Aseptic meningitis

Aseptic meningitis is an inflammation of the meninges with lymphocytic pleocytosis in the cerebrospinal fluid in the absence of an agent based on the results of a biochemical bacteriological study of the CSF.

The most common cause of aseptic meningitis is viruses, other causes may be infectious or non-infectious. The disease is manifested by increased body temperature, headache and meningeal symptoms. Aseptic meningitis of viral etiology is usually resolved independently. Treatment is symptomatic.

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What causes aseptic meningitis?

Aseptic meningitis develops under the influence of infectious causes (for example, rickettsia, spirochetes, parasites) and non-infectious nature (eg, intracranial tumors and cysts, chemotherapy, systemic diseases).

In the predominant majority of cases, pathogens are enteroviruses, primarily ECHO viruses and Coxsackie viruses. In many countries, the virus of mumps is a frequent pathogen, in the United States it has become rare due to vaccination programs. Enteroviruses and the mumps virus penetrate the respiratory tract or gastrointestinal tract and are disseminated by the hematogenous pathway. Meningitis Mollare is a benign serous recurrent meningitis characterized by the appearance of large atypical monocytes (previously considered endothelial cells) in the CSF; the cause of the disease is presumably a herpes simplex virus type II or other viruses. The viruses that cause encephalitis usually lead to the development of weakly expressed serous meningitis.

As a causative agent of aseptic meningitis, some bacteria, in particular spirochaetes (causative agents of syphilis, lime-borreliosis and leptospirosis) and rickettsia (causative agents of typhus fever, spotted fever of the rocky mountains and erlichiosis) may also appear as causative agents of aseptic meningitis. Pathological changes in the CSF can be transient or persistent. At a number of bacterial infectious diseases - mastoiditis, sinusitis, brain abscess and infective endocarditis - observe reactive changes in cerebrospinal fluid, characteristic for aseptic meningitis. This is due to the fact that the generalized inflammatory process induces the development of systemic vasculitis and reactive pleocytosis in CSF and in the absence of bacteria.

Causes of aseptic meningitis

Infection	Examples
Bacterial	Brucellosis, cat scratch disease, cerebral form of Whipple disease, leptospirosis, Lyme disease (neuroborreliosis), venereal lymphogranuloma, mycoplasmal infection, rickettsial infection, syphilis, tuberculosis
Post-infection reactions of hypersensitivity	Possible for many viral infections (for example, measles, rubella, smallpox, cowpox, chicken pox)
Viral	Chickenpox; Coxsackie virus, ECHO virus; polio; fever of the Western Nile; eastern and western equine encephalitis; herpes simplex virus; HIV infection, cytomegalovirus infection; infectious hepatitis; Infectious mononucleosis; lymphocytic choriomeningitis; parotitis; encephalitis St. Louis
Fungal and parasitic	Amebiasis, coccidioidomycosis, cryptococcosis, malaria, neurocysticercosis, toxoplasmosis, trichinosis

Non-infectious

Medications	Azathioprine, carbamazepine, ciprofloxacin, cytosine arabinoside (high doses), immunoglobulin, muroomob CD3, isoniazid, NVPs (ibuprofen, naproxen, sulindac, tolmetin), monoclonal antibodies 0KT3, penicillin, phenazopyridine, ranitidine, trimethoprim-sulfamethoxazole
Defeats the membranes of the brain	Behcet's disease with the defeat of the nervous system, the ingress of effusion of the intracranial epidermoid tumor or craniopharyngioma in the CSF, meningeal leukemia, dermatological tumors, sarcoidosis
Parameningeal processes	Brain tumor, chronic sinusitis or otitis media, multiple sclerosis, stroke
Reaction to endolumbral administration of drugs	Air, antibiotics, chemotherapeutic drugs, preparations for spinal anesthesia, Iofendilate, other dyes
Response to the administration of the vaccine	On many, especially anti-pertussis, rabies and antipyretic
Other	Leading meningitis, meningitis Mollare

"Aseptic" in this context refers to cases where bacteria are not detected by routine bacterioscopy and culture method. These cases include some bacterial infections.

Fungi and protozoa can cause purulent meningitis with the development of sepsis and changes in cerebrospinal fluid, characteristic of bacterial meningitis, the difference is that the pathogens are not detected by the method of bacterioscopy of the stained smear and are therefore classified in this category.

Among the non-infectious causes of inflammation of the meninges, tumor infiltration, the breakthrough of the contents of the vnucral cysts into the liquor circulation, the endolumbal administration of preparations, lead poisoning and irritation by means for contrasting can be indicated. It is possible to develop a reactive inflammation for systemic administration of drugs by the type of hypersensitivity reaction. Most often, hypersensitivity reactions cause NSAIDs (especially ibuprofen), antimicrobial drugs (especially sulfonamides) and immunomodulators (intravenous immunoglobulins, monoclonal antibodies OKTZ, cyclosporine, vaccines).

Symptoms of aseptic meningitis

Aseptic meningitis follows a premorbid influenza-like syndrome (without a common cold), manifested by an increase in body temperature and headache. Meningeal signs are less pronounced and develop more slowly than with acute bacterial meningitis. The general condition of the patient is satisfactory, systemic or nonspecific symptoms prevail. Focal neurological symptoms are absent. In patients with noninfectious inflammation of the membranes of the brain, body temperature is usually normal.

Diagnosis of aseptic meningitis

Suspicion of aseptic meningitis is justified in the presence of fever, headache and meningeal symptoms. Before performing a lumbar puncture, CT or MRI of the skull should be done, especially if there is a suspicion of a large intracranial process (with focal neurological symptoms or edema of the optic discs). Changes in CSF in aseptic meningitis are reduced to a moderate or significant increase in intracranial pressure and lymphocytic pleocytosis in the range of 10 to more than 1000 cells / μl. At the very beginning of the disease, it is possible to detect a small amount of neutrophils. The concentration of glucose in the CSF is within normal limits, the protein is within normal limits or moderately elevated. To identify the virus, PCR with a CSF sample is carried out, in particular, Mollare's meningitis is confirmed when a virus of the herpes simplex type II is detected in the CSF DNA sample. Reactive aseptic meningitis for the administration of medications is a diagnosis of exclusion. The diagnostic algorithm is formed on the basis of clinical and anamnestic data suggesting a targeted search in a number of possible pathogens (rickettsiosis, lymoborrelosis, syphilis, etc.).

Differential diagnosis of bacterial meningitis requiring emergency specific treatment, and aseptic meningitis, which does not require this, is sometimes problematic. Identification of even a minor neutrophilia in cerebrospinal fluid, acceptable in the early stage of viral meningitis, should be interpreted in favor of the early stage of bacterial meningitis. CSF parameters are also similar in cases of partially treated bacterial meningitis and aseptic meningitis. Representatives of Listeria spp. on the one hand, are practically not identified with the bacterial staining of a Gram stained smear, but on the other - induce a monocyte reaction in the cerebrospinal fluid, which should be interpreted more in favor of aseptic than bacterial meningitis. It is well known that a tubercle bacillus is very difficult to detect bacterioscopically and that changes in CSF parameters in tuberculosis are almost identical to changes in aseptic meningitis; nevertheless, verification of the diagnosis of tuberculous meningitis is based on the results of a clinical examination, as well as on an elevated protein level and a moderately reduced concentration of glucose in the CSF. Sometimes under the guise of aseptic meningitis debut idiopathic intracranial hypertension.

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Treatment of aseptic meningitis

In most cases, the diagnosis of aseptic meningitis is obvious, the therapeutic algorithm includes mandatory rehydration, anesthesia and the intake of antipyretic drugs. If during the examination it was not possible to completely exclude the possibility of listeriosis, partially treated or bacterial meningitis at an early stage, antibiotics effective against traditional pathogens of bacterial meningitis before the final results of cerebrospinal fluid testing are obtained. In the case of reactive aseptic meningitis, the abolition of the causative drug usually leads to rapid relief of symptoms. To treat meningitis, Mollare is prescribed acyclovir.