Meningitis Facts and Statistics: What You Need to Know
Meningitis is inflammation of the membranes called meninges that protect and support the brain and spinal cord. Meningitis symptoms usually include a severe headache, a stiff neck, and a fever.
Viral meningitis is the most common type and typically resolves independently without treatment. Bacterial meningitis, however, can be deadly without fast antibiotic treatment. Early diagnosis is essential to determine the correct course of treatment.
Here are the meningitis facts you should know.
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Meningitis Overview
Meningitis is an inflammation of the tissues called meninges that surround the brain and spinal cord. There are several types:
Viral: The most common type, with mild cases usually clearing up in seven to 10 days without treatment, but antiviral treatments may be needed for strains caused by herpesviruses or influenza
Bacterial: Can be deadly and requires immediate treatment
Fungal: A rare type of meningitis caused by the inhalation of fungal spores
Parasitic: A rare type caused by eating animals or foods contaminated with parasites
Amebic: A rare and almost always fatal brain infection caused by an amoeba swimming up the nose in contaminated waters and infecting the brain
Noninfectious: Caused by some cancers, autoimmune diseases, head injuries, or brain surgeries
Vaccines are available to protect people against some kinds of bacterial meningitis but not other types.
How Common Is Meningitis?
Viral meningitis is the most common type of meningitis in the United States and worldwide. Although painful and uncomfortable, this type typically resolves independently without medical intervention.
Cases of fungal, parasitic, and amebic meningitis occur in the United States. However, they are incredibly uncommon.
Here is a brief overview of the prevalence of different types of meningitis in the United Sates:
Viral: Children younger than 5 and those with weaker immune systems are more likely to get this disease. The incidence of viral meningitis has been estimated to range from 0.26 to 17 cases per 100,000 people. In the United States, there are up to 75,000 cases of enteroviral meningitis annually.
Bacterial: There are about 2,600 U.S. cases each year. About 70% of cases occur in children 5 and under.
Amebic: There have been only about 148 U.S. cases since 1962.
Noninfectious: This type is also rare and is not contagious. People with cancer and other diseases may be more susceptible to it than healthy individuals. Meningitis due to cancer is sporadic and affects less than 5% of cancer patients.
Meningitis by Age & Gender
Meningitis can affect people of any age and gender. However, infants, teens, young adults, and older adults have the highest rates of meningococcal disease in the United States.
Bacterial meningitis affects men slightly more than women, accounting for about 55% of all cases. There are approximately 1.2 cases per 100,000 in men, compared to 1 case per 100,000 population among women.
Also, meningitis symptoms may present differently in men and women. One study on bacterial meningitis patients at a hospital reported that:
Women presented with stiff necks more often than men.
Fever, cerebral spinal fluid glucose (CSF) less than 45 milligrams per deciliter (mg/dL), and an abnormal neurological examination were predictors of an adverse outcome in male patients.
People older than 60 with an abnormal neurological examination have a higher likelihood of a poor prognosis in female patients.
The study concluded that bacterial meningitis in males differs significantly from females regarding presenting symptoms and signs, abnormal laboratory and imaging analysis, and predictors of adverse clinical outcomes.
Causes of Meningitis and Risk Factors
Most meningitis cases are caused by a viral infection. However, only a very small number of people infected with a virus will develop meningitis.
Viruses that can cause meningitis include:
Non-polio enteroviruses
Arboviusis, such as West Nile virus
Certain bacteria cause meningitis. Strains responsible for causing the most U.S. bacterial meningitis cases include:
Streptococcus pneumoniae
Group B Streptococcus
Neisseria meningitidis
Haemophilus influenzae
Listeria monocytogenes
Escherichia coli (E. coli)
Research shows a slightly higher risk for bacterial meningitis in college students (particularly those living in dorms) compared to others their age who are not in college. Some college campuses have reported outbreaks of bacterial meningitis in recent years.
Amebic meningitis is caused by an amoeba swimming up the nose in contaminated waters and infecting the brain. Fungal meningitis is caused by the inhalation of fungal spores. Parasitic meningitis is caused by eating animals or foods contaminated with parasites.
What Are the Mortality Rates for Meningitis?
Mortality rates (incidence of death) are determined by the type of meningitis, the person's age, and overall health status. Viral meningitis typically resolves on its own without treatment and rarely, if ever, is deadly. However, some viral causes of meningitis require antiviral treatment.
According to the World Health Organization (WHO), about 1 in 10 people with bacterial meningitis die. Also, about 1 in 5 have severe complications such as brain damage, hearing loss, and learning disabilities. Some infected people can die in a few hours to a few days.
According to one study, the case fatality rate of fungal meningitis patients was about 9% with treatment. However, the fatality was 100% without treatment. Amebic meningitis is almost always fatal. However, there have only been about 148 U.S. cases since 1962. Parasitic meningitis infection is almost always fatal within 72 hours of the onset of symptoms.
Screening and Early Detection
Symptoms of meningitis disease can vary depending on the type of disease. However, the most universally common symptoms include:
Sudden fever
Headache
Stiff neck
Other symptoms may include:
Nausea
Vomiting
Increased sensitivity to light
Confusion
Irritability
Poor reflexes in infants
Diagnosing spinal meningitis requires a visit to a healthcare provider. They will start by collecting your medical history and gathering data about your symptoms.
Other diagnostic tests for meningitis include:
Blood tests
Lumbar puncture (spinal tap)
Diagnostic imaging of the brain and spine is also used to diagnose meningitis and can include:
Summary
Meningitis is inflammation of the meninges that protect and support the brain and spinal cord. Meningitis symptoms usually include a severe headache, a stiff neck, and a fever. Early diagnosis is essential to determine the correct course of treatment and improve the chances for a full recovery.
Viral meningitis is by far the most common type of meningitis in the United States and worldwide. Although it causes significant head pain, this type's treatment depends on what virus caused it. Other types of meningitis include bacterial, fungal, parasitic, amebic, and noninfectious, which are much more deadly and require quick intervention.
Screening and early diagnosis for meningitis are essential. If you or a loved one is experiencing any signs or symptoms of meningitis, contact your healthcare provider as soon as possible.
