Caused by:


  • bacteria
  • viruses
  • fungi
  • parasites

Non-infective causes

  • autoimmune
  • medications

Meningitis is most often caused by a bacterial or viral infection.

(But can be caused by reaction to medications or interventions, fungal infection, rheumatological diseases such as lupus, some cancers or trauma)

Bacterial Meningitis

  • Rare but potentially fatal
  • Different bacteria can cause it
  • First the bacteria cause and upper respiratory tract infection
  • Haematological spread to brain

Can result in:

  • Stroke
  • Hearing loss
  • Brain damage

Streptococcus pneumoniae causes pneumococcal meningitis which is the most common for of meningitis ad the most serious form of bacterial meningitis.

Strep pneumoniae is a bit of a bugger. It causes pneumonia, septicaemia , ear and sinus infections.

At particular risk from strep pneumoniae:

  • Children under 2
  • Immunosuppressed
  • Elderly

People who contract pneumococcal meningitis often suffer neurological damage ranging from deafness to severe brain damage.

Immunisations are available against certain strains of pneumococcal bacteria.

Neisseria Meningitides is another bacteria, causing Meningococcal Meningitis, it’s highly contagious.

Those particularly at risk are:

  • Kids under 1
  • Immunosuppressed
  • Travellers to places of high disease prevalence
  • College students – freshers in particular

Between 10 and 15 per cent of cases of  meningococcal meningitis are fatal. Anther 10 – 15% cause brain damage or serious side effects.

If it is diagnosed, people who come into close contact with the affected individual should be given preventative antibiotics.

Haemophilus Influenzae B once was responsible for the most common form of bacterial meningitis  Haemophilus Meningitis. Fortunately the HiB vaccine has greatly reduced its prevalence. Those most at risk now are children who haven’t been vaccinated.

Other Bacteria that can cause meningitis:

  • E. coli – common in the elderly and newborns
  • listeria monocytogenes meningitis (from unpasteurised dairy or deli meats)
  • Mycobacterium tuberculosis meningitis  – rare

Viral / Aseptic Meningitis

These are usually caused by Enteroviruses

  • common viruses present in mucus, saliva / faeces
  •  they enter he mouth/nose by direct contact or touching an infected object / surface

Other virsuses (apart from enteroviruses) that cause meningitis:

  • varicella zoster
  • influenza
  • mumps
  • HIV
  • heres simplex type 2


Many funguses cause meningitis – most commonly Cryptococcus neoformans  

  • manly found in dirt and bird droppings
  • crytococcal meningitis most commonly occurs in the immunocompromised but can occur in health people.
  • Some case can be indolent and smolder for weeks
  • Treatable but recurs in 50%

Amoebic Meningitis

  • Rare.
  • Sometimes related to fresh water swimming.
  • Can be rapidly fatal