The most common causes of meningitis are viral infections that usually resolve without treatment. However, bacterial infections of the meninges are extremely serious illnesses, and may result in death or brain damage, even if treated. Meningitis is also caused by fungi, chemical irritation, drug allergies, and tumors.
Types of Memingitis include :
- Meningitis – cryptococcal
- Syphilitic aseptic meningitis
- Meningitis – H. influenza
- Meningitis – meningococcal
- Meningitis – pneumococcal
- Meningitis – staphylococcal
- Meningitis – tuberculous
- Aseptic meningitis
- Meningitis gram negative
- Carcinomatous meningitis (meningitis due to cancer)
- Acute bacterial meningitis is a true medical emergency, and requires immediate hospital-based treatment.
Bacterial strains that cause meningitis include Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis (meningococcus), Listeria monocytogenes, and many other types of bacteria. In the U.S. almost 20,000 cases of bacterial meningitis occur yearly.
The causes of spinal meningitis are usually a bacterial or viral infection (known as bacterial meningitis and viral meningitis, respectively). Other causes include :
- Fungal infection
- Some types of cancer
- Traumatic injury to the head or spine
- Inflammatory disease (such as lupus)
- Reaction to certain medications or medical treatments.
Viral Meningitis is milder and occurs more often than bacterial meningitis. It usually develops in the late summer and early fall, often affects children and adults under 30. Seventy percent of the infections occur in children under the age of 5. Most Viral Meningitis is associated with enteroviruses, which are viruses that commonly cause intestinal illness.
However, many other types of viruses can also cause meningitis. For example, Viral Meningitis may occur as a complication in people with genital herpes. Recently, West Nile virus spread by mosquito bites has become a cause of Viral Meningitis in most of the U.S. In addition to causing Viral Meningitis, West Nile virus may cause encephalitis in some patients and a polio-like syndrome in others.
