Cystic Fibrosis and Nasal Polyposis.docx

Cystic Fibrosis and Nasal Polyposis.docx

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CysticFibrosisandNasalPolyposis

CysticFibrosisandNasalPolyposis

FordD.AlbrittonIV,MD,andToddT.Kingdom,MD,EmoryUniversity,Atlanta,Ga.

MedscapeGeneralMedicine2

（1）,2000.©2000Medscape

Posted02/18/2000

Abstract

Nasalpolyposisisasinonasalmanifestationofcysticfibrosis（CF）--anautosomalrecessiveexocrinopathy.Upto67%ofallCFpatientswillmanifestpolypsintheirlifetime.Symptomsincludenasalairwayobstruction,anosmia,rhinorrhea,andexacerbationoftherhinosinusitisthataffectsthesepatients.Thepolypsareprobablyaconsequenceofchronicinflammation;however,theirspecificetiologyisunclear.Treatmentincludesantibiotics,topicalnasalsteroids,decongestants,andmucolytics.Surgeryisnecessarywhenconservativemeasuresfail.Endoscopicsinussurgery（ESS）hasreplacedtraditionaltreatmentssuchasintranasalpolypectomyandCaldwell-Lucprocedure.ESScombinedwithmedicaltherapyhassuccessfullydelayedthetimetorecurrence,decreasedtheneedforsurgery,andimprovedtheunderlyingpulmonarystatusinseveralstudiedpatientgroups.Thisarticlereviewstypicalpatientsymptoms,physicalexamination,theuseofcomputedtomography（CT）,nasalendoscopicfindings,patientprognosis,andthelatestresearchandinnovations.

CasePresentation

A7-year-oldwhitefemalewasadmittedtothepediatricunitforrecurrentbronchitis.Shewasreferredtotheotolaryngologyclinicwithcomplaintsofchronicnasalstuffiness,usuallyclearwithepisodesofpurulentrhinorrhea,anosmia,andoccasionalheadaches.Antibioticswereusedinthepasttotreatsimilarsymptoms.Pastmedicalhistorywassignificantonlyforrecurrentepisodesofbronchitis.Reviewofsystemswasnegative.Oneofhersiblingswasfoundtohavesimilarbutmildercomplaints.

Physicalexamrevealedayoungwhitefemaleinthe40thpercentileforweightandheight.Cranialnerve,otologic,andoropharyngealexamswerewithinnormallimits.Anteriorrhinoscopyrevealedgreen,mucoidcrustingbilaterally.Aftersuctionanddecongestion,endoscopicexaminationwasperformed（Figure1）.

Figure1.Endoscopicviewofleftnasalcavityshowingpolyposisinmiddlemeatus.Noticehowthepolypsexhibitaglistening,almosttranslucentmucosaincontrasttothenormalnasalmucosaseenintheremainderofthephoto.Thenasalairwayisvirtuallynonexistentsecondarytoobstruction.

Sinuscomputedtomography（CT）wasobtainedwithaxial（Figure2）andcoronal（Figure3）views.

Figure2.AxialCTscanofayoungpatientwithCF.Hypoplasticmaxillarysinusesareseenbilaterally.Bothmaxillarysinusesarecompletelyopacifiedwithbulgingmedialwalls.Thispictureofcompleteopacificationwithsinuswallexpansionisoftendescribedbytheradiologistassinusitiswithfindingsconsistentwithpolyposisormucocele.

Figure3.Coronalviewofsamepatient.Again,noticethesmallsizeofthemaxillarysinusescomparedwiththeboneofthemaxilla.Alsonoteopacificationofthemaxillaryandethmoidsinuses.Cutsthroughtheexpectedlocationsofthefrontalandsphenoidsinusesrevealedthesesinusesabsent.AbsenceorhypoplasiaoftheparanasalsinusesisamuchmorefrequentfindinginCFthaninthegeneralpopulation.

Thispatientwasdiagnosedwithcysticfibrosis（CF）atage3yearsafter2positivesweatchloridetests.GenotypeanalysiswasperformedbyherCFpulmonologistandthistestrevealedshewashomozygousfortheDelta-F508mutation.

AfterpathologyandCTreview,andbecauseofherrecurrentsymptoms,thispatientunderwentendoscopicpolypectomy,limitedethmoidectomy,andmaxillaryantrotomy.Sheremainedinhospitalpostoperatively;2dayslatershewasdischargedtotheCFcenter.Postoperatively,herheadaches,nasalobstruction,andrhinorrheahadmuchimproved,andrhinologicexamsoverthenext6monthsdemonstratedimprovedsinusdrainage,improvedsinusaccess,andnorecurrentpolyps.

Introduction

Sinonasalpolypsarecharacterizedbysmooth,pale,almosttranslucentmucosaonapedunculatedorsessilebase.Theycanoccuranywhereinthesinuscavity,oftenalongthemiddlemeatus.Polypsarefrequentlymultipleandbilateral,andtheirsymptomsrelatetotheirobstructivenatureandincludenasalstuffiness,mouthbreathing,facialpain/pressure,anosmia,andevenrhinorrhea.[1]

Allthatresemblesapolypisnotapolyp.Thedifferentialdiagnosisincludesothernasalmasses,suchasgliomasandencephaloceles,aswellasnormalvariantsofnasalanatomy.Workupshouldincludeathoroughhistoryandrhinoscopicexam.Sinonasalpolyposismaybeseeninamyriadofclinicalsituationsincludingasthma,allergicrhinitis,immotileciliasyndrome,allergicfungalsinusitis,chronicsinusitis,andCF.MostcommonlytheyareassociatedwithallergicrhinitisandCF.[2,3]

Pathophysiology

CFisthemostlethalautosomalrecessivediseaseaffectingCaucasians,withanestimatedcarrierrateof1in25.[4]TheCFgenehasbeenisolatedtochromosome7andencodesforatransmembraneproteintermedtheCFtransmembraneconductanceregulator（CFTR）.Itisthoughttobeacyclicadenosinemonophosphate（cAMP）-dependentchloridetransportpump,andmutationsoftheCFTRleadtoionpumpdysfunction.Over550differentmutationshavebeendocumentedthusfar.[5]ThesweatglandepitheliumofCFpatientsfailstoabsorbbothchlorideandsodiumfromtheglandularlumen,resultinginelevatedsweatconcentrationsoftheseions.Consequently,extracellulardehydrationensues,leadingtoavarietyofcomplications.Inspissatedsecretionsinthebronchi,pancreas,andsinonasaltractleadtodysfunctionineachofthesesystems.

Thefunctionofthesinonasaltractishumidification,temperaturemodification,andfiltrationofinspiredairinadditiontoolfaction.Thenoseislinedwithciliatedpseudostratifiedcolumnarepitheliumincombinationwithgobletcells--theso-called"respiratoryepithelium."Amucousbilayerlinesthisepithelium,workingprimarilytotrapinspiredforeignparticles.Nasalciliaryfunctionmovesthemucouslayerinwell-establishedroutestohelpclearthesinusesandnasalcavityofinspireddebris.Anyconditionthataltersmucociliaryflowwillresultinstasisandcausemicrobialcolonizationandinfection.

InCF,intracellularwaterfluxincreasesmucousviscosity,leadingtomucociliarydysfunction,stasis,andsinonasalobstruction.ItisthissequenceofeventsthatpredisposestheCFpatienttobacterialcolonizationbyPseudomonasandStaphylococcusspeciesandleadstothedevelopmentofchronicrhinosinusitis.Chronicinfectionmaybetheunderlyingcatalystbehindtheformationofthecharacteristichyperplasticmucosalchangesanddevelopmentofnasalpolypssocommonlyseeninthispatientgroup.[6]

Thepathogenesisofnasalpolypsinthegeneralpopulationisnotwelldefined.Thereareanumberoftheoriesregardingspecificpathogenesis,withsomeinvestigatorsproposingthatCFpolypsaredistinctfromnon-CFpolyps.Comparativehistopathologicstudies,suchasa1979studybyOppenheimer,describedhistologicdifferencesinbasementmembranethicknessandeosinophildensitybetweenCFpolypsandatopicpolyps.[7]However,similarstudiesbyotherinvestigatorsfailtodemonstratedifferences.[6,8]CFpolypsappeartocontainhighernumbersofneutrophilsthannon-CFpolyps,buteosinophilsexistinbothvarieties.[9]

Epidemiology

CFaffectsover18,000peopleintheUnitedStatesalone.[10]TheincidenceofpolyposisinCFisapproximately67%[11-14]andthepeakincidenceoccursbetween4and12yearsofage.[15]EstimatesoftheincidenceofpolyposisinCFaremoreaccuratenow,duetothelargernumbersofpatientsbeingstudiedandthequalityofthediagnostictechnologyavailable,particularlytheendoscope,whichhasallowedtheotolaryngologistamorecomprehensiveviewofthenasalcavity.

MeansurvivalofCFpatientsisnowapproaching30years[16]duetoadvancesinnutrition,drugtherapy,andsupportivecare.Thisincreaseinsurvivalhasnecessitatedcomprehensivecareofthesepatients.

Diagnosis

Anypatientwithafindingofnasalpolyposis/chronicsinusitisandrecurrentpulmonaryorGIcomplaintsshouldbeconsideredforCFwork-up.Otherpatientsatriskarethosewhopresentwithnasalpolyposisalone,thosewithrecurrentsinusitisrefractorytostandardantibiotictreatment,andsomeasthmatics.Eighty-fivepercentofpatientswithCFarediagnosedbyage5,[17]butadolescentsandyoungadultsmayalsocarryanunrecognizedCFphenotype.

SweatchlorideanalysisisthemostcommonlyuseddiagnostictestforCF.[18]Somelaboratoriesarealsoperforminggenotypeanalysis,whichismoresensitiveandmorelikelytoidentifymildcases.Although70%ofCFpatientshavetheDeltaF508mutation,genotypeanalysiscanconfirmthediagnosisandprovideinformationondiseaseseverity.ItappearsthatpolyposismaybemorecommoninpatientshomozygousfortheDeltaF508genotype[5]andthereissomeevidencethatalowerincidenceofpulmonaryandGImanifestationsexistinpatientswithnasalpolyposis.Itishopedthatthefutureofgenotypeanalysiswillincludeprenataldiagnosis.[18]

MedicalTherapy

Medicaltherapyemphasizesrelievingtheobstructionwithdecongestantsandtopicalnasalsteroids,inconcertwithantistaphylococcalandantipseudomonalantibiotics.Antimicrobialsattempttolowercolonizationandinfectionrates.Additionaladjunctivemeasuresincludemucolyticssuchasguaifenesenandnasalsaline.Bylooseninganddebridingsecretions,drainageimprovesandtheprobabilityofstasis/colonizationdiminishes.

AntihistaminesshouldbereservedfortheatopicCFpatientbecausetheydrysecretions,impairingmucociliarytransitandexacerbat