Non-Infectious Meningitis: Causes And Symptoms

Did you know that the 5^th of October is World Meningitis Day? Are you aware of the symptoms or even the different types of meningitis? If you want to learn more about it, you are in the right place; we will delve into the causes and symptoms of meningitis, specifically the non-infectious type.

Introduction

Our body is designed to protect itself from all different types of damage. Today, we will discuss one of the protective mechanisms our body has developed to protect some of our most vital structures - the brain and the spinal cord - and what happens when this mechanism is dysregulated. The meninges are the protective structure consisting of multiple very thin layers of membrane that house the cerebrospinal fluid (CSF), blood vessels, neurons and other protective cells. This structure is tightly wrapped around your brain and spinal cord. Think of it as the cling wrap you put around the meal you have prepped for the week: it protects against dust, bugs and air, which can introduce bacteria that can spoil your food (and day). 

Meningitis can be essentially described as the inflammation of these protective membranes of the brain and spinal cord. Inflammation is a natural defence mechanism of the body that may be caused by various harmful factors, such as viral or bacterial infections, fungi or parasites, and it acts to destroy and remove those factors. However, meningitis may also be caused by non-infectious conditions, which include trauma to the brain, cancer progression or tumour formation, and even surgical complications. This type of meningitis is known as non-infectious or aseptic. When left untreated, inflamed meninges could result in severe complications and even death. 

Almost 20% of people show severe symptoms following meningitis diagnosis. That being said, there is no need to panic - with the advances in medicine, there are ways to treat this condition. This article will further explore non-infectious meningitis, its causes, common symptoms and available treatments. An important takeaway from this article is to be aware of the symptoms in order to act promptly and reduce the chances of permanent damage.

Causes of non-infectious meningitis

Autoimmune causes

Lupus

Systemic lupus erythematosus (SLE), also known as lupus, is a complex autoimmune disease that is characterised by neurological and psychiatric symptoms. Autoimmune diseases happen when your immune system is not working properly, causing it to attack your own healthy cells. Meningitis may develop as a secondary disease in lupus patients following chronic or recurrent cases. Approximately 1-2% of lupus patients may develop meningitis as a secondary complication. Almost half of the meningitis cases seen in lupus patients are non-infectious.¹

Rheumatoid arthritis (RA)

Rheumatoid meningitis is another type of non-infectious meningitis that occurs extra-articulary (meaning it develops in areas other than the joints) in RA patients.² Current research has yet to indicate clearly how and why a condition associated with joints may result in brain membrane inflammation. Adding to that, its diagnosis is more challenging due to the stroke-like episodes seen in rheumatoid meningitis patients, which may be misleading. However, cases of rheumatoid meningitis are extremely rare, which may also explain the lack of research.³ 

Medications

Drug-induced meningitis has a complex pathology that is not yet fully understood. However, it is understood that hypersensitivity to drugs or drug toxicity may cause it. Repeated exposure to a particular drug may also be another cause of aseptic meningitis. 

Nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics (especially sulphonamides and penicillins), immunoglobulins, and monoclonal antibodies are the drugs that are most commonly associated with aseptic meningitis.⁴

Traumatic causes

Head injury 

As mentioned in the introduction, trauma to the head may lead to post-traumatic meningitis, which is unfortunately known to have high mortality rates.⁵ Diagnosis is challenging due to more general symptoms and a lack of markers in clinical tests that can accurately identify this type of meningitis. 

Surgical complications

Post-operative meningitis is one of the complications of central nervous system surgeries (which include brain and spinal cord injuries). It is also known to have high mortality rates, and it can happen between 0.3% and 8.6% of patients.^6,7,8 

Cancer-related causes

Malignant meningitis can develop due to the spreading of cancer tissues along the central nervous system. Sometimes benign (non-harmful) tumours formed between the skull and brain may lead to meningitis as well if they rupture, causing irritation to the meninges.

Symptoms of non-infectious meningitis 

The symptoms of non-infectious meningitis are similar to infectious meningitis. Therefore, it is usually difficult to identify the leading causes of this condition, and it requires professional help. If you suspect that you or someone you know might be suffering from meningitis, you should pay attention to the following symptoms, especially if you are experiencing multiple symptoms at once, the symptoms persist, or their severity increases over time. Multiple symptoms may also overlap with other acute or chronic health problems. Nonetheless, it should be stressed that you should always consult with your doctor.

General symptoms

• Severe headache
• Sudden fever
• Stiff neck (neck rigidity)
• Nausea or vomiting

Neurological symptoms

• Photophobia (sensitivity to light)
• Altered mental status (AMS)
• Seizures
• Double vision

Symptoms related to underlying causes

• Joint pain (in lupus-related meningitis)
• Skin rashes (in lupus-related meningitis)
• Cognitive impairment (in cancer-related meningitis)

Diagnosis of non-infectious meningitis

Clinical examinations such as physical examinations are performed for the initial diagnosis, which is then followed by a lumbar puncture to examine the spinal fluid for any bacterial causes. A lumbar puncture, otherwise referred to as a spinal tap, is the process of inserting a needle into the lower part of one’s back to collect fluid around the spinal cord. This fluid is then examined to detect diseases of the central nervous system. 

Differentiating non-infectious meningitis from bacterial or viral meningitis is usually done by checking for bacterial or viral presence by blood tests or spinal fluid analyses.⁹ 

To differentiate drug-induced meningitis from other forms of aseptic meningitis, the time of occurrence of the symptoms should be considered. Below is a list of the common diagnostic tools used to investigate the presence of non-infectious meningitis.

1. Medical history and physical examination
2. Lumbar puncture (spinal tap)
3. Blood tests
4. Imaging (CT or MRI scans)
5. Analysis of cerebrospinal fluid

Treatment of non-infectious meningitis

With the implementation of universal immunisation, the incidence of meningitis has decreased significantly as some types of meningitis can be prevented with vaccination.⁹ However, non-infectious meningitis does not have vaccination as a preventable option since it is not related to infectious agents such as viruses and bacteria. There are different treatment options available depending on the underlying causes of the condition and the age group of the patient.

Addressing the underlying cause

As non-infectious meningitis is caused by inflammation that is not caused by germs, attempting to differentiate and identify its underlying cause is the primary approach employed by experts. For example, treating meningitis caused by a head trauma may be different than cancer-related meningitis.

Symptomatic relief

Some symptoms, such as pain and fever, may be managed with the administration of appropriate medications; however, symptomatic relief does not cure meningitis. Inflammation may be relieved with these medications, although treatment is required for the primary underlying cause. 

Other underlying health conditions such as kidney failure, diabetes, or immunocompromisation are considered by an expert in order to decide the mode of treatment. For example, steroid therapy may be preferred in some cases to reduce inflammation. Steroid therapy works by toning down the action of your immune system so that less inflammation will take place. A toned-down immune system is risky nonetheless as it can make you more vulnerable to other diseases. Radiation therapy or chemotherapy may also be an option to treat cancer-related cases of meningitis.¹⁰ 

Usually, monotherapy (a single approach for treatment) may not be sufficient for full treatment or prevention of relapse (when the symptoms of a condition come back worse after a period in which they were improved). Therefore, the application of multiple medications or methods may be preferred, depending on the case.¹⁰

Long-term effects and complications

Even though most people achieve full recovery following non-infectious meningitis, some long-term complications (sequelae) may persist in some cases. These complications can have emotional and mental repercussions for both patients and their families. 

Potential complications may include:

• Recurrence of the disease
• Neurological damage
• Cognitive impairment

Such complications may lead to deafness, behavioural problems or learning impairment in the long term.

Risk factors for non-infectious meningitis

Some risk factors that increase the chance of developing non-infectious meningitis may include:

• Medical conditions such as cancer may increase the risk of getting non-infectious meningitis, as tumour growth may lead to uncontrolled damage to the meninges.
• Medication use may lead to chemical damage to the protective layers, which in turn could interrupt the immune system response.
• Trauma, and especially head trauma, may damage the skull and brain, causing a primary inflammation that could result in meningitis.⁹

Summary

While infectious meningitis caused by bacteria or viruses is the type of meningitis that is well-known to the public, non-infectious meningitis is a less-discussed but just as important category. It causes inflammation and swelling in the central nervous system, consisting of our brain and spinal cord. As the name implies, non-infectious meningitis is not caused by infectious components such as bacteria or viruses. Instead, it is caused by various other conditions, including autoimmune illnesses, cancer, brain trauma, and even medication use. Sometimes, a combination of these factors may result in non-infectious meningitis. Therefore, understanding the origins and symptoms of non-infectious meningitis is critical for its early detection and treatment. Seeking urgent medical attention increases the success rate of treatment and can consequently save lives.

FAQs

Are people assigned females at birth (AFAB) or assigned males at birth (AMAB) affected more?

As the causes can range widely from injuries to other conditions such as cancer, it is challenging to consider gender assigned at birth as a factor for a higher prevalence of non-infectious meninges. 

Can non-infectious meningitis spread?

Viral and bacterial meningitis may spread with contact; however, non-infectious meningitis is not contagious.