Chronic meningitis

Chronic meningitis is an inflammatory disease that, unlike the acute form, develops gradually over several weeks (sometimes more than one month). Symptomatology of the disease is similar to that of acute meningitis: patients have pain in the head, high fever, sometimes neurological disorders. There are also characteristic pathological changes in the cerebrospinal fluid.

Epidemiology

One of the most pronounced outbreaks of meningitis occurred in 2009 in epidemic-prone areas of West Africa, in the "meningitis belt" region south of the Sahara, between Senegal and Ethiopia. The outbreak affected such countries as Nigeria, Mali, Niger: almost 15 thousand sick people were registered. Such outbreaks in these regions occur regularly, approximately every 6 years, and the causative agent of the disease is most often meningococcal infection.

Meningitis, including chronic meningitis, is characterized by a fairly high risk of death. Complications, immediate and distant, often develop.

In European countries, the disease is registered much less frequently - about 1 case per hundred thousand population. Children are more often affected (about 85% of cases), although people of any age are generally capable of getting the disease. Meningitis is especially common in infants.

The pathology was first described by Hippocrates. The first officially registered meningitis outbreaks occurred in the 19th century in Switzerland, North America, then in Africa and Russia. At that time, the lethality of the disease was more than 90%. This figure decreased significantly only after the invention and introduction into practice of a specific vaccine. The discovery of antibiotics also contributed to the reduction of mortality. By the 20th century, epidemic outbreaks were registered less and less frequently. But even now, acute and chronic meningitis are considered to be lethal diseases that require immediate diagnosis and treatment.

Causes of the chronic meningitis

Chronic meningitis is usually provoked by an infectious agent. Among the many different microorganisms "culprits" of the development of the disease most often become:

• Mycobacterium tuberculosis; [1]
• the causative agent of Lyme disease (Borrelia burgdorferi);
• Fungal infection (including Cryptococcus neoformans, Cryptococcus gatti, Coccidioides immitis, Histoplasma capsulatum, Blastomycetes).

Mycobacterium tuberculosis can provoke rapidly progressive chronic meningitis. The disease develops when the patient is initially infected, but in some people the pathogen remains in the body in a "dormant" state, becoming active under favorable conditions and causing the development of meningitis. Activation can occur against the background of taking drugs that depress immunity (e.g., immunosuppressors, chemopreventive drugs), or other sharp reductions in immune defense.

Meningitis resulting from Lyme disease is both acute and chronic. Most patients have a slow progression of the pathology.

Fungal infection provokes the development of chronic inflammation of the cerebral membranes mainly in immunocompromised individuals suffering from various immunodeficiency conditions. Sometimes fungal infection takes on a wave-like course: symptoms slowly increase, then disappear, and then reappear.

Less common pathologic agents of chronic meningitis are:

• pale treponema; [2]
• protozoa (e.g., Toxoplasma gondii);
• viruses (particularly enteroviruses).

Chronic meningitis is often diagnosed in HIV-infected patients, especially against the background of bacterial and fungal infections. [3] In addition, the disease may have a non-infectious etiology. Thus, chronic meningitis is sometimes found in patients with sarcoidosis, [4] systemic lupus erythematosus, [5] rheumatoid arthritis, Sjögren's syndrome, Behçet's disease, lymphoma, leukemia. [6]

Fungal chronic meningitis can develop after injection of corticosteroid drugs into the epidural space with violation of aseptic rules: such injections are practiced to control pain syndrome in patients with sciatica. In this case, signs of the disease occur for several months after injection. [7], [8]

Cerebral aspergillosis occurs in approximately 10-20% of patients with invasive disease and results from hematogenous spread of the organism or direct spread of rhinosinusitis. [9]

In some cases, people are diagnosed with chronic meningitis, but no infection is found during tests. In such a situation, idiopathic chronic meningitis is said. It is noteworthy that this type of disease does not respond well to treatment, but often goes away on its own - self-healing occurs.

Risk factors

Provoking factors in the development of chronic meningitis can become almost any infectious pathology that causes inflammation. Weakness of the immune system increases the risk even more.

A person can contract an infectious disease from a sick person or a bacterial carrier (virus carrier) - an apparently healthy person who is contagious to others. The infection can be transmitted by airborne droplets or by household contact in the usual daily conditions - for example, by using common cutlery, kissing, or living together (camp, barracks, dormitories, etc.).

The risk of chronic meningitis is significantly increased in children with immature immune defenses (infancy), in persons traveling to epidemically dangerous regions, and in patients with immunodeficiency. Smoking and alcohol abuse also have an adverse effect.

Pathogenesis

In the pathogenetic mechanism of chronic meningitis, the leading role in the development of chronic meningitis is played by infectious-toxic processes. They are caused by large-scale bacteremia with marked bacterial decay and release of toxic products into the blood. Endotoxin effect is caused by the release of toxins from the cell walls of the pathogen, which entails a violation of hemodynamics, microcirculation, leads to intense metabolic disorders: gradually increasing oxygen deficiency and acidosis, aggravated hypokalemia. Suffers coagulation and anti-coagulation blood systems. At the first stage of the pathological process is hypercoagulability with an increase in the level of fibrinogen and other clotting factors, and at the second stage in small vessels falls fibrin, thrombi are formed. With a further decrease in the level of fibrinogen in the blood increases the likelihood of hemorrhage, bleeding in various organs and tissues of the body.

Entry of the pathogen into the brain membranes becomes the start for the development of symptoms and pathomorphologic picture of chronic meningitis. At first, the inflammatory process affects the soft and spider membrane, then it can move to the substance of the brain. The type of inflammation is predominantly serous, and in the absence of treatment passes into a purulent form. A characteristic sign of chronic meningitis is a gradually increasing lesion of the spinal roots and cranial nerves.

Symptoms of the chronic meningitis

The main symptoms of chronic meningitis include persistent head pain (possibly combined with occipital muscle tension and hydrocephalus), radiculopathy with cranial nerve neuropathy, personality disorders, impaired memory and mental performance, and other cognitive impairment. These manifestations may occur simultaneously or separately from each other.

Due to excitation of the nerve endings of the brain membranes, the pronounced pain in the head is supplemented by pain in the neck and back. Hydrocephalus and increased intracranial pressure may develop, which in turn causes increased headache, vomiting, apathy, drowsiness, irritability. There is edema of the optic nerves, deterioration of visual function, paresis of looking up. Possible phenomena of facial nerve damage.

With the addition of vascular disorders, cognitive problems, behavioral disorders, seizures appear. Acute cerebral circulatory disorders and myelopathies may develop.

With the development of basal meningitis on the background of deterioration of vision, weakness of mimic muscles, deterioration of hearing and smell, sensory disorders, weakness of masticatory muscles are detected.

With the aggravation of the inflammatory process can develop complications in the form of edema and swelling of the brain, infectious toxic shock with the development of DIC.

First signs

Since chronic meningitis progresses slowly, the first signs of pathology do not immediately make themselves known. The infectious process is manifested by a gradual increase in temperature, headache, general weakness, deterioration of appetite, as well as symptoms of an inflammatory reaction outside the central nervous system. In immunodeficient individuals, body temperature readings may be within normal limits.

Chronic meningitis should be ruled out first if the patient has persistent persistent headache, hydrocephalus, progressive cognitive impairment, radicular syndrome, or cranial nerve neuropathy. If these signs are present, a spinal tap should be performed, or at least an MRI or CT scan should be performed.

The most likely initial symptoms of chronic meningitis:

• Increased temperature (stable values between 38-39°C);
• pain in the head;
• psychomotor disorders;
• deterioration in gait;
• double vision;
• spastic muscle twitches;
• visual, auditory, olfactory problems;
• meningeal signs of varying intensity;
• disorders of mimic muscles, tendon and periosteal reflexes, appearance of spastic paraparesis and paraparesis, rarely - paralysis with hyper or hyposthesia, coordination disorders;
• cortical disorders in the form of mental disorders, partial or complete amnesia, auditory or visual hallucinations, euphoric or depressive states.

Symptomatology in chronic meningitis can last for months or even years. In some cases, patients may experience apparent improvement, followed by relapse.

Complications and consequences

The consequences of chronic meningitis are almost impossible to predict. In most cases, they develop in the remote period, and can be expressed in the following disorders:

• neurological complications: epilepsy, dementia, focal neurological defects;
• systemic complications: endocarditis, thrombosis and thromboembolism, arthritis;
• neuralgia, cranial nerve palsies, contralateral hemiparesis, visual impairment;
• hearing loss, migraines.

In many cases, the likelihood of complications depends on the underlying cause of chronic meningitis and the state of a person's immunity. Meningitis provoked by parasitic or fungal infection is more difficult to cure and tends to recur (especially in HIV-infected patients). Chronic meningitis, which developed against the background of leukemia, lymphoma or cancerous neoplasms, has a particularly poor prognosis.

Diagnostics of the chronic meningitis

If chronic meningitis is suspected, a general blood test should be performed and a spinal tap should be performed to examine the liquor (unless contraindicated). After the spinal tap, blood is examined to assess glucose levels.

Additional tests:

• blood chemistry;
• determination of the white blood cell count;
• blood culture with PCR.

If there are no contraindications, a spinal tap is performed as soon as possible. A sample of cerebrospinal fluid is sent to the laboratory: this procedure is fundamental for the diagnosis of chronic meningitis. Standard determinations are:

• cell count, protein, glucose;
• Gram staining, culture, PCR.

The following signs may indicate the presence of meningitis:

• elevated blood pressure;
• turbidity of the liquor;
• Increased number of leukocytes (mainly polymorphonuclear neutrophils);
• elevated protein levels;
• low value of the ratio of glucose indicators in the liquor and blood.

Other biological materials - such as urine or sputum samples - may be collected for bacterial seeding for microflora.

Instrumental diagnosis may include magnetic resonance imaging, computed tomography, biopsies of altered skin (for cryptococcosis, systemic lupus erythematosus, Lyme disease, trypanosomiasis) or enlarged lymph nodes (for lymphoma, tuberculosis, sarcoidosis, secondary syphilis, or HIV infection).

A thorough examination by an ophthalmologist is performed. Uveitis, dry keratoconjunctivitis, iridocyclitis, deterioration of visual function due to hydrocephalus may be detected.

General examination reveals aphthous stomatitis, hypopyon or ulcerative lesions - particularly those characteristic of Behçet's disease.

Enlargement of the liver and spleen may indicate the presence of lymphoma, sarcoidosis, tuberculosis, brucellosis. In addition, chronic meningitis can be suspected if there are additional sources of infection in the form of purulent otitis media, sinusitis, chronic pulmonary pathologies, or provoking factors in the form of intrapulmonary blood shunting.

It is very important to collect epidemiologic information in a competent and comprehensive manner. The most important anamnestic data are:

• Having tuberculosis or being in contact with a tuberculosis patient;
• travel to epidemiologically unfavorable regions;
• The presence of immunodeficiency conditions or severe weakening of the immune system. [10]

Differential diagnosis

Differential diagnosis is performed with different types of meningitis (viral, tuberculosis, borreliosis, fungal, provoked by protozoa), as well as:

• with aseptic meningitis associated with systemic pathologies, neoplastic processes, chemotherapy;
• with viral encephalitis;
• with a brain abscess, subarachnoid hemorrhage;
• with neoblastosis of the central nervous system.

The diagnosis of chronic meningitis is based on the results of cerebrospinal fluid examination, as well as information obtained during etiologic diagnosis (culture, polymerase-chain reaction). [11]

Treatment of the chronic meningitis

Depending on the origin of chronic meningitis, the doctor prescribes the appropriate treatment:

• If diagnosed with tuberculosis, syphilis, Lyme disease, or other bacterial process - prescribe antibiotic therapy according to the sensitivity of specific microorganisms;
• if there is a fungal infection - prescribe antifungal agents, mainly Amphotericin B, Flucytosine, Fluconazole, Voriconazole (orally or injected);
• If the non-infectious nature of chronic meningitis is diagnosed - in particular, sarcoidosis, Behçet's syndrome - corticosteroids or immunosuppressants are prescribed for a long time;
• if cancer metastases to the brain membranes are detected - combine radiation therapy of the head area, chemotherapy.

In chronic meningitis provoked by cryptococcosis, Amphotericin B is prescribed together with Flucytosine or Fluconazole.

In addition, apply symptomatic treatment: when indicated, analgesics, non-steroidal anti-inflammatory drugs, diuretics and detoxification drugs. [12]

Prevention

Preventive measures to prevent the development of chronic meningitis include these recommendations:

• personal hygiene;
• avoiding close contact with sick people;
• inclusion in the diet of food rich in vitamins and trace elements;
• During periods of seasonal disease outbreaks, avoid staying in crowded areas (especially indoors);
• Drinking only boiled or bottled water;
• Consumption of thermally processed meat, dairy and fish products;
• Avoiding swimming in standing water;
• wet cleaning of living quarters at least 2-3 times a week;
• general hardening of the body;
• avoiding stress, hypothermia;
• leading an active lifestyle, supporting motor activity;
• timely treatment of various diseases, especially those of infectious origin;
• quitting smoking, alcohol and narcotic drugs;
• no self-medication.

In many cases, chronic meningitis can be prevented by timely diagnosis and treatment of systemic diseases.