Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/12/27 15:56:11」(JST)

wiki en

Ageusia (/əˈɡjuːziə/ ə-GEW-zee-ə) is the loss of taste functions of the tongue, particularly the inability to detect sweetness, sourness, bitterness, saltiness, and umami (meaning "pleasant/savory taste"). It is sometimes confused with anosmia – a loss of the sense of smell. Because the tongue can only indicate texture and differentiate between sweet, sour, bitter, salty, and umami, most of what is perceived as the sense of taste is actually derived from smell. True ageusia is relatively rare compared to hypogeusia – a partial loss of taste – and dysgeusia – a distortion or alteration of taste.

Diagnosis

Both taste and smell disorders are diagnosed by an otolaryngologist, a doctor of the ear, nose, throat, head, and neck. An otolaryngologist can determine the extent of your taste disorder by measuring the lowest concentration of a taste quality that you can detect or recognize. You may also be asked to compare the tastes of different substances or to note how the intensity of a taste grows when a substance’s concentration is increased. Scientists have developed taste testing in which the patient responds to different chemical concentrations. This may involve a simple “sip, spit, and rinse” test, or chemicals may be applied directly to specific areas of the tongue.

Causes

Neurological damage

Tissue damage to the nerves that support the tongue can cause ageusia, especially damage to the [chordatympani nerve] and the glossopharyngeal nerve. The chordatympani nerve passes taste for the front two-thirds of the tongue and the glossopharyngeal nerve passes taste for the back third of the tongue. Neurological disorders such as Bell's palsy, Familial dysautonomia, and Multiple sclerosis cause similar problems to nerve damage, as do certain infectious conditions like primary amoeboid meningoencephalopathy. The lingual nerve (which is a branch of the trigeminal V3 nerve, but carries taste sensation back to the chorda tympani nerve to the geniculate ganglion of the facial nerve) can also be damaged during otologic surgery, causing a feeling of metal taste.

Problems with the endocrine system

Deficiency of vitamin B₃ (niacin) and zinc can cause problems with the endocrine system, which may cause taste loss or alteration. Disorders of the endocrine system, such as Cushing's syndrome, hypothyroidism and diabetes mellitus, can cause similar problems. Ageusia can also be caused by medicinal side-effects from antirheumatic drugs such as penicillamine, antiproliferative drugs such as cisplatin, ACE inhibitors, and other drugs including azelastine, clarithromycin, terbinafine, and zopiclone.

Other causes

Local damage and inflammation that interferes with the taste buds or local nervous system such as that stemming from radiation therapy, glossitis, tobacco use, and denture use also cause ageusia. Other known causes include loss of taste sensitivity from aging (causing a difficulty detecting salty or bitter taste), anxiety disorder, cancer, renal failure and liver failure.

References

MedTerms Online Medical Dictionary. "Ageusia". Retrieved April 15, 2005.
Family Practice Notebook. "Taste Sensation". Retrieved April 15, 2005.
Massachusetts Eye and Ear Infirmary. "Taste Disorders". Retrieved May 26, 2010.

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 味覚および嗅覚障害の解剖学および病因 anatomy and etiology of taste and smell disorders
2. 慢性副鼻腔炎：臨床症状、病態生理、および診断 chronic rhinosinusitis clinical manifestations pathophysiology and diagnosis
3. 頭頸部癌患者の言語および嚥下リハビリテーション speech and swallowing rehabilitation of the patient with head and neck cancer

English Journal

Taste-blind mice make tangled sperm.

Greenwood V.
Scientific American.Sci Am.2013 Oct;309(4):23.
PMID 24137848

Reversible ageusia associated with romidepsin therapy.

Cooper MR1, Brewer S, Broketa G.Author information 1School of Pharmacy, MCPHS University, Manchester, NH 03101, USA. maryann.cooper@mcphs.eduAbstractPURPOSE: The case of a patient who reported the complete loss of his sense of taste after about 3.5 months of romidepsin therapy is presented.
American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists.Am J Health Syst Pharm.2013 Sep 1;70(17):1502-5. doi: 10.2146/130024.
PURPOSE: The case of a patient who reported the complete loss of his sense of taste after about 3.5 months of romidepsin therapy is presented.SUMMARY: A man with a 12-year history of treatment-refractory cutaneous T-cell lymphoma (CTCL) developed taste disturbances progressing to ageusia (the absenc
PMID 23943181

U.S. Food and Drug Administration approval: vismodegib for recurrent, locally advanced, or metastatic basal cell carcinoma.

Axelson M1, Liu K, Jiang X, He K, Wang J, Zhao H, Kufrin D, Palmby T, Dong Z, Russell AM, Miksinski S, Keegan P, Pazdur R.Author information 1Office of Hematology and Oncology Products, Office of New Drugs, Center for Drug Evaluation and Research, United States Food and Drug Administration, Silver Spring, Maryland 20993, USA.AbstractThe data and regulatory considerations leading to the U.S. Food and Drug Administration (FDA) January 30, 2012 approval of Erivedge (vismodegib) capsules for the treatment of patients with recurrent, locally advanced, or metastatic basal cell carcinoma (BCC) are described. The FDA's approval decision was based primarily on the results observed in a single-arm, parallel cohort, international trial of vismodegib, administered orally at 150 mg daily until disease progression, in patients with pathologically confirmed, recurrent, locally advanced basal cell carcinoma (laBCC) or metastatic basal cell carcinoma (mBCC). An independent review committee confirmed an overall response rate (ORR) of 30.3% [95% confidence interval (CI): 15.6-48.2] in 33 patients with mBCC and an ORR of 42.9% (95% CI: 30.5-56.0) in 63 patients with laBCC; median response durations were 7.6 months and 7.6 months for patients with mBCC and laBCC, respectively. The most common adverse reactions were muscle spasms, alopecia, dysgeusia, weight loss, fatigue, nausea, diarrhea, decreased appetite, constipation, cough, arthralgias, vomiting, headache, ageusia, insomnia, and upper respiratory tract infection. Animal toxicology studies confirmed that vismodegib is a potent teratogenic agent. Approval was based on durable objective tumor responses supported by knowledge of the pathologic role of Hedgehog signaling in BCC and acceptable toxicity in a population without effective alternative therapies.
Clinical cancer research : an official journal of the American Association for Cancer Research.Clin Cancer Res.2013 May 1;19(9):2289-93. doi: 10.1158/1078-0432.CCR-12-1956. Epub 2013 Mar 20.
The data and regulatory considerations leading to the U.S. Food and Drug Administration (FDA) January 30, 2012 approval of Erivedge (vismodegib) capsules for the treatment of patients with recurrent, locally advanced, or metastatic basal cell carcinoma (BCC) are described. The FDA's approval decisio
PMID 23515405