cns infection in chidren

Acute CNS infection

• What is it?

• What causes it?

• What happens in the system?

• How to recognize it?

• How to prove it?

• How to treat it?

• How to prevent?

Significance

• Significant morbidity & mortality in children [1.2m cases worldwide]

• Diagnosis, challenging in young children

• High incidence of sequalae

• Fever with altered sensorium

• Virus > bacteria > fungi & parasite

• Meningitis

• Meningoencephalitis

• Brain abscess

• Common symptoms

photophobia, neckpain/rigidity, fits, stupor

• Diagnosis by CSF

Pyogenic meningitis

Etiology

• < 2months• Maternal flora, NICU/PNW flora;

• GBS, GDS, gram-ve, listeria, HIB,

• 2m-12m• Pneumococci, meningococci, HIB[now less]

• Pseudomonos, staph.aureus, CONS.

Reasons for infection

• Less immunity

• Contact with people with invasive disease

• Occult bacteremia [infants]

• Immunodeficiency

• Splenic dysfunction

• CSF leak , Meningomyelocele

• CSF shunt infection

Risk of infection

• Pneumococci OM, sinusitis, pneumonia, CSF rhinorrhea.

• Meningococci contact with adults, nasopharyngeal carriage

• HIBContact in daycare center

Pathogenesis

• Colonisation of nasopharynx

• Prior/concurrent viral URTI

• Bacteremia

• Hematogenous dissemination

• Contiguous spread from sinus, otitis, orbit

vertebral trauma, meningocele.

Why few only get meningitis?

• Defective opsonic phagocytosis– Developmental defects– Absent preformed anticapsular antibodies– Deficient complement/properdin system– Splenic dysfunction

Pathogenesis • Bacteria enter through choroid plexus of LV• Circulate to extra cerebral CSF & subarachnoid space• Rapidly multiply in CSF• Release of inflammatory mediators• Neutrophilic infiltrates• Increase vascular permeability• Altered BBB• Vascular thrombosis

Pathology

• Thick exudate covering all areas

• Ventriculitis, arteritis, thrombosis

• Vascular occlusion, sinus occlusion.

• Cortical necrosis, cerebral infarct

• Subarachnoid hemorrhage

• Hydrocephalus

• ICT, inflammation of spinal nerves

Clinical features • Nonspecific

– Fever,anorexia,myalgia,arthralgia,headache,– Purpura , petechiae, rash, photophobia.

• Meningeal signs– Neck rigidity, backache.– Kernig sign– Brudzinski sign– Crossed leg sign

ICT signs

Headache, vomiting, drowsy, Fits Ptosis, squint, AF bulge, widened sutures Hypertension, bradycardia Stupor, coma Abnormal posturing Papilloedema [only in chronic ICT]

• Focal neurological deficit

• Cranial neuropathy– 3rd nerve– 6th nerve– 7th nerve– 8th nerve

Diagnosis

• LP & CSF analysis– Gram stain– Culture– Cell count– Glucose, protein– [Contraindications for LP]

• Blood culture

CSF analysis• Cell count

– Normal• NB >30/mm3

• Child >5/mm3

– Meningitis >1000/mm3• Turbid 200-400/mm3

• Early; lymphocytic predominance

• Later; neutrophilic predominance

• low in severe sepsis

CSF analysis in prior antibiotic therapy

• Culture, gramstain altered

• Pleocytosis, protein, glucose unaltered

Traumatic LP

• Cell count, protein level altered

• Glucose, bacteriology unaltered.

Condition Pressure mm-h2o

Cell count/mm3 Glucose mg/dl

Protein mg/dl

microbiology

Normal 50-80 <5,lymphocyte >50, 75% of blood level

20-40mg

Bacterial meningitis

100-300 100-1000, >75% neutrophils

<40mg 100-500 Gram stain+ve

Partially treated meningitis

N / elevated

5-1000,Lymphocytes?

N /decreased 100-500 Gramstain ,c/s maybe -veAntigens +ve

Viral meningitis

Normal Less cells,lymphocytes

N, less in mumps

<200

TBM More <500,lymphocytes

<40 100-3000 Stain –veCulture ± ve

Fungal More 5-500 N More? Culture

Treatment • Rapidly progressive [ ~24h]

LP antibiotics

ICT , FND CTbrain & antibiotics

Manage shock, ARDS

• Subacute course [4-7d]

• Assess for ICT, FND

• Antibiotics CT LP

Supportive care• Monitoring

– Vitals– BUN,electrolytes,HCO3,IO, CBC,Platelets,Ca– Periodic neurologic assessment

• PR,sensorium,power,cranial N ex, head circ,

• Supportive care– IVF restrict for ICT,SIADH, more for shock – ICT ETI & ventilation,frusemide,mannitol– Seizures diazepam,phenytoin

Antibiotic therapy• Vancomycin & cefataxime/ceftrioxone

– Pneumococci,meningococci,HIB.

• Ampicillin / cotrimaxazole I.V– Listeria

• Ceftazidime & aminoglycoside– Immunocompromised

Duration of therapy

Pneumococci : 7-10 days Menigococci: 5-7 days HIB; 7-10 days E.coli,Pseudomonos ; 3 weeks Antibiotics started before LP [partially

treated meningitis] ; ceftrioxone 7-10 days.

Repeat LP

• After 48h

• For ; resistant pneumococci, gram-ve meningitis

Corticosteroids

• Rapid bacterial killing

• Cell lysis

• Release of inflammatory mediators

• Edema

• Neutrophilic infiltration

• 1-2h before antibiotics

• Dexamathasone q6h for 2 days.

• Less fever, less deafness.

Complications • ICT, Herniation

• Fits, Cranial N palsy

• Dural Vein sinus thrombosis

• Subdural effusion

• SIADH

• Pericarditis, Arthritis

• Anemia, DIC

Prognosis

• Mortality >10% [more in pneumococci]

• Prognosis poor in– Infants– Fits >4days– Coma, FND on presentation

• Neurological sequalae 20%– Behavior changes 50%– Deafness [pneumo,HIB], visual loss– MR,fits,

Prevention

• Meningococci– Rifampacin for close contacts [10mg/kg/day q12h for 2days]– Quadrivalent vaccine for high risk children

• HIB– Rifampacin for contacts for 4days– Conjugate vaccine

• Pneumococci – Heptavalent conjugate vaccine

Thank you

TBM

• Subacute / ?chronic meningitis

• From lymphohematogenous dissemination

• Caseous lesion in cortex / meninges

• Discharge of TB bacilli in CSF

• Thick exudate infiltrate blood vessels

• Inflammation,obstruction,infarct.

• Brainstem affected

• Cranial N dysfunction

• Hydrocephalus

• Infarcts

• Cerebral edema

• SIADH

• Dyselectrolytemia

Features • 6m-4yrs

• 3 stages

• Prodrome stage; 1-2 wks, nonspecific symptoms, stagnant development

• Abrupt stage;lethargy,fits,meningeal signs focal ND,cranial neuropathy,hydrocephalus.

Encephalitic picture

• Coma stage; posturing,hemi/paraplegia,poor vital signs

Diagnosis • Contact with adult TB

• Mx nonreactive 50%

• CSF – lymphocytes

• Glucose <40mg/dl

• Protein high: 400-5000mg/dl

• AFB +ve 30%

Thank you

Meningoencephalitis

• Acute inflammation of meninges & brain tissue

• CSF – pleocytosis

• Gram stain & culture negative

• Mostly self limiting

Etiology

• Enterovirus

• Arbovirus

• Herpes virus

Pathogenesis

• Direct invasion & destruction by virus• Host reaction to viral antigens• Meningeal congestion• Mononuclear infiltration• Neuronal disruption• Neuronophagia• Demyelination

Structures affected

• HSV; temporal lobe

• Arbovirus; entire brain

• Rabies; basal parts

Clinical features• Depends on parenchymal involvement• Preceding mild febrile illness & exantheme• Acute onset of high fever, headache,

irritability,lethargy,nausea,myalgia• Convulsions,stupor,coma• Fluctuating FND,emotional outburst• Ant.horn cell injuryflaccid paralysis [west

nile,entero virus]

DD

• Meningitis of various organisms

Diagnosis • CSF: lymphocytic predominance

– Protein: normal,high in HSV– Glucose: normal,low in mumps– Culture of organism [entero V]– Viral antigen by PCR– Culture from NPswab,feces,urine

• EEG: focal seizures [temporal];HSV• CT/MRI: swollen brain parenchyma

Treatment

• Acyclovir for HSV

• Non aspirin analgesic

• Nursing in a quiet room