兒科英文化膿性腦膜炎Bacterialmeningitis

1、兒科英文化膿性腦膜炎BacterialmeningitisIntroductionAnnual incidence in the developed countries is approximately 5-10 per 100000. 30000 infants and children develop bacterial meningitis in United States each year. Approximately 90 per cent of cases occur in children during the first 5 years of life.Introductio

2、nCases under age 2 years account for almost 75% of all cases and incidence is the highest in early childhood at age 6-12 months than in any other period of life.There are significant difference in the incidence of bacterial meningitis by season. EtiologyCausative organisms vary with patient age, wit

3、h three bacteria accounting for over three-quarters of all cases:Neisseria meningitidis (meningococcus)Haemophilus influenzae (if very young and unvaccinated)Streptococcus pneumoniae ( pneumococcus)EtiologyOther organisms Neonates and infants at age 2-3 months Escherichia coliB-haemolytic streptococ

4、ciStaphylococcus aureusStaphylococcus epidermidisListeria monocytogenesEtiologyElderly and immunocompromisedListeria monocytogenesGram negative bacteriaHospital-acquired infectionsKlebsiellaEscherichia coliPseudomonasStaphylococcus aureusEtiologyThe most common organisms Neonates and infants under t

5、he age of 2monthsEscherichia coli Pseudomonas Group B StreptococcusStaphylococcus aureus EtiologyChildren over 2 monthsHaemophilus influenzae type bNeisseria meningitidisStreptococcus pneumoniaeChildren over 12 yearsNeisseria meningitidisStreptococcus pneumoniaeEtiologyMajor routes of leptomening in

6、fectionBacteria are mainly from blood.Uncommonly, meningitis occurs by direct extension from nearly focus (mastoiditis, sinusitis) or by direct invasion (dermoid sinus tract, head trauma, meningo-myelocele).PathogenesisSusceptibility of bacterial infection on CNS in the children Immaturity of immune

7、 systemsNonspecific immuneInsufficient barrier (Blood-brain barrier)Insufficient complement activityInsufficient chemotaxis of neutrophilsInsufficient function of monocyte-macrophage systemBlood levels of diminished interferon (INF) -and interleukin -8 ( IL-8 ) PathogenesisSusceptibility of bacteria

8、l infection on CNS in the childrenSpecific immuneImmaturity of both the cellular and humoral immune systemsInsufficient antibody-mediated protectionDiminished immunologic responseBacterial virulence PathogenesisA offending bacterium from blood invades the leptomeninges. Bacterial toxics and Inflamma

9、tory mediators are released.Bacterial toxicsLipopolysaccharide, LPSTeichoic acidPeptidoglycan Inflammatory mediatorsTumor necrosis factor, TNFInterleukin-1, IL-1Prostaglandin E2, PGE2PathogenesisBacterial toxics and inflammatory mediators cause suppurative inflammation.Inflammatory infiltrationVascu

10、lar permeability alterTissue edema Blood-brain barrier detroyThrombosis PathologyDiffuse bacterial infections involve the leptomeninges, arachnoid membrane and superficial cortical structures, and brain parenchyma is also inflamed.Meningeal exudate of varying thickness is found.There is purulent mat

11、erial around veins and venous sinuses, over the convexity of the brain, in the depths of the sulci, within the basal cisterns, and around the cerebellum, and spinal cord may be encased in pus. Ventriculitis (purulent material within the ventricles) has been observed repeatedly in children who have d

12、ied of their disease.PathologyInvasion of the ventricular wall with perivascular collections of purulent material, loss of ependymal lining, and subependymal gliosis may be noted. Subdural empyema may occur.Hydrocephalus is an common complication of meningitis.Obstructive hydrocephalus Communicating

13、 hydrocephalus PathologyBlood vessel walls may infiltrated by inflammatory cells.Endothelial cell injuryVessel stenosisSecondary ischemia and infarctionVentricle dilatation which ensues may be associated with necrosis of cerebral tissue due to the inflammatory process itself or to occlusion of cereb

14、ral veins or arteries.PathologyInflammatory process may result in cerebral edema and damage of the cerebral cortex.Conscious disturbanceConvulsionMotor disturbance Sensory disturbance Meningeal irritation sign is found because the spinal nerve root is irritated.Cranial nerve may be damagedClinical m

15、anifestationBacterial meningitis may present acutely (symptoms evolving rapidly over 1-24 hours) in most cases.Symptoms and signs of upper respiratory or gastrointestinal infection are found before several days when the clnical manifestations of bacterial meningitis happen.Some patients may access s

16、uddenly with shock and DIC.Clinical manifestationToxic symptom all over the body HyperpyrexiaHeadachePhotophobiaPainful eye movementFatigued and weak Malaise, myalgia, anorexia, Vomiting, diarrhea and abdominal painCutaneous rashPetechiae, purpura Clinical manifestationClinical manifestation of CNSI

17、ncreased intracranial pressureHeadacheProjectile vomiting Hypertension Bradycardia Bulging fontanel Cranial sutures diastasisComa Decerebrate rigidity Cerebral hernia Clinical manifestationClinical manifestation of CNSSeizuresSeizures occur in about 20%-30% of children with bacterial meningitis.Seiz

18、ures is often found in haemophilus influenzae and pneumococal infection.Seizures is correlative with the inflammation of brain parenchyma, cerbral infarction and electrolyte disturbances. 第一課件網(wǎng)站 Clinical manifestationClinical manifestation of CNSConscious disturbanceDrowsiness Clouding of consciousn

19、ess ComaPsychiatric symptom Irritation Dysphoria dullness Clinical manifestationClinical manifestation of CNSMeningeal irritation signNeck stiffnessPositive Kernigs signPositive Brudzinskis signClinical manifestationClinical manifestation of CNSTransient or permanent paralysis of cranial nerves and

20、limbs may be noted. Deafness or disturbances in vestibular function are relatively common.Involvement of the optic nerve, with blindness, is rare. Paralysis of the 6th cranial nerve, usually transient, is noted frequently early in the course.Clinical manifestationSymptom and signs of the infant unde

21、r the age of 3 monthsIn some children, particularly young infants under the age of 3 months, symptom and signs of meningeal inflammation may be minimal.Fever is generally present, but its absence or hypothermia in a infant with meningeal inflammation is common. Only irritability, restlessness, dulln

22、ess, vomiting, poor feeding, cyanosis, dyspnea, jaundice, seizures, shock and coma may be noted. Bulging fontanel may be found, but there is not meningeal irritation sign.Complication Subdural effusionSubdural effusions occur in about 10%-30% of children with bacterial meningitis.Subdural effusions

23、appear to be more frequent in the children under the age of 1 year and in haemophilus influenzae and pneumococal infection.Clinical manifestations are enlargement in head circumference, bulging fontanel, cranial sutures diastasis and abnormal transillumination of the skull.Subdural effusions may be

24、diagnosed by the examination of CT or MRI and subdural pricking. ComplicationEpendymitis Neonate or infant with meningitis Gram-negative bacterial infection Clinical manifestation Persistent hyperpyrexia, Frequent convulsion Acute respiratory failure Bulging fontanel Ventriculomegaly (CT) Cerebrospi

25、nal fluid by ventricular punctureWBC50109/LComplicationCerebullar hyponatremiaSyndrem of inappropriate secretion of antidiuretic hormone (SIADH)Hyponatremia Degrade of blood osmotic pressureAggravated cerebral edemaFrequent convulsion Aggravated conscious disturbance ComplicationHydrocephalus Increa

26、sed intracranial pressureBulging fontanelAugmentation of head circumferenceBrain function disorder Other complicationDeafness or blindnessEpilepsyParalysis Mental retardationBehavior disorder Laboratory FindingsPeripheral hemogramTotal WBC count 20109/L 40109/L WBCDecreased WBC count at severe infec

27、tionLeukocyte differential count80%90% NeutrophilsLaboratory FindingsRout examination of cerebrospinal fluid (CSF) Increased pressure of cerebrospinal fluid Cloudiness Evident Increased total WBC count (1000109/L)Evident Increased neutrophils in leukocyte differential countEvident Decreased glucose

28、(1.1mmol/l) Evident Increased protein level Decreased or normal chloridateCSF film preparation or cultivation : positive result Laboratory FindingsEspecial examination of CSFSpecific bacterial antigen testCountercurrent immuno-electrophoresisLatex agglutinationImmunofluorescent test Neisseria mening

29、itidis (meningococcus)Haemophilus influenzae Streptococcus pneumoniae ( pneumococcus)Group B streptococcusLaboratory FindingsEspecial examination of CSFOther test of CSFLDHLactic acidCRPTNF and IgNeuron specific enolase (NSE)Laboratory FindingsOther bacterial testBlood cultivationFilm preparation of

30、 skin petechiae and purpuraSecretion culture of local lesion Imageology examinationDiagnosisDiagnostic methodsA careful evaluation of history A careful evaluation of infants signs and symptomsA careful evaluation of information on longitudinal changes in vital signs and laboratory indicatorsRout exa

31、mination of cerebrospinal fluid (CSF)Differential diagnosisClinical manifestation of bacterial meningitis is similar to clinical manifestation of viral, tuberculous , fungal and aseptic meningitis. Differentiation of these disorders depends upon careful examination of cerebrospinal fluid obtained by

32、 lumbar puncture and additional immunologic, roentgenographic, and isotope studies. Characteristics of CSF on common disease in CNS PM TM VW FM TE Pressure or Cloudiness or Pandy T or or or or WBC N L orL M Protein or or Glucos Chloridate or Cultivation Bacterium TB Viral Fungus Treatment Antibiotic

33、 TherapyTherapeutic principleGood permeability for Blood-brain barrier Drug combination Intravenous drip Full dosage Full course of treatment Antibiotic TherapySelection of antibioticNo Certainly BacteriumCommunity-acquired bacterial infectionNosocomial infection acquired in a hospitalBroad-spectrum

34、 antibiotic coverage as noted belowChildren under age 3 monthsCefotaxime and ampicillinCeftriaxone and ampicillin (children over age 1months)Children over 3 monthsCefotaxime or Ceftriaxone or ampicillin and chloramphenicolAntibiotic TherapyCertainly BacteriumOnce the pathogen has been identified and

35、 the antibiotic sensitivities determined, the most appropriate drugs should selected.N meningitidis : penicillin, tert- cephalosporin S pneumoniae: penicillin, tert- cephalosporin, vancomycin H influenzae: ampicillin, tert- cephalosporin S aureus: penicillin, nefcillin, vancomycin E coli: ampicillin, chloramphenicol, tert- cephalosporin Antibiotic TherapyCourse of treatment7 days for meningococcal infection1014 days for H influenzae or S pneumoniae infectionMore than 21 days for S aureus or E coli