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Toronto Notes 2019 Infectious Diseases Pediatrics P55 Meningitis
Definition
• inflammationofthemeningessurroundingthebrainandspinalcord
Epidemiology
• peakage:6-12mo;90%ofcasesoccurinchildren<5yrold
Etiology
• viral: enteroviruses, HSV
• bacterial:age-relatedvariationinspecificpathogens
• fungalandparasiticmeningitisalsopossible
• mostoftenduetohematogenousspreadordirectextensionfromacontiguoussite
Risk Factors
• unvaccinated
• immunocompromised: asplenia, DM, HIV, prematurity
• recentorcurrentinfections:AOM,sinusitis,orbitalcellulitis
• neuroanatomical:congenitaldefects,dermalsinus,neurosurgery,cochlearimplants,recentheadtrauma • exposures:daycarecentres,householdcontact,recenttravel
History
• signsandsymptomsvariableanddependentonage,durationofillness,andhostresponsetoinfection • infants:fever,lethargy,irritability,poorfeeding,vomiting,diarrhea,respiratorydistress,seizures
• children:fever,headache,photophobia,N/V,confusion,back/neckpain/stiffness,lethargy,irritability
Physical Exam
• infants:toxic,hypothermia,bulginganteriorfontanelle,respiratorydistress,apnea,petechial/purpuric rash, jaundice
• children: toxic,iLOC, nuchal rigidity, Kernig’s and Brudzinski’s signs, focal neurologic findings, petechial/purpuric rash
Investigations
• bloodwork:CBC,electrolytes,Cr,BUN,glucose,C&S • LPrequiredfordefinitivediagnosis
■ Gram stain, bacterial C&S, WBC count and differential, RBC count, glucose, protein concentration ■ acid-fast stain if suspect TB
■ PCR for specific bacteria if available (helpful if already treated with antibiotics)
■ urinalysis and urine C&S in infants, Gram stain and culture of petechial/purpuric lesions
■ HSV and enterovirus PCR if suspected
Table 22. CSF Findings of Meningitis
Component
WBC (x105/L)
Neutrophils (x105/L)
Glucose (CSF:Blood)
Protein (g/L) RBC (/μL)
Normal Child Normal Newborn
≤5 0-30 <20
00
≥0.6 (or ≥2.5 ≥0.6 (or ≥2.5 mmol/L) mmol/L)
<0.4 <1.0
Bacterial Meningitis
Usually <100
100-10,000 (can be normal)
<0.4 (can be normal) >1.0 (can be normal) 0-10
Viral Meningitis
10-1000 (can be normal)
Usually <100
Usually normal
0.4-1.0 (can be normal)
0-2
Herpes Meningitis
50-1000 (can be normal)
Usually <100
<0.3 (can be normal) 1-5 (Can be normal) 10-50
Modified from https://www.rch.org.au/clinicalguide/guideline_index/CSF_Interpretation/
Management
• supportivecare
■ preservation of adequate cerebral perfusion by maintaining normal BP and managinghICP ■ close monitoring of fluids, electrolytes, glucose, acid-base disturbances, coagulopathies
• bacterialmeningitis
■ if suspected or cannot be excluded, commence empiric antibiotic therapy while awaiting cultures or
if LP contraindicated or delayed
■ isolation with appropriate infection control procedures until 24 h after culture-sensitive antibiotic
therapy
■ fluid restrict if any concern for SIADH
■ hearing test
■ report to Public Health; prophylactic antibiotics for close contacts of Hib and N. meningitidis
meningitis