Viral meningitis
Release time : 01/18/2025 18:13:27
Viral meningitis is the most common form of aseptic meningitis in clinical practice and mainly manifests as fever, headache, vomiting, etc. It is more common in children.
Although viral meningitis is contagious, it has been in a sporadic state for the past few years. Moms need not worry too much; all that's needed is to ensure that children exercise regularly and strengthen their immunity and receive vaccinations on time.
Viral meningitis is a group of diffuse inflammation syndrome caused by various viruses in the meninges (meninges and arachnoid mater). The main symptoms are fever, headache, vomiting and meningeal signs. It is the most common form of aseptic meningitis, mostly seen in children.
Viral meningitis is mostly caused by enteroviruses, including poliovirus, coxsackievirus A and B, echovirus, followed by adenovirus, mumps virus, herpesvirus, and varicella zoster virus.
Viral encephalitis, which may present as a common cold, specifically involves the nervous system and manifests as muscle weakness. In some children, there may be an upper eyelid droop, decreased limb activity, and feeling of being weak.
Positive signs of meningeal irritation, bilateral asymmetrical response of Babinski's sign in both feet, etc.
Viral meningitis presents with a clear cerebrospinal fluid, with predominantly lymphocytic leukocytosis, and normal glucose and chloride levels.
The course is benign, generally lasting no more than 2 weeks or up to 3 weeks, and it has self-limiting characteristics, with a good prognosis.
Although viral encephalitis is contagious, it has been in an endemic state recently. Parents need not worry too much; it is important to encourage children to exercise more and enhance their immunity.
Vaccination according to schedule.
Avoid overexertion and excessive startling of children.
Children, after being excessively frightened, are prone to catching colds and fevers. This is due to the endocrine system being affected, leading to a reduced immune response.
Viral meningitis is caused by various viruses, most commonly enteroviruses such as poliovirus, coxsackievirus A and B, echovirus, etc. It is often epidemic or sporadic, mainly transmitted through fecal-oral route, but a minority through respiratory secretions.
The following are the most common viruses: mumps virus, herpes virus, and adenovirus.
Sarcoidosis is more common in winter and spring seasons, and often presents as a self-limiting disease.
Herpesviruses include the herpes simplex virus, Epstein-Barr virus, cytomegalovirus, and varicella zoster virus.
Insect-borne viruses are a class of viruses that survive in nature by transmitting between vertebrate and blood-sucking arthropod hosts. They belong to several virus families, with at least 80 species that can infect humans.
There are many causes of viral meningitis, and below we will specifically explore the etiology of this condition.
1. Various pathogens can cause meningitis. Many pathogens can lead to meningitis, meningoencephalitis, or meningoencephalomyelitis, such as Mycobacterium tuberculosis, Mycoplasma pneumoniae, Leishmania, Treponema, Borrelia, Treponema, Corynebacterium, Histoplasma, Cryptococcus, Coccidioidomyces, and Toxoplasma among others.
Additionally, certain diseases such as atypical bacterial endocarditis, bacteremic meningitis, brain abscesses, and collagen-vascular disease may present with symptoms of encephalitis. However, the most important pathogen in encephalitis is virus.
Viral infections can also affect the meninges, leading to meningitis. Meningitis can be classified into bacterial and aseptic types. The latter refers to meningitis where both cerebrospinal fluid smear and culture are negative for bacteria.
Since aseptic meningitis is mostly caused by virus infection, aseptic meningitis and viral meningitis are almost synonymous.
The course of viral meningitis is generally short, with a favorable prognosis.
Viral meningoencephalitis refers to the simultaneous infection of the brain tissue and meninges.
2. Various viruses can cause viral encephalitis, with over a hundred types of viruses capable of this condition. These include vector-borne viruses such as mosquito-borne viruses, herpesviruses, enteroviruses, paramyxoviruses, rubeola virus, reovirus, adenovirus, retroviruses, poxviruses, etc.
Virus encephalitis can be divided into epidemic and sporadic types. The former is typically caused by viruses transmitted through vectors, such as Japanese encephalitis, Eastern equine encephalitis, Western equine encephalitis, Venezuelan equine encephalitis, respiratory-transmitted encephalitis, etc., while the latter can be caused by herpesviruses or rubella virus, etc.
The common vector-borne viral encephalitis in China includes Japanese encephalitis transmitted by mosquitoes and forest encephalitis transmitted by ticks.
Herpesvirus encephalitis is a worldwide distribution, with herpes simplex virus, varicella-zoster virus, Epstein-Barr virus and measles-mumps-rubella virus.
Human Herpesvirus 6 (HHV-6) and 7 (HHV-7) are also neurotropic.
In addition, at least 4 enteroviruses can cause meningitis, meningoencephalitis and meningoencephalomyelitis, including poliovirus, coxsackie virus, echovirus (also known as Enterovirus-71) and newly discovered enterovirus-71.
Viral meningitis symptoms are typically acute onset with severe headache, fever, vomiting, neck stiffness, and characteristic signs of meningeal irritation such as Kernig's sign positive. Additionally, patients may experience general malaise, sore throat, photophobia, dizziness, lethargy, sensory abnormalities, muscle pain, abdominal pain, and chills.
Additionally, some patients may also experience symptoms such as pharyngitis and blurred vision.
If it is caused by a viral infection, rashes may also occur, usually accompanied by fever and lasting for 4 to 10 days.
Korea disease virus (KD) 5, 9, and 16 viruses and echoviruses 4, 6, 9, 16, 30 are the most common viruses causing skin rash. The typical skin rash consists of maculopapular eruptions, which may be localized to the face, trunk or involve the hands and feet.
The infection of Coxsackie B group virus may cause epidemic myalgia (chest pain) and myocarditis.
Clinical neurological damage is less common, and occasional findings include strabismus, diplopia, sensory disturbances, ataxia, asymmetric tendon reflexes, and positive pathological reflexes.
In severe cases, symptoms such as coma may occur in the nervous system.
Viral meningitis, like influenza, initially presents with symptoms similar to those of a common cold, including fever, generalized soreness, and loss of appetite. However, as the disease progresses, patients may experience lethargy, convulsions, and other neurological manifestations.
As the condition progresses, it may lead to changes in emotional and behavioral behaviors such as light coma or excessive excitement.
Since this condition is generally observed in children, parents must closely monitor their child's symptoms and report any abnormalities to the doctor promptly.
The less severe the condition is, the less likely it is to result in brain damage and subsequent sequelae.
The severity of the condition varies greatly, depending on whether the lesion primarily affects the meninges or the brain parenchyma.
Severe encephalitis is more prone to acute death or sequelae during its acute phase.
Viral meningitis diagnosis involves various examinations and tests, including peripheral blood leukocyte count and differential count, cerebrospinal fluid analysis, cranial CT scan, cranial MRI, and electroencephalography.
1. Blood count and differential examination: WBC count normal or decreased, or mildly elevated; lymphocyte ratio increased, often with atypical lymphocytes.
2. Cerebrospinal Fluid Examination: The cerebrospinal fluid is colorless and clear, with normal pressure or increased pressure, with a mild increase in cell count, which can reach (10-1000) × 10^6/L. Early predominantly consists of polymorphonuclear cells, shifting to lymphocytes after 8 to 48 hours, with the sugar and chloride content remaining normal, protein levels slightly elevated, and no bacterial presence detected on smear or culture.
3. Virological examinations revealed that a portion of patients had positive results for virus nucleic acid detection in cerebrospinal fluid, virus culture, and specific antibody testing. The specificity of the antibodies detected post-recovery was fourfold higher than during acute phase, indicating diagnostic significance.
4. Imaging examinations such as CT or MRI of the brain generally show no abnormalities.
5. Electroencephalograms (EEGs) can only indicate abnormal brain function, but cannot confirm the nature of viral infection.
Characterized by diffuse or localized abnormal slow wave background activity, with a minority of spikes and spike-and-wave complexes.
It is noteworthy that some patients may have normal electroencephalograms.
After conducting relevant examinations of the body, how is viral meningitis diagnosed? The diagnosis of viral meningitis primarily relies on the acute onset of systemic infection and toxic symptoms, signs of meningeal irritation, and a mild to moderate increase in lymphocytes in cerebrospinal fluid (CSF), excluding other diseases. The definitive diagnosis requires CSF pathogenicity testing.
Can viral meningitis be cured? This is a question that many parents are concerned about.
Viral meningitis can be cured depending on the severity of the condition.
The primary treatment for this disease involves symptomatic relief, supportive care, and the prevention and management of complications.
Symptomatic treatment such as the use of analgesics for severe headaches and mannitol for cerebral edema may be appropriate.
Antiviral therapy can significantly shorten the course and relieve symptoms. For simplex herpes virus and EB virus, acyclovir is commonly used, three times daily.
Valacyclovir was the first choice for treatment of JCMV meningitis, which was administered twice daily.
The disease course is benign, often within 2 weeks, generally not exceeding 3 weeks, has self-limiting nature, and has a favorable prognosis, with few complications.
How to Prevent Viral Meningitis? 1. General measures include regular exercise to enhance resistance to illness, preventing colds and gastrointestinal infections.
2. Vaccinations for measles, rubella, mumps, and other vaccines should be administered on schedule.
Children are vaccinated according to the schedule of immunization, which can prevent viral infections (such as measles and encephalitis, or typhoid fever) causing encephalitis.
Vaccination against mosquitoes, prevention of mosquito bites and the preventive vaccination for Japanese encephalitis.
Children should keep away from small animals in the home, such as cats, dogs, squirrels, etc.
Because the small animals may carry different kinds of viruses, once they bite you, there is a possibility that the virus will be introduced into your body.
The prognosis of viral encephalitis is closely related to the pathogenic agent involved.
In cases caused by the herpes simplex virus, the prognosis is generally poor, with a significant number of survivors experiencing varying degrees of residual sequelae.
In addition to paying attention to physical exercise, injecting various antiviral vaccines is the fundamental way to prevent viral encephalitis. Moms should pay attention.
This text pertains to medical aspects and is for reference only.
In case of discomfort, it is recommended to seek medical attention immediately for a definitive diagnosis and treatment.