Meningitis is the inflammation of the meninges, which are the protective membranes that surround the brain and spinal cord. Although this inflammation is most commonly caused by a viral infection, meningitis may also occur as a result of a bacterial or fungal infection, an adverse reaction to certain drugs, or physical injury. The severity of illness can differ depending on the cause, although some symptoms such as fever, headache and a stiff neck occur in a majority of cases regardless of the cause of meningitis. Treatment and duration of the illness may also vary depending on the infectious agent. Bacterial meningitis can be life threatening, therefore if you suspect that you or a family member may have meningitis, seek medical attention right away.
Meningitis is characterized by the sudden onset of a fever, headache, and a stiff neck. These classical meningitis symptoms may also be accompanied by:
- Sensitivity to light
- Nausea and vomiting
- Altered mental status
- Loss of appetite
- Skin rash
Newborns and infants may not exhibit the hallmark symptoms (headache, fever, or stiff neck) of meningitis, but instead may present with the following:
- Constant crying
- Excessive sleepiness
- High Fever
- Inactivity or sluggishness
- Lack of interest in feeding
- A bulge in the soft spot on top of a baby's head
- Stiffness in a baby's body and neck
Meningitis can be caused by the following the infectious agents:
- Bacteria. Bacterial meningitis is the most severe and serious type of meningitis. It occurs when bacteria migrates to the brain and spinal cord from the bloodstream. In some cases, bacteria can directly invade the meninges as a result of physical trauma to the skull or from an ear or sinus infection. Streptococcus pneumoniae is the most common cause of bacterial meningitis in the United States and affects all age groups. The bacteria Neisseria meningitides is highly contagious and is another leading cause of meningitis, but mostly afflicts teenagers and young adults.
- Virus. Viral meningitis is the most common cause of meningitis. Thirty percent of viral meningitis cases in the United States are caused by enteroviruses. Other viruses that cause meningitis include herpes simplex virus, La Crosse virus, and West Nile virus. In many cases of viral meningitis the viral agent was not identified.
- Fungi. Fungal meningitis is uncommon and causes chronic meningitis. Cryptococcal meningitis is a common fungal type of meningitis and mostly affects immuno-deficient people. Fungal meningitis can be life threatening.
Meningitis may also be caused by such noninfectious agents as:
- Drug allergies
- Physical injury to the skull
- Inflammatory diseases
A doctor can initially diagnose meningitis based on a comprehensive medical history and a physical exam. However, in order to confirm their diagnosis and identify its cause, the following diagnostic tests may be ordered.
- Blood cultures. Blood is placed in a special dish to see if it supports the growth of microorganisms, particularly bacteria. A sample may also be placed on a slide to which a Gram's stain is added and then examined under a microscope for bacteria.
- X-rays and CT scans of the head, chest or sinuses. These imaging techniques may reveal swelling or inflammation in the central nervous system.
- Spinal tap (lumbar puncture). This is one of the most important and definitive diagnosis tools utilized for diagnosing meningitis. In this procedure a medical professional will remove a small sample of cerebrospinal fluid from within your spinal canal for laboratory analysis. Usually, if a patient has meningitis they will exhibit low levels of glucose as well as an increased white blood cell count and protein. This procedure also enables the doctor to discern what type of bacteria is causing the meningitis.
Treatment for meningitis may vary according to the type of meningitis.
Bacterial meningitis: Bacterial meningitis requires immediate treatment with intravenous antibiotics and cortisone-like medications. The antibiotic or combination of antibiotics that your doctor may choose depends on the type of bacteria causing the infection. Your doctor may recommend a broad-spectrum antibiotic until he or she can determine the exact cause of the meningitis.
Viral meningitis: Viral meningitis is not life threatening and will often resolve itself within two weeks without any medical interventions. Treatment of mild cases of viral meningitis usually includes:
- Drinking plenty of fluids
- Over-the-counter pain medications to help reduce fever and relieve body aches
If the cause of your meningitis is a herpes virus, there's an antiviral medication available.
Other types of meningitis: If the cause of your meningitis is unclear, your doctor may preemptively begin antiviral and antibiotic treatment while a cause is being determined.
- Anti-fungal treatments are often associated with adverse side effects, so treatment is often deferred until a laboratory can confirm that the cause is fungal.
- Non-infectious meningitis due to allergic reaction or autoimmune disease may be treated with cortisone-like medications. In some cases, no treatment may be required, because the condition can resolve on its own. Cancer related meningitis will also resolve itself when the underlying cancer is treated.