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Toronto Notes 2019 Systemic Infections
Clinical Presentation
• 80%areasymptomatic
• mostsymptomaticcasesaremild(WestNilefever):acuteonsetofheadache,backpain,myalgia,
anorexia, maculopapular non-pruritic rash involving chest, back, arms
• severe complications: encephalitis, meningoencephalitis, and acute flaccid paralysis (especially in
those >60 yr)
Investigations
• IgMantibodyinserumorCSFisthebesttest(crossreactivitywithyellowfeverandJapanese encephalitis vaccines, and with dengue fever and St. Louis virus infection); may not reflect current illness as IgM antibody can last for >6 mo
• viralisolationbyPCRfromCSF,tissue,blood,andfluids(allhavelowsensitivity)
• CSF:elevatedlymphocytesandproteinifCNSinvolvement
Treatment and Prevention
• treatment: supportive
• prevention:mosquitorepellant(DEET,picaridin),drainstagnantwater,communitymosquitocontrol
programs
Syphilis
Etiology
• Treponemapallidum:thickmotilespirocheteshistoricallydetectablebydark-fieldmicroscopy • transmittedsexually,vertically,orparenterally(rare)
Clinical Presentation
• seeDermatology,D31andGynecology,GY29
• multi-stagedisease
1. primary syphilis (3-90 d post-infection)
■ painless chancre at inoculation site (any mucosal surface)
■ regional lymphadenopathy
■ acute disease lasts 3-6 wk, 25% progress to secondary syphilis without treatment
2. secondary syphilis = systemic infection (2-8 wk following chancre)
■ maculo-papular non-pruritic rash including palms and soles
■ generalized lymphadenopathy, low grade fever, malaise, headache, aseptic meningitis, ocular/otic
syphilis
■ condylomata lata: painless, wart-like lesion on palate, vulva, or scrotum (highly infectious)
3. latent syphilis
■ asymptomatic infection that follows untreated primary/secondary syphilis
■ early latent (<1 yr post-infection) or late latent/unknown duration (>1 yr post-infection)
■ increased transmission risk with early latent; longer treatment duration required for late latent
4. tertiary syphilis (1-30 yr post-infection)
■ gummatous syphilis: nodular granulomas of skin, bone, liver, testes, brain
■ aorticaneurysmandaorticinsufficiency
■ neurosyphilis: dementia, personality changes, Argyll-Robertson pupils, tabes dorsalis
5. congenital syphilis
■ causes spontaneous abortions, stillbirths, congenital malformations, developmental delay, deafness ■ most infected newborns are asymptomatic
■ clinical manifestations in early infancy include rhinitis (snuffles), lymphadenopathy,
hepatosplenomegaly, pseudoparalysis (bone pain associated with osteitis) and rash (usually
maculopapular and involving palms and soles)
■ late onset manifestations (>2 yr of age) include saddle nose, saber shins, Glutton joints, Hutchinson’s
teeth, mulberry molars, rhagades, CN VIII deafness, interstitial keratitis, juvenile paresis
Investigations
• syphilistestsareconductedbypublichealthlabs.Thusordersetforsyphilisissimplifiedanddoesnot require specification of which test to complete. Below are details on what tests are conducted at the public health lab
• screeningtests:CMIA,CLIA,EIA(treponemal),RPR,orVDRL(non-treponemal)
• confirmatory tests: TPPA, FTA-ABS, MHA-TP, TPI
• LP for neurosyphilis if: seropositive and symptoms of neurosyphilis or treatment failure/other tertiary
symptoms, or with HIV and late latent/unknown duration syphilis; consider in others
• forcongenitalsyphilis,LPisessential;longbonex-raysmayalsobehelpful
Treatment
• for1o,2o,earlylatent:benzathinepenicillinG2.4millionunitsIMx1
• for3o,latelatent:benzathinepenicillinG2.4millionunitsIMweeklyx3
• iftrulyallergictopenicillin:doxycycline100mgPObidx14disasecondlinetherapy
• forpregnantpatientsallergictopenicillin,oraldesensitizationtechniquesareconsideredsafe
• neurosyphilis:aqueousPenicillinG18-24millionunits/dIVx14d±singledoseofbenzathinepenicillin • forcongenitalsyphilis,penicillinGIVx10d
• seeFamilyMedicine,FM43forgeneralizedSTIworkup
Infectious Diseases ID25
Argyll Robertson Pupil
Accommodates but does not react to light
Those with Untreated 1o or 2o Syphilis
1/3 cure
1/3 latent indefinitely 1/3 3o syphilis
Causes of False Positive VDRL and RPR Tests
Viruses (mononucleosis, hepatitis) Drugs and substance abuse Rheumatic fever
Lupus and leprosy
Patients with 2o or 3o syphilis treated with penicillin may experience a Jarisch- Herxheimer reaction. Lysis of organisms release pyrogens thought to cause fever, chills, myalgia, flu-like symptoms may last upto24h
VDRL Venereal Disease Research Laboratory
RPR Rapid Plasma Reagin
EIA Enzyme Immunoassay
CLIA ChemiLuminescent ImmunoAssay CMIA ChemiLuminescent Microparticle
ImmunoAssay FTA-ABS Fluorescent Treponema
Antibody-Absorption MHA-TP Microhemagglutination Assay
T. pallidum
TPPA T. pallidum Particle
Agglutination Assay
TPI T. pallidum immobilization test