epidemic outbreaks, there are also epidemics. Meningococcal disease is most widespread in the countries of Central Africa, South America, and China. Outbreaks of this disease often occur where large population crowding is combined with unsanitary living conditions.
In our country, the incidence of meningococcal disease has stabilized and on average remains at the level of 5 per 100 thousand population. As the geographical analysis shows, there are several disadvantaged areas where the incidence rate is higher. These are, first of all, the Far Eastern regions located near the border of China and Mongolia.
Etiology and pathogenesis
The causative agent of meningococcal disease is meningococcus Neisseria meningitidis. This is a gram-negative diplococcus that does not have flagella and capsules and does not form spores. Meningococci are clearly visible on preparations painted with aniline paints from pure culture. They are arranged in pairs, like two beans facing each other with a concave surface. The optimal temperature for the growth of meningococci is 37 ° C. In the external environment, they are poorly resistant, quickly die when exposed to sunlight, disinfectants, when drying and lowering the temperature to 22 ° C. There are several serological types of meningococci, the main of which are four: A, B, C, D.
As a result of the airborne mechanism of infection spread, meningococci penetrate into the nasopharynx, oral cavity, upper respiratory tract of healthy people, then begin to spread hematogenically in the body. In the pathogenesis of meningococcal disease, a combination of toxic and septic processes with associated allergic reactions plays a decisive role.
The only source of the causative agent of meningococcal disease is a person with clinically pronounced signs of the disease, as well as a carrier of meningococci. The route of transmission of meningococci is aspiration. The spread of infection occurs when talking, sneezing, coughing, when pathogens enter the air space surrounding the patient with droplets of mucus. Close contact between people, especially indoors, contributes to infection.
Meningococcal disease is characterized by some seasonality. The number of cases in the wet and cold season increases, reaching a peak in March-May. For meningococcal disease, periodic rises in morbidity are typical, with intervals of 10-15 years. The disease can affect people of almost any age, but mostly children are sick. They make up almost 70% of the total number of all patients. A weakened human immune system is of great importance in the development of meningococcal disease.
According to the clinical classification, meningococcal disease is divided into localized and generalized. Localized forms include meningococcal disease, acute nasopharyngitis and isolated meningococcal pneumonia. Generalized forms: acute and chronic meningococcemia, meningococcal meningoencephalitis, meningococcal meningitis. There are rare forms: meningococcal arthritis or polyarthritis, meningococcal endocarditis and iridocyclitis. Mixed forms of meningococcal disease have become common.
The incubation period for meningococcal disease lasts from 1 to 10 days, on average 2-3 days. With meningococcal disease, most often the state of health is not disturbed. Usually the disease begins acutely, but some patients have a prodromal period: weakness and sweating, headache and a slight increase in temperature.
Meningococcal acute nasopharyngitis may have a subclinical course when there are no clinical symptoms. It can also occur in mild, moderate and severe forms. Most often there is a mild form of nasopharyngitis with mild intoxication and subfebrile temperature. In the medium-heavy form, the temperature rises to 38-38.5 ° C. Patients have symptoms of general intoxication such as headache and dizziness, weakness and weakness. Along with these symptoms, there are additionally tickling and sore throat, nasal congestion and small mucopurulent discharge, occasionally dry cough. The skin is usually dry and pale. The severe course of nasopharyngitis is manifested by a high temperature, which reaches 39 ° C or more. In addition to headache, vomiting is observed, meningeal symptoms often join. Nasopharyngitis can often precede the development of generalized forms of the disease.
Meningococcal meningitis usually begins acutely with chills and an increase in temperature to 38-40 ° C. The general condition of the patient deteriorates sharply. The main complaint is severe headaches, photophobia is noted. Meningeal symptoms appear and progress rapidly. There is rigidity of the occipital muscles, a positive symptom of Kernig and others. Motor restlessness, facial hyperemia, hot to the touch skin, red dermographism are characteristic, sometimes hyperesthesia of the skin is observed. The patient takes a forced position in bed, which is characterized by throwing back his head and pulling his legs up to his stomach.
With meningococcal meningitis, a disorder of consciousness and mental disorders may occur. Delirium, excitement, hallucinations or adynamia, lethargy, sopor, even coma are possible. Children often have seizures, sometimes hyperkinesis. In most patients, there is suppression or strengthening of periosteal and tendon reflexes, as well as their unevenness, there is a lesion of cranial nerves. Purulent labyrinthitis may develop, which leads to complete hearing loss. Optic neuritis is less common.
Meningococcemia is an acute meningococcal sepsis, which is characterized by an acute onset, high fever, a number of septic phenomena, including significant changes in the activity of the cardiovascular system, the early appearance of a rash and a severe course. The rash appears more often on the trunk and lower extremities in the form of roseolous and papular elements of an intense pink or slightly bluish hue. In addition, there are hemorrhagic elements of different sizes on the skin and stellate red spots that turn into necrosis.
With meningococcemia, hemorrhages in the conjunctiva, sclera and mucous membranes of the nasopharynx are noted. Patients may experience nasal, uterine, gastric bleeding, subarachnoid hemorrhages, micro- and macrohematuria. In some cases, arthritis and polyarthritis occur. Severe meningococcemia in adults is often combined with meningitis.
Meningococcal meningoencephalitis is characterized by seizures and impaired consciousness from the very first days of the disease, visual or auditory hallucinations often appear. Early paralysis and paresis are typical for him.
There may be specific complications in the early and late course of the disease. These include:
- toxic and infectious shock;
- acute renal failure;
- gastrointestinal and uterine bleeding;
- parenchymal-subarachnoid hemorrhage;
- acute swelling and swelling of the brain;
- cerebral hypotension;
- pulmonary edema;
- paralysis and paresis;
- hormonal dysfunction;
Non-specific complications include such as herpes, otitis media, pneumonia, pyelonephritis and others.
To make a correct diagnosis, it is necessary to study the clinical picture of the disease. Epidemiological data, anamnesis, results of laboratory tests of blood and cerebrospinal fluid taken by lumbar puncture are also taken into account. If meningococcal disease or meningococcal nasopharyngitis is suspected, a bacteriological examination of mucus is carried out, which is collected from the back wall of the pharynx. Immunological methods are also used.
Differential diagnosis should be carried out with other diseases. Nasopharyngitis is differentiated with acute viral infections, sore throat, pharyngitis. The mixed form of meningococcal disease and meningococcemia is compared with other infectious diseases. Meningococcal meningitis is differentiated from purulent meningitis of a different etiology.
With meningococcal disease, early hospitalization in specialized departments of an infectious diseases hospital is necessary. With the development of complications, patients are assigned to the intensive care unit. In cases of severe intoxication, fever, antibiotics are prescribed. In severe cases, anti-shock measures, dehydration and detoxification, anticonvulsant therapy are carried out. Analgesics are prescribed, corticosteroids, oxygen therapy, artificial lung ventilation and other means are used. According to indications, vitamins, nootropic drugs and cardiac glycosides are used. Discharge from the hospital can be made after the disappearance of clinical symptoms, upon the onset of recovery and the absence of meningococcal mucus from the pharynx and nose in bacteriological studies.
In most cases, with timely treatment of meningococcal disease, the prognosis is favorable. According to statistics, fatal outcomes are possible with complications such as swelling and swelling of the brain, infectious and toxic shock. Residual phenomena occur in patients whose treatment was started only in the late stages of the disease. There may be functional disorders of neuropsychiatric activity. Patients who have had meningococcal disease are shown outpatient follow-up and follow-up with a neurologist.
It is important to diagnose patients with different types of meningococcal disease in time and hospitalize them. Antiepidemic measures are the identification of carriers of infection and their rehabilitation of the nasopharynx. Of great importance for prevention is an increase in people’s immunity. For those who have been in contact with the patient, medical supervision is established and a bacteriological examination is carried out. According to the indications, vaccination is carried out with a complex polysaccharide vaccine against meningococci of serological groups A and C, immunity from which persists for 3-5 years. Repeated immunization with the threat of an epidemic can be carried out in three years.