Bacterial meningitis is an inflammatory process that occurs in the soft membrane of the brain when pyogenic microorganisms (pneumococci, meningococci, streptococci, etc.) penetrate into it. Disease is characterized by high body temperature, intense headache, nausea, vomiting, disorders of the cranial nerves, early appearance of meningeal symptoms, hyperesthesia, disorder of consciousness, psychomotor agitation. Bacterial meningitis can be diagnosed on the basis of a typical clinical picture and data from the analysis of cerebrospinal fluid. Pathology is an indication for mandatory antibiotic therapy. Decongestants, glucocorticosteroids, tranquilizers, anticonvulsants, etc. are used. symptomatic therapy.
G00 Bacterial meningitis, not classified elsewhere
Bacterial meningitis is an inflammation of the meninges (meningitis), which has a bacterial etiology. Bacterial meningitis occurs with a frequency of 3.3 cases per 100 thousand population. All age categories are susceptible to the disease, but most often bacterial meningitis develops in children under 5 years of age. It is noted that bacterial meningitis often occurs against the background of a weakened state of the immune system. The increase in morbidity is observed in the winter-spring period. Since the beginning of the 90s of the last century, there has been a significant decrease in the incidence, a decrease in the number of deaths and cases of severe complications.
Not only meningococcal infection, but also pneumococci, Hemophilus bacillus and other bacteria can lead to the development of this disease. Almost half of cases are due to hemophilic bacillus. In 20% of cases, bacterial meningitis is caused by meningococcus, in 13% of cases — pneumococcus. In newborns, bacterial meningitis often occurs as a result of streptococcal infection, salmonellosis or infection with E. coli.
Depending on the mechanism of penetration of the pathogen into the membranes of the brain, primary and secondary form are distinguished in neurology. Primary form develops with the hematogenic spread of the pathogen from the nasal cavity or pharynx, where it gets from the external environment. Infection occurs from sick persons and carriers by airborne droplets and by contact. Direct infection of the meninges is possible with a skull fracture and open craniocerebral trauma, open injuries of the mastoid process and paranasal sinuses, insufficiently careful observance of the rules of asepsis during neurosurgical interventions.
Secondary form occurs against the background of a primary septic focus in the body, the infection from which penetrates into the membranes of the brain. Contact spread of pyogenic microorganisms can be observed in brain abscess, osteomyelitis of the skull bones, septic synustrombosis. Hematogenic and lymphogenic spread of the pathogen is possible from an infectious focus of any localization, but most often occurs with long-term infections of the ENT organs (acute otitis media, chronic purulent otitis media, sinusitis).
The penetration of pathogens through the blood-brain barrier is facilitated by a weakened state of the body’s immune system, which can be caused by frequent acute respiratory infections, hypovitaminosis, stress, physical overload, a sharp change in climate.
Depending on the severity of clinical manifestations, bacterial meningitis is classified into mild, moderate and severe forms. Severe forms of the disease are observed mainly against the background of a sharp decrease in immunity and in patients with a removed spleen.
According to the peculiarities of the course, there are lightning-fast, abortive, acute and recurrent bacterial meningitis. The most common is acute bacterial meningitis with typical cerebral and shell symptoms. The lightning-fast course from the first hours of the disease is characterized by a rapid increase in cerebral edema, leading to a violation of consciousness and vital functions. The abortive option is characterized by an erased clinical picture, in which the symptoms of intoxication come to the fore. Recurrent bacterial meningitis can be observed with insufficient or delayed treatment of the acute form of the disease, as well as in the presence of a chronic focus of purulent infection in the body.
Bacterial meningitis symptoms
The incubation period of primary bacterial meningitis lasts on average from 2 to 5 days. Typically acute onset with a sharp increase in body temperature to 39-40 ° C, severe chills, intense and increasing headache, nausea and repeated vomiting. There may be psychomotor agitation, delirium, disorders of consciousness. In 40% of cases, bacterial meningitis occurs with convulsive syndrome. Meningitis-specific shell symptoms (Kernig’s, Brudzinsky’s, Guillain’s symptom, rigidity of the occipital muscles) are pronounced from the first hours of the disease and intensify on the 2nd-3rd day. Pronounced hyperesthesia and a decrease in abdominal reflexes are typical against the background of a general increase in deep reflexes. A diffuse hemorrhagic rash may appear.
The focal symptoms accompanying bacterial meningitis most often consist in a violation of the functions of various cranial nerves. The most common lesion of the oculomotor nerves is observed, leading to double vision, the development of strabismus, drooping of the upper eyelid and the appearance of a difference in the size of the pupils (anisocoria). Neuritis of the facial nerve, trigeminal nerve damage, disorder of the optic nerve function (loss of visual fields, decreased visual acuity) and the vestibular cochlear nerve (progressive hearing loss) are less common. More severe focal symptoms indicate the spread of inflammatory changes to the brain substance or the development of vascular disorders of the type of ischemic stroke caused by vasculitis, reflex spasm or thrombosis of cerebral vessels.
When the inflammatory process passes to the brain substance, they talk about the development of meningoencephalitis. At the same time, bacterial meningitis proceeds with the addition of focal symptoms characteristic of encephalitis in the form of paresis and paralysis, speech disorders, changes in sensitivity, the appearance of pathological reflexes, increased muscle tone. Hyperkinesis, hallucinatory syndrome, sleep disorders, vestibular ataxia, behavioral and memory disorders are possible. The spread of the purulent process to the ventricles of the brain with the development of ventriculitis is manifested by spastic attacks of the type of gormetonia, flexion contractures of the arms and extensor legs.
An early and formidable complication that can be accompanied by bacterial meningitis is cerebral edema, which leads to compression of the brain stem with vital centers located in it. Acute cerebral edema, as a rule, occurs on the 2nd-3rd day of the disease, with a lightning form — in the first hours. Clinically, it is manifested by motor anxiety, impaired consciousness, respiratory disorders and disorders of the cardiovascular system (tachycardia and hypertension, in the terminal stage, followed by bradycardia and arterial hypotension).
Among other complications can be observed: septic shock, adrenal insufficiency, subdural empyema, pneumonia, infectious endocarditis, pyelonephritis, cystitis, septic panophthalmitis, etc.
Typical clinical signs, the presence of meningeal symptoms and focal neurological symptoms in the form of damage to the cranial nerves, as a rule, allow the neurologist to assume bacterial meningitis in the patient. Diagnosis is more difficult in cases when bacterial meningitis has an abortive course or occurs a second time against the background of symptoms of an existing septic focus of another localization. To confirm bacterial meningitis, it is necessary to perform a lumbar puncture, during which an increased pressure of the cerebrospinal fluid, its turbidity or opalescent color is detected. Subsequent examination of the cerebrospinal fluid determines an increased content of protein and cellular elements (mainly due to neutrophils). The pathogen is detected during microscopy of cerebrospinal fluid smears and when it is seeded on nutrient media.
For diagnostic purposes, blood and excretory elements of the skin rash are also analyzed. Under the assumption of the secondary nature, additional examinations are conducted aimed at finding the primary infectious focus: consultation of an otolaryngologist, pulmonologist, therapist; radiography of the paranasal sinuses, otoscopy, lung radiography.
It is necessary to differentiate bacterial meningitis from viral meningitis, subarachnoid hemorrhage, meningism phenomena in other infectious diseases (typhus, leptospirosis, severe forms of influenza, etc.).
Bacterial meningitis treatment
All patients with bacterial meningitis should be treated in a hospital. Such patients should urgently undergo lumbar puncture and bacterioscopic examination of the cerebrospinal fluid. Immediately after the etiology of meningitis is established, the patient is prescribed antibiotic therapy. In most cases, it is a combination of ampicillin with drugs of the cephalosporin series (ceftriaxone, cefotaxime, ceftazidime). In bacterial meningitis of unknown etiology, the initial therapy consists in intramuscular administration of aminoglycosides (kanamycin, gentamicin) or their combination with ampicillin. Severe bacterial meningitis may require intravenous or intrathecal administration of antibiotics.
In order to reduce hydrocephalus and cerebral edema in bacterial meningitis, dehydration therapy (furosemide, mannitol) is prescribed. Pathogenetic treatment also includes the use of glucocorticosteroid drugs (dexamethasone, prednisone), the doses of which depend on the severity of the disease. Along with this, the necessary symptomatic therapy is performed. In case of sleep disorders, tranquilizers are prescribed; for the relief of psychomotor agitation and convulsions, lytic mixtures (chlorpromazine, diphenhydramine, trimeperidine), diazepam, valproic acid; with hypovolemia and the development of infectious and toxic shock, infusion therapy is performed.
In the recovery period after the acute phase, it is recommended to take nootropic and neuroprotective drugs, vitamin therapy and general restorative treatment. Treatment of patients with secondary bacterial meningitis should include the elimination of the primary septic focus, including by surgical intervention (sanitizing operation for otitis media, frontotomy, ethmoidotomy, sphenotomy, removal of intracerebral abscess, etc.).
According to some data, bacterial meningitis leads to death in 14% of cases. However, with timely and correctly conducted treatment, bacterial meningitis has a generally favorable prognosis. After meningitis, asthenia, cerebrospinal-dynamic disorders, sensorineural hearing loss, and some mild focal symptoms may occur. Severe consequences of purulent meningitis (hydrocephalus, amaurosis, deafness, dementia, epilepsy) are rare nowadays.
To date, the most effective way to prevent bacterial meningitis is vaccination. Vaccinations are carried out against the main pathogens of bacterial meningitis: hemophilic bacillus, meningo- and pneumococci.
Vaccination against hemophilic infection is carried out mainly for children aged 3 months to 5 years and people suffering from immunodeficiency conditions as a result of HIV infection, immunosuppressive therapy of cancer, removal of the thymus or spleen, etc. Vaccination against meningococcal infection is recommended for children after 18 months and adults. Children under 18 months of age are vaccinated according to epidemic indications (for example, if meningococcal bacterial meningitis is diagnosed in one of the family members). In regions that are dangerous for meningococcal bacterial meningitis, vaccination should be carried out for patients with immunodeficiency and people with anatomical defects of the skull. Vaccination against pneumococcal infection is indicated for frequently ill children, patients with frequent pneumonia and otitis media, in cases of reduced immunity.