Rare types of meningitis

There can be many causes of meningitis, commonly bacteria and viruses, but also rarely fungi, chemicals and amoeba

Types and causes - rare meningitis LB

Hib (haemophilus influenzae type b) disease

  • Prior to the introduction of a Hib vaccine in 1992, Hib bacteria were the most common cause of bacterial meningitis in children under five years old in the UK
  • A Hib vaccine is available as part of the UK routine immunisation schedule and has significantly reduced the number of cases of Hib disease
  • Every year there are around 30 cases of Hib meningitis in the UK
  • Most people make a good recovery, but around 3% will die
  • 3 – 5% of survivors will suffer severe after-effects, such as hearing loss and long-term neurological complications
  • Hib bacteria can also cause other infections such as epiglottitis (rapid swelling of the epiglottis), septic arthritis, osteomyelitis, pericarditis, cellulitis, bronchitis and otitis media

Listeria meningitis (listeria monocytogenes)

  • Listeria bacteria can be found in foods such as unpasteurised soft cheeses, pate and shellfish
  • These bacteria may cause flu-like illness with diarrhoea in pregnant women, but may also cause premature labour
  • A baby with a Listeria infection will usually be unwell from the time of birth, although late onset disease is also recognised
  • Very few cases of Listeria meningitis now occur each year in the UK. This is the result of a successful education campaign warning about the dangers of eating certain foods during pregnancy

Mollaret’s meningitis

Mollaret’s meningitis is a rare type of chronic, recurrent, lymphocytic meningitis, often caused by infection with Herpes Simplex virus type 2.

  • The disease was first described as a form or recurrent meningitis in 1944 by Pierre Mollaret
  • Herpes Simplex virus type 2, which usually causes genital herpes, is present in many cases of Mollaret’s meningitis
  • Herpes Simplex viruses can directly infect the central nervous system and can be inactive for a time without the person showing any signs or symptoms
  • Reactivation of the infection can then cause a recurrent episode of disease
  • About one in five people who have an initial episode of Herpes Simplex virus type 2 meningitis will have a recurrence. If symptoms recur more than three times, this is then called Mollaret’s meningitis

How long does Mollaret’s meningitis last?

An episode of Mollaret’s meningitis can last anything between a few days to a few weeks (usually between two - seven days) and usually resolves without any need for treatment. 

  • Episodes of Mollaret’s meningitis can be months or years apart and can be a considerable burden to sufferers
  • There is usually complete recovery between episodes, with no permanent after-effects
  • An antiretroviral medication called ‘acyclovir’, which can also be used to treat genital herpes and cold sores, can be used to treat Mollaret’s meningitis episodes, although there is a lack of evidence to support this
  • Anyone with recurrent episodes of viral meningitis should be assessed by a neurological infection specialist

Parasitic meningitis

Certain parasites can cause meningitis; however, this is very rare.

  • The most common cause of parasitic meningitis is an amoeba; Naegleria fowleri
  • This organism can cause Primary Amoebic Meningoencephalitis (PAM), a very serious condition
  • Naegleria fowleri lives in warm fresh water lakes or ponds and poorly maintained swimming pools, and can infect people who swim or dive in the water
  • The organism enters the body through the nose and then migrates to the brain, where it damages brain tissue, causing PAM
  • Young males appear to be at the highest risk for this type of meningitis, however it is extremely rare that contact with contaminated water results in disease

Non-infectious meningitis

Bacteria, viruses, fungi and parasites are organisms that infect the body and cause disease. However, meningitis can also develop due to other, non-infectious reasons, which include certain chemicals and cancers. Non-infectious meningitis is not contagious, so it does not spread from person to person.

Chemical meningitis

  • Chemical meningitis is disease that is not caused by infectious agents, such as bacteria or viruses, but by a certain substance or chemical
  • Certain drugs may cause chemical meningitis, including contrast agents used during X-rays or scans and some medicines used to treat cancer
  • Fat droplets leaking into the space between the skull and brain due to rupture of benign tumours can also cause chemical meningitis
  • Chemical meningitis is said to be ‘sterile’ and is characterised by the absence of bacteria or other organisms in the cerebrospinal fluid
  • Chemical meningitis may resolve with little treatment, however, depending on the underlying cause, it may require steroid therapy to limit inflammation and/or surgery to remove a tumour

Malignant or carcinomatous meningitis

  • Malignant or carcinomatous meningitis is meningitis caused by cancer
  • This type of meningitis is quite rare and affects less than 5% of cancer patients with a solid tumour, such as breast cancer, lung cancer or melanoma
  • Malignant meningitis may develop when the cancer spreads to the central nervous system
  • Malignant meningitis may resolve with successful treatment of the cancer through chemotherapy

Cryptococcal meningitis

  • Cryptococcal meningitis is caused by a type of fungus which is found in the soil and bird droppings
  • This type of meningitis mainly affects people with a weakened immune system e.g. HIV positive or people taking immunosuppressive drugs
  • It is not contagious, meaning that it cannot be spread from person to person
  • Symptoms may develop over several weeks and include headache, fever, nausea and vomiting, dislike of bright lights and altered mental state
  • People with cryptococcal meningitis are treated with antifungal medication. Some will require life-long maintenance treatment to help prevent recurrence

Other non-infectious causes of meningitis

  • Meningitis may also develop due to systemic lupus erythematosus (SLE or lupus), anatomical defects or brain surgery
  • Anatomical defects and brain surgery can result in open wounds or spaces which make it easier for bacteria that can cause meningitis to directly infect the meninges and cause disease. However these causes of meningitis are rare

Been affected by a rare type of meningitis?

Don’t face meningitis alone. Call our Meningitis Helpline on 0808 80 10 388 to speak to our experienced staff. You can access our free support or ask us any questions. Whatever your experience, whenever it was, please get in touch. Our support is for life.

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