Taste abnormalities

dentistry

1. TASTE ABNORMALITIES PRESENTED BY DR: SUMITA LECTURE (ORAL MEDICINE)

2. INTRODUCTION Taste is a flavour , a combination of taste, smell, texture (touch sensation) and other physical features ( e.g temperature) Taste buds on the tongue are on the fungiform , circumvallate and foliate but not on the filliform papillae. Fungiform papillae are innervated by chorda tympani branch of facial nerve, responding mainly to Nacl or both Nacl and sucrose Foliate papillae are predominantly sensitive to sour taste , innervated by glossopharyngeal , responding mainly to bitter.

3. Circumvallate papillae confer a sour/bitter sensitivity to the posterior two-third of the tongue, innervated by glossopharyngeal nerve , they respond mainly to bitter.

4. There are five basic types of taste: salt taste Sour taste Sweet taste Bitter taste Umami taste.

5. TERMINOLOGIES FOR TASTE DISORDERS ABSENCE – ( AGEUISA) DIMINISHED – ( HYPOGEUISA / PARTIAL TASTE LOSS) DISTORTED – ( DYSGEUSIA/ PERSISTENT ABNORMAL TASTE) HEIGHTENED – (HYPERGEUISA)

6. CAUSES Taste abnormalities can be caused by anything that interrupts the taste pathways from the mucosa, taste buds , non- myelinated nerves or cranial nerves to the brain stem and brain or conditions that affect the way the brain interprets taste stimuli.

7. LOCAL CAUSES XEROSTOMIA IRRADIATION OF THE ORAL CAVITY DRUGS ANTIHISTAMINES ANTIHYPERTENSIVE ANTIDEPRESSANT CYTOTOXIC AGENTS PROTEASE INHIBITORS

8. VIRAL INFECTIONS UPPER RESPIRATORY TRACT INFECTIONS COMMON COLD INFLUENZA NASAL INFECTION NASAL POLYPS SINUSITIS VIRAL PHARYNGITIS HEAD INJURIES DUE TO TEARING OF OLFACTORY FIBERS AND AGING

9. METABOLIC DISORDERS CHRONIC RENAL FAILURE HEPATIC DISEASE NUTRITIONAL DEFICIENCY GASTRIC REGURGITATION ZINC DEFICIENCY VITAMIN B DEFICIENCY

10. ENDOCRINE DISORDERS ADDISON’S DISEASE DIABETES CUSHING’S SYNDROME HYPOPITUITARISM HYPTHYROIDISM AGEING

11. NEUROLOGICAL CAUSES ALZEIHMERS DISEASE CHORDA TYMPANI DAMAGE FACIAL PALSY HEAD TRAUMA MULTIPLE SCLEROSIS PARKINSON’S DISEASE TEMPORAL LOBE EPILEPSY

12. DIAGNOSIS SUBJECTIVE A-CHEMICAL GUSTOMETRY Solutions applied via drps,paper disks swabs Detection of lowest concentration (threshold) Supra-threshold concentration also used b . ELECTROGUSTOMETRY Recognition of electrical change but does not define taste quality.

13. 2.OBJECTIVE Positron emission tomography (PET) and magnetic resonance imaging TASTE TESTING Studies of threshold in human subjects commonly use: Sucrose for sweet taste Vinegar or citric acid to produce sour taste concentrations Sodium chloride for the taste of salt.

14. TREATMENT Dietary counselling / modifications e.g. add seasoning , avoid unpleasant foods, extend dietary choice (pleasing colour,smell etc) Manage xerostomia Manage oral disease Tab: zinc sulphate (reduce severity and duration of taste dysfunction)