Common in neonates and infants because of poor immunity.
COMMON ORGANISMS
- Neonates (upto 28 days): E.coli, Streptococcus pneumoniae, Pseudomonas
- 3 months to 3 years: Hemophilus influenzae, S. pneumoniae, N. meningitidis
- Beyond 3 years: S. pneumoniae, N. meningitis
RISK FACTORS FOR NEONATAL MENINGITIS
- Low birth weight
- Prematurity
- Complicated labour
- Prolonged rupture of membranes
- Maternal sepsis
- Babies given artificial respiration or intensive care
PATHOGENESIS /ETIOLOGY
- Hematogenous spread from primary foci: Pneumonia, Osteomyelitis
- Direct contiguous spread: Mastoiditis, Infected paranasal sinus, fracture of base of skull
- Head injury may lead to purulent meningitis
- Recurrent meningitis :Immunosuppression, CSF rhinorrhea
PATHOLOGY
Entry of bacteria in the leptomeninges ———> bacteria release endotoxins——–> Host cells produce cytokines and PAF in response ——–>Endothelial cell injury ——–> Cerebral edema, exudate ——–> Exudates block Foramen of Luschka and Magendie ——–> Hydrocephalus
CLINICAL FEATURES IN NEONATES AND YOUNG INFANTS
Fever or hypothermia
Sepsis
Persistent vomiting (projectile)
Bulging fontanelle
Poor tone, Poor cry, refusal to suck
Vacant stare, Photophobia
Alternating irritability and drowsiness
Shock, circulatory collapse
Tremor, convulsions
Neurological deficits
Brudzinski’s sign is positive
Neck rigidity and Kernig sign are seldom positive
COMPLICATIONS
Subdural effusion, Hydrocephalus
Empyema, Brain abscess
Ventriculitis, Arachnoiditis
Neurodeficit: Hemiplegia, Hemianopia, Deafness, Aphasia
SIADH
DIAGNOSIS
1.History
2.CSF examination, microscopy and culture:
-Turbid
-Elevated pressure
-Elevated cell count >1,000/cu.mm predominantly PMNs
-Elevated proteins >100 mg/dl
-Reduced sugar (below 50% of blood sugar OR <40 mg/dl
3.CT scan
4.Rapid diagnostic tests: to distinguish between viral, bacterial or tuberculous meningitis. Includes ELISA, countercurrent immunoelectrophoresis, latex particle agglutination, coagglutination, PCR
TREATMENT
1.Empirical therapy
- Third generation ceohalosporin like ceftriaxone OR
- Combination of Ampicillin and Chloramphenicol
2.Specific Antimicrobial therapy
N. meningitidis or pneumococcal meningitidis – Penicillin OR Ceftriaxone
H. influenzae -Ceftriaxone
Staphylococcus -Vancomycin in cases of MRSA
Gram negative bacilli – Ceftriaxone OR Ampicillin + Aminoglycoside
Pseudomonas – Ceftazidime+Aminogycoside
3.Duration of treatment
10 to 14 days
Staphylococcus and Gram negative infection- 3 weeks
4.Steroid therapy for preventing neurological complications
5.Symptomatic therapy
Increased ICP- Lumbar puncture + Mannitol iv
Convulsions- Diazepam followed by Phenytoin
Hypotension- iv fluids and vasopressors like dopamine and dobutamine
Retention of urine is managed by gentle suprapubic pressure or hot water bottle
Bedsores are prevented by repeated change of posture in bed, methylated spirit, soft rubber mattress, air cushion
6.Management of Complications
Hydrocephalus – Ventriculoatrial or ventriculoperitoneal shunt
Subdural empyema- Drainage and antibiotics