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ID18 Infectious Diseases
CNS Infections
Toronto Notes 2019
Corticosteroids for Acute Bacterial Meningitis
Cochrane DB Syst Rev 2015;CD004405 Objectives: To examine the effect of adjuvant corticosteroid therapy vs. placebo on mortality, hearing loss, and neurological sequelae with acute bacterial meningitis.
Methods: RCTs of corticosteroids for acute bacterial meningitis.
Results: 25 studies, 4121 participants. Corticosteroids were associated with non- significant mortality reductions (RR 0.90, 95%
CI 0.80-1.01). Corticosteroids were associated with lower rates of hearing loss (RR 0.74, 95% CI 0.63-0.87) andneurologicalsequelae(RR0.83, 95% CI 0.69-1.00). Corticosteroids were associated with increase in recurrent fever (RR 1.27, 95% CI 1.09-1.47).
Conclusions: Corticosteroids significantly reduced hearing loss and neurological sequelae, but did not reduce mortality. Data supports use in high-income countries but no benefit in low-income countries.
Brudzinski’s Sign
Passive neck flexion causes involuntary flexion of hips and knees
Kernig’s Sign
Resistance to knee extension when hip is flexed to 90o
Jolt Accentuation of headache
Headache worsens when head turned horizontally at 2-3 rotations; more sensitive than Brudzinski’s and Kernig’s
CSF Gram Stain Findings
• S. pneumoniae – GP diplococci
• N. meningitidis – GN diplococci
• H.influenzae–PleiomorphicGNcoccobacilli • L. monocytogenes – GP rods
Does this Adult Patient Have Acute Meningitis? From The Rational Clinical Examination
JAMA 2009; http://www.jamaevidence.com/ content/3482857
Study: Systematic review of articles assessing the sensitivity and specificity of clinical exam maneuvers for the diagnosis of adult meningitis. Results: In retrospective studies, sensitivity for headache was 68%, and 52% for nausea and vomiting. Sensitivity for physical exam findings
is similarly low (fever: 87%, neck stiffness: 80%, altered mental status: 69%). Sensitivity for the combination of the classic triad of fever, neck stiffness, and altered mental status was 46%.
In prospective studies, sensitivity of headache was 92%, while sensitivity of nausea/vomiting could not be pooled, and ranged from 32-70%. Brudzinski’s and Kernig’s signs had a sensitivity of 5% and Kernig’s sign only 5-9%. Jolt accentuation had a sensitivity of 97%.
Conclusions: Data were heterogeneous, and lacked standardization of clinical exams. No single item on clinical history or physical exam was sufficient to rule out meningitis, including Kernig’s and Brudzinski’s signs, or the absence of the classic triad of fever, neck stiffness, and altered mental status meningitis. Jolt accentuation has high sensitivity, but further research is needed.
LP may be performed safely without CT head in patients without altered LOC, no recent seizure, no history of CNS disease, not immunocompromised, and <60 yr.
CNS Infections
Meningitis
• seePediatrics,P55 Definition
• inflammationofthemeninges
Etiology
Table 18. Common Organisms in Meningitis
Age 0-4 wk
GBS
E. coli
L. monocytogenes Klebsiella
Risk Factors
Bacterial
Age 1-3 mo
GBS
E. coli
S. pneumoniae N. meningitidis H. influenzae
Age >3 mo
S. pneumoniae
N. meningitidis
L. monocytogenes (age >50 and comorbidities)
Viral
HSV-1, 2
VZV Enteroviruses Parechoviruses West Nile
Fungal
Cryptococcus Coccidioides
Other
Lyme disease Neurosyphilis TB
• lack of immunization against H. influenzae type b, S. pneumoniae, and N. meningitidis in children • mostcasesofbacterialmeningitisareduetohematogenousspreadfromamucosalsurface
(nasopharynx)
• direct extension from a parameningeal focus (otitis media, sinusitis) less common
• penetratingheadtraumaoriatrogenic
• anatomicalmeningealdefects–CSFleaks
• immunodeficiency (corticosteroids, HIV, asplenia, hypogammaglobulinemia, complement deficiency) • contactwithcolonizedorinfectedpersons
Clinical Presentation
• neonatesandchildren:fever,lethargy,irritability,vomiting,poorfeeding
• olderchildrenandadults:fever,headache,neckstiffness,confusion,lethargy,alteredlevelof
consciousness, seizures, focal neurological signs, nausea/vomiting, photophobia, papilledema
• petechial rash in meningococcal meningitis (purpura fulminans), seen more frequently on trunk or
lower extremities
Investigations
• bloodwork:CBCanddifferential,electrolytes(forSIADH),bloodC&S
■ CSF: opening pressure, cell count + differential, glucose, protein, Gram stain, bacterial C&S
■ AFB, fungal C&S, cryptococcal antigen in immunocompromised patients, subacute illness,
suggestive travel history or TB exposure
■ PCR for HSV, VZV, enteroviruses; in infants <6 mo, parechoviruses
■ West Nile virus serology in blood and CSF during summer and early fall if viral cause suspected
• imaging/neurologicstudies:CT,MRI,EEGiffocalneurologicalsignspresent
Table 19. Typical CSF Profiles for Meningitis
CSF Analysis
Glucose (mmol/L) Protein (g/L)
WBC Predominant WBC
Treatment
Bacterial
Decreased Markedly Increased 500-10,000/μL Neutrophils
Viral
Normal Increased 10-500/μL Lymphocytes
• bacterialmeningitisisamedicalemergency:donotdelayantibioticsforCTorLP
•
•
empiricantibiotictherapy
■ age ≤28 days: ampicillin + cefotaxime
■ age 29 days-3 mo: cefotaxime + vancomycin ■ age >3 mo: ceftriaxone + vancomycin
◆ add ampicillin IV if risk factors for infection with L. monocytogenes present: age >50, alcoholism, immunocompromised
steroidsinacutebacterialmeningitis:dexamethasoneIVwithin20minpriortoorwithfirstdoseof antibiotics
■ continueinthosepatientswithprovenpneumococcalmeningitis
■ notrecommendedforpatientswithsuspectedbacterialmeningitisinsomeresource-limitedcountries ■ not recommended for neonatal meningitis