What is meningitis? Causes, symptoms, risk factors, complications and treatment

Key takeaways

• Bacteria, viruses, fungi, cancer, or certain drugs can cause meningitis. However, the most common cause of meningitis is a viral infection.
• Bacterial meningitis is the most severe type and can lead to severe long-term complications like deafness, seizures, and brain damage. It also has a higher risk of fatality compared to other types of meningitis.
• Children are at higher risk of meningitis and experience different symptoms than adults.

Meningitis occurs when the membranes protecting the brain and spinal cord are inflamed. This inflammation can be triggered by an infection, which may be a viral, bacterial, or fungal infection. Parasites, cancer, and certain drugs like NSAIDs can also trigger the inflammation.

The membranes protecting the brain and spinal cord are called meninges, hence the name meningitis. Meningitis manifests with symptoms like a high fever, persistent headache, stiff neck, sensitivity to light, nausea, and vomiting.

Some forms of meningitis can resolve on their own after some time, while others are deadly and need immediate treatment.

This article will teach you about meningitis, its causes, symptoms, risk factors, complications, and treatment.

What is meningitis?

Meningitis is the inflammation of the membranes called meninges, which surround the brain and spinal cord. Viruses, bacteria, fungi, parasites, cancer, and drugs can cause this condition.

A common type of meningitis in Nigeria is meningococcal meningitis, a bacterial meningitis that has become a public health concern.

Is it more common in Africa?

Yes, meningitis is more common in Africa.

According to the World Health Organization (WHO), the highest incidence of meningitis stretches from Ethiopia to Senegal and northern parts of Nigeria.

Causes of meningitis

Viruses, bacteria, fungi, parasites, medical conditions like cancer, and certain drugs can cause meningitis.

Causes of viral meningitis include:

• Enteroviruses
• Herpesviruses
• Arboviruses
• Parainfluenza
• Influenza
• Mumps
• Lymphocytic choriomeningitis virus

Causes of bacterial meningitis include:

• Neisseria meningitidis
• Streptococcus pneumonia
• Haemophilus influenzae
• Escherichia coli
• Staphylococcus aureus
• Listeria monocytogenes
• Group B streptococcus agalactiae

Causes of fungal meningitis include:

• Cryptococcus
• Coccidioides
• Blastomyces
• Histoplasma

Causes of parasitic meningitis include: 

• Angiostrongylus cantonensis
• Baylisascaris procyonis
• Gnathostoma spinigerum 

Other causes of meningitis include:

• Cancer
• Head injury
• Brain surgery
• Systemic lupus erythematosus
• Drugs like NSAIDs and antibiotics

Types of meningitis

Here are the different types of meningitis:

1. Bacterial meningitis

Bacterial meningitis, which can be caused by Streptococcus pneumoniae and Neisseria meningitidis, is the most severe and life-threatening type of meningitis. According to the WHO, about 1 in 6 people with bacterial meningitis die, while 1 in 5 have severe complications.

Vaccination is an effective way to prevent bacterial meningitis. However, when an individual is infected, they should contact their doctor or visit a hospital promptly for treatment. Immediate treatment can help prevent death.  

2. Viral meningitis

Viral meningitis, caused by a virus infecting the meninges, is the most common type of meningitis. 

The major cause of viral meningitis is enterovirus. Other causes include herpes viruses and influenza viruses. Viral meningitis is more common in young children but can occur in people of all ages.

Viral meningitis is also common in people who have low immunity, either from other diseases such as HIV infection or autoimmune diseases or from prolonged use of certain drugs like steroids.

3. Fungal meningitis

Fungal meningitis occurs when a fungal infection spreads to the brain or spinal cord. Cryptococcus and Coccidiodes are common causes of fungal meningitis. These organisms usually live in the environment, and people can easily breathe them in, making them sick.

Also, it’s important to note that people who are immunocompromised are at a higher risk of getting fungal meningitis.

4. Parasitic meningitis

This type of meningitis is less common than viral and bacterial meningitis, and it occurs when parasites like Angiostrongylus cantonensis, Baylisascaris procyonis, or Gnathostoma spinigerum cause the inflammation of the meninges.

Also, parasitic meningitis cannot be spread from one person to another, unlike viral and bacterial meningitis.

5. Drug-induced meningitis

These include meningitis that is not caused by viruses, bacteria, fungi, or parasites. Drugs like NSAIDs or certain antibiotics can cause this type of meningitis.

Symptoms of meningitis in adults

The symptoms of the different types of meningitis are similar, although they differ based on severity, as the symptoms of bacterial meningitis are more severe.

Also, symptoms differ from children to adults.

Symptoms of meningitis in adults include:

• Fever
• Headache
• Stiff neck
• Lethargy
• Nausea 
• Vomiting
• Sleepiness
• Irritability
• Seizures 
• Altered mental state
• Sensitivity to light
• Decreased appetite

Symptoms of meningitis in children

Symptoms of meningitis in children include:

• Fever
• Headache 
• Vomiting 
• Diarrhea 
• Sleepiness
• Constant crying 
• Sluggish movements
• Refusal to eat
• Respiratory problems
• A soft bulge on the baby’s head

Risk factors for meningitis

Certain factors increase your chances of contracting meningitis, such as age, disease conditions, and where you live or visit. 

Factors that can increase the risk of meningitis include:

• Age: Newborns, children, and older people are at an increased risk of meningitis 
• Disease conditions: Chronic medical conditions like renal failure, chronic hepatitis, and diabetes
• Location: People living in the African Meningitis Belt
• Unvaccinated individuals
• Immunocompromised people, like those living with HIV and cancer patients.

Complications of meningitis

Bacterial meningitis is dangerous and often leads to morbidity and mortality in adults and children. These complications can either be short-term or long-term.

Some short-term complications include:

• Focal neurological deficits like speech disorders or visual deficits
• Subdural effusion (collection of cerebrospinal fluid trapped between the surface of the brain and the outer lining of the brain)

While long-term complications include:

• Hearing loss
• Seizures
• Cognitive impairment
• Hydrocephalus (abnormal buildup of cerebrospinal fluid in the brain)

These neurological complications are more common in children, and bacterial meningitis caused by Streptococcus pneumonia.

Diagnosis of meningitis

The diagnosis of meningitis can be done using a variety of tests. Standard diagnostic tests for meningitis include:

1. Blood culture: A blood culture can be done by collecting a blood sample and testing for bacteria.
2. Lumbar puncture: Healthcare professionals carry out this by collecting a sample of your cerebrospinal fluid (CSF), which they then analyze for the presence of microorganisms. Other properties of the cerebrospinal fluid that they may analyze include the white blood cell count, protein, and glucose levels. 
3. Brain scans: A brain scan can be done using Computerized Tomography (CT) or Magnetic Resonance Imaging (MRI) to check for inflammation or swelling.

Your doctor can also order some diagnostic tests to check for the presence of specific organisms. For instance, multiplex and specific Polymerase Chain Reactions (PCRs) can be used to test for viral organisms, while CSF fungal culture can be used to test for the presence of fungal organisms.

Treatment of meningitis

Treatment of meningitis is usually based on the type of meningitis.

• Bacterial meningitis can be treated with antibiotics like ceftriaxone and vancomycin.
• Viral meningitis has no specific treatment and often resolves on its own[1]. Antiviral medications such as acyclovir may also be used. 
• Fungal meningitis can be treated using antifungals like amphotericin B and fluconazole. 
• Parasitic meningitis has no specific treatment, but pain medications and corticosteroids are usually given for headaches and inflammation.
• Drug-induced meningitis can be treated by withdrawing the drug.

Meningitis can only be properly diagnosed by a healthcare provider, so ensure you visit a hospital for proper diagnosis and treatment if you notice any symptoms. A delay in diagnosis and commencement of treatment can lead to complications and death.