Epidemic cerebrospinal (meningococcal) meningitis

Meningococcal infection is an acute infectious disease, the first sign of which is acute nasopharyngitis or inflammation of the nasopharynx, followed by the development of meningococcemia and purulent meningitis.

The causative agent of purulent meningitis and meningococcemia is Neisseria meningitidis, a gram-negative bacterium that exists in the form of different serological types, that is, it has a fairly large variety of antigens against which the human immune system will have to produce antibodies in case of contact with this infection.

Large epidemics of meningitis are most often caused by group A meningococcus. However, group B meningococcus is also of great importance in the epidemiology of meningitis.

Meningococcal infection, routes of infection

Meningococcal infection is transmitted by airborne droplets. The source of infection is always a person suffering from acute nasopharyngitis, with an acute generalized form of meningococcal infection, or a healthy carrier. Usually the number of carriers of meningococcus is no more than 5 percent, but during an epidemic in the source of infection the proportion of carriers can reach 50%. In this case, carriage of meningococcus is usually short-lived, about a week.

Periodic rises in the disease occur approximately every 10 to 12 years.

Symptoms

Meningococcal infection, signs and symptoms

As already mentioned, the most common form of meningococcal infection is nasopharyngitis. When meningococcus enters the upper respiratory tract, a local inflammatory process develops on the mucous membrane of the nasopharynx. The incubation period is 2–3 days, followed by the prodromal or initial period of the disease, during which the patient with meningococcal infection is most contagious. Acute nasopharyngitis develops over 1 to 3 days and is characterized by a rise in temperature to 38.0 C, bright hyperemia (redness) and granularity of the posterior wall of the pharynx, which is covered with mucopurulent discharge. Redness of the tonsils, cough, runny nose with mucous discharge mixed with greenery and pus are also noted. The disease can last 3-5 days and end with recovery, or it can become a generalized form. In this case, penetration of the pathogen into the bloodstream is accompanied by the appearance of chills, headache, and a rise in temperature to 40 C. Generalized meningococcal infection can lead to the development of purulent foci in various internal organs: lungs, heart, joints. But the worst complication is meningococcemia (meningococcal sepsis). Moreover, in young children, meningococcemia can occur suddenly against the background of complete health, with an increase in body temperature to 40 - 41 degrees C in a few hours and is accompanied by headache, uncontrollable vomiting, pain in the muscles and limbs. A characteristic sign of meningococcemia is the appearance of a star-shaped hemorrhagic rash (small pinpoint hemorrhages on the skin that resemble a starry sky).

And finally, another severe form of meningococcal infection is meningitis, which also develops against the background of acute nasopharyngitis. Meningococcal meningitis begins acutely, with a rise in body temperature to high numbers, a sharp painful headache, and uncontrollable vomiting not associated with food intake.

All forms of generalized meningococcal infection require immediate hospitalization in a specialized infectious diseases department and antibacterial and intensive detoxification therapy.

Diagnostics

• Hemogram (leukocytosis up to 30x10/9l, shift of leukocyte formula to the left, increased erythrocyte sedimentation rate).
• Examination of the cerebrospinal fluid (cerebrospinal fluid is cloudy, purulent, increased pressure, pleocytosis due to neutrophils - several tens of thousands of cells per microliter; increase in protein to 1-16 g/l, decrease in glucose and chlorides).
• Bacterioscopy (detection of meningococcus).

Differential diagnosis:

• Other purulent meningitis.
• Meningism syndrome in common infections.
• Subarachnoid hemorrhage.

Meningococcal infection and vaccination

The main group of people subject to vaccination against meningococcal infection are children living in closed communities, as well as those going on vacation to organized summer holiday camps. Polysaccharide meningococcal vaccines, such as Meningo A+C or Mencevax, are widely used in medical practice.

These vaccines are intended for immunization of children from 2 years of age and adults using a single dose of vaccine, followed by revaccination after 2 to 3 years.

Thus, meningococcal infection is certainly one of the diseases against which it is easier and cheaper to vaccinate in order to protect yourself from possible unpleasant complications. Naturally, the feasibility and safety of each vaccination must first be discussed with your attending physician, and, if necessary, with a specialist, an immunologist.

Treatment of epidemic cerebrospinal meningitis (meningococcal)

Treatment is prescribed only after confirmation of the diagnosis by a medical specialist. Antibiotic therapy, corticosteroids, detoxification, analgesics, antiemetics, and sedatives are indicated. Isolation for 14 days is required.

Essential drugs

There are contraindications. Specialist consultation is required.

• Ampicillin (bactericidal, antibacterial agent). Dosage regimen: IM, IV stream or IV drip, a single dose for adults is 250-500 mg, a daily dose is 1-3 g; for severe infections, the daily dose can be increased to 10 g or more.
• Chloramphenicol (bactericidal, antibacterial agent). Dosage regimen: administered intramuscularly or intravenously at a dose of 0.5-1 g per injection in the form of a 20% solution (1 g in 5 ml of solvent) 2-3 times a day. The maximum daily dose is 4 g.
• Ceftriaxone (broad spectrum antibacterial agent). Dosage regimen: adults and children over 12 years of age intramuscularly, intravenously at a dose of 1-2 g of ceftriaxone once a day or 0.5-1 g every 12 hours. In severe cases or in cases of infections caused by moderately sensitive pathogens, the daily dose can be increased to 4 g.
• Vancomycin (bactericidal, antibacterial agent). Dosage regimen: intravenous drip for adults - 0.5 g every 6 hours or 1 g every 12 hours. Infusion duration is at least 60 minutes at a rate of 10 mg/min. Children are prescribed a daily dose of 40 mg/kg, divided into single doses every 6 hours, each dose should be administered for at least 60 minutes.
• Rifampicin (broad spectrum antibacterial agent). Dosage regimen: administered intravenously to adults in a daily dose of 0.3-0.9 g (2-3 injections). The duration of treatment is determined individually depending on the effectiveness and tolerability of the drug and can be 7-10 days. When the opportunity arises, switch to taking the drug orally.

Complications

Often the combined form of the disease - meningococcemia in children - causes a number of irreversible consequences, such as:

• DIC syndrome;
• cerebral edema;
• infectious-toxic shock;
• renal failure;
• pulmonary edema;
• cerebral hypotension syndrome;
• myocardial infarction;

In an adult, complications of meningococcal infection may include the following:

• arthritis;
• dyspnea;
• deafness;
• epilepsy;
• tachycardia;
• leukocytosis;
• osteomyelitis;
• fulminant liver failure;
• myocarditis;
• decreased intellectual abilities;
• purulent meningoencephalitis;
• development of gangrene;
• cerebral hypotension;
• hormonal dysfunction.

Causes and risk factors

Meningoencephalitis is most often infectious, but can also be toxic and autoimmune.

Infectious inflammation can be triggered by viruses, bacteria, fungi, protozoa and parasites.

The most common infectious agents of meningoencephalitis are:

Infectious (parasitic) pathogens include Halicephalobus gingivalis from the class of nematodes, the causative agent of cysticercosis (Taenia solium), and echinococcus.

The disease can be caused by the fungus Cryptococcus neoformans. It should be noted that meningoencephalitis of parasitic and fungal origin is extremely rare.

Autoimmune inflammation is spoken of when the cause of tissue damage, in this case the brain tissue and its membranes, is an attack of one’s own immune system. Autoimmune encephalitis can be caused by antibodies to amyloid beta peptide proteins, antibodies to anti-N-methyl-D-aspartate receptor (anti-NMDA; anti-NMDA receptor encephalitis), and several others.

In extremely rare cases, post-vaccination meningoencephalitis occurs.

Pathogenesis

The entrance gates are the mucous membranes of the upper respiratory tract (nasopharynx and oropharynx), where the pathogen multiplies. With a high level of local protection and no local changes in the mucous membranes, the person will be a carrier of meningococcus for several weeks. With an insufficient level of local protection, inflammation of the mucous membrane of the nasopharynx develops - nasopharyngitis. In some patients, meningococcus overcomes the local barrier and enters the blood, which can lead either to transient bacteremia without clinical manifestations, or can lead to the development of meningococcemia (meningococcal sepsis). In this case, bacteria are carried through the bloodstream into various organs and tissues: skin, adrenal glands, kidneys, lungs, etc. Meningococcus is able to overcome the blood-brain barrier and cause damage to the meninges and brain matter.

Endotoxin plays an important role in the pathogenesis of generalized forms of meningococcal infection - it is a powerful vascular poison and is released in large quantities when the pathogen dies. By affecting the vascular endothelium, endotoxin causes microcirculatory disorders, which ultimately leads to massive hemorrhages in the internal organs (including the adrenal glands with the development of fatal Waterhouse-Friderichsen syndrome). Edema develops in the brain.

Etiology of the disease

The key reason for the development of meningitis is the entry of meningococcus into the body. Under favorable conditions (reduced immunity, the presence of chronic diseases), these bacteria begin to actively divide and spread along the bloodstream to all tissues and organs, settling in biological fluids. Penetrating into the brain, generalized foci are formed that provoke changes in the functioning of the whole organism.

People who frequently come into contact with potential carriers of the bacteria, as well as patients with pathologically weakened immune systems, are at risk. When a bacterium enters the body, protective reactions do not work immediately or not in full, as it should in a healthy person.

Stages of the disease

During meningoencephalitis, the beginning (the appearance of the first signs), the height and the outcome are distinguished. Infectious types of disease also have a prodromal, or latent (latent) stage, which can be asymptomatic or have minor and nonspecific clinical manifestations. The latent period, i.e. the time from infection to the appearance of the first signs of the disease, can last from several hours to several months, depending on the etiology. The height of the disease is characterized by severe and progressive symptoms. The outcome can be recovery or death if brain damage reaches a critical level and affects vital centers.

Some types of disease have stages that are characteristic of them. For example, during meningoencephalitis, three periods are distinguished: the precursor stage (corresponding to the prodromal stage), the stage of excitation, and the stage of paralysis.

Possible complications

In the absence of timely medical care, the risk of developing serious complications increases:

• hormonal disorders;
• partial or complete paralysis;
• epileptic seizures;
• toxic-infectious shock;
• swelling of the brain;
• cerebral hypotension;
• pulmonary edema;
• acute renal failure;
• gastrointestinal bleeding.

It is rare that meningococcal infection in an adult occurs without consequences.

Sometimes the development of asthenic syndrome is observed. The patient recovers completely, but is troubled by weakness, lethargy and headaches. In some situations, a complication after pathology is increased intracranial pressure (hypertensive syndrome). Hearing deteriorates or muscle strength decreases on one side of the body.

Meningococcal infection is a serious disease, complications in which arise not only during treatment, but also after recovery. Timely emergency care will help save the patient’s life, which is recommended to go to the hospital when the first symptoms appear in adults.

Prevention

Prevention of meningococcal meningitis involves minimizing risk factors that predispose it to its occurrence:

1. Reducing contact with sick people who suffer from a runny nose and cough. Personal protective equipment should be used, and mucous membranes should be washed after each contact.
2. Avoid visiting places with large crowds of people (potential carriers of bacteria) during periods of increased respiratory diseases.
3. Strengthen the immune system through hardening, balanced nutrition and vitamin complexes.

If alarming signs and acute pain in the back of the head appear, which is accompanied by high temperature, chills and fever, you should immediately call a doctor. Delay can speed up the process of intoxication and the development of pathogenic microflora, which will not be without consequences for later life.