Miscellaneousrespiratorytractinfections

By:NaderAlaridah MD,PhD

AtypicalPneumonia• AtypicalpneumoniacausedbyMycoplasma andChlamydia,Legionella.. TheserelatedtoGram-ve bacteria..Attachedtorespiratorymucosa..NotcommonpartofRespiratoryflora..Opportunisticpathogens

• Causingmostlymilderforms ofpneumonia ..characterizedbyslowdevelopmentofsymptomsunlikeotherformsofpneumoniawhichcandevelopmorequickly..moresevereearlysymptoms.

• M.pneumoniae : ThesmallestsizeBacteria..LackCellWall..Lipidbi-layerMembrane..AerobicGrowth,Respiratory/UrinaryMucosa..VariousMycoplasma spp. Associatedwithdisease..Human,Animals,Birds

Mycoplasma• M. pneumoniae ..spreadbydropletinfection..oftendevelopLowfever&drycoughsymptoms ..fewdays-weeks..anemia,rashes,neurologicalsyndromes..meningitis,encephalitis.

• Acute/Subacute Pharyngitis..Bronchitis..CommonInfectioninFall-Winter..MostlyOldchildren &youngAdults.

• SevereformsofMpneumoniahavebeendescribedinallagegroups.

• LabDiagnosis: Specialculturemedium..PCR..,Pleuralfluid,Blood.SerologicalCold-AgglutinationTest..Increasedantibodytiters.

• Treatment:levofloxacin,moxifloxacin,Macrolides/Azithromycin..NoVaccine

Chlamydiaspecies

• Chlamydia..Attachedhumanmucosalmembrane.. ..obligateintracellular.. intracytoplasmic inclusions..Rapidlykilledoutsidebody,dryness&hightemperature>4C.• Lifecycle:Infectiouselementarybodies attachedtothehostmucosaandpromotingitsentry..Cytoplasmphagosome..producingreticulatebodies ininclusion..releasedelementarybodies..• Chlamydiatrachomatis..SerotypesC,K :Commoncauseofsexuallytransmitteddisease(STD)Nonspecificurethritis..mothertonewbornbabies..maternalfluid..Atypicalpneumonia..Eyeinfection..Opthalmianeonatorum• AbouthalfofallnewbornswithChlamydial pneumoniadevelopinclusionconjunctivitis..1-2weeksstartsmild- severeeyesredness,swolleneyelids,inflammation&yellowthickdischargeeyes.• A&CserotypesofendemicCh.trachomatis causeTrachoma..conjunctival scarring,damageeyelids&Cornea..blindness.

ChlamydiaLifeCycle

ChlamydophilaPneumonia• C.pneumoniae: dropletsinfection..Infants/childrenoftendevelopsgradually..severalweeksmildrespiratorysymptoms,dryirritatingprolongedcough..nasalcongestion..with/withoutfever..Fewweeks..Nobloodsepsis.

• C.pneumoniae infectionsinadults..oftenasymptomatic,mild,Mayincludesorethroat,headache,fever,drycough.

• ClustersofinfectionhavebeenreportedmorecommoninChildrenthanAdults.

• Diagnosis&treatment: Sputum,throat-nasalswab..MaCoy CellCulture,ELSASpecificantibodies,PCRandMicroimmunofluorescence MIF.

• Treatment:Tetracyclines,Macrolides,levofloxacin,moxifloxacin ..NoVaccine

ChlamydophilaPsittaci• C.psittaci causesZoonotic diseases..Humaninfectionfollowedcontactwithbirds(parrots,pigeons,turkeys,andducks).. Ararehumandiseasecalledpsittacosis (ornithosis).

• Humansrespiratorytractcanbeinfectedviainhalationbacteriashedfromfeathers,secretions,anddroppingslocalizedinflammationinBronchi&lungtissues.

• Signs Symptoms: Startsmild..flu-like&endedwithseverediseaseincludingfatalpneumonia, associatedhighfever,drycough,headache.

• Diagnosis&TreatmentsimilartootherChlamydia.

Legionella pneumonphila• Leginonella Gramnegative,Pathogenic-Nonpahogenic spp.oftenfoundinnaturalaquaticbodies andwetsoil.FacultativeAnaerobesGrowthinCold/Hot(4- 80C)Water..Transmitted,InhalationviaAirCondition,WetSoil..Causeoutbreakofdisease.• LungMucosa..multiplyintracellularwithinthemacrophages..HighFever..Incub.period2-10days..Nonproductive/Productivedrycough..Shortnessofbreath,Chestpain,Muscleaches,Jointpain,Diarrhea,RenalFailure,highermortalityrate.Legionnaires'diseaseisnotcontagious• Riskfactors includeheavycigarettesmoking,0ldageunderlyingdiseasessuchasrenalfailure,cancer,diabetes,orchronicobstructivepulmonary,suppressedimmunesystems,corticosteroid.• Diagnosis&treatment: SpecialCultureMedia,blood/urinespecimenfordetectionSpecificantibodiesorAntigensbyPCR,orElSA ..Macrolides (azithromycin),levofloxacin,moxifloxacin ..NoVaccine.

OPPORTUNISTICMYCOSES

• Opportunisticmycosesarecausedbygloballydistributedfungithatareeithermembersofthehumanmicrobiota,suchaCandida species,orenvironmentalyeastsandmolds.

• Theycanproducediseaserangingfromsuperficialskinormucousmembraneinfectionstosystemicinvolvementofmultipleorgans.

• Patientsatriskincludethosewithhematologicdyscrasias(eg,leukemia,neutropenia), patientswithHIV/AIDS withCD4countslessthan100cells/μL,aswellasthosetreatedwithimmunosuppressive(eg,corticosteroid)orcytotoxicdrugs

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Cryptococcusneoformans

• Cryptococcusneoformans causescryptococcosis.• Awidespreadencapsulated yeast thatinhabitssoilaroundpigeonroosts

• CommoninfectionofAIDS,cancerordiabetespatients

• Infectionoflungs leadstocough,fever,andlungnodules

• Disseminationtomeninges andbraincancausesevereneurologicaldisturbanceanddeath.

Diagnosis

Microscopic• IndiaInkforcapsulestain(50-80%+CSF)

Culture• Birdseedagar• Routinebloodculture

PCR

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Aspergillosis:DiseasesoftheGenusAspergillus

• Verycommonairbornesoilfungus• 600species,8involvedinhumandisease;A.fumigatusmostcommonly• SeriousopportunisticthreattoAIDS,leukemia,andtransplantpatients• Infectionusuallyoccursinlungs – sporesgerminateinlungsandformfungalballs;cancolonizesinuses,earcanals,eyelids,and conjunctiva• BronchopulmonaryallergyorInvasiveaspergillosisinpreformedcavitis canproducenecroticpneumonia,andinfectionofbrain,heart,andotherorgans.• Surgery,AmphotericinBandnystatin

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Zygomycosis

• Zygomycota areextremelyabundantsaprophyticfungifoundinsoil,water,organicdebris,andfood.

• GeneramostofteninvolvedareRhizopus,Absidia,andMucor.

• Usuallyharmlessaircontaminantsinvadethemembranesofthenose,eyes,heart,andbrain ofpeople(Rhinocerebral mucormycosis)withdiabetesandmalnutrition,withsevereconsequences.• main host defense is phagocytosis

Diagnosis is made by direct smear and by isolation of molds from respiratory secretions or biopsy specimens.

Treatment: Control Diabetes ,surgery &amphotericin B

Prognosis: very poor

PNEUMOCYSTIS

• Pneumocystisjirovecii isthecauseofalethalpneumoniainimmunocompromisedpersons,particularlythosewithAIDS.

• Definitediagnosisofpneumocystosis dependsonfindingorganismsoftypicalmorphologyinappropriatespecimens(Sputum,BAL)

• Theorganismhasnotbeengrowninculture

• TMP-SMXistreatmentofchoice

Endemicmycosis

• Endemicmycosisiscausedbyathermallydimorphicfungus,andtheinfectionsareinitiatedinthelungsfollowinginhalationoftherespectiveconidia.

• Eachofthefourprimarysystemicmycoses—coccidioidomycosis,histoplasmosis,blastomycosis,andparacoccidioidomycosis—isgeographicallyrestrictedtospecificareasofendemicity.

• Mostinfectionsareasymptomaticormildandresolvewithouttreatment.However,asmallbutsignificantnumberofpatientsdeveloppulmonarydisease.

DimorphicFungus:Histoplasmosis-1

• Histoplasma capsulatum..Dimorphicfunguswithconidiaandyeastformsatbodytemperatureandhyphae &marcoconidia invitroculture..Commoninsoilenrichedwithexcretaofbirds.EndemicinsouthernU.S.A,Australia..Lessothercountries.• Theprimarysiteofinfectionisusuallypulmonary..inhalationdustwithmicroconidia..Phagocytosed bymacrophages,obligateintracellularparasites..Causingslightinflammatoryreaction..Mostcasesofhistoplasmosis areasymptomatic/subclinical,benign..Flu-likesyndrome.• Fewmaydevelopchronicprogressivelungdisease..Granuloma &fibrosis,chroniccutaneous orsystemicdiseaseinvolveanyinternalorgan..Fatalsystemicdisease.• Allinfectedpersonsbecomepositivebyhistoplasmin skintest.

HistoplasmacapsulatumininfectedWhiteBloodcells

Coccidioidomycosis&Blastomycosis

• Coccidioides immitis &Blastomyces dermatitidis..soilinhabitingDimorphicFungus..Endemicinsouth-westernU.S.A.,northernMexicoandvariouspartsSouthAmerica.

• Respiratoryinfection,resultingfromtheinhalationofmicroconidia,oftenresolvesrapidlyleavingthepatientwithastrongspecificimmunitytore-infection.

• Someindividualsthediseasemayprogresstoachronicpulmonaryconditionorasystemicdiseaseinvolvingthemeninges,bones,joints,subcutaneous,cutaneous tissues..AntigenSkintestpositive..Notsignificantindiagnosis.

LaboratoryDiagnosis• Directmicroscopyandcultureshouldbeperformedonallspecimens(sputum,bronchialwashings,CSF,pleuralfluidtissuebiopsiesfromvariousvisceralorgans).

• wetmountsin10%KOHwithindia ink..Ovoid-buddingyeastcells(b)Gram-stainsmear..

• CulturesonSabouraud dextroseagarshouldbemaintainedforonemonthat25C....fungalgrowths&WetMount..Identification..produceshyphae-likeconidio-phores &Spores..Coloroffungalgrowth

• Serologicaltestsareoflimitedvalue..notsignificant• Detection of Histoplasm antigen in blood & urine is significant

Paracoccidioidomycosis

• Paracoccidioides brasiliensis isthethermallydimorphicfungalagentofparacoccidioidomycosis (SouthAmericanblastomycosis),whichisconfinedtoendemicregionsofCentralandSouthAmerica.

• Pbrasiliensis isinhaled,andinitiallesionsoccurinthelung.Afteraperiodofdormancythatmaylastfordecades,thepulmonarygranulomasmaybecomeactive,leadingtochronic,progressivepulmonarydiseaseordissemination.

TheEnd