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CNS Infections

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Amal Al Dabbagh, Consultant Pediatrician MBBCH, MSc, CABP * Not always identified. Viruses usually responsible. Enteroviruses in 85% of cases (Coxackie virus B5.& – PowerPoint PPT presentation

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Title: CNS Infections


1
CNS Infections
  • Amal Al Dabbagh,
  • Consultant Pediatrician
  • MBBCH, MSc, CABP

2
Definitions
  • Infection of the CNS may be diffuse or focal.
  • Meningitis and encephalitis are examples of
    diffuse infection.
  • Meningitis implies 1ry infection of the meninges.
  • Encephalitis indicates brain parenchymal
    involvement.
  • Many patients have meningeal parenchymal
    involvementmeningoencephalitis.
  • Brain abscess is the best example of a focal
    infection.

3
Epidemiology
  • Risk factors
  • Lack of immunity to specific pathogens associated
    with young age.
  • Recent colonization with pathogenic bacteria.
  • Close contact( household, daycare, dorms) with
    individuals having invasive disease caused by N.
    meningitides H. infl type b, crowding,
    poverty, black race male gender.
  • Mode of transmission is person-person thru resp
    secretions or droplets.
  • Infants children with occult bacteremia.

4
Pathogenisis
  • Inflammation of the meninges when cell wall
    membrane products of the organism disrupt the
    capillary endothelium of the CNS(BBB).
  • Hematogenous or direct invasion.
  • Disruption will lead to migration margination
    of PMNs across endothelia into CSF leading to a
    cascade of events (cytokine chemokines release
    within the CNS ) resulting in inflammation
    signs and symptoms of meningitis.

5
Pathology
  • Cerebral edema.
  • Increased ICP.
  • Thrombosis
  • Infarction
  • High CSF protein and low Glucose

6
Associations risk factors
  • Defects of complement system (C5-C8).recurrent
    meningococcal infection.
  • Defects of the properdin system.lethal
    meningococcal disease.
  • Splenic dysfunction ( SCD) or asplenia ( trauma,
    cong. ) .Pneumococcal, H.infl b, rarely
    meningococcal sepsis meningitis.
  • T-lymphocyte defects ( malignancy, HIV)..L
    monocytogenes infections of the CNS.
  • CSF leak across midline facial defect, middle
    ear, basal skull fracture.Pn.coccal meningitis.
  • Lumbosacral dermal sinus mmcele.staph G-ve
    enteric bacterial meningitis.
  • CSF shunt..coagulase ve staph meningitis.

7
CNS Infections, Etiology
  • Many microorganisms can cause infection,
    nonetheless, specific pathogens are identifiable
    and are influenced by the age ,immune status of
    the host epidemiology of the pathogen.
  • Viral infections of the CNS are much more common
    than bacterial ones.
  • Bacterial infections are in turn much more common
    than fungal, parasitic infections.
  • Rickettsia ( Rocky mountain spotted fever) are
    relatively uncommon, but important under specific
    circumstances.
  • Mycoplasma spp. Can also cause CNS infections,
    but their contribution is often difficult to
    determine.

8
Etiology OF Bacterial Meningitis according to age
  • Newborn Groups B D streptococci
    (enterococcus),gram ve enteric bacilli ( E-coli,
    Klebsiella), Listeria monocytogenous.
  • Gp B D streptococci Listeria persist as
    important CNS pathogens through the 3rd mo of
    life.
  • 2m-12yrs N. meningitides in the US, bacterial
    meningitis caused by S. Pneumoniae H.
    influenzae type b in incompletely vaccinated
    individuals or those in developing countries.

9
Clinical Manifestations
  • Regardless of etiology, most patients with CNS
    infection have similar clinical manifestations.
  • Common symptoms include headache, nausea,
    vomiting, anorexia, restlessness, altered state
    of consciousness, and irritabilitynon specific.
  • Common signs, in addition to fever, include
    photophobia, neck pain rigidity, obtundation,
    stupor, coma, seizures, focal neurologic
    deficits.
  • The severity constellation of signs are
    determined by the specific pathogen, the host,
    the area of CNS affected.

10
Meningeal Irritation signs
  • Nuchal rigidity.
  • Back pain.
  • Kernig sign ( flexion of the hip 90 degrees with
    subsequent pain with extension of the leg) .
  • Brudzinski sign ( involuntary flexion of the
    knees hips after passive flexion of the neck).
  • Tripod posture The Patient sits with partial
    support from the arms which are held back
    straight with the hands on the sitting surface

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Other Findings
  • Arthralgia, Myalgia.
  • Transient arthritis.
  • Peticheal or purpuric rash.
  • Anemia.
  • DIC picture

14
Increased ICP
  • Is due to cell death ( cytotoxic CE), cytokine
    induced increased cerebral permeability(
    vasogenic), and increased hydrostatic pressure (
    interstitial CE).
  • Headache, emesis.
  • Bulging fontanel, Diastasis of the sutures.
  • Oculomotor or abducens nerve paralysis.
  • Hypertension with bradycardia.
  • Apnea or hyperventilation.
  • Decorticate or decerebrate posturing.
  • Stupor, coma or signs of herniation

15
Papilledema
  • Uncommon in uncomplicated meningitis.
  • Suggest a more chronic process, as IC abscess,
    subdural empyema, or occlusion of a dural venous
    sinus.

16
Diagnosis
  • The diagnosis of CNS infections depends on
    examination of CSF, obtained by lumbar puncture.

17
C/I to LP
  • Increased ICP.
  • Suspicion of mass lesion.
  • Infection of LP site.
  • Extreme patient instability.
  • Hemorrhagic disease.

18
Cerebrospinal Fluid Findings in Central Nervous
System Disorders
19
Uncommon forms of meningitis
20
Differential Diagnosis
  • Other microorganisms which cause CNS infection
    with similar clinical manifestations.
  • TB, Treponema pallidum, Borellia, fungi.
  • Brain abscess parameningeal abscess.
  • Acute viral meningoencephalitis.

21
Acute Complications of Bacterial Meningitis
  • Systemic effects
  • Cardiovascular instability-? inotropes
  • Depressed level of consciousness? intubation
  • Prolonged seizure activity-? mechanical
    ventilation.
  • SIADH-? fluid restriction
  • Persistent fever.

22
Persistent Fever
  • Common with H. Influenza type b
  • Subdural effusion.
  • Pericardial or joint effusion.
  • Drug Fever.
  • Thrombophlebitis.
  • Nosocomial Infections

23
Acute complications of Bacterial Meningitis, cont
  • Localized effects to the CNS
  • Cerebral vascultis.
  • Stenosis of cerebral arteries.
  • Infarction.
  • Intracerebral hemorrhage.
  • Abscess formation especially with G-ve
    pathogens as Salmonella Citrobacter.
  • Subdural effusion ventriculitis

24
Long term sequelae of Bacterial Meningitis
  • These findings occur in 25 to 50 of patients
    and include
  • Spasticity
  • Blindness.
  • Hearing loss.
  • Persistent seizures.
  • Hydrocephalus.
  • Developmental delay.
  • Decreased IQ.
  • Subtle cognitive deficits , learning disabilities
    school behavioral problems.

25
Treatment
  • Supportive
  • Ventilation.
  • Rx of shock/DIC
  • Rx of Increased ICP/Seizure
  • Rx of SIADH.
  • Rx of complications

26
Antibiotic Initial Therapy
  • Ceftriaxone 100mg/kg/24hrs divided into 2 doses.
  • Cefotaxime 200mg/kg/24hrs div. Into 4 doses.
  • Penicillin G 300,000 iu/kg ,div. Into 4 doses for
    Str.pn Meningococcus.
  • Penicillin Resistant Pneumococci.Ceftriaxone or
    Cefotaxime plus Vancomycin

27
Antibiotics,Infantslt2months
  • Ceftriaxone or
  • Cefotaxime plus Ampicillin 300mg/kg/24hrsto
    cover Listeria.

28
Treatment Course
  • 7 days for Meningococcus
  • 10 days for H.Influenza Str.Pn.
  • Dexamethazone 0.15 mg/kg/dose Q 6hrs for 2 days
    for H.Influenza( 1-2 hrs before antibiotics
    initiated).
  • Prior to discharge home give Rifampicin

29
prevention
  • H.Influenza ( Vaccines, Rifampicin)
  • N.Meningitidis ( Vaccine, Rifampicin,
    Ciprofloxacin)
  • Pneumococcal ( pneumovax, Prevnar).

30
Mortality
  • H.Influenza 8
  • Meningococcus 15
  • Pneumococcus 35

31
Poor Prognosis
  • Young Age
  • Delayed Rx
  • The organism
  • Concn. of Organism or Ag in CSF.
  • Late onset seizure.

32
Poor Prognosis, cont
  • Coma at presentation.
  • Shock.
  • Low or absent CSF WBC(with visible bacteria on
    gram stain)
  • Immune compromised status.

33
Acute Aseptic Meningitis
  • An acute inflammation of the meninges is a common
    illness with many causes.
  • Lymphocytic Pleocytosis.
  • Normal Glucose in CSF.
  • Slightly raised CSF protein.
  • No bacterial growth.

34
Acute Aseptic meningitis,Etiology
  • Not always identified.
  • Viruses usually responsible.
  • Enteroviruses in 85 of cases (Coxackie virus
    B5. Eccho viruses 4,6,9,11).
  • Arboviruses ( EEV, WEV, WNV).
  • Herpes simples(12).

35
Acute Aseptic Meningitis,Etiology
  • HIV,Varicella,EBV.
  • Lymphocytic Choriomeningitis.
  • Natural or Vaccine related(MMR,Polio,Rabies)
  • Influenza ParaInfluenza viruses.

36
A A Meningitis,Etiology
  • Mycoplasma
  • Chlamydia
  • Fungi
  • Protozoa
  • Parasites
  • Post infectious
  • Mycobacterium tuberculosis.

37
Encephalitis
  • Inflammation of the cerebral cortex with clinical
    symptoms ranging from slight confusion to coma.
  • Symptoms usually are coupled with headaches
    photophobia.
  • CSF shows fewer inflammatory cells(PMN) than
    meningitis.
  • It is an unusual complication of common viral
    illness.

38
Viral Encephalitis
  • Virus gains access through
  • Hematogenous (common arthropod borne viral
    disease).
  • Neuronal ( Herpes Simplex,Rabies).

39
Encephalitis,Etiology
  • HSV,sporadic.
  • Rabies, rare but important.
  • M,M,R.
  • Yellow Fever.
  • Poliomyelitis, vaccine related.
  • Picorna viruses(enteroviruses, coxackie, eccho
    viruses),also cause aseptic meningitis.

40
Encephalitis,Etiology
  • Arthropod-borne viruses
  • St Louis Encephalitis,from bird reservoir.
  • Eastern Equine Encephalitis.
  • La Crosse Virus.
  • Post Infectious Encephalomyelitis
  • associated with URTI especially Influenza
    measles where vaccination is not a routine.

41
Encephalitis,Epidemiology
  • Winter Fall.
  • HSV cause 10 of non neonatal virus infections.

42
Encephalitis,clinical manifestation
  • Confusion.
  • Hallucinations.
  • Memory loss.
  • Combativeness.
  • Seizure.
  • Coma

43
Differential Diagnosis
  • BacterialTB
  • ParasiticMalaria,Toxoplasma.
  • Non infectiousVasculitis,Malignancy.
  • EncephalopathyToxins,hypoglycemia,Reye Syndrome.

44
Diagnosis
  • Full history Exposure to animals
  • Mosquito,Ticks
  • Travel
  • Full Examination.
  • Investigations.

45
Encephalitis,Investigations
  • CSFcell,glucose,protein.
  • CulturesCSF,throat,stool.
  • SerologyInitial 2-3 wks later.
  • EEG focal diffuse changes.
  • CT,MRI.

46
Encephalitis,Treatment
  • Supportive care.
  • Specific drugs
  • acyclovir for HSV
  • Zidovidin for HIV
  • Doxycycline Erythromycin for Mycoplasma

47
Encephalitis,Prognosis
  • Most children recover without major sequelae.
  • Poorer prognosis with
  • HSV, Rabies,Mycoplasma
  • Seizure,Coma

48
Neisseria meningitidis in CSF G-ve diplococci
49
Streptococcus pneumoniae in CSF(Gve diplococci)
50
Haemophilus influenza in CSF(G-ve coccobacilli)
51
Gp B streptococcus in CSF(Gve coccobacilli)
52
Listeria monocytogenes in CSF( Gve rods and
coccobacilli)
53
Meningococcal meninigitis
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Figure 1. A. CT of cerebral edema. Note "ground
glass" appearance, loss of normal gray-white
matter differentiation, and effacement of
left-sided sulci and gyri compared with the right
side. B. CT of epidural hematoma. Note midline
shift and compression of ipsilateral ventricle
and brain tissue
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