Smelling Disorders

Smell (Olfactory) Disorders

Congenital Anosmia, Anosmia, Hyposmia, Dysosmia, Cacosmia, Phantosmia, Heterosmia,
Disturbances related to smell can be due to many different causes. Inability to smell "Anosmia", decrease in smell "Hyposmia", hypersensitivity to odors "Hyperosmia", misperception of odors "Dysosmia", perception of odors as bad odor "Cacosmia", perceiving the opposite of odors "Parosmia", perception of odor even though there is no odor in the environment " While it is called as "Phantosmia"; difficulty in distinguishing different odors from each other is called "Heterosmia". The absence of sense of smell from birth is called "Congenital Anosmia".

It is not easy to measure the amount and find the cause of the problem in smelling problems.

Olfactory Disorders May Show Many Different Situations!

Toasted bread… Soil after the rain… Freshly ground coffee… Freshly baked cake… What if we hadn't heard their scent, would we still perceive them in the same way? Could they make us feel the same? Sometimes, when our memories come alive with just a smell we hear, what would happen if we could not smell? Smell and taste are among our important senses that enable us to enjoy life. Therefore, disturbances in these senses can lead to a decrease in the quality of life.

Although the sense of smell is not considered much in daily life, its deficiency can have important consequences. Problems related to smell can be seen as a result of the inability of scent molecules to reach the olfactory region in the nose, or the inability to reach the olfactory center in the brain or to provide the necessary transformation even if they reach there.

Eating habits of people with smell and taste disorders change and the pleasure they get from eating decreases. These senses also warn us of dangers such as fire, toxic gases, and spoiled food.

Smell and taste disorders are becoming more common day by day, and many people apply to doctors every year for this ailment. Before the smell and taste disturbances took their place among the symptoms of Covid-19, they were seen as an insignificant situation by the society. However, these types of problems can appear as the harbinger of acute or chronic important diseases as well as a serious viral infection such as Covid-19. Apart from the taste and smell disorders caused by chronic rhinitis, allergies and colds, it is necessary to apply to health institutions and undergo an examination as soon as possible in cases that develop suddenly. In addition to adversely affecting nutrition, these types of problems can also lead to negativities such as consumption of spoiled foods and inability to perceive dangers such as gas leakage. 

Problems arising in the sense of smell and taste; It can be a symptom of sinus diseases or structural disorders in the nose, as well as a harbinger of more serious diseases such as brain tumors. Therefore, when such a problem is encountered, it is important to consult an otolaryngologist.

How do we smell and taste?

Molecules released from objects are perceived by nerve endings in the nose, mouth and throat, and these perceptions are sent to the brain with neural stimuli.

Olfactory nerves; It is stimulated by the smells coming from the flower or fresh bread and these messages are collected and transmitted to the brain through the nerve endings in the nose.

In the sense of taste, foods that react with saliva are perceived by taste bodies in the tongue and these messages are sent to the brain. Mainly four main flavors are perceived; sweet, sour, bitter and salty. With the blends of these main flavors, the essence of the food comes out.

The sense of smell also helps us taste most. This is the reason why there is no mouthfeel in situations that cause nasal congestion such as colds.

There are two types of smell disorder

Conduction type smell disorder develops due to the inability of odor molecules to reach the area called the olfactory epithelium in the nose. This picture is seen in conditions such as cold, acute sinusitis, nasal bone curvature, allergic rhinitis, nasal polyps. In neural-type odor disorder, although the scent molecules reach the olfactory region, there is a problem in their transmission to the brain and it is mostly seen with neurological diseases such as Alzheimer's, Parkinson's, Multiple Sclerosis.

First of all, a full ENT examination should be done to the patient who comes with the complaint of not being able to smell. With this clinical evaluation, after investigating the presence of an accompanying upper respiratory tract infection, when the problem started, whether it was experienced for the first time, history of trauma and drug use, the method of diagnosis is followed.

Smell test for definitive diagnosis

After the ENT and head and neck examination, the patient has been given odor tests, which have been increasingly used in recent years, so that the smell disorder can be fully revealed, treatment and follow-up is much easier. Smell disorder is also examined in a laboratory environment just like a hearing and vision examination, the treatment is arranged accordingly, and this is the best option.

With the tests performed in Smell Laboratories, it can determine the sense of smell as a descriptive test, distinctive test and threshold values ​​and reveal the situation in the patient. In the Smell Laboratory, we determine the results such as Anosmia (no smell), Hyposmia (decrease in smell), Parosmia (detection of different smells) with these tests, and we plan the treatment of the patient accordingly. Again, the same tests can be done in the follow-up to follow up somehow.

Odor disorder is too important to be neglected and it is a harbinger of many diseases. The Smell Laboratory in Bayındır İçerenköy Hospital, the first Odor Laboratory in the Anatolian side of Istanbul, and the diagnosis and treatment of all kinds of odor disorders can be done here.

The sense of smell can be restored!

After the necessary determinations are made in patients, the treatment stage is reached. A conductive loss present in the patient; In other words, if there is a situation such as nasal bone curvature, nasal growth, chronic sinusitis, nasal polyps, surgical procedure is planned. If there is no problem in the nasal endoscopic examination, it may be necessary to have a brain MRI or CT scan to rule out central (cerebral) diseases when necessary. If no cerebral disease is detected, "Smell Therapy", which lasts for about two months, is started and the patient is re-evaluated at regular intervals. During the Scent Therapy, certain scents are taught to the patient at certain intervals to regain the sense of smell.

Smell test in diagnosing Alzheimer's and Parkinson's Disease

Since the sense of smell is one of the first senses to disappear in Alzheimer's and Parkinson's patients, scent tests have been used in the early diagnosis of these diseases in recent years. Since odor tests provide early diagnosis of such diseases, it is also of great importance in terms of starting treatment immediately.

What are the causes of smell and taste disorders?

The causes of smell and taste disorders are as follows:

- Age (ages 30-60 when the sense of smell and taste is the best. From the age of 60, these senses gradually decrease.)
- Congenital reasons (in some people, congenital sense of smell and taste are less perceived)
- Head injury
- Upper respiratory tract infections
- Sinus or nasal diseases
- Some medications
- Some hormonal irregularities
- Dental problems
- Prolonged contact with certain chemicals such as pesticides
- Smoking
- Radiotherapy (radiation therapy)
- Surgical interventions such as laryngectomy

In the links below, you can find information about the causes, diagnosis and treatment of disturbances related to the sense of smell.

Smell  and Taste Problems That Caused by Covid-19

Nowadays, when the Covid-19 pandemic affects many people and causes loss of life, everyone is very careful about the symptoms that indicate the disease. In patients with coronavirus infection; In addition to the main symptoms such as high fever, dry cough, and shortness of breath, taste and smell problems can also be observed. However, taste and smell disorders are not only symptoms of Covid-19, but can also be seen in colds and many other types of diseases caused by other factors. Other symptoms seen in the individual are decisive in determining the cause of the problem in question.

Smell and Taste Disorders Can Be Caused by Many Diseases

Causes of taste and smell disorders include:

• Old age
• Colds and flu infections
• Allergies • Nasal polyps
• Psychiatric illnesses
• Dry mouth and tooth decay
• Exposure to chemicals
• Smoking and drug use, use of various drugs
• Facial paralysis, concussion and head trauma
• Diseases such as multiple sclerosis, Alzheimer's, Parkinson's and dementia
• Skull base tumors
• Vitamin and mineral deficiencies
• Some diseases related to the salivary glands
• Sinusitis

How to understanded of smell and taste problems are caused by Covid-19 infection?

Symptoms in smell and taste disorders are generally in the form of a decrease or complete loss of these senses, the inability to feel some of the sweet, salty, bitter and sour tastes, and the perception of tastes differently than normal. Since the sense of taste is a sensation related to the sense of smell, smell disorder also directly affects taste. It is necessary to apply to health institutions in especially the sudden onset of taste and smell disorders, which are felt other than the diagnosed diseases that may cause flu infections or taste-odor loss. Of course, smell and taste disorders may not develop in every individual infected with coronavirus. In patients with this problem, loss of taste and smell can be seen alone or can be seen together with other coronavirus symptoms such as cough, shortness of breath, high fever, sore throat. The most important factor in the smell and taste disorders causing the suspicion of coronavirus infection is considered to be the sudden appearance and severity of the symptom in question. In addition, other coronavirus symptoms, such as the loss of taste and smell, and the individual's contact with any coronavirus patient, are among the situations that strengthen the possibility of Covid-19 infection.

Treatment and Management For Smell Disorders

If there is a suspicion of Covid-19 in patients who apply to health institutions with taste and smell disorders, the patient should be immediately isolated and subjected to the Covid-19 test. In order to diagnose olfactory disorders other than this, odor tests, which are carried out in two ways, objective or subjective, are used. The test, which is described as objective, helps to find out whether the individual can smell the given scents using a machine. In subjective tests, in addition to the ability to smell, the ability of the individual to respond to the senses can be investigated in detail. Smell and taste disorders can be easily diagnosed with the help of odor tests performed in the form of an 8-test or a 40-test. While the 8-test is used much more frequently because it provides an advantage in terms of time, the 40-test, which requires a longer time, can make sensory studies for many different odors. If any problems in the senses are diagnosed, the reactions of the scent cells to the scent molecules are investigated by taking samples from the turbinates.

If the source of the impairment in the senses is sinus and nasal diseases, these diseases should be treated. If it is caused by structural disorders in the nose, the problem can be solved with surgical interventions. If the drugs used cause loss of sensation, it is recommended to stop or change the drugs. In case of exposure to chemicals, it is recommended to avoid them.

Normalization of the intranasal air passage, the treatment of structural disorders and other conditions that cause aeration in the nose also play an important role in the treatment of taste and smell disorders. If these do not give results, it may be possible to activate the olfactory bulb and the olfactory center in the brain with the help of scent exercises. In patients with allergy problems, antihistamine drug treatments, the use of drugs that are effective in reducing nasal discharge and dry mouth, removal of nasal tumors and polyps, treatment of dental and gum diseases, prevention of smoking and substance use are among the methods that can be preferred in the treatment of smell and taste disorders. takes place. It should be kept in mind that loss of smell and taste can indicate Covid-19 and some other serious diseases. It is important for individuals with these problems to apply to health institutions by paying attention to protective measures such as masks and distances.

Murat Enoz, MD, Otorhinolaryngology, Head and Neck Surgeon

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