Acute pyogenic meningitis

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

  1. Hematogenous spread from primary foci: Pneumonia, Osteomyelitis
  2. Direct contiguous spread: Mastoiditis, Infected paranasal sinus, fracture of base of skull
  3. Head injury may lead to purulent meningitis
  4. 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 amd dobutamin

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

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