taste disorders.pptx

8/18/2019 taste disorders.pptx

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Taste disorders

Dr.Abdullah alhayani,MBBS.


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Case scenario 1

30 Years old male came toyour clinic 2 weeks aftertympanoplasty c/o change intaste .


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Case scenario 2

25 yrs old female has history ofallergic rhinitis and nasalobstruction came to your clinic c/o

loss of smell and taste sensation .


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b!ecti"es#natomy .$hysiology

%istology

$athologyClinical application


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Anatomy of the Taste System

&aste buds are located through out the oralca"ity ' 'pharyn('epiglottis .

&otal number about )*00 / tongue .

&aste buds are contained within papillae .


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+ingual papillae ha"e the following )forms ,

1. Fungiform papillae , "isible small redstructures - tip/edges- 015 taste pores onpapillae . th C

2. Foliate papillae . on edges of tonguebase- located between ad!acent folds-deeper red th C

3. Circumvallate papillae largest inmiddle- 3) on either side formingin"erted 4- between ant 2/3 and post 1/3. th C

4. Filiform most numerous- no role in


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TASTE TA!S"#CT$%!

timuli entering the mouth 6rst interactwith sites on the micro"illi within the tastepore.

alts and sour acidic stimuli use ionchannels while sweet and bitter substancesuse with protein compounds.

&aste receptors trigger transduction

cascades' which then acti"ate synapsesand cause the e(citation of ner"e 6bers.


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nce the stimulant enters the cell there isa change in the internal electrical state ofthe cell' which leads to the secretion of aneurotransmitter and acti"ation of a ner"e6ber.

# signal is produced' which is then carriedto the brain' relaying information on theidentity and intensity of the gustatorystimulus.


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&ongue mapo map- all four taste percei"able in any area


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er"es

C! $& ' glosssopharyngeal nerve (Taste innervation to circumvallate and foliate

papillae

7eneral sensory to base of tonguetylopharyngeus is only muscle inner"ated by it

&ra"els to inferior petrosal ganglion .

8nters the medulla- nucleus solitarius


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C! )$$ * chorda tympani '+ranch of facialnerve ( &aste from fungiform papillae on ant 2,3 .

9uns with lingual' which pro"ides general sensory

7i"es preganglionic $ 6bers to submand ganglion

8nters infratemporal fossa .

$asses middle ear through '-uguier canal(

8nters fallopian canal

#:erents and "isceral e:erents lea"ing geniculate

ganglion known as ner"us intermedius- stays separatefrom motor branch within ;#C' and tra"erses C$# between4;; and 4;;;

&erminate in nucleus solitarius


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C! )$$ * S/! ' +ranch of facialnerve (

&aste to palate- buds on marginbetween hard and soft

Course with palatine n. 42- lesser

palatine foramen

$terygopalatine ganglion- !oin deeppetrosal ner"e


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Central connections

#ll three form solitary fasciculus-terminates on secondorder gustatory

neurons in rostral half of nucleussolitarius medulla;psilaterally ascend to thalamus "ia

central tegmental tract

$nsula is the taste corte0 betweentemporal and frontal lobes


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&erminology

Ageusia ;nability to taste

-ypogeusia >ecreased ability to taste

"ysgeusia ? >istorted ability to tasteCacogeusia sensation of bad taste not

related to the ingestion of speci6csubstances .


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disorders of taste and smell ha"ebeen diAcult to diagnose and treat.

#n alteration in taste or smell may

be a secondary process in "ariousdisease states' or it may be theprimary symptom .

appro0imately of tastedisorders are truly smelldisorders .


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Etiology +esions at any site from the mucosa' taste

buds' unmyelinated ner"es' or cranial ner"esto the brain stem may impair gustation.

ral ca"ity and mucosal disorders including

oral infections' inBammation' and radiationinduced mucositis can impair taste sensation.

$oor oral hygiene is a leading cause ofhypogeusia and cacogeusia. 4iral' bacterial'

fungal' and parasitic infections may lead totaste disturbances because of secondarytaste bud in"ol"ement.


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ormal aging produces taste loss due tochanges in taste cell membranes in"ol"ingaltered function of ion channels andreceptors rather than taste bud loss.

alignancies of the head and neck' as wellas of other sites' are associated withdecreased appetite and inability toappreciate Ba"ors.

Dse of dentures or other palatal prosthesesmay impair sour and bitter perception' andtongue brushing has been shown todecrease taste acuity.


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urgical manipulation may alter tastepermanently or temporarily.

9esection of the tongue and/or portions ofthe oral ca"ity' most commonly for reasons

of malignancy' decreases the number oftaste buds.

9adiation and chemotherapy damage tastereceptors and decrease sali"ary Bow'altering taste perception.


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;n ear surgery' stretching or transection ofthe chorda tympani ner"e may result intemporary dysgeusia.


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utritional de6ciencies are in"ol"ed in tastealterations. >ecreased inc5 copper5 andnic6el le"els can correlate with tastealterations. utritional de6ciencies may be

caused by anore(ia' malabsorption' and/orincreased urinary losses.


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8ndocrine disorders also are in"ol"ed intaste and olfactory disorders.

>iabetes mellitus' hypogonadism'!ogrenEs and pseudohypoparathyroidism

may decrease taste sensation' whilehypothyroidism and adrenal corticalinsuAciency may increase taste sensiti"ity.

%ormonal Buctuations in menstruation andpregnancy also inBuence taste.


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/hantoms from "amage to /eripheral Structures

Chorda tympanietallic taste sensation- occasionally a bitter

or salty taste

!ervus intermediusalty phantoms- last */12 then fade

C! $&ome report bitter phantom


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EFFECTS %F TASTE 7%SS

Fhat most indi"iduals complain of is a lossof Ba"or and en!oyment of foods' which ismost often related to the well known loss of

olfaction combined with some taste loss .

loss of appetite which puts the indi"idual athigher risk for depression' anore(ia. andweight loss.

$oor taste perception combined witholfactory loss puts the indi"idual at risk forfood poisoning from the ingestion of spoiled

foods.


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Conclusion &aste is a:ected by many diseases such as

diabetes' chronic renal failure' $arkinson'and #lGheimer.

ome common medications a:ect taste'

such as antihypertensi"es andchemotherapy drugs.

&aste may be a:ected by interruption of thesensory neural pathways such as chorda

tympani and lingual ner"e. o speci6c treatment e(ists for taste

dysfunction.


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Case scenario 1

30 Years old male came toyour clinic 2 weeks aftertympanoplasty c/o change in

taste .


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Case scenario 2

25 yrs old female has history ofallergic rhinitis and nasalobstruction came to your clinic c/o

loss of smell and taste sensation .


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taste disorders.pptx

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