What Is Meningitis?

Overview

What is meningitis? Simply put, meningitis is an infection of the meninges. The meninges are layers that protect the brain and spinal cord. They encase the central nervous system, ensuring that these structures aren’t in direct contact with bones. The function of the meninges also varies, depending on the layer:

• Dura mater - the outer layer
  • Consists of tough connective tissue
  • Covers cranial nerves 

• Arachnoid mater - the middle layer
  • Loose covering over the brain and spinal cord
  • Web-like appearance (hence arachnoid being in the name!) 
  • Provides spaces for blood vessels and nerves 
  • Useful in the regulation of cerebrospinal fluid 

• Pia mater - layer by the brain
  • The rich  supply of blood vessels
  • Contains cells that  produce the cerebrospinal fluid

Generally speaking, when we see the term ‘-itis’ in a medical sense it refers to inflammation. As such, meningitis refers to inflammation of the meninges. In a medical sense, it usually refers to inflammation following an infection. There can be various causes of infectious meningitis e.g. bacterial meningitis, viral meningitis, fungal meningitis, parasitic meningitis, etc. Having said this, there are also instances in which you can get non-infectious meningitis. 

Meningitis can have life-threatening consequences. If left untreated it can cause irreversible damage to the brain and spinal cord. If it is caused by an infection then this infection can also spread to the rest of the body, causing blood poisoning (aka sepsis). This could result in permanent damage to organs, including the brain and spinal cord, if not treated. 

Due to the severity of the infection, if meningitis occurs, there are a few vaccines available to reduce the risk of getting certain types of meningitis. These are mostly aimed at bacterial meningitis and viral meningitis. Each vaccine is designed to minimise the risk of infection from a certain pathogen. It is important to be aware of these. Most of these are delivered when a person is a child and each vaccine targets a different cause of meningitis. 

Causes of meningitis

Causes of meningitis can be broadly split into infectious meningitis and non-infectious meningitis. Bacterial meningitis is one of the more life-threatening forms of meningitis. There are a range of types of bacterial meningitis, including:

• Meningococcal meningitis (aka meningococcal disease)
  • Usually caused by meningococcal A, B, C, W and Y; you may also see these being referred to as meningitis a, meningitis b, meningitis c etc. 
  • According to the meningitis research foundation meningococcal meningitis is the most common type of bacterial meningitis.¹ 

• Pneumococcal meningitis
  • Caused by streptococcus pneumoniae 
• Neisseria meningitidis (aka  meningitidis)
• Haemophilus influenzae type b (Hib) bacteria (aka h influenzae)

Other forms of infectious meningitis include:

• Viral meningitis
  • Examples include: enterovirus, mumps virus, and herpes simplex virus
  • Very rarely life-threatening and unlikely to cause sepsis 
  • People usually recover from viral meningitis without any medical treatment 
  • Viral meningitis is the most common form of meningitis 

• Fungal meningitis
  • Very rare and usually affects those with weakened immune systems 

• Parasitic meningitis
  • Extremely rare in the UK
  • Caused by parasites that are typically found in tropical countries 

Infectious meningitis is spread through airborne particles. This means it can be spread through coughing, sneezing, or kissing. Therefore, meningitis can be spread by close contact. The infective organism (be that a virus or bacterium) can live in the nose or throat. Anyone can get meningitis, but there are certain groups of people who have an increased risk:

• Extremes of age - children and older people are more at risk
• People with a weak immune system
  • Examples of this include people who are on chemotherapy or those who have HIV
• Teenagers and young adults 

Non-infectious  meningitis is less common. Some examples of non-infectious meningitis include:

• Autoimmune conditions
  • These are conditions in which the body is incorrectly attacking its own cells, leading to damage to the cells 
  • Examples include rheumatoid arthritis and systemic lupus erythematosus

• Some medications can cause inflammation in the meninges 

• Rupture of a cyst within the brain 

Signs and symptoms of meningitis

Examples of meningitis symptoms include:

• Stiff neck
• Fever
• Nausea and/or vomiting 
• Really severe headache
• Pain in your limbs
• Pain in your stomach
• Shivering 
• Cold hands and feet
• Changes to your skin
  • Skin can appear paler or mottled 
• Fast breathing 
• Rash that doesn’t fade when pressed with and examined through a glass 
• Photophobia
  • Aversion to bright lights
• Decreased consciousness levels
• Feeling confused or drowsy
• New onset seizures

Management and treatment for meningitis

In practice, you cannot distinguish between different forms of meningitis based on a symptom or clinical signs alone. Therefore, in order to work out what type of meningitis you have the doctors will need to do a few tests. This is important to distinguish if you have bacterial meningitis or not, as bacterial meningitis will have different treatment than  other forms. Examples of tests that might be done include:

• Physical examination to look for signs
  • E.g. a non-blanching rash

• Blood tests
  • This is to look for signs of infection in the blood (septicemia septicaemia)

• Scans of the head
  • Usually a CT scan 
  • This is to ensure there isn’t excessive swelling in the brain 
  • If there is a lot of swelling then the doctors would not be able to perform a lumbar puncture

• Lumbar puncture (aka spinal tap)
  • This involves the doctors taking a sample of your cerebrospinal fluid
  • They get this sample by inserting a needle in your lower back, into the spine 
  • This fluid is analysed to see what type of meningitis is most likely 
  • This is particularly useful in differentiating between bacterial meningitis, viral meningitis, and fungal meningitis 

The management of meningitis will vary depending on the cause. As mentioned earlier, most forms of viral meningitis resolve by themselves, therefore do not require treatment. However, if the symptoms progress to the stage of requiring hospital admission supportive treatments can be offered for those with viral meningitis. Parasitic meningitis also doesn’t have any specific treatments and is treated with supportive measures. Examples of supportive treatments include:

• Oxygen treatment if oxygen levels are low
• Fluids given through a drip (IV fluids) to prevent low blood pressure and dehydration
• Steroids can help to reduce swelling in the brain and spinal cord in some instances 

Acute bacterial meningitis requires treatment with antibiotics, as well as any supportive treatments that may be required. The antibiotics will usually be given through the veins in order to ensure the efficiency of treatment. Giving them through the veins also means that they  will reach the brain and spinal cord quicker than if you were to take them orally. Bacterial meningitis can become life-threatening very fast, which is why it’s important to have the vaccine as a child! 

Fungal meningitis treatment includes antifungal medication that is given through the veins. Following this, a person who has fungal meningitis will usually require oral antifungals to complete the course of medication. 

Meningitis can sometimes become chronic meningitis. If a person has chronic meningitis it is likely there is something else also going on. As such, medical professionals may do further testing to see if there are any reasons why the meningitis isn’t resolving or is recurring. This can involve further blood tests to check for autoimmune conditions or a meningeal biopsy to evaluate the meningeal tissue itself. 

FAQs

What are the types of meningitis

There are various types of meningitis in a person, including:

• Meningococcal meningitis 
• Pneumococcal meningitis 
• Neisseria meningitidis
• Viral meningitis 
• Fungal meningitis
• Parasitic meningitis 
• Noninfectious meningitis 

How is meningitis diagnosed

If a person is suspected to have meningitis then there will be various tests that doctors will do. The first of these is to assess for any clinical signs of meningitis. If there is suspicion of meningococcal disease then further tests would be arranged, including:

• Blood tests
• Head scan
• Lumbar puncture (aka spinal tap) 

How can I prevent meningitis

The best way to prevent meningitis is to ensure you have every available vaccine, as recommended by the World Health Organisation.² There are various types of vaccine that can be offered to prevent the development of meningitis. Examples of such vaccines include:

• MenB vaccine
  • Protects against meningococcal meningitis (aka meningococcal disease) 
  • This particular vaccine protects against meningococcal group B bacteria (aka meningitis b) 
  • Given to you as a child - when the child is 8 weeks, 16 weeks and a booster at 1 year
• 6-in-1 vaccine
  • Vaccinates against a whole host of conditions, including H influenzae 
  • Given at three stages - when the child is 8, 12 and 16 weeks of age 
• Pneumococcal vaccine
  • Offered to a child at 12 weeks, with a booster given at 1 year
  • Single dose is offered to those 65 years or older
• Hib/MenC vaccine
  • Protects against meningococcal disease caused by meningococcal group C bacteria 
  • Offered when the child is 1 year of age 
• MMR vaccine
  • Protects against measles, mumps and rubella
  • Offered when the child is 1 year of age, with a second dose at 3 years and 4 months 
• MenACWY vaccine
  • Protects against 4 types of meningococcal meningitis (aka meningococcal disease)
  • Offered to people aged 14 years old
  • Can also be offered to people who are up to 25 years old if they have never had a vaccine containing MenC before 

Who are at risks of meningitis

Meningitis infection can occur in anyone, however certain groups are more at risk:

• Those with weaker immune systems e.g. those with HIV or those undergoing chemotherapy.
• Extremes of age e.g. a child or an elderly person
• Teenagers and young adults

How common is meningitis

Meningitis is a notifiable disease in the UK which allows for better understanding of the disease and disease control. It is estimated that there are 8,000 cases of meningitis in the UK each year.³

When should I see a doctor

If you are experiencing symptoms that you think are consistent with meningitis it is important to seek urgent medical attention. Meningitis is a type of infection, so a lot of the clinical signs might be present in other forms of infection as well (e.g. fever, nausea, vomiting, shivering, etc.). As such it is important to seek medical attention in order to treat any infection that is occurring. Symptoms that are particularly worrying include but are not limited to:

• Stiff neck
• Non-blanching rash
• Photophobia 

Summary

There are various forms of meningitis. Acute bacterial meningitis requires urgent treatment with antibiotics. It is often not possible to diagnose meningitis infection without specific tests, therefore if you think you or your child have symptoms that correlate with meningitis then you should seek urgent medical attention. The meningitis research foundation has a symptom checker that can help you with this. The best way to prevent meningitis is to utilise the vaccines that are available to you.