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olfactory disorder

Etiology: 1) conditions that interfere with access of the odorant to the olfactory neuroepithelium a) swollen nasal mucosa due to allergic, viral or bacterial rhinitis & sinusitis b) deviation of nasal septum c) polyps & neoplasms d) abnormalities in nasal mucus secretion - upper respiratory tract infection 2) injury to neuroepithelial receptors - destruction of neuroepithelium 1] viral infection 2] neoplasms (meningioma is the most common) 3] inhalation of toxic chemicals - smoking 4] radiation to the head 5] vitamin A deficiency (rare in USA) 3) injury to central olfactory pathways a) head trauma b) Parkinson's disease c) Alzheimer's disease [2], see UPSIT d) Korsakoff's psychosis e) nutritional deficiencies - vitamin B12 deficiency - pellagra - zinc deficiency f) brain neoplasms of the anterior cranial fossa g) neurosurgical procedures h) neurotoxic agents - ethanol, amphetamines, topical cocaine, aminoglycosides, tetracycline, tobacco smoke i) Kallmann's disease j) Cushing's syndrome k) hypothyroidism l) diabetes mellitus m) stroke 4) psychiatric disorder 5) pharmaceuticals associated with olfactory impairment - amitriptyline, amphetamine, beclomethasone, cocaine, codeine, dexamethasone. enalapril, flunisolide, flurbiprofen, hydromorphone, levamisole, morphine, pentamidine, pirbuterol, propafenone, tocainide, zalcitabine Pathology: - olfactory dysfunction may primarily originate from the pathology of the olfactory bulb or more distal structures [6] Clinical manifestations: 1) patients generally complain of lack of taste, although taste thresholds may be normal 2) dysosmia may occur with partial impairment of smell or during recovery phase from neurogenic anosmia Laboratory: 1) smell identification test (40 item microencapsulated scratch & sniff test), see UPSIT 2) detection threshold for odorant phenylethyl alcohol 3) nasal resistance measurement by anterior rhinomanometry for each nostril 4) biopsy of olfactory epithelium Radiology: - computed tomography (CT) of brain with enhancement Differential diagnosis: 1) dysosmia 2) anosmia 3) dysgeusia Complications: - olfactory impairment is an independent risk factor for cognitive impairment [4] & mortality [5,7,8] in the elderly - olfactory impairment is associated with increased risk of congestive heart failure in the elderly (RR=1.3) [9] - olfactory disorders may be associated with depression, social isolation or other mental & physical health problems [10] Management: 1) directed towards the underlying etiology 2) no effective therapy for sensorineural olfactory loss

Interactions

disease interactions

Related

age-associated changes in smell dysgeusia (taste disorder) olfaction & Alzheimer's disease olfaction (smell)

Specific

anosmia dysosmia hyposmia parosmia (troposmia, cacosmia)

General

nose disease; nasal disorder sensory impairment

References

  1. Harrison's Principles of Internal Medicine, 14th ed. Fauci et al (eds), McGraw-Hill Inc. NY, 1998, pg 173-74
  2. Wilson RS, Arnold SE, Schneider JA, Tang Y, Bennett DA. The relationship between cerebral Alzheimer's disease pathology and odour identification in old age. J Neurol Neurosurg Psychiatry. 2007 Jan;78(1):30-5. Epub 2006 Sep 29. PMID: 17012338
  3. Geriatric Review Syllabus, 7th edition Parada JT et al (eds) American Geriatrics Society, 2010 - Geriatric Review Syllabus, 8th edition (GRS8) Durso SC and Sullivan GN (eds) American Geriatrics Society, 2013
  4. Growdon ME et al. Odor identification and Alzheimer disease biomarkers in clinically normal elderly. Neurology 2015 May 26; 84:2153. PMID: 25934852 - Devanand DP et al. Olfactory identification deficits and increased mortality in the community. Ann Neurol 2015 Jun 1; PMID: 26031760
  5. Liu B, Luo S, Pinto JM et al Relationship Between Poor Olfaction and Mortality Among Community-Dwelling Older Adults: A Cohort Study/ Ann Intern Med. 2019. April 30. PMID: 31035288 https://annals.org/aim/article-abstract/2732078/relationship-between-poor-olfaction-mortality-among-community-dwelling-older-adults - Kamath V, Leff B Mortality Risk in Older Adults: What the Nose Knows. Ann Intern Med. 2019. April 30. PMID: 31035295 https://annals.org/aim/article-abstract/2732079/mortality-risk-older-adults-what-nose-knows
  6. Lu R, Aziz NA, Reuter M et al Evaluation of the Neuroanatomical Basis of Olfactory Dysfunction in the General Population. JAMA Otolaryngol Head Neck Surg. Published online August 26, 2021 PMID: 34436517 https://jamanetwork.com/journals/jamaotolaryngology/article-abstract/2783603
  7. Choi JS, Jang SS, Kim J, Hur K, Ference E, Wrobel B Association Between Olfactory Dysfunction and Mortality in US Adults. JAMA Otolaryngol Head Neck Surg. 2021 Jan 1;147(1):49-55. PMID: 33090196 Free PMC article
  8. Pang NYL, Muhammad Danial Son HJJ, Tan BKJ et al Association of Olfactory Impairment With All-Cause Mortality. A Systematic Review and Meta-analysis. JAMA Otolaryngol Head Neck Surg. Published online April 7, 2022. https://jamanetwork.com/journals/jamaotolaryngology/fullarticle/2790855
  9. Chamberlin KW, Yuan Y, Li C et al Olfactory Impairment and the Risk of Major Adverse Cardiovascular Outcomes in Older Adults. J Am Heart Assoc. 2024 Jun 7:e033320. PMID: 38847146 Free article. https://www.ahajournals.org/doi/full/10.1161/JAHA.123.033320
  10. Gorodisky L, Honigstein D, Weissbrod A et al Humans without a sense of smell breathe differently. Nat Commun. 2024 Oct 22;15(1):8809. PMID: 39438441 https://www.nature.com/articles/s41467-024-52650-6