What Is Aseptic Meningitis? Causes, Symptoms, and Treatment

Medically Reviewed By Heidi Moawad, M.D.
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The cerebrospinal fluid (CSF) and the meninges protect the brain and spinal cord. Aseptic meningitis is inflammation of the meninges that is not caused by a bacterial infection. Aseptic meningitis can occur in people of all ages, including infants. Viral meningitis is a common type of aseptic meningitis, and most people recover without treatment.

In contrast, bacterial meningitis is more serious and requires medical treatment, such as antibiotics.

Read on to learn more about aseptic meningitis, its causes, symptoms and treatment.

What is aseptic meningitis?

woman with hands clasped behind her head
Pati Gagarin/Stocksy United

Meningitis is a general term for any condition that causes inflammation of the meninges. The meninges are three layers of membrane that surround the brain and spinal cord. They line and cushion the brain and spinal cord.

There are several possible causes of meningeal inflammation, including infections, drugs, and autoimmune conditions.

Doctors can remove a sample of the cerebrospinal fluid (CSF) to help identify the underlying cause.

One of these CSF tests is a bacterial culture. If bacteria grow in a CSF sample, doctors diagnose it as bacterial meningitis.

Aseptic meningitis vs. meningitis

The Centers for Disease Control and Prevention (CDC) defines aseptic meningitis as an illness that has the characteristic symptoms of meningitis without the presence of bacteria or fungi in a CSF sample.

However, aseptic meningitis is an outdated description because the term “aseptic” means sterile, or free of any organisms.

Today, the CDC categorizes meningitis as one of the following:

  • bacterial meningitis
  • viral meningitis
  • fungal meningitis
  • parasitic meningitis
  • amebic meningitis
  • noninfectious meningitis

What are the symptoms of aseptic meningitis?

The symptoms of aseptic meningitis are similar to those of bacterial meningitis. Viral meningitis is the most common type of meningitis. People of different ages may experience different symptoms.

Infants may display the following symptoms:

Call 911 if you cannot wake an infant.

Children and adults may experience or complain of:

  • severe headache
  • stiff or rigid neck
  • fever
  • nausea or vomiting
  • irritability
  • sleepiness
  • low or no appetite
  • eye sensitivity to light (photophobia)

Call 911 for anyone who is difficult to wake.

Symptoms of viral meningitis usually resolve in 7–10 days, according to the CDC.

If you develop or are at risk of developing severe disease, you may need care in a hospital.

When to see a doctor

Anyone who suspects that they or their child has meningitis should contact a doctor right away.

Call 911 for difficulty awakening or changes in mental status.

You cannot diagnose the type of meningitis yourself. A diagnostic test can determine if bacteria are the cause.

Aseptic meningitis is typically less severe than bacterial meningitis but can still be serious.

If medical professionals cannot identify an underlying cause, they may diagnose it as idiopathic meningitis.

What causes aseptic meningitis?

The causes of aseptic meningitis include:

Viruses

Viral infections are the most common cause of aseptic meningitis. Non-polio enteroviruses are the most common cause of viral meningitis in the United States, explains the CDC. These viruses include those that cause the common cold. Only a small number of people with these infections develop meningitis.

Other viruses that can cause meningitis include:

Drugs

Drug-induced aseptic meningitis may be due to direct irritation of the meninges or to hypersensitivity. Classes of medications associated with aseptic meningitis include:

  • nonsteroidal anti-inflammatory drugs such as ibuprofen (Advil, Motrin)
  • monoclonal antibodies like cetuximab, used to treat certain cancers
  • sulfonamide and penicillin antibiotics like amoxicillin

Meningitis may go away after stopping the drug.

Autoimmune conditions

Conditions that can inflame the meninges include:

  • sarcoidosis
  • Sjögren’s syndrome
  • systemic lupus erythematosus
  • granulomatosis with polyangiitis

Cancer

Cancers that can involve the meninges include:

Other causes

Other causes include brain surgery and head injury. Spinal injections can also lead to meningitis, but they are more likely to cause bacterial meningitis due to contamination, as the CDC explains.

In more than half of cases, the specific cause of aseptic meningitis is not known.

What are the risk factors?

Some people have a higher likelihood of developing viral meningitis. Children younger than 5 years and people of any age with low immune system function are especially at risk. This includes people who take medication(s) that suppress the immune system.

Read What Does It Mean to Be Immunocompromised?

How do doctors diagnose aseptic meningitis?

Your doctor will ask you about your symptoms and perform a physical exam. If you have symptoms of meningitis, tests may include:

A laboratory will analyze the CSF, a clear fluid with relatively stable levels of protein and other components. Analyzing it can help identify the cause of meningitis symptoms. In particular, the lab will determine if bacteria or fungi grow from a sample of CSF. This is a CSF culture.

How do doctors treat aseptic meningitis?

Meningitis treatment depends on the cause. In case you have bacterial meningitis, your care team may administer antibiotics before your test results are available.

For aseptic meningitis (not due to bacteria), your doctor will evaluate your treatment needs. Possible treatments include:

  • steroids to decrease inflammation
  • antiviral medications
  • medications to manage autoimmune meningitis

If you have drug-induced aseptic meningitis, stopping the medication or switching to another may resolve the inflammation.

If meningitis is due to chemotherapy, your doctor will explain adjustments to your treatment plan.

What are the potential complications?

Meningitis can cause the pressure inside the skull to rise due to inflammation and excess fluid in the area. Since the skull is rigid, increased pressure can damage the brain.

Aseptic meningitis has a lower complication rate than bacterial meningitis but can still produce serious disease, especially in infants. Potential complications include:

  • developmental delays
  • seizure disorder
  • hearing loss

What is the outlook?

In general, the outlook for aseptic meningitis is favorable. Most people with viral meningitis get better on their own in 7–10 days.

A small number of people may experience complications if their illness is severe or they have other conditions.

The outcome depends, in part, on the diagnosis and treatment.

Can you prevent aseptic meningitis?

Steps you can take to lower your chance of aseptic meningitis include:

  • Wash your hands frequently and thoroughly.
  • Stay current with vaccinations.
  • Avoid close contact with sick people.
  • Control mosquitoes and protect yourself with mosquito repellent, if you live in an area known to have mosquitoes carrying West Nile virus or other arboviruses that can cause meningitis.
  • Call your doctor if you develop headaches or a stiff neck after starting a new medication.

Frequently asked questions

Heidi Moawad, M.D. reviewed the following questions.

Is aseptic meningitis contagious?

The viruses that cause aseptic meningitis are contagious, but these infections usually do not lead to meningitis. In other words, most people who develop viral meningitis contract the infection from someone who had a cold, not meningitis.

Does aseptic meningitis require isolation?

Some isolation precautions may be necessary in the emergency room or hospital to prevent transmission of viruses to other patients. If you have viral meningitis and you live with infants or others with reduced immune system function, your doctor may recommend that you avoid close contact with them.

Summary

Aseptic meningitis is a type of meningitis not due to bacteria. This includes viral meningitis and noninfectious meningitis. It can be serious but is generally self-limiting and gets better in 7–10 days.

You should contact your doctor right away if you have symptoms of meningitis.

You can take steps to prevent aseptic meningitis by taking precautions to prevent infections.

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Medical Reviewer: Heidi Moawad, M.D.
Last Review Date: 2022 Sep 9
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.