Nursing College

1.  Meninges are three layers of membranes that cover and protect brain and spinal cord
(your central nervous system [CNS]). They’re known as:
1. Dura mater: it is the outer layer, closest to the skull.
contains a drainage system, called the dural venous sinuses,
which allows blood to leave brain and allows cerebrospinal
fluid to re-enter the circulation.
dura mater receives its blood supply from middle meningeal
artery and vein, and your trigeminal nerve runs through it.
2. Arachnoid mater: This is the middle layer..
3. Pia mater: is the inner layer, closest to brain tissue.
Many blood vessels pass through this layer to supply brain tissue
with blood
 the arachnoid mater and pia mater are called leptomeninges.
Their function is :
 protect and anchor your brain and provide a support system for blood vessels, nerves,
lymphatics and the cerebrospinal fluid that surrounds your central nervous system.

2. spaces within the meninges:
1. The epidural space:- is a space between skull and dura mater.
2. The subdural space :- is a space between dura mater and arachnoid mater. Under
normal conditions, this space isn’t a space, but can be opened if there’s trauma to
your brain (such as a brain bleed) or other medical condition.
3. The subarachnoid space :- is a space between your arachnoid mater and pia
mater. It’s filled with cerebrospinal fluid.

3. • Meningitis is an infection of the protective membranes that surround the brain and spinal
cord (meninges).
• It can affect anyone, but is most common in babies, young children, teenagers and young
adults
• It can cause life-threatening blood poisoning (sepsis) and result in permanent damage to
the brain or nerves.

4. 1) Bacterial meningitis
o Streptococcus pneumoniae
o Group B Streptococcus
o Neisseria meningitidis
o Haemophilus influenzae
o Listeria monocytogenes
o Escherichia coli
o Mycobacterium tuberculosis,, is a less common cause of bacterial meningitis
(called TB meningitis).
• Group B Streptococcus and E. coli: Mothers can pass to babies during birth.
• H. influenzae, M. tuberculosis, and S. pneumoniae: these bacteria spread by coughing or
sneezing while in close contact with others
• N. meningitidis: People spread these bacteria by respiratory or throat secretions (saliva or
spit). This typically occurs during close (coughing or kissing)
• E. coli: People can get these bacteria by eating food prepared by people who did not wash
their hands well after using the toilet.

5. 2) Viral meningitis: -
 Non-polio enteroviruses are the most common cause of viral meningitis it can be
found in an infected person’s
o feces (stool)
o eye, nose, and mouth secretions (such as saliva, nasal mucus, or sputum)
o blister fluid
 Mumps virus spreads through direct contact with saliva or respiratory droplets
from the mouth, nose, or throat
 Herpesviruses, including Epstein-Barr virus, herpes simplex viruses, and varicella-
zoster virus (which causes chickenpox and shingles)
 Measles virus
 Influenza virus
 Arboviruses, such as West Nile virus West Nile virus is most commonly spread to
people by the bite of an infected mosquito.
 Lymphocytic choriomeningitis virus spreads through direct contact with saliva
or respiratory droplets from the mouth, nose, or throat

6. 3) fungal meningitis include:-
o Cryptococcus.
o Histoplasma
o Blastomyces
o Coccidioides
o Candida.
4) Parasitic meningitis:- called eosinophilic meningitis
o can be caused by a tapeworm infection in the brain or cerebral malaria.
o Amoebic meningitis is a rare type that is sometimes contracted through
swimming in fresh water and can quickly become life-threatening.
5) Other meningitis causes
o Meningitis also can result from noninfectious causes. They include chemical
reactions, drug allergies, some types of cancer and inflammatory diseases
such as sarcoidosis.