Smell and taste in clinical neurology
Loss of smell can be an independent disease or a symptom of any other pathology. Therefore, doctors argue that the causes and treatment of anosmia as the problem in question is classified in medicine should go side by side. The choice of the therapeutic regimen will depend on what triggered the loss of smell.
Doctors use smell testing to measure the loss of smell. As everyone already knows, SARS-CoV-2 is a type of coronavirus that infects humans and causes COVID-19. This disease is characterized by respiratory complications, usually with mild symptoms (80% of cases). In some cases, these respiratory symptoms are accompanied by other manifestations. In particular, according to the latest research, up to 88% of COVID-19 patients lose their sense of smell and taste. In most of these patients (80%), their sense of smell and taste recover on their own over time. For those whose sense of smell is not recovering or is recovering incompletely, at the moment, there is only one treatment option- training the sense of smell.
Moreover, one of the characteristic symptoms of coronavirus infection is loss of smell. Olfactory dysfunction, considered the earliest and most important predictor of disease, differs significantly from anosmia caused by other infectious agents. For a certain proportion of patients, it can have severe psychological consequences. Therefore, recovery of the sense of smell after coronavirus is becoming the cornerstone of clinical neurology.
Causes of loss of smell in clinical neurology
Loss of smell and taste can be triggered by:
- The malformation of the nose and sinuses. Either congenital or acquired. In the first case, we say that a person is already born with a similar problem and, from birth, does not distinguish between aromas. On the other hand, acquired disorders of the nose structure are the consequences of trauma, and in this case, the sense of smell is lost immediately after the onset of the pathology.
- Diseases of the nasal cavity are chronic and acute. In this case, they talk about a temporary problem; for example, loss of smell with a cold does not require any specific treatment, and everything is restored on its own.
- Head trauma. If there was a severe traumatic brain injury, then the nerve fibers are damaged by the bones of the skull (their fragments). Most often, the problem occurs when the occipital, temporal, and ethmoid bones are damaged.
- Tumors of the brain, nose, and sinuses are benign or malignant. A distinctive feature of such anosmia is its slow development; the patient may not pay attention to an already progressing problem for a long time.
- Smoking. Tobacco smoke and toxins in it and tar act on the nasal mucosa and sinuses irritatingly. With prolonged smoking, combined anosmia may develop, loss of taste and smell at the same time.
Intoxication can also affect the intensity level of smell. If the body is constantly influenced by benzene, cadmium, then over time, the development of anosmia is inevitable; this can happen against the background of specific working conditions.
In addition, post-viral anosmia occurs in 66-70% of cases of COVID-19 infection. It appears earlier than other symptoms and is often accompanied by taste disorders. Unfortunately, to date, a complete understanding of the reason for this deviation remains unclear. 4 etiological factors underlying olfactory dysfunction in clinical neurology are considered:
- obstruction of the nasal passages due to acute inflammation and congestion in the mucous membrane
- penetration of the pathogen through the ethmoid bone directly into the area of the cerebral cortex that recognizes odors (in many patients, anosmia is not accompanied by a runny nose and nasal congestion)
- infection of peripheral neurons, destruction of the neuroepithelium, which performs a receptor function, and disruption of central communication with the olfactory nerve
- combined disorder.
In other words, the loss of the ability to sense odors can be caused both by a violation of the structure of the nasal mucosa and by damage to the sensory olfactory system itself.
In clinical neurology, treatment for loss of smell should begin with an examination by a physician. First, it is necessary to find out the cause of this condition, carry out smell testing and choose a treatment method:
- Surgical intervention for the abnormal structure of the nose and sinuses. The problem lies in the fact that the operation must be done in early childhood (maximum four years), and doctors are categorically against interventions in the structure of the face until the growth of a person stops. Even if the work has been done, full recovery cannot be achieved.
- Restoration and treatment of the main pathology with injuries of the nose, face, and head. If the nerve fibers have not been damaged, then the sense of smell returns after the end of the main therapy. This recovery happens gradually; full rehabilitation ends no earlier than three months later.
- Colds, chronic sinusitis, sinusitis, and rhinitis are factors that provoke a temporary loss of smell. How to cure anosmia in this case, the attending physician will explain, and most likely, these will be recommendations for the use of anti-inflammatory nasal drops.
- The degree of recovery of the sense of smell directly depends on which centers are affected. If the peripheral variant (nerve fibers are not damaged), the chances of regaining the lost ability to perceive and distinguish odors are very high.
How to speed up the recovery of your sense of smell after coronavirus? Symptomatic therapy is recommended, aimed at stopping inflammation in the nasal cavity to alleviate the condition. To do this, rinse the nose with saline and use vasoconstrictor, anti-inflammatory, or hormonal intranasal sprays. Of course, before using these drugs, it is necessary to consult a doctor, as they can lead to harmful side reactions.
Experts advise adding natural enhancers of taste and smell to food to train the gustatory and olfactory function. With a disorder associated with damage to the sensory system of smell, neurologists recommend correcting through internal listening and remembering tastes and scents. This procedure, called olfactory training, is used to reconstruct neural connections and activate olfactory receptors. You must choose at least five powerful aromas (coffee, garlic, mint, aromatic oils, vanilla, citrus, etc.) and sniff each ingredient for 10-20 seconds, at least two times a day. And the most important thing is not to panic and remember the success of restoring the work of taste and olfactory receptors after coronavirus largely depends on the quality of auxiliary therapy.
The return of the ability to distinguish between odors is a favorable sign of recovery in clinical neurology. Recovery of the sense of smell after coronavirus can vary from 8-14 days to 1-3 months after the resolution of the disease. Unfortunately, in rare cases, irreversible damage is possible. A similar situation is associated with a history of chronic pathologies of the paranasal sinuses, neurological diseases, trauma, or surgical interventions on the brain.
Recovery of taste after coronavirus most often coincides with the return of the sense of smell or is shifted by another 1-2 weeks from the onset of the regression of symptoms. However, in severe cases, the taste can return within six months, and sometimes not completely.