Bacterial Meningitis – Types, Causes, and Complications.

Definition

Meningitis is an infection of the membranes (meninges) surrounding the brain and spinal cord. Meningitis can be caused by a bacterial, fungal or viral infection. Meningitis can be acute, with a quick onset of symptoms, it can be chronic, and lasting a month or more, or it can be mild or aseptic. In the case of Bacterial meningitis, bacterial infection can cause the tissues around the brain to swell. This in turn interferes with blood flow and can result in paralysis or even stroke.

Bacterial Meningitis

Types of Bacterial Meningitis

1. Haemophilus influenza type b (Hib) – Leading cause of Bacterial Meningitis before 1990’s in children caused by bacteria Haemophilus influenzae.
2. Listeriosis – Caused by bacteria Lesteriamonocytogenes which are found almost everywhere. In soft cheese, hot dogs and luncheon meats. Most healthy people don’t get infected from this. More susceptible to pregnant women, new born and older adults. People are most vulnerable when they are weakened immune system.

History

Meningitis outbreak was first recorded in Geneva in 1805. Gaspard Vieusseux (1746-1814) and Andre Matthey (1778-1842) in Geneva, and Elisa North (1771-1843) in Massachusetts, described epidemic (meningococcal) meningitis. Several other epidemics in Europe and the United States were described shortly afterward.

In Africa the first outbreak was described in 1840. African epidemics became much more common in the 20th century. The first major one was reported in Nigeria and Ghana in 1905–1908. In early reports large number of people died of the disease. The first evidence that linked bacterial infection as a cause of meningitis was written by Austrian bacteriology Anton Vaykselbaum who described meningococcal bacteria in 1887.

Heinrich Quincke (1842-1922) utilized his new technique of lumbar puncture (1891) to provide an early analysis of cerebrospinal fluid (CSF). William Mestrezat (1883-1929), and H. Houston Merritt (1902-1979) compiled large series of CSF profiles in meningitis. Organisms causing meningitis were identified in the late 19th century including:

• Streptococcus pneumonia
• Neisseria meningitidis
• Haemophilus influenzae

Epidemiology of bacterial meningitis

The estimated annual incidence of bacterial meningitis is 2 to 5 per 100,000 people in the Western world. In the US, the overall incidence of bacterial meningitis is 1.38 to 2.0/100,000 population per year. However, incidence rates are age-specific. Incidence measured between 2006 and 2007 found the highest rates among neonates <2 months of age (80.7/100,000), followed by children aged 2 months to 23 months (6.91/100,000), with a further decline in children 2 to 10 years of age (0.56/100,000) and in children 11 to 17 years of age (0.43/100,000), and an increase in adults with a maximum in the age group of 65 plus years (1.92/100,000).

The incidence rate is also high among males, black people, and people of low socio-economic status. In less-developed countries, the incidence may be as much as 10 times greater than that for the Western world.  The epidemiology of bacterial meningitis has changed due to widespread immunization programmes with new vaccines. For example, in countries that use universal immunization with Haemophilus influenzae type b (Hib) vaccine, the incidence of bacterial meningitis caused by this pathogen has declined more than 99%.

Causes

Bacterial meningitis can be caused by a range of bacteria, including:

• Haemophilus influenzae ( influenzae) type B (Hib)
• Neisseria meningitides ( meningitides)
• Streptococcus pneumoniae ( pneumonia)
• Listeria monocytogenes ( monocytogenes)
• Group B Streptococcus

At different ages, people are more likely to be affected by different strains. The bacteria that cause meningitis usually pass from one person to another, for example, through droplets in coughs and sneezes or through saliva or spit. Some types can spread through food. Group B Streptococcus can pass from mothers to newborns during delivery.

Some people are carriers. They have the bacteria, but they do not develop symptoms. Living in a house with either a carrier or someone who has meningitis increases the risk. It is important to follow the recommended vaccination schedule to prevent meningitis. H. influenza is the main cause of bacterial meningitis in children under 5 in countries that do not offer the Hib vaccine.

Risk factors

Bacterial meningitis can happen at any age, but infants are more susceptible.

Other factors that increase the risk include:.

• An anatomical defect or trauma, such as a skull fracture, and some kinds of surgery, if these allow a way for bacteria to enter the nervous system
• An infection in the head or neck area
• Spending time in communities, for example, at school or college
• Living in or traveling to certain locations, such as sub-Saharan Africa
• Having a weakened immune system, due to a medical condition or treatment
• Working in laboratories and other settings where meningitis pathogens are present

Symptoms of bacterial meningitis

Bacterial meningitis symptoms typically begin suddenly and progress rapidly, within 24 hours. In adults and elderly patients, bacterial meningitis symptoms may include the following:

• Sudden high fever
• Headache
• Stiff neck
• Confusion
• Drowsiness
• Irritability
• Seizures
• Stroke

Diagnosis and Tests

• CT-Scan
• X-Ray
• Meningitis rash glass test:

A meningitis rash occurs if blood leaks into the tissue under the skin. It may start as a few small spots in any part of the body, then spread rapidly and look like fresh bruises. The glass test can assist in identifying a meningeal rash.

• Press the side of a drinking glass firmly against the rash
• If the rash fades and loses color under pressure, it is not a meningitis rash
• If it does not change color, you should contact a doctor immediately. The rash or spots may fade and then come back.

 

Meningitis rash test

• Treatment for bacterial meningitis normally involves admission to the hospital, and possibly an intensive care unit. Antibiotics are essential, and these may be started before the results of tests come back, possibly before arrival at the hospital.

Treatment and Medications

Treatment and medications includes:

• Antibiotics: These are usually given intravenously (For example: forms of penicillin and cephalosporins)
• Corticosteroids: These may be given if inflammation is causing pressure in the brain, but studies show conflicting results.
• Acetaminophen, or paracetamol: Together with cool sponge baths, cooling pads, fluids, and room ventilation, these reduce fever.
• Anticonvulsants: If the patient has seizures, an anticonvulsant, such as phenobarbital or Dilantin, may be used.
• Oxygen therapy: Oxygen will be administered to assist with breathing.
• Fluids: Intravenous fluids can prevent dehydration, especially if the patient is vomiting or cannot drink.
• Sedatives: These will calm the patient if they are irritable or restless.
• Antiviral drugs: May be helpful in shortening the course of viral meningitis, and antifungal medications are available as well (For example acyclovir)

Blood tests may be used to monitor the patient’s levels of blood sugar, sodium, and other vital chemicals.

Prevention and vaccinations

Prevention of meningitis primarily involves the appropriate treatment of other infections an individual may acquire, particularly those that have a track record of seeding to the meninges (such as ear and sinus infections). Preventive treatment with antibiotics is sometimes recommended for the close contacts of an individual who is ill with meningococcal or H. influenzae type b meningitis.

A meningococcal vaccine exists, and is sometimes recommended to individuals who are traveling to very high risk areas. A vaccine for H. influenzae type b is now given to babies as part of the standard array of childhood immunizations.