原文題目

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口腔病理科 On-Line KMU Student Bulletin

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原文題目(出處)： Taste dysfunction: a practical guide for oral medicine. Oral Diseases 2011;17:2-6

原文作者姓名： Cowart BJ

通訊作者學校： Monell Chemical Senses Center, Philadelphia, PA, USA 報告者姓名(組別)：朱妙盈 Intern K 組

報告日期： 2011/07/08

內文：

 Taste (or gustation)

 Regarded as a minor sense, less important than smell (or olfaction).

 Provides information about only a limited number of stimulus qualities (sweet, salty, sour, bitter, umami, and possibly fat and a few others), and has received much less medical and clinical research attention.

 The gatekeeper of the body

 Protecting humans and other animals from consuming dangerous substances and encouraging consumption of nutritious ones.

 Disruptions occurs

 Substantial impact on nutriture and quality of life.

 Dental practitioners are often the first clinicians to be presented with complaints about changes in taste.

 Two forms

 Diminished or lost taste perception (hypogeusia or ageusia).

 The presence of a persistent, unpleasant taste sensation, frequently in conjunction with distortions in taste quality and or burning mouth symptoms (BMS).

 Difficult issue

 Common confusion between smell and taste problems

 The lack of widely accepted standardized techniques to assess true taste function.

 Taste vs. smell

 True taste loss is rare, whereas loss of smell is more common.

 About 70% of patients presenting with a complaint of taste loss evidenced smell loss, fewer than 10% evidenced measurable taste loss.

 Anatomy

 Olfaction a single cranial nerve (I).

 In a vulnerable position in that its axons must pass through the cribriform plate of the ethmoid bone prior to dissemination on the surface of the olfactory bulb.

 Subject to the coup contra coup forces associated with head injurytearing or severing of the axonal processes.

 Gustationmultiple branches of three cranial nerves (VII, IX and X).

 taste receptors are found on a large portion of the tongue dorsum, as well as on the soft palate, larynx, pharynx, and epiglottis.

 Nature and assessment of taste dysfunction

 Assessment

 Can be assessed via chemical or electrogustometric measure.

 Correlations among measures of threshold sensitivity for different substances are significantly lower for tastes than for smells.

 Impossible for the dental practitioner, and even difficult for specialized

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clinics.

 Quality identification

 Useful tool but limited by common taste quality confusions in the general population (sour-bitter, sour-salty and salty-bitter).

 Taste strips on the anterior tongue

 Does not distinguish either quality specific losses or spatial losses other than anterior tongue right ⁄ left.

 In short, there are no specific measurement techniques to identify. However, this is not the patient’s fault, and does not invalidate his ⁄ her complaint.

 Etiologies

 The bases of general taste losses are simply not known.

 Head trauma and upper respiratory viral infections.

 Medication usage

The most common etiologic factor contributing to taste dysfunction.

 Direct impact of medications on taste receptor function or of residual tastes associated with either the drug’s presence in saliva or in the blood (tastes can be perceived intravascularly).

 Nutrient deficiency—Zinc

 Poor oral hygiene

 Periodontal diseases

 The overgrowth of oral Candida xerostomia.

 The use of dentures, antibiotics or corticosteroids, or with immunological

deficiencies or diabetes.

 Gastroesophageal reflux disease (GERD)

 Intermittent or persistent

 Sour

 Dental erosion particularly of the posterior teeth.

 Surgical procedures

 The chorda tympani (CT) nerve.

 Middle ear surgery-- stretching or severing of the chorda tympani (CT) nerve.

 CTmediates taste perception on the anterior tongue.

 Resulting in the loss or diminution of taste sensation on one or both (if the surgery is bilateral) anterior quadrants of the tongue.

 third molar extraction mandibular block analgesia (IAN)

 Localized taste dysfunction

 Depression

 Aging

 Nonetheless, in a chemosensory clinic population, Cowart et al (1997) found that elderly patients (>65 years) were significantly more likely than young or middle-aged patients to report phantogeusia and to evidence diminished taste.

 Practical guidelines for assessment and referral

 First be assessed for olfactory function using one of the standardized tests that are now commercially available.

 olfactory problemreferred to an otorhinolaryngologist or sub-specializing in diseases of the nose and sinuses.

 It is essential to rule out oral health problems that may contribute to

 A thorough oral examination

 Assessment of possible abnormalities in the microbial flora of the oral

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cavity.

 A detailed consideration of changes in medications and oral health procedures..

 Dental erosion

 Refer to a gastroenterologist should be considered to rule out the possible contribution of GERD to the persistent taste.

 Suspicion of iatrogenic damage to the CT

 microsurgical repair may be possible

 Psychological state

 Referral for psychological counseling should be considered.

 Conclusion

 Taste is a resilient system

 two-thirds of patients with dysgeusias have been reported to

experience spontaneous resolution of symptoms within an average of 10 months

 Taste complaints present a number of difficulties to the oral medicine practitioner

 Can impact significantly on nutriture and quality of life.

 Clinicians should be attuned to these issues, and be prepared to make appropriate evaluations and referrals.

題號題目

1 以下何種疾病不致味覺減弱(hypogeusia)或喪失(dysgeusia)?

(A) Oral candidiaisis (B) Xerostomia (C) Hairy tongue (D) Periodontitis

答案(C) 出處：OMP, Neville, 2nd edition, ch.18, p.753, box 18-9

題號題目

2 以下何種藥物, 未被公認可能致味覺減弱(hypogeusia)或喪失

(dysgeusia)?

(A) Ampicillin (B) Tetracycline (C) Ibuprophen (D) Tegretol

答案( D) 出處：見 OMP, Neville, 2nd edition, ch.18, p.754, Table 18-2