Tài liệu Allergic and Non‐Allergic Sinusitis for the Primary Care Physician: Pathophysiology, Evaluation and Treatment pdf

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REFERENCES
1.MelenI.Chronicsinusitis:clinicalandpathophysiologicalaspects.ActaOtolaryngolSuppl(Stockh)1994;515:45‐
48.
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2.GliklichRE,MetsonR.Thehealthimpactofchronicsinusitisinpatientsseekingotolaryngologiccare.Otolaryngol
HeadNeckSurg1995;113:104–109.
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3.GliklichRE,HilinskiJM.Longitudinalsensitivityofgenericand
specifichealthmeasuresinchronicsinusitis.Qual
LifeRes1995:4:27–32.
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4.Gliklich,RE,MetsonR.Thehealthimpactofchronicsinusitisinpatientsseekingotolaryngologiccare.Otolaryngol
HeadNeckSurg1995;113:104–109.
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5.RayNF,BaraniukJN,ThamerM.Directexpendituresforthetreatmentofallergicrhinoconjunctivitisin1996,
including
thecontributions ofrelatedairwayillnesses.JAllergyClinImmunol1999;103:401–407.
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6.RayNF,BaraniukJN,ThamerM.Healthcareexpendituresforsinusitisin1996;contributionsofasthma,rhinitis, 
andotherairwaydisorders.JAllergyClinImmunol1999;103:408–414.
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7.PankeyGA,GrossCW,MendelsohnMG.ContemporaryDiagnosis
andManagementofSinusitis.NewtownPA:
HandbooksinHealthCare,2000.
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8.DereberryJ,MeltzerE,NathanRA,StangPE,CampbellUB,CorraoM,StanfordR.OtolaryngolHeadNeckSurg,
2008Aug;139(2):198‐205.RhinitissymptomsandcomorbiditiesintheUnitedStates:burdenofrhinitisinAmerica
survey
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9.KennedyDW,
BolgerWE,ZinreichSJ.DiseasesoftheSinuses:DiagnosisandManagemet,London:BCDecker,2001
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AllergicandNon‐AllergicSinusitisforthePrimaryCarePhysician:
Pathophysiology,EvaluationandTreatment
CHAPTER1
SINUSANATOMYANDPHYSIOLOGYWITHSINUSITISOVERVIEW
DEFINITIONS
Thesinusesarechambersinthebonesofthefaceandskullthatarenormallylinedwithathinmucus
producingmembrane(calledmucosa).Therearefourpairedparanasalsinuses—themaxillary,ethmoid,frontal,and
sphenoidsinuses(Fıg.1).They
communicatewiththenasalcavityvianarrowopenings.Airandmucusenterandexit
thesinusthroughtheseopenings.Blockageofthesmallopeningsfromswelling(causedbyinfection, allergy,and
othercauses)canresultinsinusitis.(1,2,3)
SINUSITIS
Sinusitisliterallymeans“i nflammationofthesinuscavities.”(4‐6)
Thisinflammationiswhathappensoccurs
whenapatient’snoseandsinusesareexposedtoanythingthatmightirritatethemembranouslinings.These
irritantsmayincludedustandpollution,cigarettesmoke,andotherirritants.Allergicreactiontomold,pollen,and
soforthmayalsoirritatethenasallinings.Furthermore,infection
byavirusorbacteriamayirritatethenasallinings.
Theswellingthatoccursmaycausethenarrowopeningsinthenoseandsinuscavitiestonarrowevenfurtheror
eventoshutcloseentirely.Thickabnormalmucussecretionscanalsoblockthesinuses further.
Rhinitisreferstoinflammationofthenasal
mucosalliningsonly.Sinusitisreferstoinflammationofthe
mucosalliningsofthesinusesandisusuallyassociatedwithandoftenprecededbyrhinitis.Becausethetwogo
together,ear,nose,andthroatspecialiststodayoftenusethetermrhinosinusitis.However,thewordsrhi nitis, 
sinusitisandrhinosinusitisareoftenused
interchangeably.Inthisarticle,wewillusethetermsinusitistomean
inflammationofthesinusandnasalpassageways.Expertsonsinusitishavetriedtopreciselydefinesinusitis.The
RhinosinusitisTaskForceoftheAmericanRhinologicSocietyhasdefinedrhinosinusitisasaconditionmanifestedby
aninflammatoryresponseinvolvingthe
mucousmembranesofthenasalcavityandparanasalsinuses,fluidswithin
thecavities,and/orunderlyingbone.(4‐6).
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Symptomsassociatedwithrhinosinusitisincludenasalobstruction,nasalcongestionanddischarge,post‐
nasaldrip,facialpressureandpain,cough,andothers.(Table1).Astronghistoryconsistentwithchronicsinusitis
includesthepresenceoftwoormoremajorfactorsoronemajorandtwominorfactorsforgreaterthan12
weeks.
(4‐6).
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TABLE1:FactorsAssociatedwiththeDiagnosisofChronicRhinosinusitis

Majorfactors
Minorfactors

Facialpain/pressure* Headache
Facialcongestion/fullness Fever
Nasalobstruction/blockage Halitosis
Nasaldischarge/purulence/discolorednasaldrainage Fatigue
Hyposmia/anosmia Dentalpain
Purulenceinnasalcavityonexamination Cough
Earpain/pressure/fullness
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*Facialpain/pressurealonedoesnotconstituteasuggestivehistoryforchronicrhinosinusitisintheabsenceof
anothermajornasalsymptomorsign.
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ANATOMY
Sinusdevelopmentcontinuesthroughoutchildhood,andisusuallycompletebyadolescence(Figure1).(1,2)
Mostpeoplehavealleightsinusespresentbythistime,althoughinaminorityofpatientssomeofthesinusesdo
notfullyform.Thesehypoplastic(incompletelyformed)oraplasticsinuses(completelyunformed)areoftenan

incidentalfinding,usuallynotassociatedwithanyincreasedsinusproblems,althoughinsomeins tancestheyshould
beaddressed.(7‐10)
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

FIGURE1–Coronal(upperillustration)andsagittal(lowerillustration)viewsintotheparanasalsinuses.
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Thesinusescommunicatewiththenasalcavityvianarrowopeningscalledostia.(11)Ostiadrainintospaces
withinthenosecalledmeatiwhichareborderedbyverticallyorientedbonesknownasturbinates.Thetearduct
(naso‐lacrimalduct)drainsintotheinferiormeatus(whichisborderedbytheinferior
turbinatebone).Thisisone
reasonwhyournosedripswhenwecry.Themaxillary,frontal,andethmoidsinusesdrainintothemiddlemeatus,
whichisborderedbythemiddleturbinatebone(FIGURE2).Someoftheethmoidsinusesalsodrainintothe
superiormeatus,whichisaspacedefined
bysuperiorturbinatebone.Whilethemaxillary,frontal,andsphenoid
sinusesaresolitary,well‐definedcompartments,theethmoidsinusis–inactuality–acollectionofseveralsmall
sinuses,structuredlikeabeehive.Itisforthisreasonthattheethmoidsinuseshavevarieddrainagepatterns.The
sphenoidsinusdrains
intothespheno‐ethmoidalrecess,locatedbetweenthesuperiorturbinateboneandthenasal
septum.(3,11,12)
Airandmucusenterandexitthesinusthroughthesinusostia.Thefunctionsofthenoseandsinusesinclude
olfaction(senseofsmell),respiration,anddefense.(3,11,12)
Thenoseandsinusesproducemucustokeepthe
nasalandupperrespiratorypassagewaysmoist,andhaveaneffectonvocalresonance.Amongtheimportant
physiologicalrolesofthesinusesarethehumidificationandwarmingofinspiredair,andtheremovalofparticulate
matterfromthisair.Humidificationandwarmingof
inspiredairareaccomplishedbythewaterysecretionsofthe
serousglands,whichcanproduceupto1–2litersofsecretionsperday.
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
FIGURE2–Themaxillary,frontal,andethmoidsinusesdrainintothemiddlemeatus,whichisborderedbythe
middleturbinatebone.Theosteomeatalcomplex(OMC)istheGrandCentralStationofthesinuses.Anyprocess
thatcausesswellingandblockageofthiscriticalareacontributestothesymptomsof
sinusitis.


Whilethewateryseroussecretionsplayaroleinhumidificationandwarming,thesecretionsofthegoblet
cellsandmucousglandsfacilitatetheremovalofparticulatematter.Thismucous is veryeffective,trappingupto
80%ofparticleslargerthan3–5microns.(3)Thisincludesnotonlyinorganicpathogens
butalsoupto75%ofthe
bacteriaenteringthenose.(3)Themucousblanketofthenoseisaverydynamicstructure,continuouslyrenewing
itselfevery10–20minutes.(3)Themucousblanketalsodefendsthebodyagainstinfection.Besidestrappingorganic
pathogens,theblanketconstitutesarichimmunologicbarrier
withinthemucosa.Whenexposedtothetrapped
antigens,itcanfurtherenhancetheresponsebystimulatingtheimmunesystem.Theciliatedepitheliumcontinually
beats,propellingthemucusinasynchronizedfashiontowardthenaturalopeningorostiumofeachsinus.These
ostiadrainintothenasalcavity.Themucusis
thenpropelledtothenasopharynxtobeswallowed.Atthispointthe
acidsecretionsofthestomachcan helpdestroytheinhaledpathogens.(3,11‐13)
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Thenormalfunctionofthesinusesdependsonthreeessentialcomponents:thinnormalmucussecretions,
normallyfunctioningmicroscopichairs(calledcilia)thatmovethemucusoutofthesinuses,andopensinusdrainage
openings(calledsinus ostium).Thesecomponentsallowforthecontinuousclearanceofsecretions.I nterference
withanyof
thesethreecomponentsofthenormalsinuses maypredisposethepatienttosinusitis.Inotherwords,
thicksecretionsmalfunctionofthemicrohairs,orblockageofthenaturalsinusopeningsmayleadtosymptomsof
sinusitis.Themicrohairsmoveatafrequencyof10strokespersecondinacoordinatedfashion.
Theactionofthese
microhairsmoveanygivenmucusparticlefromthesinusesandoutintothenoseinabout10minutes.Ciliafunction
ismosteffectiveatatemperatureabove18°Candarelativehumidityofabout50%.(3)Thismaybeafactorwith
commoncolds,whichoccur
inthewintermonths.Forthemucociliarysystemtoclearthesecretionsfromthe
sinuses,thenaturalsinusopeningsmustbepatent.(14)

PHYSIOLOGYOFSINUSITIS
Thegrandcentralstationofmucociliaryclearanceistheosteomeatalcomplex.(FIGURE2).(3‐6,15‐17)
Whenariverisdammed,
waterflowisslowedorhaltedandwatergathersbehindthedam.Thewa terlevelrises
andareservoirforms.Similarly,iftheosteomeatalcomplexisblocked,abackupofmucusoccurs.Thiscanleadtoa
conditionthatleadstoinfection.Bacterialiveinthenoseandsinuses;however,
inaninfectiousstatesomesubset(s)
ofbacteriahavereproducedoutofproportiontoothers.Thisbacterialovergrowthisoftenpresentinsinusitis–
particularlyacutesinusitis.Anyprocessthatcausesmucosalinflammationintothesensitiveareaofthe
osteomeatalcomplex(OMC)canoccludetheothersinusesthatdrainintothis
crossroadzone.(16‐20)
Blockageofthesmallopeningsfromswelling(causedbyinfection,allergy,andothercauses)canalsoresult
insinusitis.Whenobstructionoccurs,themucusisretainedinthesinuscavity.Thesestagnantsecretionsthicken
andprovideamediumforbacterialgrowth.Obstructionalsoimpairsaeration
andgasexchangewithinthesinus
cavity.Absorptionoftrappedoxygenleadstohypoxiaordecreasedoxygenlevelswithinthesinus,which
exacerbatessinusitis.Thesechangesleadtodamageanddysfunctionoftheciliaandepithelium.Theretained
secretionsandinfectionleadtofurthertissueinflammation,whichinturnleads
tofurtherblockage.Thesechanges

12
maybereversiblewithappropriatemedicaland‐ifneeded‐surgicalmanagement.Onoccasion,surgeryisneeded
toallowrestorationofnormalmucosallining.Inthesecases,surgeryallowsforrestorationofnormalsinusaeration
andmucociliaryclearance .(21‐23)
Animportantgoalofanytreatmentforsinusitisisto
breakthe“viciouscyle.”Thisphrasereferstothefact
thatonceapatientdevelopssinusitis,itmaypersistandworseninadownwardspiralingcycle..Swellingleadsto
moreobstruction,whichleadstomoreswelling,andsoon.Inotherwords,ifswellingcausesnarrowingofa
patient’s
sinusoutflowtracts,thentheycanmalfunction.Thedrainageofmucusisimpaired,andthepatient’s
mucussecretionscanstagnateandthicken.Themucusinthenoseandsinusescanalsodevelopinfectionifithas
difficultydrainingfromthenoseandsinuses.Infectioncausesevenmoreswelling,compoundingtheproblem
and
causingthesinusestospiraldownwardintheviciouscycle.Itisforthisreasonthattreatmentsshouldbetargeted
andfocused–tobreakthe“viciouscycle.”

ANATOMICALABNORMALITIESANDSINUSITIS
Asnotedabove,chronicsinusitisis–for themostpart–amucosaldiseaseofthe
sinonasallining.
(3,11,16,17,20‐23)
 Whilenon‐anatomicirritantssuchasinhaledallergens,chemicalirritants,andsmokemaystartthiscycleof
mucosalswelling,therearealsoanatomicalabnormalitiesthatmaycontributetothisprocess.Thesearediscussed
below.
Thenasalseptumdividestherightandleftnasalcavities.The
septumiscomprisedofbothboneand
cartilagewithamucosallining,andsitsroughlyinthemidlineofthenose.Itisnotuncommonforthenasalseptum
tobeslightlydeviated.Insomeinstances,however,thisseptaldeviationmaybesignificant.Severeseptaldeviation
willnotonlycausenasal
obstructionbyblockingtheairflowintotheaffectedside,butmayalsoimpactmucociliary
clearanceby“pushing”themiddleturbinateandotherstructurestowardstheinfundibulumleadingtoimpairment
ofthissinusdrainageoutflowtract(FIGURE3).(3,11,12,24‐25)

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
FIGURE3A–CoronalCTscanofthesinusesdemonstratingseptaldeviationtowardsthepatient’srightside.The
ostiomeatalcomplexisswollenandblocked.


FIGURE3B–ThisisacoronalCTscanofthesinusesofanotherpatientdemonstratingseptaldeviationtowardthe
patient’srightside.Theostiomeatalcomplexisswollenandblocked.

Themiddleturbinateisanormalstructurethatprovidesthemedialboundaryforthemiddlemeatus–
wherethemaxillary,
ethmoid,andfrontalsinusesdrain.Aparadoxicallycurvedmiddleturbinatemaypushagainst
theinfundibulumblockingthesinusoutflowpathway.Aconchabullosa,orairfilledmiddleturbinate,(FIGURE4)

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mayimpededrainageoftheinfundibulumonitsownsideofthenoseor,inextremecircumstances,maypushthe
septumtotheoppositesideofthenoseandblockdrainage onthatside.(24‐25)
 Sinonasalpolypsarepresentinasmallpercentageofpatientswithsinus
disease.Bytheirsheermasseffect
andlocation–oftenwithinthemiddlemeatus –thesepolypsimpedesinusdrainageandmucociliaryclearance,
therebycontributing tothe“viciouscycle.”Ofcoursethepolypsare,themselves,productsofinflammationso
furthersinusinflammationjustleadstopersistentpolypswhichareincreasedin
size(FIGURE5).(25)

OTHERCAUSATIVEFACTORSINSINUSITIS
 Causativefactorsinsinusitiscanbeconsideredbyca tegories. 
 Inflammatoryfactorsincludeupperrespiratorytractinfections(example,thecommoncold),allergicrhini tis, 
vasomotorrhinitis,recentdentalwork,barotrauma,andswimming.
 Systemicfactorsincludeimmunodeficiency,ciliarydyskinesiasyndrome,cystic
fibrosis,rhinitisofpregnancy,
andhypothyroidism.
 Mechanicalfactorsincludechoanalatresia,sinonasalpolyps,deviatedseptum,foreignbody,trauma,tumor,
nasogastrictube,turbinatehypertrophy,conchabullosa,adenoidhypertrophy.
 Medicativecausesincludebeta‐blockers,birthcontrolpills, antihypertensives,aspirinintolerance,rhinitis
medicamentosa(overuseoftopicaldecongestants),andcocaineabuse.Manyof
thesecauseswillbe
discussedbelow.(3,26‐29)