A neurologist has named the causes of loss of sense of smell

Loss of sense of smell, or anosmia, can have various causes, including infectious, traumatic, age-related and other diseases, Galina Chudinskaya, a neurologist at JSC Medicine (Academician Roitberg's clinic), told Izvestia on November 30.

"It can be associated with damage to the olfactory neuroepithelium, as well as with disorders in central olfactory processing, which leads to a decrease or change in the structure of sensory neurons," the expert specified.

According to her, one of the most common causes of olfactory loss is post-infectious disorders, which can occur due to damage to the olfactory neuroepithelium or changes in the olfactory pathways, which affects the perception of odors. These changes can affect both peripheral and central parts of the olfactory system, resulting in impaired or complete loss of the ability to perceive odors, the doctor emphasized.

"Post-traumatic loss of sense of smell is also a common problem. Mechanical damage to the nose, such as fractures of the nasal bones or septum, as well as direct trauma to the olfactory neuroepithelium can interfere with normal odor perception. Another serious factor is damage to the olfactory filament - for example, in skull base fractures. All these injuries can interfere with the transmission of signals from olfactory receptors to the brain, resulting in loss of smell or partial loss of it," Chudinskaya explained.

In addition, loss of the sense of smell is also common in diseases such as Parkinson's disease and dementia with Lewy bodies, the neurologist added. These diseases can cause olfactory centers in the brain, such as the hippocampus and amygdala, to become less active in response to odors.

"Abnormal deposits in the central olfactory system, including the olfactory bulbs, can impair odor perception. In addition, increased levels of inhibitory dopaminergic neurons also affect the ability to perceive odors," Chudinskaya said.

Another cause is exposure to toxins, drugs, medications and smoking. Chronic exposure to toxic substances can damage both peripheral neuroepithelial cells and the central olfactory system. Smoking has dose-dependent adverse effects, causing inflammation of the nasal mucosa and impaired olfactory receptor function.

"Congenital disorders such as Kallman syndrome can also lead to functional anosmia or hyposmia (reduced sensitivity to odors). These diseases are accompanied by hypoplasia or aplasia of olfactory bulbs and impaired development of sensory neurons," the doctor specified.

In addition, according to her, olfactory dysfunction may also be associated with the aging process. With age, blood flow in the nasal mucosa decreases, there are fibrotic changes in the lattice opening, as well as age-related mucociliary dysfunction. All of these changes can lead to decreased sensitivity to odors, especially unpleasant odors. Age-related changes in the olfactory neuroepithelium, olfactory bulbs and the central olfactory system have also been noted, the expert added.

Among the causes of this situation are also intracerebral tumors, endocrine disorders (such as hypothyroidism or Addison's disease), metabolic diseases such as diabetes mellitus, vitamin B12 deficiency, and psychiatric disorders. In addition, increased apoptosis of sensory neurons and replacement of the olfactory epithelium can lead to this condition.

"Loss of the sense of smell requires a mandatory examination, which should include consultation with a neurologist, otolaryngologist, and endocrinologist. The treatment approach will depend on the identified cause," the doctor concluded.

Earlier, on November 14, the director of the State Research Center "NMRC Endocrinology" of the Ministry of Health of the Russian Federation, head of the Department of Personalized and Translational Medicine, corresponding member of the Russian Academy of Sciences Natalia Mokrysheva reported at a press conference in the MRC "Izvestia" that the risk of type 2 diabetes increases six to seven times in obesity.