Definition

The brain and spinal cord are covered by layers of tissue. These layers are called the meninges. Certain bacteria can cause an infection in these layers. This is called bacterial meningitis.

It is a serious infection that causes inflammation of the brain and spinal tissue. Bacterial meningitis is a medical emergency and requires immediate treatment. Depending on the severity of the infection, it can result in death within hours.

Bacterial Meningitis

Meningitis

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Causes

Bacterial meningitis is caused by many different bacteria and varies by age group. The most common are pneumococcal meningitis, meningococcal meningitis, and Hemophilus influenza B meningitis. The brain and spinal cord are protected from the bloodstream by the blood-brain barrier. Under certain circumstances bacteria in the bloodstream can travel through the blood-brain barrier into the cerebrospinal fluid that surrounds the brain and spinal cord causing meningitis. Severity of the infection depends on the bacteria causing it.

Transmission of the bacteria usually occurs by direct contact with oral or respiratory secretions, such as inhaling droplets from someone who sneezes or coughs, or by kissing. The spread of the bacteria depends on the time of the year, crowding, and the presence other respiratory infections.

Risk Factors

Bacterial meningitis is more common in infancy and childhood. For adults the risk increases as you age. Other factors that increase your chance of getting bacterial meningitis include:

    
  • Not having recommended vaccinations
  • Community living arrangements, such as a college dormitory or military base.
  • People in close and prolonged contact with patients with meningitis due to Hemophilus influenza B or Neisseria meningitidis
  • Supressed immune system caused by certain health conditions or medications
  • Penetrating head trauma
  • Previous brain surgery, or cerebrospinal fluid shunts
  • Birth defects, such as dermal sinus or meningomyelocele, a type of spina bifida
  • A history of epidural steroid injections or other invasive spinal procedures
  • Cochlear implants
  • Smoking, or exposure to second-hand smoke
  • congenital dura defects such as dermal sinus or meningomyelocele

    Symptoms

    Classic symptoms can develop over several hours or may take one to two days:

        
  • High fever
  • Headache
  • Very stiff, sore neck
  • Other symptoms may include:

        
  • Red or purple skin rash
  • Bluish skin color
  • Nausea
  • Vomiting
  • Sensitivity to bright lights
  • Sleepiness
  • Mental confusion
  • Seizures
  • In newborns and infants, symptoms are hard to see. As a result, infants under three months old 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 skin color)
  • Feeding poorly or refusing to eat
  • Tightness or bulging of soft spots between skull bones
  • Difficulty awakening
  • Complications of bacterial meningitis include:

        
  • Sepsis (serious bodily reaction to infection)
  • Shock (very low blood pressure)
  • Seizures
  • Brain swelling
  • Hydrocephalus (build-up of fluid in the brain)
  • Hearing loss
  • Vision problems
  • Paralysis
  • Coma
  • Death
  • Diagnosis

    Your doctor will ask about your symptoms and medical history. A physical exam will be done.

    Tests may include the following:

        
  • Blood tests—A complete blood count and c-reactive protein
  • Lumbar puncture —removal of a small amount of cerebrospinal fluid to check for bacteria if intracranial pressure is not too high infections
  • Cultures of blood, urine, mucous, and/or pus from skin
  • Imaging tests of the brain and spinal cord may be done with an MRI or CT scan .

    Treatment

    More than 90% of all people with this infection survive with immediate care, including:

        
  • Antibiotics and corticosteroids—often given together
  • Fluids
  • Antibiotics

    Antibiotics are given through an IV. This is started as soon as the infection is suspected. The antibiotics may be changed once tests find the exact bacterial cause. Patients usually stay in the hospital until the fever has fallen and the fluid around the spine and the brain is clear of infection. This may require a hospital stay of several days.

    Corticosteroids

    These are usually given by IV early in treatment. but only for those caused by the Hemophilus influenza B or pneumococcal virus. They control brain pressure and swelling. They also reduce the body’s production of inflammatory substances. This treatment can prevent further damage. Specifically it reduces the risk of hearing loss and neurological complications.

    Fluid Replacement

    Fluids can be lost due to fever, sweating, or vomiting. They may be replaced through an IV. It will be done carefully to avoid complications of fluid overloading.

    Other Medications

    Your doctor may also recommend:

        
  • Pain medications
  • Sedatives
  • Anticonvulsants
  • Medications to help reduce brain swelling
  • Prevention

    To help reduce your chance of getting bacterial meningitis, take these steps:

        
  • If you have been exposed to meningitis or are a carrier, your doctor may recommend prophylactic antibiotics to prevent infection.
  • Find out the status of you and your families vaccinations. In particular:     
  • Haemophilus influenzae(H. flu) type B vaccine vaccine
  • Pneumococcal vaccine
  • Meningococcal vaccine
  • If you are a healthcare worker or have close contact with someone who is infected, take preventive antibiotics against Hemophilus influenza B and neisseria meningitidis .
  • Buy pasteurized milk and milk products. This can prevent meningitis caused by Listeria monocytogenes .
  • If you are pregnant, your doctor will monitor you to make sure the infection is not passed to your baby.