Why is meningitis so dangerous? - Melvin Sanicas
- 1,518,537 Views
- 8,198 Questions Answered
- TEDEd Animation
Meningitis is the inflammation of the meninges, the protective membranes that cover the brain and spinal cord. Meningitis may be caused by a fungus, bacteria, or virus. Viral meningitis is more common, but is not usually life-threatening. Fungal meningitis is rare and only happens in people with weakened immune system. Bacterial meningitis, on the other hand, is serious and can be life-threatening.
The 3 most common causes of bacterial meningitis are Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenza—all respiratory pathogens spread from person to person through mucus and saliva expelled when a person sneezes, coughs, talks or laughs. Once acquired, bacteria can colonize the nasal cavity, the throat, including the base of the tongue, tonsils, and soft palate—this is known as the pharyngeal carriage. From there, bacteria may cross the membrane that lines various cavities in the body and enter the blood.
While in the blood, the bacteria can reach the meninges, thereby causing inflammation of the brain and spinal cord. A headache is an early warning sign. When there is swelling in the brain, the senses go haywire. Swelling of the temporal lobe can cause ringing in the ears (tinnitus) or partial hearing loss; swelling of the occipital lobe may cause light sensitivity. Swelling of the medulla oblongata causes nausea and vomiting.
A stiff neck and back are common too. In severe cases, spasms of the muscles cause backward arching of the head, neck, and spine (a state called opisthotonus). Babies and young children are more likely to experience opisthotonus. A baby with meningitis may produce a high-pitched scream when you try to pick them up. For infants, a tight or bulging fontanel (the soft spot on top of a baby’s head) is a sign of inflammation of the brain. Excessive sleepiness is also a common symptom, and it may be hard to wake a sleeping child.
Bleeding also occurs under the skin and starts off looking like a mild rash. As the infection worsens, the rash spreads and gets darker, eventually looking like large bruises. The “glass test” is used to test for meningitis. If you press a drinking glass against a rash, it fades away. If it’s meningitis, the rash can still be seen through the glass. The glass test is not 100% accurate but with the other symptoms described present, seek medical attention immediately.
Bacterial meningitis is common in countries such as the “meningitis belt’ in Sub-Saharan Africa. People traveling to or residing in these countries are at high-risk of getting infected.
Outbreaks are most likely to happen in places where people live close to each, including college dorms or military barracks.
Fortunately, the most serious forms of bacterial meningitis can be prevented with the following vaccines: (1) Haemophilus influenzae type b (Hib) vaccine, (2) Pneumococcal vaccine, (3) Meningococcal conjugate vaccine. Getting vaccinated against measles, mumps, rubella, and chickenpox can help prevent diseases that can lead to viral meningitis. New vaccines are being developed to protect against other common causes of meningitis. Since 2010, a special vaccine called MenAfriVac has been designed for use throughout the African “meningitis belt.”
Learn the symptoms to protect you and your loved ones. Click here to find out more about meningitis.
Create and share a new lesson based on this one.