Chapter 136. Meningococcal Infections (Part 7) ppsx

Meningococcal Infections Part 7 Complications Patients with meningococcal meningitis may develop cranial nerve palsies, cortical venous thrombophlebitis, and cerebral edema.. Diagnosis

Chapter 136 Meningococcal Infections

(Part 7)

Complications

Patients with meningococcal meningitis may develop cranial nerve palsies, cortical venous thrombophlebitis, and cerebral edema Children may develop subdural effusions Permanent sequelae can include mental retardation, deafness, and hemiparesis The major long-term morbidity of fulminant meningococcemia is the loss of skin, limbs, or digits that results from ischemic necrosis and infarction

Diagnosis

Few clinical clues help the physician distinguish the patient with early meningococcal disease from patients with other acute systemic infections The most useful clinical finding is the petechial or purpuric rash (see Fig 52-5), but it must be differentiated from the petechial lesions seen with gonococcemia (see Fig 137-2), Rocky Mountain spotted fever (see Fig 167-1), hypersensitivity vasculitis (see Fig 52-4), endemic typhus, and some viral infections In one case series,

one-half of the adults with meningococcal bacteremia had neither meningitis nor a rash

The definitive diagnosis is established by recovering N meningitidis, its

antigens, or its DNA from normally sterile body fluids (e.g., blood, CSF, or synovial fluid) or from skin lesions Meningococci grow best on Mueller-Hinton

or chocolate blood agar at 35˚C in an atmosphere that contains 5–10% CO2

Specimens should be plated without delay N meningitidis bacteria are

oxidase-positive, gram-negative diplococci that typically utilize maltose and glucose

A Gram's stain of CSF reveals intra- or extracellular organisms in ~85% of patients with meningococcal meningitis The latex agglutination test for meningococcal polysaccharides in the CSF is less sensitive PCR amplification of DNA in buffy coat or CSF samples is more sensitive than either of these tests; like the latex agglutination test, PCR is unaffected by prior antibiotic therapy, as neither method requires viable organisms

Throat or nasopharyngeal specimens should be cultured on Thayer-Martin medium, which suppresses the competing oral flora Throat or nasopharyngeal cultures are recommended only for research or epidemiologic purposes, since a positive result merely confirms the carrier state and does not establish the existence of systemic disease

Meningococcal Infections: Treatment

(Table 136-1) A third-generation cephalosporin, such as cefotaxime or ceftriaxone, is preferred for initial therapy One of these cephalosporins in

combination with other agents may cover other bacteria (such as Streptococcus

pneumoniae and Haemophilus influenzae) that can cause the same syndromes

(Chap 376) Penicillin G remains an acceptable alternative for confirmed invasive meningococcal disease in most countries However, the prevalence of meningococci with reduced susceptibility to penicillin has been increasing, and high-level penicillin resistance has been reported Other options include meropenem In the patient who is allergic to β-lactam drugs, chloramphenicol is a suitable alternative; chloramphenicol-resistant meningococci have been reported from Vietnam and France The newer fluoroquinolones gatifloxacin,

moxifloxacin, and gemifloxacin have excellent in vitro activity against N

meningitidis, with measurable central nervous system (CNS) penetration, and

appear promising in animal models Patients with meningococcal meningitis should be given antimicrobial therapy for at least 5 days While glucocorticoid therapy for meningitis in adults is controversial, many experts administer dexamethasone, beginning if possible before antibiotic therapy is initiated; the schedule is 10 mg IV given 15–20 min before the first antibiotic dose and then every 6 h for 4 days The data regarding steroid use to diminish CNS inflammation

are strongest for H influenzae and S pneumoniae meningitis, especially in

children

Table 136-1 Antibiotic Treatment, Chemoprophylaxis, and Vaccinations for Invasive Meningococcal Disease

Antibiotic Treatmenta

1 Ceftriaxone 2 g IV q12h (100 mg/kg per day) or cefotaxime 2 g IV q4h

2 For penicillin-sensitive N meningitidis: Penicillin G 18–24 million units

per day in divided doses q4h (250,000 units/kg per day)

3 Chloramphenicol 75–100 mg/kg per day in divided doses q6h

4 Meropenem 1.0 g (children, 40 mg) IV q8h

5 In an outbreak setting in developing countries: Long-acting chloramphenicol in oil suspension (Tifomycin), single dose

Adults: 3.0 g (6 mL)

Children 1–15 years old: 100 mg/kg

Children <1 year old: 50 mg/kg

Chemoprophylaxisb

Rifampin (oral)

Adults: 600 mg bid for 2 days

Children ≥1 month old: 10 mg/kg bid for 2 days

Children <1 month old: 5 mg/kg bid for 2 days

Ciprofloxacin (oral)

Adults: 500 mg, 1 dose

Ofloxacin (oral)

Adults: 400 mg, 1 dose

Ceftriaxone (IM)

Adults: 250 mg, 1 dose

Children <15 years old: 125 mg, 1 dose

Azithromycin (oral)

500 mg, 1 dose

Vaccinationc

A, C, Y, W-135 vaccine (Memomune, Aventis Pasteur) or A, C vaccine

Single 0.5-mL subcutaneous injection

New C; A, C; and A, C, Y, W-135 meningococcal conjugate vaccinesd

a

Patients with meningococcal meningitis should receive antimicrobial therapy for at least 5 days

b

Use is recommended for close contacts of cases or if ceftriaxone is not used for primary treatment

c

At present, use is generally limited to the control of epidemics and to individuals with increased risk of meningococcal disease Vaccine efficacy wanes after 3–5 years, and vaccine is not effective in recipients <2 years of age

d

These vaccines appear to provide immunity in young children, a prolonged immune response, and herd immunity (decreased transmission and colonization)