Olfactory dysfunction: prevalence, diagnosis and treatment
Authors: Tsepkolenko Oleksandra V. 
Published: February 2022

Topicality: Odors affect the vital body functions, the general psychophysiological state. The sense of smell plays an important role in regulating human behavior. For example, the olfactory impulse reaches the brain faster than the impulse of pain, and therefore very effectively regulates us, regardless of awareness.
Odors can change the work of various body systems: they affect the rhythm of our breathing, the excitability of muscles, the work of the brain and the entire nervous system. The sense of smell affects the limbic system, the part of the brain that controls hunger, feelings of aggression, sexual emotions and other "animal" feelings of a person.
OD violates the informational and controlling roles of odorous substances (attractants, repellents, pheromones), therefore disorganizing the performance of nutritional, sexual, protective, orientation functions. For people of some specialties (taster, perfumer, cook), the decrease in the sense of smell can mean job loss and social maladaptation.
Complaints about problems with taste perception more often reflect violations of the sense of smell, since the taste of a number of foods (chocolate, coffee, vanilla, strawberries, etc.) in reality depends on the stimulation of the sense of smell by volatile components that enter the nasopharynx when swallowing.
Aim: To offer an otorhinolaryngologist guidance in the information stream regarding the problem of olfactory dysfunction, its prevalence, diagnosis and treatment.
Materials and methods: The Sniffin’ Sticks test (CST) has been certified in the EU since 1995, and is used in Germany, Austria, Switzerland, and Italy. Odors are offered in the form of markers, in which the odorous substance takes the place of the coloring one. There is a version with 16 odors from the extended test [extendid] or with 12 odors [screening]. The test is well validated, can, unlike CCSIT, be used repeatedly, the shelf life is 0.5-1 year, depending on the intensity of application. The test can be used by patients independently. The study consists of 3 stages: threshold test (THR) – determination of the minimum odor concentration that the patient feels; discrimination test (D) is aimed at identifying the patient's ability to distinguish odors; identification test (I) for odor recognition. "University of Pennsylvania Smell Identification Test" (UPSIT) – the test is used exclusively to identify 40 odors (some of them are little known outside of North America). Odorous substances are microcapsulated on paper in the form of a rectangle and are released as a result of friction when held over it with a simple pencil.
The patient is given 4 possible answers. Normally, a healthy man correctly identifies 34-40 odors, a healthy woman – 35-40. If the subject scores 18 or less, it is considered that he has a complete loss of sense of smell. The test system is a single-use and expensive. Digital volumetric tomography (CT). The visualization of the olfactory cleft, the upper nasal concha, and the configuration of the olfactory groove (OJ) turned out to be informative.
Results and discussions: The review discusses the unique properties of OE and the potential use of olfactory epithelial grafts to restore olfactory function.
Permanent population of multipotent stem cells proliferating throughout the life of the organism is located in the mammal OE. The cells formed during division go through several stages of differentiation and replace the dying olfactory receptor neurons. Neural stem cells were isolated from the olfactory region of the mucous membrane of humans, rats and mice. It is this population of neural stem cells that is being investigated as an autologous material for transplantation and the future use of olfactory transplants as a potential method of restoring the sense of smell. OE survives when transplanted to various areas of the brain, can be grafted directly to OL.
Conclusions: A new direction in the treatment of OD is associated with cell therapy technologies, for example, using platelet-rich plasma (PRP), plasma in which the concentration of platelets is several times higher than normal. The term PRP is legitimate at a concentration of 700 thousand to 1 million platelets in 1 ml of plasma (the physiological plasma concentration of platelets is (180-360) x109 per liter). PRP is used to accelerate tissue regeneration, reduce scarring, stimulate angiogenesis, as well as a local antiseptic. The spectrum of pharmacological action of PRP is determined by growth factors: platelet growth factor (PDGF), transforming growth factor (TGF-β), vascular endothelial growth factor (VEGF), epithelial growth factor (EGF), fibroblast growth
factor (FGF), insulin-like growth factor (IGF). The active secretion of these growth factors by platelets begins within 10 minutes after activation (activation can be stimulated by almost any environmental disturbance, up to a simple mechanical stress), while more than 95% of the previously synthesized growth factors are secreted within 1 hour.