|Specialty|| Neurology |
Haemophilus meningitis is a form of bacterial meningitis caused by the Haemophilus influenzae bacteria. It is usually (but not always) associated with Haemophilus influenzae type b.Meningitis involves the inflammation of the protective membranes that cover the brain and spinal cord. Haemophilus meningitis is characterized by symptoms including fever, nausea, sensitivity to light, headaches, stiff neck, anorexia, and seizures. Haemophilus meningitis can be deadly, but antibiotics are effective in treating the infection, especially when cases are caught early enough that the inflammation has not done a great deal of damage. Before the introduction of the Hib vaccine in 1985, Haemophilus meningitis was the leading cause of bacterial meningitis in children under the age of five. However, since the creation of the Hib vaccine, only two in every 100,000 children contract this type of meningitis. Five to ten percent of cases can be fatal, although the average mortality rate in developing nations is seventeen percent, mostly due to lack of access to vaccination as well as lack of access to medical care needed to combat the meningitis.
Haemophilus influenzae is a Gram-negative, coccobacillary, facultatively anaerobic pathogenic bacterium belonging to the Pasteurellaceae family. H. influenzae was first described in 1892 by Richard Pfeiffer during an influenza pandemic.
The Haemophilus influenzae type B vaccine, often called Hib vaccine, is a vaccine used to prevent Haemophilus influenzae type b (Hib) infection. In countries that include it as a routine vaccine, rates of severe Hib infections have decreased more than 90%. It has therefore resulted in a decrease in the rate of meningitis, pneumonia, and epiglottitis.
In epidemiology, a case fatality rate (CFR)—or case fatality risk, case fatality ratio or just fatality rate—is the proportion of deaths within a designated population of "cases" over the course of the disease. A CFR is conventionally expressed as a percentage and represents a measure of risk. CFRs are most often used for diseases with discrete, limited time courses, such as outbreaks of acute infections.
Possible symptoms of Haemophilus meningitis include:
Nausea is an unpleasant, diffuse sensation of unease and discomfort, often perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged, and has been described as placing discomfort on the chest, upper abdomen, or back of the throat.
Fever, also known as pyrexia and febrile response, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using values between 37.5 and 38.3 °C. The increase in set point triggers increased muscle contractions and causes a feeling of cold. This results in greater heat production and efforts to conserve heat. When the set point temperature returns to normal, a person feels hot, becomes flushed, and may begin to sweat. Rarely a fever may trigger a febrile seizure. This is more common in young children. Fevers do not typically go higher than 41 to 42 °C.
Headache is the symptom of pain anywhere in the region of the head or neck. It occurs in migraines, tension-type headaches, and cluster headaches. Frequent headaches can affect relationships and employment. There is also an increased risk of depression in those with severe headaches.
While the Haemophilus influenzae bacteria are unable to survive in any environment outside of the human body, humans can carry the bacteria within their bodies without developing any symptoms of the disease. It spreads through the air when an individual carrying the bacteria coughs or sneezes.The risk of developing Haemophilus meningitis is most directly related to an individual's vaccination history, as well as the vaccination history of the general public. Herd immunity, or the protection that unvaccinated individuals experience when the majority of others in their proximity are vaccinated, does help in the reduction of meningitis cases, but it does not guarantee protection from the disease. Contact with other individuals with the disease also vastly increases the risk of infection. A child in the presence of family members sick with Haemophilus meningitis or carrying the bacteria is 585 times more likely to catch Haemophilus meningitis. Additionally, siblings of individuals with the Haemophilus influenzae meningitis receive reduced benefits from certain types of immunization. Similarly, children under two years of age have a greater risk of contracting the disease when attending day care, especially in their first month of attendance, due to the maintained contact with other children who might be asymptomatic carriers of the Hib bacteria.
An asymptomatic carrier is a person or other organism that has become infected with a pathogen, but that displays no signs or symptoms.
An airborne disease is any disease that is caused by pathogens that can be transmitted through the air. Such diseases include many of considerable importance both in human and veterinary medicine. The relevant pathogens may be viruses, bacteria, or fungi, and they may be spread through breathing, talking, coughing, sneezing, raising of dust, spraying of liquids, toilet flushing or any activities which generates aerosol particles or droplets. Human airborne diseases do not include conditions caused by air pollution such as Volatile Organic Compounds (VOCs), gases and any airborne particles, though their study and prevention may help inform the science of airborne disease transmission.
Herd immunity is a form of indirect protection from infectious disease that occurs when a large percentage of a population has become immune to an infection, thereby providing a measure of protection for individuals who are not immune. In a population in which a large number of individuals are immune, chains of infection are likely to be disrupted, which stops or slows the spread of disease. The greater the proportion of individuals in a community who are immune, the smaller the probability that those who are not immune will come into contact with an infectious individual.
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Before the widespread use of the Hib vaccine, Haemophilus meningitis accounted for 40%-60% of all meningitis cases in children under the age of fifteen, and 90% of all meningitis cases in children under the age of five.Vaccination can reduce incidence. Vaccination has reduced the occurrences of Haemophilus meningitis by 87-90% in countries with widespread access to the Hib vaccine. Rates are still high in areas with limited levels of vaccination. Less-developed countries as well as countries with medical infrastructure that has been damaged in any way, such as from warfare, do not have such widespread access to the vaccine and thus experience higher rates of meningitis cases. Multiple conjugate Hib vaccines are available for use, though, and are extremely effective when given to infants. Additionally, the vaccine has only the side effects of reddened skin and swelling at the location of the injection.
Vaccination is the administration of a vaccine to help the immune system develop protection from a disease. Vaccines contain a microorganism in a weakened or killed state, or proteins or toxins from the organism. In stimulating the body's adaptive immunity, they help prevent sickness from an infectious disease. When a sufficiently large percentage of a population has been vaccinated, herd immunity results. The effectiveness of vaccination has been widely studied and verified. Vaccination is the most effective method of preventing infectious diseases; widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the elimination of diseases such as polio, measles, and tetanus from much of the world.
Conjugate vaccines combine a weak antigen with a strong antigen so that the immune system has a stronger response to the weak antigen.
Because it is a bacterial disease, the primary method of treatment for Haemophilus meningitis is anti-bacterial therapy. Common antibiotics include ceftriaxoneor cefotaxime, both of which can combat the infection and thus reduce inflammation in the meninges, or the membranes that protect the brain and spinal cord. Anti-inflammatories such as corticosteroids, or steroids produced by the body to reduce inflammation, can also be used to fight the meningeal inflammation in an attempt to reduce risk of mortality and reduce the possibility of brain damage.
Pathogenic bacteria are bacteria that can cause disease. This article deals with human pathogenic bacteria. Although most bacteria are harmless or often beneficial, some are pathogenic, with the number of species estimated as fewer than a hundred that are seen to cause infectious diseases in humans. By contrast, several thousand species exist in the human digestive system.
Ceftriaxone, sold under the trade name Rocephin, is an antibiotic used for the treatment of a number of bacterial infections. These include middle ear infections, endocarditis, meningitis, pneumonia, bone and joint infections, intra-abdominal infections, skin infections, urinary tract infections, gonorrhea, and pelvic inflammatory disease. It is also sometimes used before surgery and following a bite wound to try to prevent infection. Ceftriaxone can be given by injection into a vein or into a muscle.
Cefotaxime is an antibiotic used to treat a number of bacterial infections. Specifically it is used to treat joint infections, pelvic inflammatory disease, meningitis, pneumonia, urinary tract infections, sepsis, gonorrhea, and cellulitis. It is given either by injection into a vein or muscle.
Survivors of Haemophilus meningitis may experience permanent damage caused by inflammation around the brain, mostly involving neurological disorders. Long-term complications include brain damage, hearing loss, and mental disability.Other possible long-term effects are reduced IQ, cerebral palsy, and the development of seizures. Children that survive the disease are more often held back in school, and are more likely to require special education services. Negative long-term effects are more likely in subjects whose treatments were delayed, as well as in subjects who were given antibiotics to which the bacteria was resistant. Ten percent of survivors develop epilepsy, while close to twenty percent of survivors develop hearing loss ranging from mild loss to deafness. About 45% of survivors experience no negative long-term effects.
Encephalitis is inflammation of the brain. Severity is variable. Symptoms may include headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, trouble speaking, memory problems, and problems with hearing.
Conjunctivitis, also known as pink eye, is inflammation of the outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may occur. The affected eye may have increased tears or be "stuck shut" in the morning. Swelling of the white part of the eye may also occur. Itching is more common in cases due to allergies. Conjunctivitis can affect one or both eyes.
Pneumonia is an inflammatory condition of the lung affecting primarily the small air sacs known as alveoli. Typically symptoms include some combination of productive or dry cough, chest pain, fever, and trouble breathing. Severity is variable.
Waterhouse–Friderichsen syndrome (WFS) is defined as adrenal gland failure due to bleeding into the adrenal glands, commonly caused by severe bacterial infection: Typically it is caused by Neisseria meningitidis.
A febrile seizure, also known as a fever fit or febrile convulsion, is a seizure associated with a high body temperature but without any serious underlying health issue. They most commonly occur in children between the ages of 6 months and 5 years. Most seizures are less than five minutes in duration and the child is completely back to normal within an hour of the event.
Acute bronchitis, also known as a chest cold, is short-term inflammation of the bronchi of the lungs. The most common symptom is a cough. Other symptoms include coughing up mucus, wheezing, shortness of breath, fever, and chest discomfort. The infection may last from a few to ten days. The cough may persist for several weeks afterward with the total duration of symptoms usually around three weeks. Some have symptoms for up to six weeks.
The HACEK organisms are a group of fastidious gram-negative bacteria that are an unusual cause of infective endocarditis, which is an inflammation of the heart due to bacterial infection. HACEK is an abbreviation of the initials of the genera of this group of bacteria: Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella. The HACEK organisms are a normal part of the human microbiota, living in the oral-pharyngeal region.
Asplenia refers to the absence of normal spleen function and is associated with some serious infection risks. Hyposplenism is used to describe reduced ('hypo-') splenic functioning, but not as severely affected as with asplenism.
Bacterial pneumonia is a type of pneumonia caused by bacterial infection.
Epiglottitis is inflammation of the epiglottis—the flap at the base of the tongue that keeps food from going into the trachea (windpipe). Symptoms are usually rapid in onset and include trouble swallowing which can result in drooling, changes to the voice, fever, and an increased breathing rate. As the epiglottis is in the upper airway, swelling can interfere with breathing. People may lean forward in an effort to open the airway. As the condition worsens stridor and bluish skin may occur.
The schedule of childhood immunizations in the United States is given by the Centers for Disease Control and Prevention (CDC). The vaccination schedule is broken down by age: birth to six years of age, seven to eighteen, and adults nineteen and older. Childhood Immunizations are key in preventing children for diseases that were once epidemics.
Meningococcal disease describes infections caused by the bacterium Neisseria meningitidis. It has a high mortality rate if untreated but is vaccine-preventable. While best known as a cause of meningitis, it can also result in sepsis, which is an even more damaging and dangerous condition. Meningitis and meningococcemia are major causes of illness, death, and disability in both developed and under-developed countries.
Immunization during pregnancy, that is the administration of a vaccine to a pregnant woman, is not a routine event as it is generally preferred to administer vaccines either prior to conception or in the postpartum period. When widespread vaccination is used, the risk for an unvaccinated pregnant patient to be exposed to a related infection is low, allowing for postponement, in general, of routine vaccinations to the postpartum period. Nevertheless, immunization during pregnancy may occur either inadvertently, or be indicated in a special situation, when it appears prudent to reduce the risk of a specific disease for a potentially exposed pregnant woman or her fetus.
A pneumococcal infection is an infection caused by the bacterium Streptococcus pneumoniae, which is also called the pneumococcus. S. pneumoniae is a common member of the bacterial flora colonizing the nose and throat of 5–10% of healthy adults and 20–40% of healthy children. However, it is also a cause of significant disease, being a leading cause of pneumonia, bacterial meningitis, and sepsis. The World Health Organization estimate that in 2005 pneumococcal infections were responsible for the death of 1.6 million children worldwide.
Meningitis is an acute inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The most common symptoms are fever, headache, and neck stiffness. Other symptoms include confusion or altered consciousness, vomiting, and an inability to tolerate light or loud noises. Young children often exhibit only nonspecific symptoms, such as irritability, drowsiness, or poor feeding. If a rash is present, it may indicate a particular cause of meningitis; for instance, meningitis caused by meningococcal bacteria may be accompanied by a characteristic rash.
A vaccine-preventable disease is an infectious disease for which an effective preventive vaccine exists. If a person acquires a vaccine-preventable disease and dies from it, the death is considered a vaccine-preventable death.
Rachel Schneerson was a senior investigator in the Laboratory in Developmental and Molecular Immunity and head of the Section on Bacterial Disease Pathogens and Immunity within the Laboratory at the Eunice Kennedy Shriver National Institute of Child Health and Human Development within the National Institutes of Health. She is best known for her development of the vaccine against bacterial meningitis with her colleague John B. Robbins.