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Toronto Notes 2019 Infectious Diseases Pediatrics P53 Infectious Mononucleosis
Definition
• systemicviralinfectioncausedbyEBVwithmultivisceralinvolvement;oftencalled“thegreatimitator”
Epidemiology
• peakincidencebetween15-19yrold
• ~50%ofchildrenindevelopedcountrieshaveaprimaryEBVinfectionby5yrold,but<10%of
children develop clinical infection
Etiology
• EBV:amemberofherpesviridae
• transmissionismainlythroughinfectedsaliva(“kissingdisease”)andsexualactivity(lesscommonly);
incubation period of 1-2 mo
Risk Factors
• infectiouscontacts,sexuallyactive,multiplesexualpartnersinthepast
History
• prodrome:2-3dofmalaise,anorexia
• infantsandyoungchildren:oftenasymptomaticormilddisease
• olderchildrenandadolescents:malaise,fatigue,fever,sorethroat,abdominalpain(oftenLUQ),
headache, myalgia
Physical Exam
• classictriad:febrile,generalizednon-tenderlymphadenopathy,pharyngitis/tonsillitis(exudative) • ±hepatosplenomegaly
• ±periorbitaledema,±rash(urticarial,maculopapular,orpetechial)–morecommonafter
inappropriate treatment with β-lactam antibiotics
• any“-itis”(includingarthritis,hepatitis,nephritis,myocarditis,meningitis,encephalitis,etc.)
Investigations
• heterophilantibodytest(Monospot®test)
■ 85% sensitive in adults and older children, but only 50% sensitive if <4 yr of age ■ false positive results with HIV, SLE, lymphoma, rubella, parvovirus
• EBVtitres
• CBCanddifferential,bloodsmear:reactivelymphocytes,lymphocytosis,Downeycells±anemia±
thrombocytopenia
• throatculturetoruleoutstreptococcalpharyngitis
Management
• supportive:adequaterest,hydration,salinegargles,andanalgesicsforsorethroat
• splenicenlargementisoftennotclinicallyapparentsoallpatientsshouldavoidcontactsportsfor6-8wk • ifairwayobstructionsecondarytonodaland/ortonsillarenlargementispresent(especiallyyounger
children), admit for steroid therapy
• acyclovirdoesNOTreducedurationofsymptomsorresultinearlierreturntoschool/work
Prognosis
• mostacutesymptomsresolvein1-2wk,thoughfatiguemaylastformonths • short-termcomplications:splenicrupture,Guillain-Barrésyndrome
Infectious Pharyngitis/Tonsillitis
Definition
• inflammationofthepharynx,especiallythetonsilsifpresent,causingasorethroat
Etiology
• viral(~80%):adenoviruses,enteroviruses,coxsackie,upperrespiratorytractviruses,EBV,CMV
• bacterial(~20%):mainlyGAS,M.pneumoniae(olderchildren),N.gonorrhoeae(sexuallyactive),
C. diphtheriae (unvaccinated), Fusobacterium necrophorum (anaerobe causing Lemierre syndrome)
• fungal:Candida
Epidemiology
• season:GASpharyngitismorecommoninlatewinterorearlyspring;viralallyearlong
• age:GASpharyngitispeakincidenceat5-12yrofageanduncommon<3yr;viralpharyngitisaffectsallages
Presentation
• GAS:sorethroat(maybesevere),febrile,malaise,headache,abdominalpain,N/V,absenceofother URTI symptoms, pharyngeal/tonsillar serythema and exudates, enlarged (>1cm) and tender anterior cervical lymph nodes, palatal petechiae, strawberry tongue, scarlatiniform rash
• viral:sorethroat(oftenmild),afebrile,conjunctivitis,cough,rhinorrhea,hoarseness,diarrhea,flu-like symptoms (fever, malaise, myalgias), absent/mild tonsillar exudates, minor and non-tendor adenopathy, viral exanthems