Download Taste Disorders

Five basic tastes: sweet, salty, biter , sour, umami (savory or meaty)
DYSGEUSIA: persistent distorted, frequently unpleasant, sense of taste. All food taste sour,
sweet, bitter, metallic (most commonly reported).
Sweet dysgeusia deserves special mention because it has often been reported to occur with neoplasms in the
thorax and also with myasthenia gravis
Causes: Dysgeusia can be caused by
 Sinus and other upper respiratory Infections
 Medications side effect(one of the most common cause of taste loss) – antibiotics;
antipsychotics; antiarthritics; antihypertensives
 Vitamin or mineral deficiency – vitamin B, zinc
 Medical conditions that can result in Dysgeusia include: Dry mouth (xerostomia);
inflammation; nerve damage; GERD (Chronic acid reflux); Alzheimer’s
disease, Parkinson’s disease and multiple sclerosis (MS); Diabetes,
hypothyroidism, kidney disease and other metabolic conditions;
Dental prosthesis;
pregnancy;
tobacco;
aging
toxins
radiation for treatment of head and neck cancers
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 Lesions of the peripheral nervous system
 as part of syndromes affecting the facial (most frequent), glossopharyngeal, or vagal
nerves, e.g., idiopathic cranial nerve VII palsy (Bell palsy)
 cranial nerve lesions have to be considered (e.g., neuroborreliosis or zoster, processes
in the cerebellopontine angle, 49,53 or dissection of cervical arteries).
 Central causes of dysgeusia include lesions along taste pathway from brainstem to its
cortical representation.
 Brainstem taste disorders (ipsilateral disturbance) may be due to demyelinating
processes, ischemia or hemorrhage, or vascular lesions. 55 Thalamic lesions are also
known to result in taste disorders, 56 and cortical taste disorders have been described in
epilepsy.
Medications alter taste perception by:
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Reducing the quality and production of saliva
Interfering with the taste buds and their taste cells
Causing inflammation of the cells lining the mouth, tongue, and pharynx
Altering the nerves and brain function involved in the taste system
Several common medications can reduce saliva production:
 Antidepressants, such as amitriptyline (Elavil) and paroxetine(Paxil)
 Antihistamines, such as diphenhydramine (Benadryl)
 Diuretics, such as furosemide (Lasix)
 Anticholinergics, such as tolterodine (Detrol)
Most of these medications cause dry mouth by blocking a neuro-transmitter (a chemical that
relays signals between nerves and the brain) called acetylcholine, which is also necessary for
salivary glands to release saliva into the mouth.
 Several medications used to control high blood pressure and heart failure interfere with the
action of zinc in the salivary glands and taste cells. Zinc action is necessary for saliva to
digest our food and for taste cells to function normally. Captopril (Capoten) and Lisinopril
(Prinivil)are examples of these medications.
 Some medications can impair the function and renewal of taste buds and taste cells.
Chemotherapy, for example, can interfere with the body’s normal, routine replacement of
taste cells.
 Medications used in the treatment of Parkinson’s disease, like levodopa, and antiseizure
medications, like phenytoin (Dilantin) and carbamazepine (Tegretol), interfere with taste
cells and the nerve pathways of the taste system.
 Another example is topiramate (Topamax), commonly used for migraine headaches and
seizures. It can affect taste generally, and it is particularly known to affect the taste of
carbonated beverages, causing them to taste flat or metallic.
 Cholesterol-lowering medications such as atorvastatin (Lipitor) and pravastatin (Pravachol)
can cause taste alteration in a small number of cases.
Symptoms: Hall mark signs
 Food that used to taste good now taste bad and sometimes rotten
 Sweet or salty food no longer tastes sweet or salty
 All foods taste metallic or bitter
Treatment: Most common include
amoxicillin, metronidazole, diuretics, calcium channel blockers and some blood pressure
medications such as captopril.
HYPOGEUSIA: Decreased sense of taste
HYPERGUESIA: enhanced sense of taste (gustatory sensitivity)
Phantogeusia: perception of taste in the absence of tastant
AGEUSIA: Rare condition with complete loss of taste
Causes:
 damage to the nerve of taste sensation (lingual and glossopharyngeal nerve) in the anterior
and posterior portion
 dietary deficiencies – zinc,
 systemic conditions such as hypothyroidism, and diabetes mellitus, pernicious anemia,
Sjogren syndrome, and Crohn disease
 Cranial nerve lesions affecting gustatory function include neuritis due to herpes zoster,
dissection of the cervical arteries, space-occupying processes in the cerebellopontine angle
(meningioma or neurinoma), and the neoplastic lesions affecting the skull base. It can also
result from iatrogenic lesions (following laryngoscopic manipulations), neuralgia, and
polyneuropathies (due to conditions such as diphtheria, porphyria, lupus, or amyloidosis)
 drugs including antibiotics (ampicillin, macrolides, metronidazole, quinolones, tetracycline),
antineoplastic agents, neurologic medications (anti parkinsonism, CNS stimulants, migraine
medications) cardiovascular drugs (antihypertensives, diuretics, statins, antiarrhythmics),
antipsychotics, tranquilizers, tricyclic antidepressants, thyroid medications, antihistamines,
bronchodilators, antifungals, and antivirals
Ageusia
Hypogeusia or microgeusia
Dysgeusia
Parageusia
Phantogeusia
Cacogeusia
Torquegeusia
Hypergeusia
Gustatophobia
Heterogeusia
Presbygeusia
Type 1 Hypogeusia
Type 2 Hypogeusia
Type 3 Hypogeusia
Normosmia
Anosmia
Hyposmia or microsmia
Dysosmia
Parosmia or Troposmia
Phantosmia
Cacosmia
Torquosmia
Hyperosomia
Osmophobia
Heterosmia
Presbyosmia
Absence of taste
Reduction of taste
Distortion of taste
Distortion of taste due to specific stimulus
Distortion when there is no external stimulus (in the
absence of stimulus)
Unpleasant type of distortion
burning type of distortion
Increased sensitivity to common taste
Dislike of certain tastes
All food and drink taste the same
Decline of taste sense with age
Absence of stimulus recognition with varying degrees of
taste detection
Decreased detection or recognition of stimuli
Decreased ability to judge stimulus intensity with normal
detection and recognition
Normal sensitivity to smell
Absence of Smell
Reduction of smell
Distortion of smell
Distortion of smell due to specific stimulus
Distortion when there is no external stimulus (in the
absence of stimulus)
Unpleasant type of distortion
burning type of distortion
Increased sensitivity to common odor
Dislike of certain smells
All odors smell the same
Decline of smell sense with age
Type 1 Hyposmia
Type 2 Hyposmia
Type 3 Hyposmia
Absence of stimulus recognition with varying degrees of
taste detection
Decreased detection or recognition of stimuli
Decreased ability to judge stimulus intensity with normal
detection and recognition
Figure: Peripheral and central taste pathways. Taste disorders can be classified into peripheral or central taste
disorders. MS, multiple sclerosis.
Diagnosis of taste disorders
Otolaryngologist-ear nose throat specialist
Figure: SUMMARY FO POPULAR TASTE TESTS