Definition
The brain and spinal cord are encased by layers of tissue. These layers are
called the meninges. Certain bacteria can cause an infection in
these layers called bacterial meningitis, a serious infection that can cause death
within hours. A quick diagnosis and treatment are vital.
Causes
Many times, the bacteria first cause an upper respiratory tract infection. Then the bacteria travel through the bloodstream to the brain. Worldwide, three types of bacteria cause the majority of cases of acute bacterial meningitis: Streptococcus pneumoniae
(the bacterium that causes pneumonia); Neisseria meningitidis
; and Haemophilus influenzae type B (Hib). In the United States, widespread immunization has almost eliminated meningitis caused by Hib. Other forms of bacterial meningitis include Listeria monocytogenes meningitis, Escherichia coli meningitis, Mycobacterium tuberculosis meningitis, and group B Streptococcus meningitis.
Newborn babies and the elderly are more prone to get sick. Some forms are spread by direct contact with fluid from the mouth or throat of an infected person. This can happen during a kiss or by sharing eating utensils. In general, meningitis is not spread by casual contact.
Risk Factors
Risk factors for bacterial meningitis are close and prolonged contact with persons with meningitis caused by Hib or N. meningitidis; a weakened immune system caused by human immunodeficiency virus (HIV) infection or other conditions; alcoholism; smoking (for meningitis caused by N. meningitidis); and living in proximity to others, such as in dormitories and military barracks (for meningitis caused by N. meningitidis). At higher risk are infants, young children, and persons older than age sixty years.
Symptoms
Classic symptoms can develop over several hours or may take one to two days.
These symptoms are a high fever, headache, and a stiff, sore neck. Other symptoms
may include red or purple skin rash, cyanosis (bluish skin), nausea,
vomiting, photophobia (sensitivity to bright lights), sleepiness, and mental
confusion.
In newborns and infants, symptoms are hard to see. As a result, infants younger than three months of age with a fever are often checked for meningitis. Symptoms in newborns and infants may include inactivity; unexplained high fever or any form of temperature instability, including a low body temperature; irritability; vomiting; jaundice (yellow color to the skin); feeding poorly or refusing to eat; tautness or bulging of soft spots between skull bones; and difficulty awakening. As the illness progresses, seizures or hearing loss, or both, can occur. This can happen to patients of all ages.
Screening and Diagnosis
A doctor will ask about symptoms and medical history and will conduct a
physical exam. Tests may include a spinal tap (removal of a small amount of
cerebrospinal
fluid to check for bacteria); other cultures (testing of
samples of blood, urine, mucus, and pus from skin infections); magnetic resonance
imaging (a scan that uses radio waves and a powerful magnet
to produce detailed computer images) to be sure the inflammation is not from some
other cause, such as a tumor; and a computed tomography scan (a detailed
X-ray picture that identifies abnormalities of fine tissue structure).
Treatment and Therapy
More than 90 percent of all people with this infection survive when they
receive immediate care that includes antibiotics and corticosteroids, which are often given together, and fluids.
Options include antibiotics, which are given intravenously (IV). This is started
as soon as the infection is suspected. The antibiotics may be changed once tests
name the exact bacterial cause. The patient usually stays in the hospital until
his or her fever has fallen. The fluid around the spine and the brain must also be
clear of infection.
Another treatment option is corticosteroids. These are usually given by IV early in treatment. They control brain pressure and swelling and reduce the body’s production of inflammatory substances. This treatment can prevent further damage. Also, fluids can be lost because of fever, sweating, or vomiting. They may be replaced through an IV, but replaced carefully to avoid complications of fluid overloading. The doctor might prescribe pain medications and sedatives, and also anticonvulsants to prevent seizures.
Prevention and Outcomes
To help reduce the chances of infection with bacterial meningitis, one should
consider getting the recommended vaccines (for oneself and one’s child). The vaccines include Hib vaccine (for
babies), pneumococcal vaccine (for children younger than two years of
age, for adults older than age sixty-five years, and for others with certain
medical conditions), and meningococcal vaccine (for children age
eleven to twelve years and for others at high risk; people in the high-risk group
may need to be vaccinated every five years).
Persons such as health care workers, who have close contact with someone who is infected, should take preventive antibiotics. Another preventive measure is to use only pasteurized milk and milk products, which can prevent meningitis caused by L. monocytogenes. Persons who are pregnant will be monitored by a doctor to ensure the infection is not passed to the fetus.
Bibliography
"Bacterial Meningitis." Centers for Disease Control and Prevention. CDC, 1 Apr. 2014. Web. 29 Dec. 2015.
Centers for Disease Control and Prevention. “An Updated Recommendation from the Advisory Committee on Immunization Practices (ACIP) for Revaccination of Persons at Prolonged Increased Risk for Meningococcal Disease.” Morbidity and Mortality Weekly Report 58.37 (2009): 1042–043. Print.
Christodoulides, Myron, ed. Meningitis: Cellular and Molecular Basis. Boston: CABI, 2013. Print.
Ferreiros, C. Emerging Strategies in the Fight Against Meningitis. New York: Garland Science, 2002. Print.
Greenlee, John. "Meningitis." Merck Manual Consumer Version. Merck, n.d. Web. 29 Dec. 2015.
Shmaefsky, Brian. Meningitis. Rev. ed. Philadelphia: Chelsea, 2010. Print.
Tunkel, Allan R. Bacterial Meningitis. Philadelphia: Lippincott, 2001. Print.
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