兒保留學(xué)生實(shí)習(xí)meningitis

1、Purulent Meningitis Julia Mao Acute infection of central nervous system (CNS). 90% of cases occur in the age of 1mo-5yr. The inflammation of meninges caused by various bacteria. Common features in clinical practices include: fever, increased intracranial pressure, meningeal irritation. One of the mo

2、st potentially serious infections, associated with high mortality (about 10%) and morbidity. Pathogens:Main pathogens: Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae. (2/3 of purulent meningitis are caused by these pathogens)Pathogens in special populations (neonates & 3mo

3、infants , malnutrition, immunodeficiency): gramnegative enteric bacilli, group B streptococci, staphlococcus aureus1.Etiology2. Pathology Structure of meninges Characterized by leptomeningeal and perivascular infiltration with polymorphonuclear leukocytes and inflammatory exudate. Exudate which may

4、be distributed from convexity of brain to basal region of cranium.Pathology The younger the child is, the higher incidence of meningitis will be. 1/2-2/3 of cases occur less than 1yr of age. Mode of presentation: Acute or fulminant onset: symptoms and signs of sepsis; meningitis evolve rapidly over

5、a few hours and death within 24 hours; usually infected with Neisseria meningitidis (N. meningitidis). Subacute onset: Precede by several days of upper respiratory tract or gastrointestinal symptoms; difficult to pinpoint the exact onset of meningitis; usually with meningitis due to Haemophilus infl

6、uenzae (H influenzae) and streptococcus pneumococcus (S pneumococcus). 3. Clinical manifestations Common features of meningitis: signs of systemic infection : fever(90-95%), anorexia, shock, alteration of mental status and consciousness neurological signs: increased intracranial pressure: headache,

7、vomiting(82%), herniation meningeal irritation: nuchal rigidity(77%), kernig sign, brudzinski sign Clinical manifestationsA positive Brudzinskis sign (flexion of the hips and knees in response to passive flexion of the neck) signals meningeal irritation. Passive flexion of the neck stretches the ner

8、ve roots, causing pain and involuntary flexion of the knees and hips. Kernigs sign elicits resistance and hamstring muscle pain when the examiner attempts to extend the knee while the hip and knee are flexed 90 degrees Seizure (20-30%) Focal or generalized Due to cerebritis, infarction, electrolyte

9、disturbances Frequently noted with Haemophilus influenzae & Streptococcus pneumococcal meningitis Clinical manifestations Clinical manifestations Alteration of mental status and consciousness Including: irritability, lethargy, stupor and coma Due to increased intracranial pressure, cerebritis, hypot

10、ension Often with pneumococcal or meningococcal meningitis The symptoms and signs are not evident in neonates or infants younger than 3mo of age or patients already received irregular antibiotic therapy.Clinical manifestations Earlier diagnosis and prompt initiation of effective antibiotic treatment

11、 is critical for minimizing sequelae of purulent meningitis. Suspected cases: febrile infants with seizure, meningeal irritability, increased intracranial pressure, altered mental status Pay attention to the atypical symptoms and signs in neonates, infants and patients already received antibiotic th

12、erapy 4. DiagnosisDiagnosis is confirmed by analysis of cerebrospinal fluid ( CSF) DiagnosisLumber punctureDiagnosis Suggestion bacterial meningitis Increased pressure (90%) Appearance: slightly cloudy to purulent Raised white blood cells, consisting chiefly of polymorphonuclear leukocytes Raised pr

13、otein concentration, decreased glucose concentration (80%) analysis of cerebrospinal fluid ( CSF) Viral meningitis: Less severe systemic infectious symptoms Usually not develop after 2-3weeks CSF: normal glucose 5. Differential diagnosis Tuberculous meningitis Subacute onset and progress A history o

14、f close contact with known cases of tuberculosis Evidence of acute or healed tubercular infection on chest x-ray Tuberculin skin test : PPD CSFDifferential diagnosisDiseasePressure(Kpa)aspectTotal WBC(x106/L)Protein(g/L)Glucose(mmol/L)smearsculturesnormal0.69-1.96(0.29-0.78)clear0-5(0-20)0.2-0.4(0.2

15、-1.2)2.2-4.4-Purulentmeningitiscloudy(PMN)(1-5)(2.2)Grams stain +TuberculousmeningitisNormal or cloudy(MN)AFB stain +Viral meningitis/encephalitisNormal or Normal Normal or (MN)Normal or (2ml, protein0.4g/L6. Complications Indications: No response to a sensitive antibiotic therapy Prolonged fever or

16、 fever reoccurring after an afebrile interval with effective treatment Bulging fontanel, widening of sutures, enlarging head circumference, emesis, seizure and altered consciousness. may be diagnosed by the examination of CT or MRI and subdural puncture. subdural effusion Diagnosis methods:subdural

17、effusion Subdural puncture CT 6.2 Ependymitis Usually occurs in neonates and infants (50 x106/L, glucose400mg/L.Ependymitistransorbital puncture of the lateral ventricles Complications6.3 hydrocephalus T2-weighted MRIshowing dilatation of ventricles out of proportion to sulcal atrophy 6.4 syndrome o

18、f inappropriate secretion of antidiuretic hormone; SIADAComplicationshyponatremiaplasma osmotic pressurecerebral edemaseizureconscious disturbancecomaClinical menifeststion:Complications6.5 cerebral abscess 6.6 others: Deafness, blindness, paralysis, epilepsy, mental retardationComplications7.1 Anti

19、bacterial therapy TreatmentTherapy principlesearly treatmentsusceptible to pathogens high permeability through BBBgiven intraveninouslyenough doseenough course Susceptible to pathogens First choice: Cefotaxime, Ceftriaxone (3dr generation of cephalosporins, high permeability through BBB) Other choice: Penicillin, Chloromycin, Cefuroxime, Ceftazidime ( delayed effect to make