What Is Meningitis?

Meningitis refers to diffuse inflammatory changes in the pia mater. It is caused by various biological pathogenic factors such as bacteria, viruses, fungi, spirochaete, protozoa, rickettsia, tumors and leukemias invading the pia mater and spinal membrane. Bacterial meningitis is a particularly serious disease that requires timely treatment. If treatment is not timely, it may die within hours or cause permanent brain damage. Although viral meningitis is more serious, most people can fully recover, and a few have sequelae. Meningitis can involve the dura, arachnoid, and pia mater. Dural meningitis is usually secondary to a skull infection. Since the widespread use of antibiotics, the incidence of dural meningitis has been greatly reduced. Meningitis is quite common and includes inflammation of the arachnoid and meninges. Therefore, at present meningitis actually refers to meningitis. Meningitis is mostly caused by pathogens. Epidemic meningitis caused by meningococcus is the most important type; a few are caused by irritating chemicals (such as procaine and methotrexate). There are three basic types of meningitis: purulent meningitis, lymphocytic meningitis (mostly caused by a virus), and chronic meningitis (can be caused by Mycobacterium tuberculosis, Treponema pallidum, Brucella, and fungi).

Basic Information

English name

meningitis

Visiting department

Neurology

Common causes

Caused by infection of meninges or meninges

Common symptoms

Fever, headache, vomiting, loss of appetite, mental illness, etc.

Causes of meningitis

Purulent meningitis

It is a meningitis caused by various pyogenic bacteria, which is a large category of bacterial meningitis. It is one of the severe intracranial infections, often coexisting with purulent encephalitis and brain abscess. The common pathogenic bacteria are three types, namely Haemophilus influenzae type B, Neisseria meningitidis (diplococcus) and Streptococcus pneumoniae (diplococcus pneumoniae). Usually a small number of healthy people carry these bacteria in the nose or body without harming the human body and are transmitted by coughing or sneezing. People are most susceptible to germs when they catch a cold, because rhinitis makes it extremely easy for bacteria to enter the skull.

2. Tuberculous meningitis

It is non-purulent inflammation of the meninges caused by Mycobacterium tuberculosis. About 6% of systemic tuberculosis is the most common central nervous system tuberculosis, not only the most serious form of tuberculosis, but also the leading cause of death in children with tuberculosis. After the Mycobacterium tuberculosis infection is disseminated through the blood, it is planted under the pia mater to form tuberculosis nodules. After the nodule ruptures, a large number of tuberculosis bacteria enter the subarachnoid space. In recent years, the incidence and mortality of tuberculous meningitis have increased. Early diagnosis and treatment can improve efficacy and reduce mortality.

3. Viral meningitis

Central nervous system infection caused by a variety of viruses. Meningitis-causing viruses include arbovirus, enterovirus, ecovirus, poliovirus, coxsackie virus A and B, ecovirus, myxovirus and paramyxovirus, herpes virus, grit virus, etc. Followed by mumps virus, herpes simplex virus and adenovirus. The virus often invades the brain parenchyma and manifests as meningoencephalitis, which is aseptic meningitis.

4. Cryptococcal meningitis

Meningitis can also be caused by fungi. The most common one is Cryptococcus, which can be found in pigeon droppings. Cryptococcal meningitis is a deep fungal infection caused by the invasion of the central nervous system by certain species or variants of the genus Cryptococcus. Healthy people are not susceptible to fungal meningitis, but are not the same for those infected with HIV. Cryptococcal meningitis can occur after infection with cryptococcus.

Meningitis clinical manifestations

Tuberculous meningitis

Early manifestations are changes in the mental state of the child, such as irritability and crying; mental sluggishness; dislike of games; low fever, loss of appetite, vomiting, restless sleep, and weight loss.

Older children may complain of headaches. If the condition is severe, the headache is persistent and exacerbated, the vomiting may become exacerbated, drowsiness may gradually occur, and convulsions may occur. If the condition is further aggravated, coma will occur, frequent convulsions, muscle relaxation and paralysis of the limbs. Irregular breathing can also occur, and some children die.

2. Purulent meningitis

Meningitis caused by various purulent bacteria is common in children and the elderly. Main symptoms are fever, headache, vomiting, and irritability. Neurological examination and cerebrospinal fluid examination are abnormal. Because the children's resistance is weak, the blood-brain barrier is not fully developed, and bacteria easily enter the nervous system of the brain. It is usually caused by infection in other parts of the body caused by sepsis and bacteria entering the brain. Partly due to otitis media, infection after head trauma, bacteria directly into the meninges.

Onset in childhood is acute, high fever can reach above 39 ° C, children often complain of severe headache, poor mental energy, fatigue, loss of appetite, and frequent vomiting. At the onset of childhood, the child is conscious, drowsiness may occur during the progress of the disease, the consciousness is blurred, the speech is disordered, the direction cannot be correctly distinguished, twitching, and coma. In severe cases, convulsions and coma occurred within 24 hours of onset. If it is not treated in time, the disease progresses, the neck is stiff, the head is tilted backwards, the back is stiff, and the entire body is bent back like a "bow". Respiratory irregularities and even respiratory failure can occur, and some children have bleeding spots on their skin.

Because lesions can cause meningeal adhesions and brain parenchymal damage, there can be sequelae of cranial nerve palsy, blindness, hearing impairment, limb paralysis, epilepsy, and mental retardation.

Meningitis test

Laboratory inspection

(1) Hematology Peripheral blood elephant white blood cell counts are significantly increased in the acute phase. Immature cells may appear mainly on neutrophils.

(2) Cerebrospinal fluid pressure is increased, appearance is cloudy, pus-like, white blood cell count is 1000 ~ 10000 / mm, a few cases are higher, mainly neutrophils, which can account for more than 90% of the total number of white blood cells. Sometimes the accumulation of pus cells is lumpy. At this time, smears and pathogenic bacteria culture are mostly positive. Occasionally, the first lumbar puncture was normal, and reexamination became purulent several hours later. The protein rises to more than 1.0g / L, the sugar content decreases, usually less than 2.2mmol / L, the chloride content also decreases, and the immunoglobulin IgM and IgG significantly increase.

(3) Bacterial antigen determination Commonly used methods include polymerase chain reaction, convection immunoelectrophoresis, latex agglutination test, enzyme-linked immunosorbent test, and radioimmunoassay.

(4) Other optional tests include: hematuria routine, blood electrolytes, blood glucose, liver and kidney function.

2. Other auxiliary inspections

(1) X-ray examination The chest radiograph of patients with purulent meningitis is particularly important. Pneumonia lesions or abscesses can be found. Craniocerebral and sinus plain radiographs can detect cranial osteomyelitis, sinusitis, and mastoiditis, but the CT examination of the above lesions is more clear.

(2) CT, MRI examination Early CT or cranial MRI examination can be normal. When there are neurological complications, abnormal manifestations such as enlarged ventricles, narrowed sulci, brain swelling, and brain displacement can be seen. And can find epidural inflammation, subdural effusion and local brain abscess. Enhanced MRI scans are more sensitive to meningitis diagnosis than enhanced CT scans. MRI scans can show meningeal exudation and cortical response. Adopting appropriate technical conditions can show venous occlusion and infarction in the corresponding site.

Meningitis diagnosis

In addition to clinical manifestations and examinations. Lumbar puncture should be performed for the diagnosis of meningitis.

Meningitis complications

If improperly treated, the disease can change from acute to chronic, and the following sequelae can occur:

Hydrocephalus

Due to meningeal adhesions, cerebrospinal fluid circulation disorders;

2. Cranial nerve palsy

Such as deafness, visual impairment, strabismus, facial nerve paralysis, etc .;

3. Vascular obstruction caused by cerebral vasculitis

Causes cerebral ischemia and infarction at the corresponding site.

Meningitis treatment

Bacterial meningitis is a life-threatening disease and should be treated immediately. Symptoms should go to the emergency department immediately.

The treatment of bacterial meningitis is mainly to find bacteria based on cerebrospinal fluid smears and cultures, and to select effective antibiotics according to drug sensitivity tests and timely treatment to reduce the incidence of sequelae. It is also necessary to symptomatically treat high fever, control convulsions, reduce intracranial pressure, reduce cerebral edema, and use hormones to reduce intracranial inflammation and adhesion.

Antibiotics have no effect on viral meningitis and antiviral drugs should be added.

Meningitis prevention

1. Early detection, in-situ isolation and treatment.

2. Do a good job in publicity during epidemics. Avoid large gatherings and group activities as much as possible. Do not bring children to public places. Wear masks when going out.

3. At the time of meningococcal epidemic, those who have fever with headache; mental debility; acute pharyngitis; skin and oral mucosal bleeding can be symptomatically preventive and can effectively reduce the incidence and prevent epidemics .

4. Vaccination.