Viral Meningitis

What is Viral Meningitis?

Meningitis is a condition where the meninges, or the protective layers covering our brain and spinal cord, become inflamed, and there’s an unusual number of cells in the cerebrospinal fluid (CSF), a fluid in our brain and spinal cord. One type of meningitis is Aseptic meningitis, which is where the inflammation is not caused by bacteria. This is the version you’re most likely to get, often due to a virus.

As more people get vaccinated, we’re seeing fewer cases of bacterial meningitis, and viral meningitis is becoming more common in many parts of the world. Symptoms of viral meningitis usually appear suddenly and can include fever, headache, sensitivity to light (photophobia), stiff neck, and often nausea and vomiting. Young children might not show these signs, making it even harder to determine if they have meningitis.

It’s very important to see a healthcare professional as soon as possible if meningitis is suspected because it’s difficult to tell the difference between bacterial and viral meningitis based only on symptoms. The good news is that viral meningitis usually gets better on its own and has a good survival rate.

What Causes Viral Meningitis?

Enteroviruses, which include the Coxsackie or Echovirus groups, are the most common viruses that cause meningitis in people of all ages. Parechoviruses also frequently cause this condition in children. Apart from these, herpesviruses such as herpes simplex virus types 1 and 2, varicella-zoster virus (the one that causes chickenpox and shingles), cytomegalovirus, Epstein-Barr virus (the one that causes mononucleosis or “mono”), and human herpesvirus 6, are other viruses that can also cause meningitis.

There are also additional viruses like adenovirus (causes cold-like symptoms), lymphocytic choriomeningitis virus (LCMV, causes brain inflammation), flu, mumps, and parainfluenza (causes respiratory infections) that can lead to this condition.

Apart from these, certain mosquito-borne viruses (known as Arboviruses), such as West Nile, Zika, chikungunya, dengue fever, LaCross, Saint Louise Encephalitis, Powassan, and eastern equine encephalitis viruses, can cause viral meningitis as well.

Risk Factors and Frequency for Viral Meningitis

Viral meningitis mostly affects young children and is less common as people age. In places where many people have received vaccinations, viral meningitis is more common than the bacterial form. It is estimated that just 3 to 18% of childhood meningitis cases are caused by bacteria. Diseases like Haemophilus influenza type B, Streptococcus pneumoniae, and Neisseria meningitidis used to cause bacterial meningitis, but this has lessened dramatically due to vaccinations. Viral meningitis affects anywhere between 0.26 and 17 people for every 100,000 people. In the United States, there can be up to 75,000 cases caused by enteroviruses each year. In countries with milder climates, it is most common during summer and autumn, but in tropical areas, it’s common all year round.

Enteroviruses are the most common cause of viral meningitis, causing up to 12 to 19 cases per 100,000 people every year in some wealthier countries.
The West Nile virus (WNV), spread by mosquitoes, can cause meningitis and encephalitis. This virus is now found everywhere in North America and is lethal in 4 to 13% of cases. It is especially dangerous for the elderly, those with weak immune systems, or diabetics.
Half of those infected with West Nile virus will have lasting neurological or psychological effects.
Human immunodeficiency virus (HIV) can lead to meningitis during the process of seroconversion. It happens in 10 to 17% of symptomatic seroconversion illnesses, and a few cases develop into chronic meningitis.
The Varicella-Zoster Virus (VZV) infection can also lead to viral meningitis. However, it’s usually seen during the reactivation phase rather than the primary infection stage. It can even occur without any skin lesions.
Herpes Simplex Virus types 1 and 2 (HSV-1 and HSV-2) can cause viral meningitis. Whereas HSV-1 is often linked to sporadic encephalitis, HSV-2 can lead to recurrent benign viral meningitis. This usually happens even without genital lesions or in the absence of a history of genital herpes infection. These viruses infect the central nervous system through the cranial nerves.
The LCMV virus is carried by rodents and usually reaches humans when they inhale aerosolized urine or droppings. It can also spread through vertical transmission or infected eye, liver, or kidney transplants. This virus is more common in winter and early spring.
Viruses like mumps were once a frequent cause of viral meningitis in the US, but due to widespread use of the MMR (measles, mumps, and rubella) vaccine, they are now less common. It is more common in male patients.

Signs and Symptoms of Viral Meningitis

Viral meningitis is a type of inflammation in the protective layers of the brain and spinal cord caused by a viral infection. The symptoms people show can differ based on their age and overall health. Generally, it suddenly starts with high body temperature, headache, sensitivity to light, stiffness in the neck, and feeling sick with or without vomiting. For young children, they may primarily show fussiness along with a fever and without obvious neck stiffness or pain.

Newborn babies with this type of meningitis may show similar symptoms to bacterial infections spread throughout the body (“sepsis”), which can also affect their liver and heart. They may develop a severe intestinal issue called “necrotizing enterocolitis”, have seizures, or show specific signs of brain or nerve damage.

Older infants and children can show a two-phase fever, with body aches and a second wave of increase in body temperature associated with signs of brain or nerve damage. In adults, this disease often features more classic symptoms like neck stiffness, along with a higher level of protein in the cerebrospinal fluid (CSF). Children with this condition are more likely to have fever, signs of a respiratory infection, and an increase in white blood cells.

A history of recent travel is important to know, as certain viruses causing meningitis are found in specific areas of the world. Though rare, if an adult has a higher white blood cells count in their cerebrospinal fluid along with signs of lower motor neuron damage, consider West Nile Virus (WNV) meningitis; it is seen more commonly in adults than in children.

Testing for Viral Meningitis

In some situations, like if you’re over 60, have had recent seizures, or display certain other symptoms, a lumbar puncture is necessary. This is a type of test where a needle is inserted into the lower part of your spine to draw a sample of cerebrospinal fluid (CSF) – the fluid that circulates around your brain and spine. It’s vital to identify specific signs before this procedure, including seizures or a low Glasgow Coma Score (a scale to measure the level of consciousness), as these could complicate the test.

Once the CSF is collected, several tests can be conducted on it. For instance, a common trait of viral meningitis is an unusually high amount of specific white blood cells. To identify the specific virus causing the meningitis, a test called Polymerase chain reaction (PCR) may be used, which can detect viruses like enterovirus, VZV, and HSV. Other substances in your blood, like C-reactive protein and white blood cells, can also be measured, but these aren’t as reliable for distinguishing viral from bacterial meningitis.

When it comes to identifying the exact type of meningitis, it can be quite challenging, therefore, experts have created a ‘bacterial meningitis score’. This assigns points based on different symptoms and test results. If a patient scores 0, it’s highly unlikely they have bacterial meningitis. On the other hand, a score of more than 2 suggests a high probability of bacterial meningitis.

This scoring system is not only used with children but has also been validated for use in adults. While determining whether meningitis is caused by a virus or bacteria, doctors also consider factors like low CSF glucose level, high CSF white blood cell counts, and abnormally high CSF protein. Additionally, the CSF lactate level can also be a great way to tell the difference between bacterial and non-bacterial meningitis. The combination of these results with the bacterial meningitis score offers a more accurate diagnosis.

Treatment Options for Viral Meningitis

For most viruses that cause meningitis, there are no specific treatments available. The main treatment approach involves supportive care. This includes managing the body’s fluid and salt levels and controlling pain. Doctors also monitor patients for possible complications affecting the nervous system, such as seizures, brain swelling, and a condition called SIADH which affects the body’s water balance.

At first, it can be challenging to distinguish between viral and bacterial meningitis. Therefore, patients are usually given antibiotics as a safety measure until bacterial meningitis is ruled out. This is a standard approach for patients who are aged one month and older. The doctor might choose vancomycin in combination with ceftriaxone or cefotaxime until the results of the bacterial culture are available.

If there’s a suspicion that inflammation of the brain or “encephalitis” might be involved, doctors might consider an antiviral medication like acyclovir given through an intravenous infusion (IV). For known or suspected infections caused by the herpes simplex virus (HSV) or varicella-zoster virus (VZV), acyclovir is the medication of choice. However, it is important to note that this drug has been found to be beneficial in HSV encephalitis but not specifically in meningitis.

If a patient has received previous antibiotic treatment, it’s essential to bear in mind the possibility of partially-treated bacterial meningitis. There are also other infections that need consideration, such as those caused by mycoplasma, spirochetes, mycobacteria, Brucella, and fungal agents, that can also cause meningitis or inflammation of the brain (encephalitis).

Non-infection related causes should also be explored. These can include reactions to drugs (like NSAIDs, trimethoprim-sulfamethoxazole, and intravenous immune globulin), exposure to heavy metals, tumors (neoplasms), diseases that affect the nervous system such as neurosarcoidosis, autoimmune diseases such as systemic lupus erythematosus, Behcet’s syndrome, and vasculitis.

In children, Kawasaki disease can sometimes show symptoms similar to bacterial or viral meningitis.

What to expect with Viral Meningitis

The outlook for viral meningitis, when it doesn’t come with brain inflammation (also known as encephalitis), is usually good. Viral meningitis often gets better on its own, unlike bacterial meningitis which could potentially lead to a worsening mental condition. Older babies and children often feel unwell for more than a week, but they typically recover fully.

Adults with a certain type of viral meningitis caused by enteroviruses might experience symptoms for a few weeks, although it’s usually less severe than in children. Even though viral meningitis typically resolves on its own, it can still lead to health complications.

Possible Complications When Diagnosed with Viral Meningitis

Enterovirus meningitis usually does not cause severe problems, but enterovirus encephalitis may lead to long-lasting brain damage. The risk for serious illness or death from enteroviral meningitis is higher in newborns and people with weak immune systems. Some types of enterovirus, like EV71 and EV68, can particularly cause severe brain disease and poor outcomes.

Some serious complications of enteroviral meningitis include meningoencephalitis, myocarditis, and pericarditis. In children, enteroviral infection can result in specific serious problems, like sudden muscle weakness and inflammation in the brainstem. Neurological damages after viral meningitis are evident, but usually not as severe as those after bacterial meningitis.

Several studies have also found that sleep issues can be a long-term effect of meningitis.

Common Complications:

Meningoencephalitis
Myocarditis
Pericarditis
Acute flaccid paralysis in children
Rhombencephalitis in children

Long-Term Effects:

Neuropsychological impairments
Sleep issues

Preventing Viral Meningitis

Viral meningitis, a type of brain inflammation, can often be spread through direct contact with feces, like not washing hands after using the bathroom. Because of this, practicing good hand hygiene is very important to prevent the spread. Additionally, getting vaccinated can also help prevent some causes of meningitis.

Frequently asked questions

Viral meningitis is a type of meningitis where the inflammation of the meninges is not caused by bacteria. It is often due to a virus and is becoming more common in many parts of the world. Symptoms include fever, headache, sensitivity to light, stiff neck, and often nausea and vomiting.

Viral meningitis affects anywhere between 0.26 and 17 people for every 100,000 people.

The signs and symptoms of viral meningitis can vary depending on the age and overall health of the individual. However, some common signs and symptoms include: - Sudden onset of high body temperature - Headache - Sensitivity to light - Stiffness in the neck - Feeling sick, with or without vomiting In young children, the primary symptoms may be fussiness and fever, without obvious neck stiffness or pain. Newborn babies with viral meningitis may show symptoms similar to bacterial infections spread throughout the body, such as sepsis. They may also experience liver and heart issues, develop necrotizing enterocolitis (a severe intestinal issue), have seizures, or show signs of brain or nerve damage. Older infants and children may experience a two-phase fever, with body aches and a second wave of increased body temperature accompanied by signs of brain or nerve damage. In adults, viral meningitis often presents with more classic symptoms like neck stiffness. Additionally, adults may have a higher level of protein in the cerebrospinal fluid (CSF). Children with viral meningitis are more likely to have fever, signs of a respiratory infection, and an increase in white blood cells. It is also important to consider a history of recent travel, as certain viruses causing meningitis are found in specific areas of the world. In rare cases, if an adult has a higher white blood cell count in their CSF along with signs of lower motor neuron damage, West Nile Virus (WNV) meningitis should be considered. WNV meningitis is seen more commonly in adults than in children.

Viral meningitis can be caused by various viruses, including enteroviruses (such as Coxsackie and Echovirus groups), parechoviruses, herpesviruses (such as herpes simplex virus types 1 and 2), varicella-zoster virus (which causes chickenpox and shingles), cytomegalovirus, Epstein-Barr virus, human herpesvirus 6, adenovirus, lymphocytic choriomeningitis virus (LCMV), flu, mumps, parainfluenza, and certain mosquito-borne viruses (known as Arboviruses) like West Nile, Zika, chikungunya, dengue fever, LaCross, Saint Louise Encephalitis, Powassan, and eastern equine encephalitis viruses.

The doctor needs to rule out the following conditions when diagnosing Viral Meningitis: 1. Bacterial meningitis 2. Partially-treated bacterial meningitis 3. Infections caused by mycoplasma, spirochetes, mycobacteria, Brucella, and fungal agents 4. Reactions to drugs (like NSAIDs, trimethoprim-sulfamethoxazole, and intravenous immune globulin) 5. Exposure to heavy metals 6. Tumors (neoplasms) 7. Diseases that affect the nervous system such as neurosarcoidosis 8. Autoimmune diseases such as systemic lupus erythematosus, Behcet's syndrome, and vasculitis 9. Kawasaki disease in children.

To properly diagnose viral meningitis, the following tests may be ordered by a doctor: 1. Lumbar puncture: This test involves inserting a needle into the lower part of the spine to collect a sample of cerebrospinal fluid (CSF). The CSF can be tested for an unusually high amount of specific white blood cells, which is a common trait of viral meningitis. 2. Polymerase chain reaction (PCR): This test can detect specific viruses like enterovirus, VZV, and HSV by analyzing the CSF sample obtained from the lumbar puncture. 3. Measurement of C-reactive protein and white blood cells in the blood: While not as reliable for distinguishing viral from bacterial meningitis, these measurements can provide additional information. 4. Bacterial meningitis score: This scoring system assigns points based on symptoms and test results to help identify the likelihood of bacterial meningitis. A score of more than 2 suggests a high probability of bacterial meningitis. 5. CSF glucose level, CSF white blood cell counts, CSF protein, and CSF lactate level: These factors are considered to differentiate between bacterial and non-bacterial meningitis and provide a more accurate diagnosis. It's important to note that there are no specific treatments available for most viruses that cause meningitis, and supportive care is the main approach. Antibiotics may be given as a safety measure until bacterial meningitis is ruled out.

For most viruses that cause meningitis, there are no specific treatments available. The main treatment approach involves supportive care. This includes managing the body's fluid and salt levels and controlling pain. Doctors also monitor patients for possible complications affecting the nervous system, such as seizures, brain swelling, and a condition called SIADH which affects the body's water balance.

When treating viral meningitis, there are several potential side effects and complications that can occur. These include: - Meningoencephalitis - Myocarditis - Pericarditis - Acute flaccid paralysis in children - Rhombencephalitis in children In addition to these immediate complications, there can also be long-term effects of viral meningitis, including neuropsychological impairments and sleep issues.

The prognosis for viral meningitis is usually good. It often gets better on its own without treatment. Older babies and children may feel unwell for more than a week, but they typically recover fully. Adults with viral meningitis caused by enteroviruses might experience symptoms for a few weeks, although it's usually less severe than in children. However, viral meningitis can still lead to health complications.

A healthcare professional or a doctor.