2. ANATOMY
• MENINGES: layers which surround the brain & spinal
cord (Pia mater, Arachanoid mater & Duramater)
• Arachanoid mater + Pia mater = Leptomeninges
• The outer layer Dura mater act as protective shield.
3. ANATOMY CONT
• CSF (cerebrospinal fluid): A watery fluid,
continuously produced and absorbed, which
flows in the ventricles (cavities) within the
brain and around the surface of the brain and
spinal cord.
5. MENINGITIS
• Meningitis is an inflammation of the meninges,
usually the leptomeninges.
• Septic meningitis
• Chronic meningitis
• Aseptic meningitis
• Neonatal meningitis
6. Mode Of Spread
• Can develop when the bacteria travel via the blood
from another infection (sinusitis, mastoiditis, otitis
media, neurosurgical procedures)
• Often severe and is a medical emergency. It
progresses rapidly, and if left untreated, can cause
permanent damage, example (hearing loss, loss of
limb)
• CDC data: 10% will die despite early diagnosis and
treatment.
• CDC :- Center for Disease Control Atlanta America
7. SEPTIC MENINGITIS
• Caused by bacteria other than Mycobacterium
• Etiology:- Depend on age, immune status, and whether
the infection is community acquired or nosocomial.
• Neisseria meningitidis
• Streptococcus pneumonae
• Hemophilus influenzae
• E. coli & other Gram negative rods
• Group b streptococci (S. agalacteae)
• Listeria monocytogenes
8. SYMPTOMS
• Fever
• Stiff neck
• Headache
• Nausea
• Change in mental status
• Manifestations :-
• Convulsions & Coma leading to shock
9. CHRONIC MENINGITIS
• Caused by M. tuberculosis or fungi
• Often occurred in immuno-compromised patient
• Mycobacterium tuberculosis
• Cryptococcus neoformans
• Candida spp.
• Histoplasma capsulatum
• Miscellaneous other fungi
13. NEONATAL MENINGITIS
• Infant meningitis is a type of meningitis with
diagnosis based on the age of the infant.
VIRAL COMMENTS BACTERIAL COMMENTS PARASITIC
Enteroviruses Most
common in
children <3
months of age
E. Coli & other
GNB
<1 month of
age
Toxoplasma
gondii
HSV Vesicular
lesions may
be present in
cluster
Streptococcus
agalactiae
<1 month of
age
14. LAB DIAGNOSIS
• SAMPLE:- CSF obtain by lumber puncture (between
L3-L4/L4-L5) and collected in three/two plain tubes
(red cap)
• Vial 1 :- biochemical examination
• Vial 2 :- microbiological examination
• Vial 3 :- cell count
• DO NOT REFRIGERATE CSF. IT SHOULD BE LEAVE AT
ROOM TEMPRATURE OR INCUBATED.
• Only 3-5 ml of fluid should be collected
• Rate of collection should be slow (4-5 drops/sec).
15. PHYSICAL APPEARANCE OF CSF
SEPTIC MENINGITIS CHRONIC MENINGITIS ASEPTIC MENINGITIS
TURBID OR CLOUDY TURBID OR SPIDER WEB IS
PRESENT ON STANDING
CLEAR
16. MICROBIOLOGICAL EXAMINATION
• If possible the sample should be divided into three
parts;
• Part I :- sample is centrifuged and Gram stain, ZN
stain, India Ink preparation should be made.
• Part II :- sample is inoculated on Blood, Chocolate
and MacConkey agar.
• Part III :- Sample is mix with glucose broth and
incubated overnight and then inoculated on above
mentioned plates.
• Incubated at 35-37°C and with 5-10% CO2 .
19. Culture of CSF
• If septic meningitis is suspected then CSF inoculated
on Blood, Chocolate and MacConkey agar
• If chronic meningitis is suspected, then for MTB
inoculate on LJ media and if Fungi is suspected then
inoculated on Blood agar, BHI agar and on SDA.
• And if viral meningitis is suspected then PCR is done
and if delay then CSF preserve by freezing it below
-70 °C
20. CULTURE & DETECTION
• Identification is based on colony characters and
biochemical reaction
• Continuous culture system like BACT/ALERT
• Molecular detection like PCR
• Latex agglutination test for
• Meningococcus, Pneumococcus, H influenzea type b &
for Cryptococcus neoformans
21. LAB DIAGNOSIS
CLINICAL
SETTING
LEUKOCYTES/mm3 PREDOMINANT
CELL TYPE
PROTEIN GLUCOSE
Normal 0-5 None 15-50 mg/dl 45-100 mg/dl
Viral
infection
2-2000 (80) Lymphocytes Slightly
elevated or
Normal
Normal
Septic
meningitis
5-20,000 (800) PMN Elevated
(>100 mg/dl)
Low
(<45 mg/dl)
Chronic
meningitis
5-2000 (100) Lymphocytes Elevated
(>100 mg/dl)
Normal or
often low
(>45 mg/dl)
22. Neisseria meningitidis
• Leading cause of bacterial meningitis and is highly
contagious.
• Crowded living conditions increase the risk (such as
daycare centers, nursing homes, dorms).
• Immunosuppressive pts, passive smoking, very
young & very old are affected.
• Prognosis: 5-10% mortality rate.
23. Streptococcus pneumoniae
• More common and serious in children <5yrs of age.
• CDC data: It has the highest mortality rate at 21%.
Vaccine is available.
24. Management
• Electrolyte imbalance, hypovolaemia and cardiac
output must be corrected.
• While colloids are administered to correct the
hypovolaemia, subsequent crystalloids are restricted.
• Other measures such as hyperventilation
(maintaining pCO2 between 3.5 and 4.5 kPa) and
careful use of mannitol are also important.
• Patients must be managed in an intensive care unit
and nursed in a quiet room with the head slightly
raised above the rest of the body.
