Hypogeusia
Hypogeusia is defined as the reduced ability to taste things.[1] Due to a lack of stratification, the prevalence of hypogeusia, as well as hyposmia, may not be accurately known.[2] Additionally, reviews do not always make distinctions between ageusia and hypogeusia, often classifying them as the same in certain circumstances and studies.[3] The severity of the loss of taste from hypogeusia is not clearly outlined in current research due to these reasons.
Causes[edit]
Hypogeusia can have many causes, including taste disorders rooted in oral cancer,[4] zinc deficiency,[5] Covid-19,[2] Chronic Rhinosinusitis (CRS),[6] and Parkinson's Disease (PD).[3]
Covid-19[edit]
Covid-19 causes symptoms that affect the central nervous system (CNS), peripheral nervous system (PNS), and skeletal muscle. Hypogeusia falls under a neurological disease and a PNS symptom, while also being the highest occurring PNS symptom, closely followed by anosmia. Due to hypogeusia being a significant symptom of Covid-19, it is often accompanied by hyposmia, even when many other Covid-19 symptoms are absent. Hypogeusia and hyposmia can be considered early indications of a Covid-19 infection.[1]
Oral Cancer & Related Treatments[edit]
Hypogeusia tied to oral cancer and tumors can affect sweet, sour, salty, and bitter tastes, but bitter taste hypogeusia occurs significantly more often compared to the other tastes. The reason for this may be due to gustatory papillae found in the base of the tongue being inhibited, often due to oropharyngeal tumors. Oral cancer treatments, such as chemotherapy, radiation therapy, and surgical treatments, are further causes of taste and smell loss with 70% of oral cancer patients noting dysgeusia.[4]
Other Causes[edit]
Nutritional zinc deficiency may cause various problems, hypogeusia being one of them.[5] CRS may cause olfactory dysfunction as well as gustatory problems, with either or both leading to the noticeable presence of hypogeusia in CRS patients.[6] The connection between hypogeusia and Parkinson's Disease is less well described. PD patients have an increased dysregulation in their taste receptors, as well as their olfactory receptors.[3] The receptors affected in PD patients were those which affected perception of bitterness.
Treatment[edit]
Hypogeusia tied to Covid-19 can serve as an early indicator of Covid-19, which can allow appropriate Covid-19 treatments to be administered earlier to patients.[1] While zinc supplementation may treat certain taste dysfunctions, there is a lack of evidence for treatment regarding hypogeusia and dysgeusia not caused by low zinc concentrations in the body.[5] While the mechanisms surrounding hypogeusia from PD are hypothesized, specific treatments are not researched enough.[3] Similarly, while treatment of olfactory related issues is known in CRS research, the treatment of gustatory problems, including hypogeusia, are unknown.[6]
References[edit]
- ^ a b c Pallanti S (July 2020). "Importance of SARs-Cov-2 anosmia: From phenomenology to neurobiology". Comprehensive Psychiatry. 100: 152184. doi:10.1016/j.comppsych.2020.152184. PMC 7211704. PMID 32422426.
- ^ a b Trott M, Driscoll R, Pardhan S (2022). "The prevalence of sensory changes in post-COVID syndrome: A systematic review and meta-analysis". Frontiers in Medicine. 9: 980253. doi:10.3389/fmed.2022.980253. PMC 9452774. PMID 36091707.
- ^ a b c d Tarakad A, Jankovic J (2017). "Anosmia and Ageusia in Parkinson's Disease". International Review of Neurobiology. 133. Elsevier: 541–556. doi:10.1016/bs.irn.2017.05.028. ISBN 978-0-12-813708-6. PMID 28802932.
- ^ a b Togni L, Mascitti M, Vignigni A, Alia S, Sartini D, Barlattani A, et al. (September 2021). "Treatment-Related Dysgeusia in Oral and Oropharyngeal Cancer: A Comprehensive Review". Nutrients. 13 (10): 3325. doi:10.3390/nu13103325. PMC 8536976. PMID 34684326.
- ^ a b c Yanagisawa H (March 2008). "Zinc deficiency and clinical practice--validity of zinc preparations". Yakugaku Zasshi. 128 (3): 333–339. doi:10.1248/yakushi.128.333. PMID 18311051.
- ^ a b c Xie DX, Leland EM, Seal SM, Lin SY, Rowan NR (March 2021). "A Systematic Review and Meta-Analysis of Taste Dysfunction in Chronic Rhinosinusitis". The Laryngoscope. 131 (3): 482–489. doi:10.1002/lary.28827. PMID 32609889.