meningitis

Causes of meningitis Bacterial Aseptic Viral Parasitic Non-infectious

What is bacterial Meningitis?? Acute bacterial meningitis is the most common form of meningitis Bacterial Meningitis occurs when pathogenic bacteria enter the subarachnoid space and cause an inflammatory response. This in turn interferes with blood flow and can result in paralysis or even stroke There are several pathogens that can cause bacterial meningitis. In the United States these include Haemophilus influenzae, Streptococcus pneumoniae, group B Streptococcus, Listeria monocytogenes, and Neisseria meningitidis. In the United States, about 4,100 cases of bacterial meningitis, including 500 deaths, occurred each year between 2003–2007 (CDC)

What is bacterial meningitis? The bacteria most often responsible for bacterial meningitis are common in the environment and can also be found in your nose and respiratory system without causing any harm. Sometimes meningitis occurs for no known reason. Other times it occurs after a head injury or after you have had an infection and your immune system is weakened. Common causes of bacterial meningitis vary by age group: Age Group Causes Newborns Group B Streptococcus, Escherichia coli, Listeria monocytogenes Infants and Children Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae type b Adolescents and Young Adults Neisseria meningitidis, Streptococcus pneumoniae Older Adults Streptococcus pneumoniae, Neisseria meningitidis, Listeria monocytogenes

Risk factors….. Age – infants are at higher risk for bacterial meningitis Community setting -infectious diseases tend to spread quickly within large cohabitating groups. College students and military personnel are at increased risk for meningococcal meningitis. Certain medical conditions - there are certain diseases, medications, and surgical procedures that may weaken the immune system or increase risk of meningitis in other ways. (ETOH abuse, sickle cell, splenectomy, corticosteroids.) Working with meningitis-microbiologists who are routinely exposed to meningitis-causing pathogens are at increased risk. Travel-travelers to Africa and travelers to Mecca during annual pilgrimages.

Meningitis & Pregnancy Pregnant women are at increased risk of developing listeriosis (caused by the bacterium Listeria monocytogenes). Pregnant women typically experience only a mild, flu-like illness with Listeria infection. Infections during pregnancy can lead to miscarriage, stillbirth, premature delivery, or life-threatening infection of the newborn, including meningitis. Pregnant women who test positive for group B Streptococcus (group B strep) can pass the bacteria to their baby, most often during labor and birth. A newborn infected with group B strep bacteria can develop meningitis or other life-threatening infections soon after birth. The risk of meningitis during pregnancy caused by Listeria monocytogenes can be reduced by learning what foods to avoid and how to safely prepare and refrigerate food. Pregnant women should get screened for group B strep at 35-37 weeks. Women who test positive for group B strep will be given antibiotics during labor to prevent infection in a newborn.

Signs and symptoms Onset of symptoms is rapid and severe and usually within 24 hours. Bacterial meningitis can cause serious complications such as brain damage, hearing loss or learning disabilities. Most people with meningitis recover however; if allowed to progress may be fatal. Signs and Symptoms include: Headache High Fever Neck Rigidity Sensitivity to light Upset stomach Fatigue Body Rash Sore throat Adult & Older Children Confusion, irritability, increasing drowsiness Seizure and stroke may occur Young Children Vomiting or loss of appetite Very irritable, crying Seizure or hydrocephalus may occur

How is it transmitted?? The pathogens that cause bacterial meningitis can be contagious. Can spread through the exchange of respiratory and throat secretions (e.g., airborne, kissing). Not spread by casual contact or by simply breathing the air where a person with meningitis has been Other meningitis-causing bacteria are not spread person-to-person, but can cause disease because the person has certain risk factors . Most of the bacteria that cause meningitis are not as contagious as diseases like the common cold or the flu. Unlike other bacterial causes of meningitis, you can get Listeria monocytogenes by eating contaminated food. Sometimes the bacteria that cause meningitis spread to other people. Usually happens when there is close or long contact with a sick person in the same household or daycare center, or if they had direct contact with a patient's oral secretions . Those who had close contact with meningococcal or Haemophilus influenzae type b meningitis are at higher risk of getting disease and may need antibiotics Close contacts of a person with meningitis caused by other bacteria, such as Streptococcus pneumoniae, do not need antibiotics.

How is it diagnosed?? If meningitis is suspected, samples of blood or cerebrospinal fluid are collected and sent to the laboratory for testing. To know the specific cause of meningitis is important because that helps doctors understand how to treat the disease, and possibly how bad it will get. In the case of bacterial meningitis, antibiotics can help prevent severe illness and reduce the spread of infection from person to person. If bacteria are present, they can often be cultured. Growing the bacteria in the laboratory is important for confirming the presence of bacteria, identifying the specific type of bacteria that is causing the infection, and deciding which antibiotic will work best. Other tests can sometimes find and identify the bacteria if the cultures do not. CAT Scans, X-Rays,

How is it treated?? It is important that treatment be started as soon as possible. Bacterial meningitis can be treated effectively with antibiotics. Appropriate antibiotic treatment reduces the risk of dying from meningitis, although the risk remains higher among young infants and the elderly. The most effective way to protect against certain types of bacterial meningitis is to complete the recommended vaccine schedule. There are vaccines available for three types of bacteria that can cause meningitis: Haemophilus influenzae type b (Hib) Neisseria meningitidis (meningococcus) Streptococcus pneumoniae (pneumococcus) Antibiotics may also be recommended for the entire family if a family member develops severe Hib infection and there’s a high risk person in the house. Maintaining healthy habits, like not smoking and avoiding cigarette smoke, getting plenty of rest, and not coming into close contact with people who are sick, can also help.

Can I get vaccinated?? The CDC recommends the meningococcal vaccine for: All children and adolescents ages 11 through 18 College freshmen living in dormitories Military recruits Scientists routinely exposed to meningococcal bacteria Anyone traveling to or living in a part of the world where the disease is common, such as Africa Anyone with a damaged spleen or who has had his or her spleen removed Anyone who has terminal complement component deficiency (an immune system disorder) The CDC does not recommend the vaccine for: Anyone who has ever had a severe (life threatening) allergic reaction to a previous dose of meningococcal vaccine. Anyone who has a severe (life threatening) allergy to any vaccine component. Tell your doctor if you have any severe allergies. The CDC recommends that the following individuals wait before receiving the vaccine:  Anyone who is moderately or severely ill at the time of their scheduled appointment to receive their shot should wait until they recover. Anyone who has ever had Guillain-Barre syndrome should discuss getting the vaccine with his or her doctor. Pregnant women should only get the vaccine if it is clinically indicated

Aseptic Meningitis The term aseptic meningitis refers loosely to all cases of meningitis in which no bacterial infection can be demonstrated. This is usually due to viruses, but it may be due to bacterial infection that has already been partially treated, with disappearance of the bacteria from the meninges, or by infection in a space adjacent to the meninges (e.g. sinusitis). Endocarditis (infection of the heart valves with spread of small clusters of bacteria through the bloodstream) may cause aseptic meningitis.

Aseptic Meningitis Aseptic meningitis may also result from infection with spirochetes, a type of bacteria that includes Treponema pallidum (the cause of syphilis) and Borrelia burgdorferi (known for causing Lyme disease). Meningitis may be encountered in cerebral malaria (malaria infecting the brain). Fungal meningitis, e.g. due to Cryptococcus neoformans, is typically seen in people with immune deficiency such as AIDS. Amoebic meningitis, meningitis due to infection with amoebae such as Naegleria fowleri, is contracted from freshwater sources.

Viral Meningitis Viruses that can cause meningitis include enteroviruses, herpes simplex virus type 2 (and less commonly type 1), varicella zoster virus (known for causing chickenpox and shingles), mumps virus, HIV, and LCMV.

parasitic Meningitis A parasitic cause is often assumed when there is a predominance of eosinophils (a type of white blood cell) in the CSF. The most common parasites implicated are Angiostrongylus cantonensis, Gnathostoma spinigerum, Schistosoma, as well as the conditions cysticercosis, toxocariasis, baylisascariasis, paragonimiasis, and a number of rarer infections and noninfective conditions.

Non-infectious Meningitis Meningitis may occur as the result of several non-infectious causes: spread of cancer to the meninges (malignant or neoplastic meningitis) and certain drugs (mainly non-steroidal anti- inflammatory drugs, antibiotics and intravenous immunoglobulins). It may also be caused by several inflammatory conditions such as sarcoidosis (which is then called neurosarcoidosis), connective tissue disorders such as systemic lupus erythematosus, and certain forms of vasculitis (inflammatory conditions of the blood vessel wall) such as Behçet's disease.

Non-infectious Meningitis Epidermoid cysts and dermoid cysts may cause meningitis by releasing irritant matter into the subarachnoid space. Mollaret's meningitis is a syndrome of recurring episodes of aseptic meningitis; it is thought to be caused by herpes simplex virus type 2. Rarely, migraine may cause meningitis, but this diagnosis is usually only made when other causes have been eliminated.