Meningitis

Dr. Kalpana MallaMD Pediatrics

Manipal Teaching Hospital

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Definitions

• Meningitis : inflammation of the lepto-meninges covering the brain and the spinal cord

• Encephalitis : inflammation of brain parenchyma, with cerebral dysfunction.

• Encephalopathy : cerebral dysfunction , due to toxins, metabolites, poisons etc , affecting neurons without inflammatory response.

Classification:

1) Viral2) Bacterial 3) Tubercular4) Others: Parasitic: malarial, amebic, toxoplamosis

Fungal: candiadiasis, cryptococcal, histoplasmosis

Bacterial Meningitis• Causes:• 0-2months: - Group B & D streptococcus - Gram neg enteric bacilli - E.coli, Klebsiella pneumoniae - L. monocytogenes - Sometimes H influenza2mo-5years: - H. influenzae typeb - Strep. Pneumoniae

- N. meningitidis>5 years: - S. pnemoniae - N. meningitidis

May spread to the meninges either Hematogenously, or by contiguous spreadPredisposing factors include:1) Septicemia2) Septic foci in skin, lungs, bones3) Trauma ie. Fracture base of the skull4) Neural tube defects5) Suppurative ear, mastoid infec

Etiology • N meningitis – epidemics• S. Pneumoniae – epidemics• H influenza – uncommon after 3 years,

incidence decreased after Hib vaccine.• Less common – staph – seen in vp shunt• Less common – E. coli, pseudo, proteus –

neonates, immuno compromised.

PATHOGENESIS Host : • Young age , close contact with bacteria , altered

immunoglobulin response, defect of complement system – C5-8 – recurrent meningococcal inf.,

• Defect of properdin system : meningococcal inf.,• Splenic dysfunction : pnemococcal and H influenza• T lymphocyte defect : L monocytogens• Altered mucocutaneous barrier : cribiform plate

damage, middle ear inf. – pneumococcal• Lumbosacral myelocele : staph and gram neg. enteric

bacilli

BACTERIAL COLONISATION OF NASOPHARYNX with pathogenic bacteria(eg N meningitis and H influenza attach to mucosal surface by pilli and enter circulation)

Blood stream Invasion / Bacteremia

CNS PENETRATION

DIRECT INVASION

THROUGH choroid plexus Lat ventricle, meninges

BLOOD CYTOKININE RELEASE

Intravascular Volume decreases

↓CSF flow

EndothelialLeukocyte activation

Release ofSecondary mediators

Bacteria rapidly multiply As CSF conc. Of complement And antibody LOW

Complement system activation CSF cytokine release

BBB disturbedPMN STIMULATION

FREE RADICAL RELEASE

↓CSF flow

Meningeal inflammation

Brain edema

Brain damage

Clinical features:

• Constitutional symptoms : Lethargy, irritability , anorexia, vomiting, fever – mild, high, hypothermia in infants, Poor

feeding, Arthralgia, myalgia

Meningeal features: Neck rigidity, kernig’s, brudzinski’s sign. These may be absent in infants, Neck pain,

Clinical features:

• Features of raised ICP: - HTN with bradycardia, - Apnea or hyperventilation, - Head ache , photophobia, - Vomiting- projectile - Buldging AF if open, 6th nerve palsy - Hypertonia, extensor plantars - Decorticate/decerebrate posturing - Papilledema

Raised ICP due to:

1) Cell death (cytotoxic cerebral edema)2) Cytokine induced increased vascular

permeability(vasogenic cerebral edema)3) Increased hydrostatic pressure after

obstructed reabsorption of CSF in the villus or obstruction of the flow of fluid from the ventricle

4) SIADH

Clinical features:

Features of parenchymal involvement: Altered sensorium, seizures, Coma and focal

neurological signs• Cutaneous features: erythamatous macular

rashes, petechiae

Clinical features:

• Extra CNS manifestations: Rashes, petechiae, athralgia, shock, DIC,

depending on etiology

In very young, immunocompromised, severely malnourished child signs of overt meningitis may be absent

Meningitis in neonates and infants

• Vacant stare, persistent vomiting, refusal to suck, poor tone, poor cry, shock, circulatory collapse, hypothermia/fever, convulsions, neurological signs.

• More risk if – premature, LBW, coplicated labour, PROM, maternal sepsis……

Signs:

• Neck rigidity• Kernig’s sign• Brudzinski’s sign• Bulged fontanelle• Sutural diastasis• Cranial n. palsies (oculomotor, abducens,

facial, auditory)• photophobia

Tubercular Meningitis• Most serious complication & fatal without Rx• Commonly affects children from 6mo- 4years

of age• Rapid progression occur in infants & young

children

TBM

• Pathogenesis:1) Rupture of subependymal tubercles – TB

bacilli in subarachnoid space2) Lymphohematogenous dissemination of

primary infection

First stage

• Over 1-2 weeks – 2-8 weeks• Stage of invasion/prodromal stage• Nonspecific and vague● Fever ● Headache● Irritability ● Drowsiness● Malaise ● Shrill cry 100% cure

Second stage - Stage of meningitis

• Over 1-2 wks• More abrupt• Lethargy - Projectile vomiting• Nuchal rigidity - Bulging frontanelle• Seizures - Cranial nerve palsies• Kernig/brudzinisky’s sign +• 25% mortality, 25 % sequelae

• Hypertonia• Cranil N palsies 3rd-7th • Ocular paralysis• Strabismus, nystagmus• Hemiplegia/quadriplegia• Semicoma/coma

Third stage - Stage of coma• Unconscious- Coma• Repeated convulsions • High fever: “terminal fever”• Severe neurological involvements – - Hemiplegia/paraplegia - Quadriplegia/ decerebrate rigidity - Decerebrate posturing - Opsithotonus - Deteriorating mental status• Deteroration of vital signs- Hypertension• 50% mortality • 50% cure but almost all have sequelae

Disabilities of TBM

• Blindness ● deafness● paraplegia /hemiplegia● squint ● MR● epilepsy ● CP● CN palsies ● Endocrine disturbances

INVESTIGATIONS

1)Lumbar puncture: should be done before any antibiotics started

precautions: C/I for an immediate LP : - EVIDENCE OF increased ICT ( other than

bulging fontanels). - Fundoscopy, to rule out papilloedema -

-infections overlying the site of puncture

-Relative C/I - Thrombocytopenia-Cardiopulmonary compromise & shock

LP• DO RBS 30 min before LP.• CHILD IN LATERAL POSITION with knee, hip, head

flexed.• Clean site L4-5, L3-4.• LP stilleted needle, with direction towards umblicus ,

perpendicular to spine.• Collect CSF – TUBE 1 – cell count, type• Tube 2 – C/S.• TUBE 3 – glucose, protein• Tube 4 – latex fixation tests• 0.5 to 1 ml each tube.

Investigations 2) Blood Culture: 3) Chest Roentogram4) S. electrolytes5) CBC, CRP6) Skin scraping for C/S7) Mantoux Test7) Serology: Latex agglutination, counter

current immunoelectrophoresis8) CT,MRI- for detection of hydrocephalus,

abcess, effusion, exudates, edema

Normal PYOGENIC VIRAL MYCOBACTERIAL

FUNGAL

GROSSCLEAR

TURBID CLEAR COBWEB CLEAR-TURBID

Pressure Mm H20

50-80

100-300 80-150 >80 >80

PYOGENIC VIRAL MYCOBACTERIAL

FUNGAL

SUGARMG/DL

>50(75% OF RBS

<40(<50% OF RBS)

N ( < 40 IN

MUMPS)

<50 <50

PROTEIN

MG/DL20-45

100-500 50-200 100-3000 25-500

PYOGENIC VIRAL MYCOBACTERIAL

FUNGAL

TOTAL CELL

<5

100-10,000 100 10-500 5-500

PREDOMINAT TYPE,>75%

Lympho

PMN lymphocytes

Lympho Monnuclear

PARTIALLY TREATED MENINGITIS

• Culture : sterile in 48 hrs• Sugar normalize by 48 hrs• Cells may increase initially, persistence of

neutrophil indicates poor response.• Protein : take longer time to normalize, thus

not good parameter for adequacy of treatment.

RAPID DIAGNOSTIC TESTS

• PCR – for diagnosis of infections ( herpes, TB, meningococci)

• Latex agglutination and ELISA- antigen antibody detection

• CSF C-RP, LDH, lactic acid – to differentiate pyogenic from non pyogenic.

ORGANISM ANTIBIOTIC DOSE DURATION

UNKNOWN

EMPERIC1)CEFTRIAXONE2)CEFOTAXIME3)AMPI/PENCILLIN G + CHRAMPHENi

100-150 MG/KGDAY4 LAC U/KG/DAY100 MG/KGDAY

10 DAYS

MENINGOCOCCUs

Pencillin G 3-4 lac U/KG/DAY

7DAYS

ORGANISM ANTIBIOTIC DOSE DURATION

Pneumococcus

Pencillin G or if resistance – Ceftriaxone plusVancomycin

40 MG/KG/D

10DAYS

Gram neg. Ceftriaxone/cefotaxime plus aminoglycogide

21DAYS

ORGANISM ANTIBIOTIC DOSE DURATION

Pseudomonas Ceftazidime 150 MG/KG/D

14-21DAYS

Staphylococci

Vancomycin 40 MG/KGDAY

28DAYS

H influenza CeftriaxoneCefotaxime

10-14 DAYS

2) Anti inflammatory therapy Dexamethasone: 0.15mg/kg/dose 6hrly for 2

daysFirst dose should be given prior to starting antibiotics

In case of TBM: prednisolone;4-6wks

STEROID THERAPY

• Rationale : to decrease cytokine related damage , esp . To 8th nerve .

• Decrease ICT• ESP. useful for children older than 6 weeks with

suspected H influenza.• Current recommendation : • Dexamethasone : 1-2 hr before first antibiotic dose• 0.15mg/kg/dose every 6 hrly for 2 days.

General Care

- Fluid and electrolytes homeostasis -Check for shock – fluid bolus NS

• NPO• Oral feeds if sensorium –ok• Care of oral cavity, eyes, bladder,bowel and skin• IF suspecting SIADH – give 2/3rd maintenance• Symptomatic Management: Paracetamol

Diazepam, Phenytoin, Phenobarbitone

Supportive care

Seizures • No role for prophylactic use of AED• For immediate control : lorazepam/diazepam, • Load on phenytion to reduce recurrence.• Phenytoin preferred than pheno as produces less

CNS depression and permits assessment of levels of consciousness.

Treatment of raised intracranial pressure• Head end elevation to 30 degree• Fluid – 2/3 rd maintaiance• Do not use hypotonic fluids• 20% mannitol• Frusemide• Acetazolamide• Glycerol

4) Treatment of complications: Shock: Volume expander, FFP,

Dopamine Subdural effusion: Aspiration

Hydrocephalus: Shunt Operation (VP)

Complications - immediate

• Seizure • Raised ICP• Stroke• Cerebral or Cerebellar herniation • Sub Dural Effusion• SIADH

• Ventriculitis• Brain abscess• Hydrocephalus• DIC• Cranial Nerve Palsy• Thrombosis of dural sinuses• Shock

CHRONIC –late

• Permanent brain damage with - CP,Mental retardation, - Epilepsy - Deafness - Blindness - Hemiplegia - Hydrocephalus• EHAVIOUR PROBLEMS

POOR PROGNOSIS

• SEIZURES THAT PERSIST after 4 days of illness and are difficult to treat

• Coma• CSF pleocytosis may be absent in

overwhelming meningitis and sepsis.• < 6 months• Focal deficit at presentation• Pnemococcal organism

PREVENTION

• Immuno prophylaxis : - Hib vaccine - routine- Meningococcal vaccine - epidemics

PREVENTION

• Chemo prophylaxis: ( for house hold contacts)1. H influenza : Rifampicin : 20 mg/kg/day, single

dose/day for 4 days 2.Meningococcus : Rifampicin : 20 mg/kg/day, in

2 divided doses for 2 days Or

Ciprofloxacin- single dose 500mg

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