Viral Meningitis

The most common cause of viral meningitis is

Enteroviruses tend to reside in the digestive tract. Infections are very contagious.

Other common causes include

HSV-2 causes genital herpes Herpes Simplex Virus (HSV) Infections Herpes simplex virus infection causes recurring episodes of small, painful, fluid-filled blisters on the skin, mouth, lips (cold sores), eyes, or genitals. This very contagious viral infection... read more , a sexually transmitted infection that causes painful blisters in the genital area. HSV-2 can also cause symptoms of meningitis. HSV-2 meningitis usually occurs when the virus first infects the body. Genital and meningitis symptoms can occur at the same time. Symptoms of meningitis may appear before the genital symptoms, and some people have meningitis but do not have any genital symptoms. After symptoms disappear, HSV-2 remains in the body in a nonactive (dormant) state. That is, it does not cause symptoms. However, it can become active again (reactivate) periodically and cause symptoms. Thus, meningitis due to HSV-2 Viruses Recurrent meningitis is meningitis that occurs more than once. Meningitis is inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space... read more can recur.

The varicella-zoster virus causes chickenpox Chickenpox Chickenpox is a highly contagious viral infection with the varicella-zoster virus that causes a characteristic itchy rash, consisting of small, raised, blistered, or crusted spots. Chickenpox... read more . Like HSV-2, the varicella-zoster virus remains in the body in a nonactive state. The virus may never cause symptoms again, or it may reactivate many years later. When it reactivates, it causes shingles Shingles Shingles is a painful skin rash caused by a viral infection that results from reactivation of the varicella-zoster virus, the virus that causes chickenpox. What causes the virus to reactive... read more (herpes zoster) and may cause meningitis. Unlike HSV infections, which can recur many times, shingles usually occurs only once in a person's lifetime. However, people with a weakened immune system Overview of Immunodeficiency Disorders Immunodeficiency disorders involve malfunction of the immune system, resulting in infections that develop and recur more frequently, are more severe, and last longer than usual. Immunodeficiency... read more (such as people with HIV infection) may have shingles more than once.

Zika virus Zika Virus Infection Zika virus infection is a mosquito-borne viral infection that typically causes no symptoms but can cause fever, rash, joint pain, or infection of the membrane that covers the white of the eye... read more and Chikungunya virus Arboviruses sometimes cause meningitis. Both viruses were once present in only a few parts of the world but now have spread.

Occasionally, meningitis develops in people with COVID-19 COVID-19 COVID-19 is an acute respiratory illness that can be severe and is caused by the coronavirus named SARS-CoV-2. Symptoms of COVID-19 vary significantly. Two types of tests can be used to diagnose... read more . Rarely, this meningitis is caused by simultaneous infection with another virus (such as varicella-zoster virus).

Viral meningitis usually begins with symptoms of a viral infection, such as fever, a general feeling of illness (malaise), cough, muscle aches, vomiting, loss of appetite, and headache. However, occasionally, people have no symptoms at first.

Later, people have symptoms that suggest meningitis. That is, they typically have fever, headache, and a stiff neck. Trying to lower the chin to the chest causes pain and may be impossible. Moving the head in other directions is not as difficult.

Symptoms may resemble those of bacterial meningitis but are usually less severe and develop and progress more slowly.

Doctors suspect meningitis when people have a headache, fever, and stiff neck. They then try to determine whether meningitis is present and whether it is caused by bacteria (requiring immediate treatment) or a virus. Viral meningitis is more likely when the symptoms are less severe.

A spinal tap Spinal Tap Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more (lumbar puncture) is done to obtain a sample of cerebrospinal fluid. However, if doctors suspect that pressure within the skull is increased, computed tomography (CT) or magnetic resonance imaging (MRI) may be done first to check for causes of the increased pressure (such as a tumor or another mass in the brain). Doing a spinal tap when pressure within the skull is increased may cause a life-threatening disorder called brain herniation Herniation: The Brain Under Pressure . After pressure within the skull is lowered or if no mass is detected, the spinal tap is done.

The sample of cerebrospinal fluid is sent to a laboratory to be examined and analyzed. Sugar and protein levels and the number and type of white blood cells in the fluid are determined. The fluid is cultured to check for bacteria and thus rule out or confirm bacterial meningitis. The fluid is not usually cultured for viruses because doing so is technically difficult.

The polymerase chain reaction (PCR) technique, which produces many copies of a gene, is used to identify enteroviruses, herpesviruses (such as HSV and varicella-zoster virus), and some other viruses. Doctors also test cerebrospinal fluid for the presence of antibodies to certain viruses. For example, detecting antibodies to West Nile virus in cerebrospinal fluid indicates infection with that virus.

Doctors sometimes also take a sample of blood, nasal or throat secretions, or stool for culture, examination, and/or, if available, PCR testing. HIV can be diagnosed based on the results of antibody tests and PCR. Levels of antibodies to other viruses are measured and sometimes remeasured a few weeks later. An increase in the level of antibodies to a particular virus indicates that the virus caused a recent infection and so probably was the cause of recent meningitis.

Most people who have viral meningitis recover within a few weeks. Occasionally, recovery can take months, as sometimes occurs when meningitis is caused by West Nile virus or lymphocytic choriomeningitis virus.

If people appear very ill, doctors start treatment right away without waiting for test results to identify the cause. These people are given antibiotics until doctors are sure that they do not have bacterial meningitis Acute Bacterial Meningitis Acute bacterial meningitis is rapidly developing inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space between the meninges (subarachnoid... read more , which, if untreated, can rapidly cause permanent brain or nerve damage or death. They are also given acyclovir (an antiviral drug) in case the meningitis is due to HSV or varicella-zoster infection.

After the cause is identified, doctors change drugs as needed.

HIV infection is treated with antiretroviral drugs Antiretroviral Treatment of Human Immunodeficiency Virus (HIV) Infection Antiretroviral medications used to treat human immunodeficiency virus (HIV) infection aim to do the following: Reduce the amount of HIV RNA (viral load) in the blood to an undetectable amount... read more . These drugs prevent HIV (a retrovirus) from reproducing and multiplying inside human cells. Almost always, people need to take a combination of several antiretroviral drugs. People must take these drugs for the rest of their life.

If the cause is HSV or varicella-zoster infection, acyclovir is continued.

For most of the other viruses that commonly cause meningitis, there are no effective drugs. However, if people have a normal immune system, they almost always recover from these infections on their own.

Symptoms are also treated. For example, acetaminophen, taken by mouth or suppository (inserted into the rectum), can reduce fever. Pain relievers (analgesics), taken as needed, can help control headache.