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BACTERIAL MENINGITIS

• INTRODUCTION• EPIDEMIOLOGICAL TRENDS• DIAGNOSTIC EVALUATION• INITIAL APPROACH TO

MANAGEMENT• PATHOGEN-SPECIFIC THERAPY• DURATION OF ANTIMICROBIAL Rx• ADJUVANT THERAPY

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Bacterial meningitis

Dr / Khalid Al-Harby

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INTODUCTION

• High morbidity and mortality• 60% of infant who survive G-ve bacillary

meningitis have developmental disabilities and/or neurological sequelae

• 25% was the case-fatality rate in a review of 493 episodes of bact.meningitis in adults.

• It is a life-threatening medical emergency• cases of meningitis are a leading cause of

malpractice suits against emergency doctors

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Cont. introduction

• Meningitis is characterized by inflammation of the pia-arachnoid and surrounding CSF.

• Nasopharyngeal mucosal colonization by potentially pathogenic bacteria is the usual first step, although the organism may be included by trauma or at the time of a neurosurgical or diagnostic procedure.

• Individuals who are especially susceptible include: -

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Cont.introduction

• Those who are asplenic ( sicklers, or splenectomized)

• who congenitally lack terminal complement components.

• Who have poor anti-body response to bacterial polysaccharides ( young children or persons with multiple myeloma ).

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Epidemiological trends

• The frequency of meningitis due to H. influenzae in children has declined dramatically because of widespread use of H. influenzae type b vaccines ( 95% reduction in incidence in the past decade).

• Lasker Award in 1996.• H. influenzae meningitis has almost

disappeared from U.S.A.

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Diagnostic evaluation

• It should be considered as a medical emergency and promptly evaluated.

• Typical CSF finding but -ve gram stain: -• latex agglutination test: -specific• c-reactive protein in CSF : sensitive• petechial scraping :- diagnostic in 70% of

cases.• A CT scan is rarely needed (? Delay diagn.)

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Diagnostic evaluation

• Prior oral antibiotics can decrease the positive yield of CSF culturs by 4-33% and of Gram’s stain 7-41%.

• Cell count, glucose, and protein usually are not affected.

• C&S obtained 24h after initial antibiotic administration are +ve only in 20% of cases

• lymphocyte predominance in a patient who otherwise appears to have bact.meningitis.

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Empirical treatment

• When lumpar puncture is delayed or Gram’s stain of the CSF is nondiagnostic.

• Ceftriaxone is avoided in neonate because of concerns regarding protein binding and displacement of bilirubin.

• Many antibiotics penetrate BBB poorly under normal circumstances (penetration improves if meninges are inflamed).

• Patients with bacterial meningitis must

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cont

• always be admitted to a hospital ward for I.V antibiotics, observation, and supportive care (no role for oral or I.M. treatment)

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Adjuvant therapy

• Inflammatory potential of G+ve cell wall and G-ve lipopolysaccharide.

• Dexamethasone 0.15mg per kg every 6 h. for 2-4 days is recommended in children over 2m of age suspected to have bact.meningitis.

• It should be initiated I.V. with or slightly before the antibiotics

• if delayed 3-4h after 1st dose of antibiotics

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Cont.

• Do not give • sever sepsis, suspected or documented is a

contra-indication.

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Meningococcal meningitis

• Sudden onset of fever, intense headache, nausea, and often vomiting, stiff neck and, a petechial rash with pink macules.

• Case fatality rate (10-50%)• in fulminant meningococcemia, the death

rate remains high despite prompt antibacterial treatment.

• Neisseria meningitidis groups(A,B,C,X,Y,W135,Z)

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cont

• It occurs in winter and springs mainly• preliminarily a disease of very small

children*(m>f).• Irregular epidemics• man is the only reservoir.• Transmitted by direct contact, including

respiratory droplets• during epidemics, over half of the men in

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cont

• In a military unit may be healthy carriers of pathogenic meningococci.

• I.P = 2-10 days• C.P = Until eradicated from the nose and

mouth.• Susceptibility decrease with age• group-specific immunity of unknown

duration follows even subclinical infections

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Preventive measures

• Health education• reduce overcrowding• quadrivalent vaccine (A,C.Y.W135) is

effective in adults and is only used vaccine in U.S.A. since 1971.

• Duration of protection is limited in children 1-3 y. of age.(poor immunogenicity especially C)

• no vaccine against B

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Control

• Report to local health authority.• Respiratory isolation for 24h. After starting

antibiotics• concurrent disinfection of discharge• close contacts (share utensils) need obsevat-

• Ion for early signs of the disease.• Rifampicine 600mg BID for 2 d. (10mg/kg

for children , 5mg/kg for neonate)• ceftriaxone 250mg IM stat, 125mg if under

15 y. of age.• Ciprofloxacin 500mg

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Cont.

• P.o stat for adults• health care personnel :- only intimate

exposure to nasopharyngeal secretions (e.g.mouth to mouth resuscitation) warrant prophylaxis.??

• Vaccination of close

• Contact is of no practical use.• The pt. should be given rifampicine prior to

discharge from the hospital*• the goal of prophylaxis is to eliminate the

carrier state from naso-pharynx