Meningitis Dr. Kalpana Malla MD Pediatrics Manipal Teaching HospitalDownload more documents and slide shows on The Medical Post [ www.themedicalpost.net ]
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.
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 eitherHematogenously, 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.
PATHOGENESISHost :• 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) DIRECT INVASION Blood stream BLOOD CYTOKININE Invasion / Bacteremia RELEASE THROUGH choroid plexus Intravascular Lat ventricle, meninges CNS PENETRATION Volume decreases Bacteria rapidly multiply ↓CSF flow As CSF conc. Of complement And antibody LOW EndothelialComplement system activation CSF cytokine Leukocyte activation release Release of PMN STIMULATION BBB disturbed ↓CSF flow Secondary mediators FREE RADICAL RELEASE Meningeal inflammation Brain damage Brain edema
Clinical features:• Constitutional symptoms : Lethargy, irritability , anorexia, vomiting, fever – mild, high, hypothermia in infants, Poor feeding, Arthralgia, myalgiaMeningeal 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 ventricle4) 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 etiologyIn 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, neur ological signs.• More risk if – premature, LBW, coplicated labour, PROM, maternal sepsis……
INVESTIGATIONS1)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.
Investigations2) 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
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 DURATIONUNKNOW EMPERIC 10 DAYS 1)CEFTRIAXONE 100-150N MG/KGDAY 2)CEFOTAXIME 4 LAC 3)AMPI/PENCILLIN U/KG/DAY G + CHRAMPHENi 100 MG/KGDAYMENINGOC Pencillin G 3-4 lac 7DAYSOCCUs U/KG/DAY
ORGANISM ANTIBIOTIC DOSE DURATIONPneumococcu Pencillin G or if 40 10DAYSs resistance – MG/KG/D Ceftriaxone plus VancomycinGram neg. Ceftriaxone/cefo 21DAYS taxime plus aminoglycogide
2) Anti inflammatory therapy Dexamethasone: 0.15mg/kg/dose 6hrly for 2 days First 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 careSeizures• 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
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• Chemo prophylaxis: ( for house hold contacts)1. H influenza : Rifampicin : 20 mg/kg/day, single dose/day for 4 days2.Meningococcus : Rifampicin : 20 mg/kg/day, in 2 divided doses for 2 days Or Ciprofloxacin- single dose 500mg
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