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Bacterial meningitis
meningitis
 An inflammation of the leptomeninges .
 bacterial meningitis is a common complication of
septicemia in children and must be treated as an
emergency.
 Caused by :
bacteria, viruses , or rarely fungi .
viral infection of the CNS are much more common
than bacterial infection
meningitis
 Bacterial meningitis is one of the most potentially
serious infection ,in infants and older children .
 Associated with a high rate of acute complications
and risk of long-term morbidity.
 The etiology of meningitis in the neonate and the
treatment are generally distinct from in older
children
meningitis
 A limited number of bacteria are associated
with meningitis in normal hosts .
 the principle of supportive management and the
initial choice of antibiotics can be generalized.
Etiology of meningitis
2 month – 12yr:
S .pneumonia, N . Meningitidis ,H .influenza
type b.
H .influenza type b is the most common cause of
meningitis in children < 4-yr
Etiology and epidemiology of meningitis
 2 month : maternal flora and environment .
Group B and D. streptococci
gram – negative enteric bacilli .
and listeria monocytogenes.
may be due H.Influenza type b and nonecapsulate
and other pathogens
Etiology and epidemiology of meningitis
 Lack of immunity ( IgM or igG anti capsular antibody )
to specific pathogens with young age.
 recent colonization with pathogenic bacteria .
 Close contact with invasive disease ( respiratory
tract secration)
 Crowding , poverty , black race , male .
 Defect in complement (C5- C8 ) associated with
recurrent meningococcal infection .
Etiology and epidemiology of meningitis
 ventricular-peritoneal shunts:
Coagulase negative staphylococci and
corynebacteria .
 CSF leaks due to fracture cribriform palate
or paranasal sinus ( pneumococcal ).
 head trauma or neurosurgical procedures (
staphylococci )
Etiology and epidemiology of meningitis
 Splenic disfunction (sickle cell anemia or
asplenia ) increased risk of pneumococcal ,
H.influenza type b ,rarely meningococcal
sepsis and meningitis .
 Immuno-suppressed patients with T-cell
defects (AIDS, and malygnancy) :
Cryptococcal and L.monocytogens.
 Open neural tube defect :
Meningomyelocele and lombosacral
dermal sinus associated with staphylococci
-Aureus and gram – negative .
pathogenesis
 Bacterial meningitis is usually hematogenous.
(endocarditis , pneumonia , or thrombophlebitis ,
burns , indwelling catheters )
 Bacteremia precedes the condition or occur at the
same time.
 microorganisms leads to nasopharyngeal
colonization , replication , invasion , and
bacteremia .
pathogenesis
 Bacteria entry to the CSF through the choroid
plexus.and meningeal seeding , binding to specific
receptors and production of local cytokines
initiates inflammation.
 Neutrophilic infiltration , increase vascular
premeablity , alterations of blood- brain barrier ,
and cerebral edema .
pathogenesis
 Meningitis rarely may be follow bacterial invasive
from a contiguous focus of infection ;
Paranasal synusitis , otitis media ,mastoiditis ,
orbital cellulitis, cranial osteomyelitis , penetrating
cranial trauma ,meningomyeloceles ,
More often brain abscesses or epidural or subdural
empyema follows contiguous infection .
Clinical manifestation

Onset has two patterns;
1.
The more dramatic and less common is sudden
onset(< 1 day ) rapidly progressive of shock
,purpura , DIC ,and reduce level of
consciousness frequntly resulting in death in 24
hr ( S.pneumoniae , or N. meningitidis )
2.
More often is preceded by several days of upper
respiratory tract symptoms or GI symptoms .
Subacute 2-3day .(H. influenzae)
Clinical manifestation
1.
In the young infants:
fever usually is present and irritablity ,poor
feeding , restlessness,may be noted.
signs of meningeal inflammation may be
minimal.
2.
Older child :
confusion , back pain , usually Kernig and
Brudzinski signs in some children particularly
age < 12-18 mo are not present
Clinical manifestation
 Increased ICP
headache , diolopia , emesis , bulging fontanel
3 or 6 nerve paralysis, hypertension with
bradicardia ,apnea or hyperventilation ,stupor
coma ( brain herniation )
 inflammation of the meninges is associated with
(headache ,nausea , vomiting , irritability , nuchal
regidity , photophobia )
 Arthritis ,arthralgia ,myalgia , anemia , petechia
,purpura
Clinical manifestation
 Papilledema is uncommon .
intracranial abcess , subdural empyema or
occlusion of a dural venous sinus
 Focal neurologic signs are due to vascular
occlusion
(10-20% )
 Seizures occur in 20-30%
Seizures that occure on presentation or within the
first 4 days of onset are no prognostic significance
Clinical manifestation
 Seizures
cerebritis, infarction , electrolyte
 Alteration of mental status
increased ICP,cerebritis ,hypotension
Clinical manifestation
 Kernig sign:
Flexion of the hip 90 degrees with subsequent
pain with extension of the leg .
 Brudzinski sign :
Involuntary flexion of the knees and hips after
passive flexion of the neck while supine.
diagnosis
 Blood culture
( reveal responsible bacteria 50-90% )
 LP
analysis CSF for WBC count with diff ,protein,
glucose ,Gram stain helpful in 90% , culture)
CSF leukocyte count elevated >1000 and
neutrophil (75-95%)

In tramatic LP Gram stain ,culture , glucose level
may not be influenced.
diagnosis
 LP should be performed in every child when
1.
2.
3.
4.
5.
bacterial meningitis is suspected. Except :
when signs of increased ICP are present .
Infection at the LP site.
Suspicion of a mass lesion.
Extreme patient instability.
Thrombocytopenia is a relative contraindication.
diagnosis
 Patient in the flexed lateral decubitus position .
 Intervertebral space L3-L4 or L4-L5.
 Turbid CSF when CSF leukocyte count >200-400.
 Pleocytosis may be absent and is a poor
prognostic sign.
 Pleocytosis with a lymphocytosis may be present
during early stage of acute meningitis
Differential diagnosis
 Acute viral meningoencephalytis( PMN may be
prodominant)
 Partial treatment of a acute bacterial meningitis .
(glucose , protein , neutrophile are not aletread)
 TB ,fungal , spirochete ,,brain abcess , encephalitis
bacterial endocarditis with embolism ,subdural
empyema , subarachnoid hemmorhage ,
 Careful examination CSF ,and additional laboratory
tests are important .
CSF findings
pressure
Normal
1 00-60,000
Partial treat
Abscess
proteinmg/dl
50-180mm <4 ,60-70%lymph
Bacterial
Viral
leukocyte
N
N
N
20-45
100-500
1-10,000
100
1000, lymph
20-100
0-100 PMN
20-200
glucosemg/dl
>50 or75% blood
<40
N
generally N
N
treatment
1.
Decreasing CSF damage caused by the
inflammation response with dexamethasone
0.6mg/kg/24hr for 2 days
2.
3.
Sterilization of CSF .
Supportive therapy :
Maintenance of adequate CNS systemic perfusion.
Treatment shock , DIC, SAIDH , seizures , ICP
increased ,apnea ,arrhythmia ,coma .
complication
 Seizure ,increased ICP ,nerves palsies ,stroke ,cerebral or
cerebellar herniation ,thrombosis venous sinuses,
 Subdural effusion :
in 10-30% that asymtomatic in 85-90%.
In Symptomatic patient with increased ICP depressed
consciousness aspiration must be done.
Fever alone is not indication of aspiration.
treatment
 Empirical choice must cover S.pneumoniae .
 Many of which are Relatively resistance to penicillin
(mic0.1-1) is more common than high – level resistance .
 Cefotaxime (200-300 mg/kg/24) or ceftrixone (100mg/kg/24)
plus vancomycin (60 mg/kg/24).
 Cefotaxime and ceftrixone also cover N.meningitidis
or H .influenza type b.
 if L-monocytogenes is suspected ( infant<2 mo )
Ampicillin 200/kg/24hr plus ceftriaxone .
Duration of treatment
 S. Pneumoniae ( 10 -14 days)
 N.Meningitidis ( 7days)
 H.influenza (10 days)
 Gram negative meningitis should be treated for 3
WK or 2 WK after CSF sterilization .
 Patients with evidence of acute bacterial meningitis
but no identifiable pathogen cetrixone for7-10 days.
repeat CSF examination

Repeat LP indicated ;
1.
2.
3.
in neonate
Gram negative meningitis
In β – lactam resistance S, pneumoniae .

CSF should be sterile within 24- 48 hr
Prevention in meningococcal meningitidis
 Chemoprophylaxis:
for all close contacts of patients with meningococcal
meningitis.
with the rifampin 10mg/kg every 12 hr for 2 days
(600mg)
 Close contacts :
household,daycare ,direct exposure with oral
secration ,
Prevention
( H, influenza)
 Rifampin should be given to all close family.
20 mg/kg /24hr once each day for 4 days.
prognosis
 Mortality rate
H,influenza 8% , meningococcal 15%,
for pneumococcal 25%.
 35% survivors have some sequelae;
Deafness: is the most common neurologic
sequelae.
30% with pneumococcal meningitis and 10%meningococ ,520% H.influ.
seizures ,learning disability ,blindness ,paresis ,
ataxia , hydrocephallus ,mental retardation
Poor prognosis
 Young age .(< 6mo)
 long duration of illness before antibiotic therapy.
 late –onset seizure (>4days).
 shock ,coma, focal neurologic sign
 low or absent CSF WBC in the presence of visible
bacteria on gram stain of CSF .
 immuno compromised status.
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