OVERVIEW
各种嗜神经病毒感染所引起的软脑膜急性炎症性病变
主要表现为发热、头痛、呕吐等，神经系统检查可发现颈强直和凯尔尼格征阳性
为病毒感染中枢神经系统导致炎症反应，以肠道病毒多见
主要分为一般治疗、抗病毒治疗及康复治疗
Definition
Viral meningitis is an acute inflammatory disease of the soft meninges caused by infection with various neuroleptic viruses.
The disease has a mostly benign course with a short duration and few complications.
Morbidity
85-95% of viral meningitis is caused by enteroviruses, the most common being coxsackievirus, echovirus, and enterovirus A71. Other viruses include mumps virus, varicella-zoster virus, adenovirus, and arboviruses.
The disease can affect all ages, but is more common in children, with infants under 1 year of age and people with weakened immune systems more susceptible.
It is highly prevalent in summer, and can occur year-round in the tropics and subtropics.
Causes
Causes
Source of infection
A person infected with an enterovirus. People are the only natural hosts of enteroviruses.
Route of transmission
Enteroviruses are mainly transmitted through the fecal-oral route, with a few cases transmitted through the respiratory tract.
Susceptible population
Children under 5 years old.
People who are malnourished, stay up late or live in poor conditions.
People who are taking immunosuppressive drugs or have immune system diseases, resulting in low immune function.
People with decreased immune function due to exertion and rain.
Pathogenesis
Enterovirus first invades the human body through the digestive tract, replicates in localized lymph nodes in the intestines, and then enters the bloodstream to produce viremia.
It invades the meninges via the choroid plexus, leading to inflammatory changes in the meninges.
Symptoms
Main symptoms
Onset is usually acute or subacute and can occur at any age and is common in adolescents. Onset usually lasts more than 1 week in children and 2 weeks or longer in adults. The following symptoms are usually present:
Systemic symptoms of viral infection, including fever, photophobia, myalgia, loss of appetite, diarrhea, and general malaise, with body temperature usually not exceeding 40°C.
Some patients will have headache, even severe headache, mostly in the frontal or orbital area, accompanied by nausea and vomiting.
Some patients may have cervical ankylosis, spasmodic contraction and pain in the neck muscles, stiffness of the neck and limitation of movement.
Accompanying Symptoms
Clinical manifestations may vary depending on age, body immune status, and the type and subtype of virus.
Echovirus type 9 meningitis may present with a rash.
Coxsackievirus (A6, 10, 16), echovirus (6, 30), and enterovirus A71 meningitis often present with hand-foot-mouth syndrome, with scattered rashes and herpes on the hands, feet, and mouth.
In the case of severe involvement of the brain parenchyma, i.e. meningoencephalitis, seizures and even loss of consciousness and coma may occur.
Medical treatment
Department of Medicine
Neurology
When symptoms such as fever, headache, stiff neck, photophobia, drowsiness, nausea and vomiting occur, it is advisable to consult a doctor promptly. After diagnosis, the patient may be transferred to the Infection Department for treatment.
Emergency Department
When there is an emergency such as high fever, convulsions, projectile vomiting, etc., it is recommended to go to the Emergency Department immediately.
Pediatrics
Children may also go to the Pediatrics Department when they experience any of the above symptoms.
Preparation for medical treatment
Information on how to get to the doctor: registration, preparation of documents, and frequently asked questions.
Tips for the doctor
Neurological examination, CT or MRI may be required. It is recommended to wear clothes that are easy to put on and take off, and to avoid wearing clothes made of metal, and to inform the doctor in advance if you are pregnant or planning to become pregnant.
For patients with high fever, physical cooling, such as applying cold compresses to the forehead and wiping hands, feet and armpits with lukewarm water, can be used first.
Preparation checklist for medical consultation
症状清单
Pay special attention to the time of onset of symptoms, special manifestations, etc.
Is there fever? What is the highest degree?
Is the neck stiff and hard to bend?
Is there a headache? What makes it worse or worse?
Is there projectile vomiting?
Any twitching of limbs?
Is the appetite normal? What is the mental state?
When did the symptoms appear?
病史清单
Was there any exertion, rain, cold, etc. during the onset of symptoms?
Have you been taking immunosuppressive drugs for a long time?
Have you recently traveled to an area where meningitis is endemic or come into contact with a person with meningitis?
检查清单
Test results in the last six months, which can be brought to the doctor’s office
Laboratory tests: routine blood tests
用药清单
Medications in the last 3 months, if available in box or package, bring with you
Antipyretics and analgesics: ibuprofen, acetaminophen
Antivirals: acyclovir, ganciclovir
Diagnosis
Diagnosis is based on
Medical History
Possible recent contact with a patient with enterovirus infection or occurrence of infection.
Clinical manifestations
Fever, headache, nausea and vomiting, muscle aches, and general malaise.
On examination viral meningitis will present with mild neck tonus, a positive Kellnig’s sign, and generally no other positive neurologic signs.
Extended reading: the examination method of Kellnig’s sign, the patient needs to go to the pillow supine in the examination bed, one side of the hip and knee joints are bent at 90 °, the doctor will straighten the patient’s calf upward, the normal person can reach 135 °, if the straightening of the resistance or the appearance of pain, it is positive.
Laboratory Tests
外周血检查
Peripheral blood white blood cell counts are usually normal, may be elevated due to enterovirus infection, and classification is mostly unremarkable.
In EBV infection there is an increase in mononuclear cells, up to 60% or more, with more than 10% heterogeneous lymphocytes.
Increased amylase may be seen in mumps virus infection.
脑脊液检查
Patients usually require a lumbar puncture to remove cerebrospinal fluid for analysis.
Cerebrospinal fluid pressure is normal or mildly to moderately elevated, colorless and transparent in appearance, with normal or mildly elevated leukocytes, predominantly polymorphonuclear cells in the early stages, and predominantly lymphocytes after 8 to 48 hours.
Protein content is normal or mildly increased, sugar and chloride content is normal.
病原学检测
Blood, urine, stool, pharyngeal swab and cerebrospinal fluid can be taken for pathogenetic examination.
Nucleic acid test: apply polymerase chain reaction (PCR) to detect viral nucleic acid, with high sensitivity and specificity, short time-consuming, and of greater significance for clinical diagnosis.
Viral antibody test: it can clarify the type of virus infected, and a 4-fold increase in IgG antibody potency in the recovery period compared with that in the acute period can be diagnosed as recent infection, and IgM antibody positivity can be used as a reference for pathogenic diagnosis.
Cerebrospinal fluid viral culture: can confirm the diagnosis of the disease, but the culture takes a long time, 3.7-8.2 days.
Imaging examination
Imaging tests for viral meningitis generally use cranial CT and MRI.
Most have no specific changes.
In some patients, thin line-like enhancement of the soft meninges is seen on enhanced MRI scans of the head.
Cranial MRI has higher resolution and can more accurately show the location, nature and extent of lesions, such as cerebral edema, cerebral hemorrhage, cerebral softening and demyelinating lesions than CT.
CT precautions: Remove metal jewelry such as hairpins or earrings before the examination, keep still and do not move your head during the examination.
MRI precautions: with a pacemaker, artificial heart metal valves, the body has a history of metal or magnetic implantation and early pregnancy of the examinee, can not be examined, in order to avoid accidents.
Differential Diagnosis
Purulent meningitis
Similarities: acute onset, obvious headache, systemic symptoms of infection and poisoning, signs of meningeal irritation.
Differences: Septic meningitis has elevated white blood cell counts and neutrophil counts, cerebrospinal fluid has a cloudy or purulent appearance, leukocytes are markedly elevated, and imaging reveals diffuse linear or striated enhancement of the supratentorial sulcus, soft meninges on the surface of the gyri, and arachnoid membranes. Viral meningitis is mostly without the aforementioned changes. It can be differentiated by laboratory tests and imaging.
Tuberculous meningitis
Similarities: fever, headache, vomiting, and positive meningeal irritation.
Differences: Tuberculous meningitis has a long course, often extending over several months, with symptoms of tuberculosis toxicity such as low-grade fever and night sweats, accompanied by cerebral nerve damage (abducens, oculomotor, and facial nerves are most likely to be involved), and cerebral infarction and corresponding manifestations. In typical cases, imaging shows that the meninges at the base of the skull and the lateral fissure pools are markedly strengthened in the form of points or clusters. It can be differentiated by laboratory tests and imaging.
Cryptococcal meningitis
Similarity: The onset of the disease is more acute, with symptoms such as fever, headache, sore throat, nausea and vomiting.
Differences: Cryptococcal meningitis is characterized by intermittent severe headache, cerebral nerve involvement, significant increase in intracranial pressure, moderately high cerebrospinal fluid cell count, ink staining to see a new type of cryptococcus can confirm the diagnosis, and imaging can be seen in obvious meningeal enhancement. Viral meningitis has no obvious high intracranial pressure and cerebral nerve involvement, and the cerebrospinal fluid cell count is mostly mildly elevated. It can be accurately identified by clinical manifestations combined with laboratory tests and imaging.
Treatment
Viral meningitis is a benign, self-limiting disease that generally does not require special treatment. Patients with severe clinical manifestations require antiviral and rehabilitation therapy.
General treatment
Generally, bed rest and drinking plenty of water are required.
When there are obvious signs of increased intracranial pressure, 20% mannitol, compound glycerol and diuretics can be used to reduce symptoms.
Antipyretics such as acetaminophen or ibuprofen can be used for high fever, or physical hypothermia can be used to control convulsions.
Adrenocorticotropic hormone can be applied for a short period of time for high fever or severe condition.
Antiviral treatment
The efficacy of antiviral therapy is not yet certain, and satisfactory results have only been achieved within a certain application range.
Clinical or experimental use of enteroviral infections includes serum immunoglobulin and the anti-microRNA drug Pleconazole, but evidence of the effectiveness of both is limited and further research is needed to support them.
Meningitis due to herpes simplex virus or varicella-zoster virus infection is treated with acyclovir, ganciclovir, and adenosine, with acyclovir being more commonly used.
Other antiviral drugs include ribavirin and interferon.
Rehabilitation
Rehabilitation should be carried out for children with severe disease that affects the brain parenchyma and may leave sequelae.
Functional training, acupuncture, massage, hyperbaric oxygen and other rehabilitation measures can be given to promote the recovery of various functions.
Rehabilitation treatment should be carried out under the guidance of professional doctors, please do not treat by yourself.
Special Reminder
Medications should be used under the guidance of a professional doctor, do not self-medicate.
Prognosis
Cure
Viral meningitis is a benign, self-limiting disease with a short course and good prognosis.
The disease starts to recover within a few days, and most of them recover completely within 1 to 2 weeks.
Usually there are no sequelae.
Hazards
Viral meningitis may cause headache, photophobia and other manifestations, which may have some impact on life and work.
Daily
Daily management
Dietary management
There are generally no special dietary requirements, and it is sufficient to ensure adequate nutritional intake.
If there are symptoms such as nausea and vomiting, you can eat foods that are easy to digest.
Eat more protein-rich foods, such as meat, eggs, dairy products, soy products, etc., and consume more vegetables and fruits to supplement enough vitamins and trace elements.
Prohibit spicy, greasy and other stimulating foods, smoking and alcohol.
Life management
Exercise appropriately, pay attention to rest, and ensure enough sleep.
Keep a good mood to promote the organism to recover as soon as possible.
Prevention
Vaccination.
Wash hands before and after meals and maintain good hygiene.
Disinfect surfaces or areas that are frequently touched regularly.
Avoid crowded places during the epidemic season.
Avoid close contact with patients and take isolation measures when there are patients at home.
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