Meningitis: types
What are the types of meningitis?
Meningitis is the inflammation of the membranes (called meninges) surrounding the brain and the spinal cord. It can be caused by a variety of infectious agents such as viruses, bacteria and fungi. Meningitis must be treated as an emergency as it can easily result in death. If diagnosed and treated quickly, a full recovery can usually be expected.
What are the symptoms of meningitis?
Initially:
- severe headache;
- high fever, sweating and rigors;
- stiffness of the neck and back muscles (meningismus);
- photophobia (abnormal sensitivity or intolerance to light); and
- Kernig’s sign (resistance to leg extension when lying down with the hip flexed).
Later:
- irritability and/or delirium;
- vomiting;
- again photophobia;
- lethargy progressing to stupor or seizures;
- convulsions; and
- coma.
Other signs may include a rash as seen in meningococcal type. In infants and small children there may be irritability, feeding problems, lethargy, very high-pitched crying, bulging fontanelles.
Complications of meningitis
Potential complications may include cranial nerve damage, resulting in hearing loss. In some cases, damage to the cerebral cortex may result in mental retardation, seizures, or motor impairment.
Types of meningitis
The term meningitis does not refer to a specific disease but rather the symptom of inflammation of the tissues of the meninges. There are a number of different types of meningitis inflammation.
- Aseptic meningitis: this is an inflammation that is not caused by bacterial infection. Viruses (e.g. mumps) are the most common cause of aseptic meningitis but there are other causes such as systemic lupus erythematosus (SLE), Behcet’s disease and some types of medications.
- Bacterial meningitis: this is an inflammation of the meninges that is caused by a bacterial infection. Dehydration is common as a result of vomiting.
- Cryptococcal meningitis: this type of inflammation of the meninges is caused by infection from a yeast called Cryptococcus which is commonly found in soil and bird droppings. To most people it is not normally a problem, but it is an opportunistic disease (one that does not normally cause problems but becomes infectious under certain conditions). This disease is often associated with AIDS.
- Infectious meningitis: this is a general term for meningitis. It is caused by infection by bacteria, viruses or protozoa. Most of the agents that cause meningitis are infectious but the majority of people are not susceptible. Those at most risk include people with AIDS, infants, transplant recipients, and others with compromised immune systems.
- Meningococcal meningitis: inflammation of the meninges due to an infection with a type of bacteria called meningococcus. Doctors call it by its correct scientific name of Neisseria meningitidis. This is an extremely dangerous type of meningitis as it can progress rapidly, is highly contagious by any type of close or intimate contact. However, most people exposed to the bacteria do not get ill.
- Neoplastic meningitis: inflammation of the meninges that is caused by the spread of solid tumours to the brain or spinal cord.
- Viral meningitis: inflammation of the meninges caused by a virus, commonly one of the enteroviruses. This type of meningitis is highly contagious and occurs frequently in children. It can often be a complication of childhood diseases such as chickenpox.
- Tuberculous meningitis: inflammation of the meninges caused by tuberculosis infection. This is very dangerous and if left untreated may cause brain damage.
- Syphilitic meningitis: inflammation of the meninges due to infection with the bacterium that causes syphilis. Some people with untreated syphilis who are in the tertiary stage develop a chronic form of meningitis.
Last Reviewed: 08 November 2001
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