Meningitis is an inflammation of the protective membranes surrounding the brain and spinal cord, primarily caused by bacterial or viral infections, with significant emphasis on bacterial meningitis from Neisseria meningitidis. The disease can be spread through respiratory droplets and can lead to severe complications, including permanent brain damage or death, particularly in certain high-risk groups. Diagnosis and treatment involve physical examinations, CSF analysis, and antibiotics, alongside preventive measures like vaccinations against specific bacteria.

1. Prepared by,
ARATHY R NATH

2. An inflammation of the
meninges, the thin lining
surrounding the brain
and the spinal cord.
Meningitis is usually
caused by bacteria or
viruses, but can be a
result of injury, cancer, or
certain drugs.
Main focus on bacterial
meningitis due to
Neisseria meningitidis
(meningococcus); causes
large scale epidemics.

3. TRANSMISSION
o Transmission is person to person from respiratory
droplet/throat secretions during close and prolonged
contact with carrier or sick untreated person. No
animal reservoirs.
o Incubation: 4 days in average (range is 2-10 days).
o Bacteria sometimes overwhelms the body’s defenses
allowing infection to spread through the bloodstream
and to the brain.

4. o Asymptomatic carriers:
-bacteria in the pharynx (throat)
unaffected by the disease themselves
-can transmit it to others
-prevalence: 1-10% (endemic situations), 10-25%
(epidemics).

5. CLASSIFICATION
Infectious meningitis is broadly classified into 3
groups:
1)Acute Pyrogenic (BACTERIAL) Meningitis
2)Aseptic (usually acute VIRAL ) Meningitis
3)Chronic ( usually TUBERCULOUS/ FUNGAL )
Meningitis

6. CAUSATIVE AGENTS OF
MENINGITIS

7. 1) BACTERIAL AGENTS
o NEONATAL : E.Coli
Group B Streptococci
o INFANTS : Hemophilus Influenzae
o ADOLESCENTS : Niesseria meningitidis ( most common)
Streptococcus pneumoniae
o ELDERLY : Listeria monocytogens
Streptococcus pneumoniae
2) VIRAL AGENTS
o Enterovirus (most common)
o Mumps virus
o Coxsackie virus
o HSVII
o EBV

8. 3) FUNGAL AGENTS:
o Candida albicans,
o Cryptococcus neoformans
o Blastomyces dermatidis
o Coccidiodesimitis
4) PARASITES
Protozoa
Nematodes
Cestodes

9. ROUTES OF INFECTION
There are 4 methods by which microbes enter the
nervous system
Hematogenous route : through arterial and venous
spread; is the most common route of entry
Direct implantation : it may be traumatic or rarely
iatrogenic i.e. through a lumbar puncture needle
Local extension : through air sinuses, infected tooth or a
surgical site.
Through peripheral nervous system : as occurs with
certain viruses.

10. Meningitis is usually caused by bacteria or viruses, but can
be a result of injury, cancer, or certain drugs.
1) BACTERIAL MENINGITIS
 Also known as septic meningitis
 Extremely serious that requires immediate care
 Can lead to permanent damage of brain or disability
and death.
 Spreads by : coughing and sneezing.
 Vaccines are available to help protect against some
kinds of bacterial meningitis.

11. Pathophysiology
Bacteria enters blood stream/ trauma
Enters the mucosal surface/ cavity
Breakdown of normal barriers
Crosses the blood brain barrier
Proliferates in the CSF
Inflammation of the meninges
Increase in ICP

12. Risk factors
Certain people are at increased risk for bacterial meningitis.
Some risk factors include:
1) Age
Babies are at increased risk for bacterial meningitis
compared to people in other age groups. However,
people of any age can develop bacterial meningitis. See
section above for which bacteria more commonly affect
which age groups.
2) Community setting
Infectious diseases tend to spread where large groups of
people gather together. College campuses have reported
outbreaks of meningococcal disease, caused by
N. meningitidis.

13. 3) Certain medical conditions
There are certain medical conditions, medications, and
surgical procedures that put people at increased risk for
meningitis.
4) Working with meningitis-causing pathogen
Microbiologists routinely exposed to meningitis-causing
bacteria are at increased risk for meningitis.

14. 5) Travel
Travelers may be at increased risk for meningococcal
disease, caused by N. meningitidis, if they travel to
certain places, such as:
o The meningitis belt in sub-Saharan Africa,
particularly during the dry season
o Mecca during the annual Hajj and Umrah pilgrimage

15. Clinical manifestation
o Fever
o Severe headache
o Nausea and vomiting
o Nuchal rigidity
o Positive Kerning’s sign
o Positive Brudzinski’s sign
o Photophobia
o A decreased level of consciousness
o Signs of increase ICP
o Coma

16. Complications
o Waterhouse-Friderichsen syndrome
o obstructive hydrocephalus
o chronic adhesive arachnoiditis
o focal cerebritis
o Phlebitis leading to venous occlusion and hemorrage of
underlying brain.

17. 2) Viral meningitis
 Meningitis caused by viruses is called ‘viral meningitis’.
 It is relatively common.
 Most cases of viral meningitis are mild. Some people may be
hospitalised for a short time.
 On rare occasions viral meningitis can be life threatening.
 It can be caused by various different viruses and is often a
complication of another viral illness.

18. 3) Chronic meningitis
Slow-growing organisms (such as fungi and
Mycobacterium tuberculosis) that invade the membranes
and fluid surrounding your brain cause chronic
meningitis.
Chronic meningitis develops over two weeks or more.
The symptoms of chronic meningitis — headaches, fever,
vomiting and mental cloudiness — are similar to those of
acute meningitis.

19. 4) Fungal meningitis
o Fungal meningitis is relatively uncommon and causes
chronic meningitis. It may mimic acute bacterial
meningitis.
o Fungal meningitis isn't contagious from person to person.
o Cryptococcal meningitis is a common fungal form of the
disease that affects people with immune deficiencies, such
as AIDS.
o It's life-threatening if not treated with an antifungal
medication.

20. 5) Other meningitis causes
Meningitis can also result from noninfectious causes,
such as chemical reactions, drug allergies, some types
of cancer and inflammatory diseases such as
sarcoidosis.

21. Diagnostic evaluation
 By +ve signs
 Physical examination
 History collection
 CSF evaluation for pressure, proteins, glucose and
leukocytes.
 Blood test
 CBC
 Blood culture
 MRI
 CT scan

22. MANAGEMENT

23. Treatment of meningitis include :
a) Specific treatment
Treatment is started with antibiotic, commonly used
antibiotics are (Cephalosporins, vancomycin, cefotaxine )
for 7-14 days & 3 weeks for gram –ve bacteria.
b) Symptomatic treatment
 Seizure management: phenobarbitone, Dilantin &
Diazepam
 Management of intracranial pressure: Mannitol, Frusemide
 Fever and headache: Aspirin or acetaminophen

30. PREVENTION
Some forms of bacterial meningitis can be prevented by vaccination
 Haemophilus influenzae type b Hib vaccine is recommended a
part of the National Immunization Program and is available fr
ee for all children at 6 weeks , 4 months, 6 months and 12
months of age and is administered in a combination vaccine.
 Meningococcal
a vaccine is available for the meningococcal B strain; however
this vaccine is not currently on the National Immunisation
Schedule, more inofrmation visit your GP or immunisation
provider.