Purulent Meningitis in Children

Jiang LiDepartment of Neurology

Children’s Hospital Chongqing University of Medical Sciences

Acute infection of central nervous system(CNS).

90% of cases occur in the age of 1mo-5yr. The inflammation of meninges caused by variou

s bacteria.Common features in clinical practices

include: fever, increased intracranial pressure,

meningeal irritation.

One of the most potentially serious infections, a

ssociated with high mortality (about 10%) and m

orbidity.

Purulent Meningitis

1.Etiology

1.1 Pathogens:

Main pathogens: Neissria meningitidis, streptoccus pneumoniae, Haemophilus influenzae. (2/3 of purulent meningitis are caused by these pathogens)

Pathogens in special populations (neonate & <3mo

infants , malnutrition, immunodeficiency): gramneg

ative enteric bacilli, group B streptococci, staphloco

ccus aureus

1.2 Major risk factors for meningitis

Immature immunologic function and attenuated

immunologic response to pathogens

Low level of immunoglobulin, defects of

complement and properdin system

Immature or impaired blood-brain-barrier (BBB)

Immature BBB function: maturation at about 1yr

Impaired BBB: Congenial or acquired defects

across mucocutaneous barrier

1.3 Access of bacteria invasion

Typical access---hematogenous dissemination

Bacteria colonizing the mucous membranes of

the nasopharynx invasion into local tissue

bacteremia hematogenous seeding to the

subarachnoid space

Mode of transmission: Person to person contact

through respiratory tract secretions or droplets

Bacteria spread to the meninges directly:

through anatomic defects in the skull or

head trauma

Invasion from parameningeal organs:

such as paranasal sinuses or middle ear

Access of bacteria invasion

2. Pathology

Structure of meninges

Characterized by leptomeningeal and

perivascular infiltration with

polymorphonuclear leukocytes and an

inflammatory exudate.

Exudate which may be distributed from

convexity of brain to basal region of cranium.

Exudate is more thickness due to

streptococcus pneumoniae than other

pathogens.

Pathology

3. Clinical manifestations

The younger the child is, the higher incidence of meningitis will be. ½-2/3 of cases occur less than 1yr of age.

Mode of presentation: Acute or fulminant onset: symptoms and signs of sepsis; meningitis evolve rapidly over a few hours and death within 24 hours; usually infected with Neissria meningitides (N. meningitides).

Subacute onset:

Precede by several days of upper respiratory

tract or gastrointestinal symptoms; difficult to

pinpoint the exact onset of meningitis; usually

with meningitis due to Haemophilus influenzae

(H influenzae) and streptoccus pneumococcus

(S pneumococcus).

Mode of presentation

Common features of meningitis:

signs of systemic infection : fever(90-95%),

anorexia,shock, alteration of mental status

and consciousness

neurological signs:

increased intracranial pressure: headache,

vomiting(82%), herniation

meningeal irritation: nuchal rigidity(77%),

kernig sign, brudzinski sign

Clinical manifestations

brudzinski sign

Seizure (20-30%)

Focal or generalized

Due to cerebritis, infarction, electrolyte

disturbances

Frequently noted with H influenzae &

S pneumococcal meningitis

Persist after 4th day and difficult to treat with

poor prognosis

Clinical manifestations

Clinical manifestations

Alteration of mental status and consciousness

Including: irritability, lethargy, stupor

obtundation, coma

Due to increased intracranial pressure,

cerebritis, hypotension

Often with pneumococcal or meningococcal

meningitis

Comatose patients with a poor prognosis

The symptoms and signs are not evident in

neonates and infants younger than 3mo of

age; and patients already received irregular

antibiotic therapy.

Clinical manifestations

Signs of systemic infection

Increased intracranial press

ure

meningeal irritation

Typical

(older children)

Fever,

altered consciousness, seizure

Headache, vomiting, herniation

nuchal rigidity, back pain, kernig sign, brudzinski sign

Atypical

(neonate & <3mo infant )

Fever,normal temperature or hypothermia; minim or subtle seizure; poor feeding;less activity

Scream,frown;

bulging or full fontanel; widening of the sutures

Not evident

Comparison of the manifestations of meningitis between different age groups

Clinical manifestations

4. Diagnosis

Earlier diagnosis and prompt initiation of effective

antibiotic treatment is critical for minimizing

sequelae of purulent meningitis.

Suspected cases: febrile infants with seizure,

meningeal irritability, increased intracranial

pressure, altered mental status

Pay attention to the atypical symptoms and

signs in neonate, infant and patient already

received irregular antibiotic therapy

Diagnosis is confirmed by analysis of cerebrospinal

fluid ( CSF)

Suggestion bacterial meningitis

Increased pressure (90%)

Appearance: slightly cloudy to purulent

Raised white blood cells,consisting chiefly of

polymorphonuclear leukocytes

Raised protein concentration, decreased

glucose concentration (80%)

Diagnosis

Confirmation of the diagnosis: isolation from the

CSF of a specific bacterial pathogen by

microscopy or a positive culture or rapid antigen-

detection test of CSF

Gram-stained smear of CSF: identify the

causative organism in 70-90% of cases

CSF culture: positive in about 80% of cases.

definitive diagnosis, determination of antibiotic

sensitivity.

PCR: amplifies bacterial DNA (H influenzae, N.

meningitidis)

Diagnosis

5. Differential diagnosis

Purulent meningitis caused by different pathogens

Neissria meningitidis:

Occur in epidemics (type A,C), which is more

common in spring, or sporadic all the year

(type B,C,Y)

Sudden onset with various cutaneous signs

( petechiae, purpura, or an erythematous

macular rash)

Streptococcus pneumoniae:

Young infants ( <1yr) are most susceptible

population

Peak season: spring and winter

Easier to have subdural effusion and

hydrocephalus

Easily have a protracted course and relapse

Differential diagnosis

Haemophilus influenzae

Occurs predominantly in infants 2mo to 2yr

of age

Many cases are in winter

Higher incidence of subdural effusion

Others pathogens: staphylococcus aureus,

gramnegative enteric bacilli

Special susceptible population: neonate,

<3mo infants, malnutrition, immunodeficiency

Severe infection, difficult to treat

Differential diagnosis

Meningitis caused by other microorganisms

Viral meningitis/encephalitisViral meningitis/encephalitis: :

Less severe systemic infectious symptoms Less severe systemic infectious symptoms

Usually not develop after 2-3weeksUsually not develop after 2-3weeks

CSF: normal glucoseCSF: normal glucose

Differential diagnosis

Tuberculous meningitisTuberculous meningitis

Subacute onset and progress Subacute onset and progress

A history of close contact with known A history of close contact with known

cases of tuberculosiscases of tuberculosis

Evidence of acute or healed tubercular Evidence of acute or healed tubercular

infection on chest x-rayinfection on chest x-ray

Tuberculin skin test : OT, PPDTuberculin skin test : OT, PPD

CSFCSF

Differential diagnosis

Disease Pressure

(Kpa)

aspect Total WBC

(x106/L)

Protein

(g/L)

Glucose

(mmol/L)

smears cultures

normal 0.69-1.96

(0.29-0.78)

clear 0-5

(0-20)

0.2-0.4

(0.2-1.2)

2.2-4.4 - -

Purulentmeningitis

cloudy (PMN)

(1-5)

(<2.2)

Gram’s stain +

+

Tuberculous

meningitis

Normal or

cloudy

(MN)

AFB stain +

Viral meningitis/

encephalitis

Normal or

Normal Normal or

(MN)

Normal or (<1)

normal -

Fungal meningitis

Normal or

Normal or

cloudy

(MN)

India ink prep

+

Cerebrospinal fluid in neurologic infection

6. Complications and sequelae

6.1 Subdural effusion

Definitive diagnosis: volume of fluid in subdural

space >2ml, protein>0.4g/L,

Incidence: develop in 10-30% of patients,

asymptomatic in 85-90% of patients; especially

common in infants 4-6 month of age ( rare in

children over 1yr);

Causative organisms: 45% of cases of

meningitis caused by H influenzae, 30% by

S pneumoniae, 9% by N meningitidis

subdural effusion

Indications:

No response to a sensitive antibiotic therapy

Prolonged fever or fever reoccurring after an

afebrile interval with effective treatment

Bulging fontanel, widening of sutures,

enlarging head circumference, emesis,seizure,

altered consciousness.

Improved CSF profile with more serious clinical

manifestations

subdural effusion

Diagnosis methods:

Cranial translucent test

B ultrasonic examination and CT

Subdural space puncture

subdural effusion

normal subdural effusion

6.2 Ventriculitis

6.3 hydrocephalus

Complications

Circulation of cerebrospinal fluid(CSF)

6.2 Ventriculitis

Usually occurs in neonates and infants (<1yr),

with severe prognosis

The main cause is delayed diagnosis and

treatment of meningitis.

Complications

Diagnosis:

B ultrasonic examination or neuroimaging

studies( CT, MRI): enlarged lateral ventricle

Lateral ventricle puncture: bacteria and

inflammatory cells in ventricular fluid,

WBC>50x106/L, Glucose<1.6mmol/L,Glucose<1.6mmol/L,

or protein>400mg/L.or protein>400mg/L.

Ventriculitis

Circulation of cerebrospinal fluid(CSF)

6.3 hydrocephalus :

Communicating hydrocephalus: adhered or

destroyed arachnoid granulation around the

cistern at the base of the brain

Obstructive hydrocephalus: following

obstructed of the cerebral aqueduct, or the

foramina of Magendie and Luschka

6.4 others:

Deafness, blindness, paralysis, epilepsy,

mental retardation

Complications

7. Treatment

7.1 Antibacterial therapy Therapy principles: early treatment, antibiotics

susceptible to pathogens and with high permeability through BBB, given intraveninously,

enough dose, enough course of antibiotic therapy

Susceptible to pathogens

First choice: Cefotaxime, Ceftriaxone (3dr

generation of cephalosporins, high permeability

through BBB, products of metabolism also has

effect, CSF sterilization within 24h)

Other choice: Penicillin, Chloromycin, Cefuroxime,

Ceftazidime ( delayed effect to make CSF sterile,

high incidence of relapse and deafness)

Antibacterial therapy

Etiology Standard antibiotics of choice Duration of therapy

H.influenzae Cefotaxime /Ceftriaxone 7-10days

N.meningitidis Cefotaxime /Ceftriaxone 7days

S.pneumoniae Cefotaxime /Ceftriaxone 2-3weeks

Staphlococcus aureus

Semisynthetic penicillins (Oxacillin sodium, Cloxacillin sodium),Norvancomycin

>3weeks

E.coli Cefotaxime /Ceftriaxone

(or + ampicillin)

> 3weeks

Unknown Cefotaxime/Ceftriaxone + ampicillin >2-3weeks

Antibiotic therapy of bacterial meningitis

Maintenance fluid and thermal energy supplement:

Fluid administration: 60-80ml/kg/day

Fluid infusion with dehydration therapy

7.2 Supportive care

Treatment

increased intracranial pressure

Osmotic therapy: intravenous mannitol 0.5-

1g/kg/every time, q4-6h

Combination with intravenous dexamethasone:

0.3-0.5mg/kg/day

Endotracheal intubation and hyperventilation

Treatment

Subdural effusion

Few volume could be absorbed with treatment

spontaneously

Subdural puncture: take out 15ml/each time

(unilateral puncture), less than 30ml/each time

( bilateral puncture), everyday or every other

day

Stripping operation: for the cases not cure after

3-4weeks

Treatment

Others:

Ventriculitis : lateral ventricle puncture and

injection of antibiotics locally

Epilepsy: AEDs

Treatment