Bacterial Meningitis

Posted by e-Medical PPT
Introduction :
     C.N.S infection is the most common cause of fever with S&S of C.N.S disease in children
     Specific pathogen influenced by :age , immune status & epidemiology
     Viral infections are more common
     Clinical syndrome are similar inspite of incriminated pathogen
      The common symptoms of the C.N.S infection are quite non-specific
      Severity & constellation of symptoms determined by specific pathogen , host & anatomic distribution
      Diagnosis depends on CSF examination

Acute bacterial meningitis beyond the neonatal period :
      Associated with high rate of acute complications & risk of chronic morbidity
      Meningitis in neonatal & post neonatal may overlap ( in 1-2 mo. old : GBS , strept. pn. , N.meningitidis , H.influenzae )

Etiology :
  1) First 2 mo : maternal lora & infant enviroment (GBS , G-ve , L.monocytogenes ) , ocasionally : H.influenzae or pathogens of older infants.
  2) 2-12 mo : Strept. pn. , N.meningitidis , H.influenzae
* Effects of immune deficits & anatomic ddefects.(Ps. Aerugenosa , staph. Aureus , coagulase –ve staph , Salmonella spp & L.monocytogenes )

Pathology :
Meningeal exudate.
Ventriculitis.
Subdural effusion.
Empyema.
Perivascular inflammatory infiltrate.
Cerebral infarction.
Inflammation of spinal nn.
Inflammation of cranial nn.
Increase of ICP :
      mechanisms.
      cerebral perfusion = MAP – ICP(<50 cmH2O).
      non-localizing sign
SIADH (ICP & hypotonicity).
Herniation usually does not occur.
Hydrocephalus :is uncommon acute complication.either communicating or non-communicating.
Increase CSF proteins.
Hypoglycorrhachia.

Clinical manifestations :
Two patterns :1.rapidly progressive.  2.insidious
Two constellations of manifestation :1)related to non-specific systemic infection :fever which presents in 90-95%, anorexia, URTI, myalgia, arthralgia, tachycardia, hypotension & cutaneous signs. 2)related to meningeal irritation.
Other manifestation :3)younger than 18 mo. 4)increased ICP. 5)papilloedema is uncommon. 6)focal neurological signs(10-20%;30% in pneumococcus). 7)seizures(20-30%). 8)altred consciousness. 9)photophobia. 10)tachycerebrale..

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