MENINGITIS

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.

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.

Blood
flow Astrocyte
Endothelial
cells
Brain
capillary
CSF Neuron Water, oxygen,
and glucose

MENINGITIS
• Meningitis is an inflammation of the meninges,
usually the leptomeninges.
• Septic meningitis
• Chronic meningitis
• Aseptic meningitis
• Neonatal meningitis

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

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

SYMPTOMS
• Fever
• Stiff neck
• Headache
• Nausea
• Change in mental status
• Manifestations :-
• Convulsions & Coma leading to shock

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

SYMPTOMS
• Fever
• Headache
• Stiff neck
• Nausea & vomiting
• Lethargy
• Confusion
• Mental deterioration

ASEPTIC MENINGITIS
• Caused by virus and usually self limiting
• Coxsackie virus A & B
• Echovirus
• Herpes simplex virus

SYMPTOMS
• Fever
• Headache
• Stiff neck
• Nausea & vomiting.

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

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).

PHYSICAL APPEARANCE OF CSF
SEPTIC MENINGITIS CHRONIC MENINGITIS ASEPTIC MENINGITIS
TURBID OR CLOUDY TURBID OR SPIDER WEB IS
PRESENT ON STANDING
CLEAR

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 .

LAB DIAGNOSIS
Staining
• Gram stain
N. meningitidis S. pneumoniae

INDIA INK
Capsulated yeast cell

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

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

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)

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.

Streptococcus pneumoniae
• More common and serious in children <5yrs of age.
• CDC data: It has the highest mortality rate at 21%.
Vaccine is available.

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.