What is Mumps meningitis?
Mumps meningitis – meningitis caused by the causative agent of mumps.
Serous meningitis prevails in the structure of lesions of the nervous system caused by the epidemic parotitis virus (80–90%). Children of preschool and school age get sick more often. The incidence of mumps meningitis increases in winter and spring.
Causes of Mumps Meningitis
The causative agent of mumps meningitis belongs to paramyxoviruses (family Paramyxoviridae, genus Paramyxovirus). The mumps pathogen was first isolated and studied in 1934 by E. Goodpascher and K. Johnson.
Virions are polymorphic, rounded virions have a diameter of 120-300 nm. The virus contains RNA, has hemagglutinating, neuraminidase and hemolytic activity. The virus agglutinates the erythrocytes of chickens, ducks, guinea pigs, dogs, etc. In vitro, the virus is cultivated on 7-8-day-old chicken embryos and cell cultures. Primarily trypsinized cultures of kidney cells of the guinea pig, monkeys, Syrian hamster, chick embryo fibroblasts are sensitive to the virus. Laboratory animals are not sensitive to the mumps virus, only in monkeys it is possible to reproduce a disease similar to human parotiditis. The virus is unstable, inactivated when heated, with ultraviolet irradiation, when in contact with lipid solvents, 2% formalin solution, 1% lysol solution. Attenuated virus strain (L-3) is used as a live vaccine. Antigenic structure of the virus is stable. It contains antigens that can cause the formation of neutralizing and complement-binding antibodies, as well as an allergen, which can be used to form an intracutaneous test.
The source of infection is only human (patients with manifest and inapparent forms of parotitis). The patient becomes infectious 1-2 days before the onset of clinical symptoms and in the first 5 days of the disease. After the disappearance of the symptoms of the disease, the patient is not contagious. The virus is transmitted by airborne droplets, although the possibility of transmission through contaminated objects (such as toys) cannot be completely ruled out.
The susceptibility to infection is high. More often sick children. Males suffer from parotiditis 1.5 times more often than women. The incidence is characterized by pronounced seasonality (seasonality index 10). The maximum incidence occurs in March-April, the minimum – in August-September. After 1-2 years, there are periodic increases in incidence. It is found in the form of sporadic diseases and in the form of epidemic outbreaks. In institutions, outbreaks last from 70 to 10 days, giving separate waves (4–5) with intervals between them equal to the incubation period. In 80-90% of the adult population, anti-parotid antibodies can be found in the blood, which indicates a wide spread of this infection (in 25% of infected people, the infection proceeds inapparently). After the introduction of live vaccine immunization, the incidence of mumps has decreased significantly.
Pathogenesis during Mumps Meningitis
The gateway of the infection is the mucous membrane of the upper respiratory tract (possibly the tonsils). The pathogen enters the salivary glands not through the parotid (stenon) duct, but by the hematogenous route. Viremia is an important link in the pathogenesis of mumps, which is proved by the possibility of isolating the virus from the blood already in the early stages of the disease. The virus spreads throughout the body and finds favorable conditions for reproduction (reproduction) in the glandular organs. The defeat of the nervous system and other glandular organs can occur not only after the defeat of the salivary glands, but also at the same time, earlier and even without damaging them (very rarely).
It has been established that in the lesions of the CNS, peripheral nervous system and pancreas, immune mechanisms play a certain role: a decrease in the number of T-cells, a weak primary immune response with a low IgM titer, a decrease in the content of IgA and IgG.
When parotitis in the body produces specific antibodies (neutralizing, complement-binding, etc.), detectable for several years, and develops an allergic restructuring of the body, continuing for a very long time (perhaps throughout life).
Symptoms of Mumps Meningitis
In males, mumps meningitis develops 3 times more often than women. As a rule, symptoms of damage to the nervous system appear after the inflammation of the salivary glands, but it is also possible that the salivary glands and the nervous system are simultaneously damaged (in 25-30%). In 10% of patients, meningitis develops before inflammation of the salivary glands, and in some patients with parotitis, meningeal signs are not accompanied by pronounced changes in the salivary glands (probably, by the time of meningitis, there were no marked changes in the salivary glands).
Mumps meningitis begins acutely, often violently (usually on the 4-7th day of illness): chills appear, the body temperature rises again (up to 39 ° C and higher), severe headache, vomiting, soon develops pronounced meningeal syndrome (stiff neck muscles, the symptoms of Kernig, Brudzinsky). Symptoms of meningitis and fever disappear after 10-12 days, recovery of cerebrospinal fluid occurs slowly (up to 1.5-2 months).
In the majority of patients, meningitis occurs on day 3 or 6 of the onset of mumps and is combined with other manifestations of the disease: an increase in salivary glands, pancreatitis, orchitis; in some cases there may be an isolated lesion of the meninges. There is a repeated rise in body temperature to 38 ° C and above, severe headache (mainly in the fronto-temporal regions), repeated vomiting. Intoxication is expressed slightly. Meningeal symptoms appear, which, as a rule, are moderately expressed, their dissociation is noted (in the presence of stiff muscles and a symptom of Brudzinsky I, Kernig and Brudzinsky II symptoms, III are doubtful or absent). Sometimes there is arousal or adynamia, transient symptoms of a central nervous system disorder (hyper- or anisoreflexia, clonus of the feet, abnormal foot signs, slight facial asymmetry, deviation of the tongue, ataxia). In severe cases, develop generalized convulsions with loss of consciousness.
Patients with parotid meningitis often have abdominal pain. They are fairly constant, but low-intensity, do not increase with palpation and do not cause tension in the muscles of the abdominal wall.
Diagnosis of Mumps Meningitis
Mumps serous meningitis should be differentiated from serous meningitis of a different etiology, primarily from tuberculosis and enterovirus. Helps in the diagnosis of a thorough examination of the salivary glands and other glandular organs (the study of urine amylase), the presence of contact with a patient with mumps, the absence of mumps in the past. Tuberculous meningitis is characterized by the presence of prodromal phenomena, a relatively gradual onset and a progressive increase in neurological symptoms. Enteroviral meningitis occurs in late summer or early autumn, when the incidence of mumps is sharply reduced.
During puncture: cerebrospinal fluid is clear, leaks under pressure, the protein content increases to 2.5 g / l, cytosis to 1000 in 1 μl, the content of chlorides and glucose is usually not changed, sometimes a film of fibrin can fall out.
Of the laboratory methods for confirming the diagnosis, the most evidential is the isolation of the mumps virus from the blood, swabs from the pharynx, secretion of the parotid salivary gland, cerebrospinal fluid and urine. Immunofluorescent methods can detect viruses on cell culture after 2-3 days (with a standard study method – only after 6 days). Immunofluorescence method allows to detect viral antigen directly in the cells of the nasopharynx, which makes it possible to get the answer most quickly. Serological methods allow to detect an increase in antibody titer only after 1-3 weeks from the onset of the disease, for which various methods are used.
The most informative is the enzyme-linked immunosorbent assay, later results are obtained using more simple reactions (RSK and RTGA). Examine paired sera; the first is taken at the beginning of the disease, the second – after 2-4 weeks. Diagnostic is the increase in titer 4 times or more. An intradermal test with an antigen (allergen) can be used. Diagnostic is the transition from negative to positive. If the skin test is positive already in the first days of the disease, then this indicates that the person has previously suffered a parotitis.
Treatment of Mumps Meningitis
When treating patients with parotid meningitis, one should be aware of the possibility of the development of polyneuropathy, isolated damage to the auditory nerve, as well as associated lesions of the pancreas (abdominal pain) and the sex glands (orchitis).
When meningitis apply a course of treatment with corticosteroids. The proposal to use intramuscular nucleases for the treatment of parotid meningitis has no scientific basis, the effectiveness of this method has not yet been proven by anyone. The course of parotitis meningitis is favored by a spinal puncture with the extraction of a small amount of cerebrospinal fluid. Some importance is moderate dehydration therapy.
Forecast. Without clinical signs of encephalitis, parotitis meningitis is usually considered a benign disease. After parotid meningitis and meningoencephalitis, asthenia is observed for a long time.
Prevention of Mumps Meningitis
For specific prophylaxis, live mumps vaccine from the attenuated Leningrad-3 (L-3) strain is used. Children aged from 15 months to 7 years who have not previously had mumps have been scheduled for prophylactic vaccination against mumps. If the medical history is unreliable, the child must be vaccinated. Vaccination is carried out once, subcutaneous or intradermal method. In the subcutaneous method, 0.5 ml of the diluted vaccine is administered (one vaccination dose is dissolved in 0.5 ml of the solvent applied to the preparation). With the intradermal method, the vaccine is injected in a volume of 0.1 ml with a needleless injector; in this case, one vaccination dose is diluted in 0.1 ml of solvent. Children who have been in contact with a sick parotitis who have not been ill and have not previously been vaccinated, can immediately be vaccinated with parotitis vaccine (in the absence of clinical contraindications).