Anosmia is a complete loss of sensitivity to odors. The symptom is physiological in elderly people, but more often olfactory disorders occur in smokers, with various diseases of the nose and paranasal sinuses, brain pathologies. To establish the root cause of anosmia, olfactometry, examination of ENT organs, X-ray and tomographic methods of brain imaging, laboratory tests are used. Medications are prescribed taking into account the underlying disease after diagnostic measures.
Causes of anosmia
A person feels odors due to the coordinated work of the receptor cells of the nasal mucosa, special nerve fibers and the olfactory center in the brain. If any link of this process is violated, olfactory disorders develop. Insensitivity to aromas is more often caused by pathologies from the nervous system or respiratory tract. Also, the symptom becomes a consequence of physiological changes in the olfactory apparatus or functional disorders. Congenital anosmia (Kallman syndrome) is less common.
Elderly people are characterized by a gradual loss of the ability to distinguish odors, which progresses over several years and as a result leads to anosmia. This condition is caused by atrophic processes — the death of the cells of the nasal mucosa, which are responsible for the recognition of odorous substances. At first, the patient notices insensitivity to weak “subtle” aromas, as the atrophy develops, the person ceases to distinguish even very sharp odors: garlic, spices, ammonia. Bilateral olfactory disorders are typical for this condition.
Usually, a decrease in the sense of smell is not accompanied by other unpleasant manifestations, so patients consider their condition a variant of the norm and do not seek help for a long time. Simultaneous violations of taste are possible. An alarming sign is the sharp loss of an elderly person’s perception of all odors, which often indicates a serious organic lesion. If the symptom is combined with constant headaches, forgetfulness, inability to concentrate, you should consult a doctor for a detailed examination.
Smoking
Decreased sense of smell is common among smokers, since nicotine negatively affects the olfactory nerve receptors in the nasal mucosa, first reducing their sensitivity, and later leading to atrophy. Patients themselves very rarely pay attention to this symptom, which is due to constant smoking and the habit of a strong tobacco smell. Complete anosmia develops very slowly, over several years. Simultaneously with disorders of the sense of smell, taste sensations may be disturbed.
Nasal polyps
Benign growths of the mucous membrane (polyps) create mechanical obstacles to the passage of air, therefore, a gradual decrease in the sense of smell (hyposmia) is possible up to its complete loss. Patients describe their condition as the inability to fully breathe through the nose, which is associated with insensitivity to odors. Complete anosmia may occur a long time after the onset of symptoms, but more often the ability to distinguish between sharp odorous substances (ammonia, gasoline) remains.
Sinusitis
With inflammation of the paranasal sinuses, anosmia is usually determined only on the side of the lesion, in the future, with the progression of the disease, anosmia becomes bilateral. Due to the pronounced swelling of the mucous membrane, patients breathe only through one nostril, which aggravates the situation. The symptom is accompanied by pain in the cheekbones, forehead, increased discomfort when tilting the head down. These signs are an indication for contacting an otolaryngologist, because without treatment, sinusitis can be complicated by severe inflammation of the brain.
Other ENT diseases
With inflammatory processes in the nasal cavity, the decrease in the sense of smell is temporary. The disorder develops simultaneously with other clinical symptoms, moderate hyposmia persists for some time after recovery. More often the process is two-sided. Sometimes a symptom is associated with the action of allergens (plant pollen, dust, pet hair). Loss of olfactory function is accompanied by nasal congestion, mucous or purulent discharge, headache. With anosmia, there are:
- Rhinitis: hypertrophic, fetid (ozone), chronic atrophic.
- Allergic pathology: hay fever.
- ARVI: rhinovirus, adenovirus infections, parainfluenza, etc.
Traumatic brain injury (TBI)
With traumatic injuries, anosmia occurs suddenly, more often immediately after the injury. Anosmia can be unilateral and bilateral, which depends on the severity of the TBI and the place of impact. The severity and duration of symptoms does not depend on the force of the impact — with moderate injuries (concussion without fractures of the skull bones), prolonged anosmia is possible. Since with massive bone fractures in the forehead and nose, the olfactory nerve fibers are often completely torn, in such cases, a persistent loss of sensitivity to all flavors is likely.
Brain damage
Anosmia is accompanied by many neurological diseases. Anosmia in this case is associated with damage to the nerve cells of the brain responsible for recognizing various odors. These pathologies are characterized by the appearance of other symptoms: impaired coordination of movements, severe headaches, memory loss. Sometimes patients complain of a constantly “haunting” fetid smell that occurs against the background of a decrease in sensitivity to familiar aromas. The weakening of the sense of smell accompanies such organic brain lesions as:
- Degenerative processes: Alzheimer’s disease, multiple sclerosis, dyscirculatory encephalopathy.
- Vascular disorders: aneurysm, arteriovenous malformation, strokes.
- Brain tumors: astrocytoma, oligodendroglioma, etc.
Poisoning
Anosmia is one of the symptoms of intoxication of the body with damage to the nervous system. At the same time, hyposmia is more often noted, complete loss of the ability to distinguish odors is rare. Sometimes the symptom occurs when the dosages of narcotic drugs with neurotoxic properties are exceeded. Depending on the type of toxin, anosmia is accompanied by dyspeptic disorders, loss of consciousness, and damage to other organs. Olfactory disorder is caused by:
- Occupational poisoning: ingestion of heavy metal salts, refined petroleum products, acrylates.
- Drug use: opiates, psychotropic substances, cannabinoids.
- Carbon monoxide poisoning.
Neurotic states
Loss of susceptibility to odors can develop against the background of long-term neuroses, severe emotional disorders, including hysterical reactions. It is typical to present a wide range of diverse complaints with their vivid description: a decrease or complete absence of smell, a haunting sensation of the same unpleasant smell. Increased symptoms are associated with stress, conflicts in the family, at work. In case of functional disorders, it is mandatory to consult a specialist, because without proper therapy, these conditions turn into psychosomatic disorders.
Complications of pharmacotherapy
Anosmia is one of the side effects of hypertension therapy, hormonal correction in women. Persistent hyposmia is often observed in patients who use vasoconstrictive nasal drops for a long time (more than 1-2 weeks). When taking other medications, the symptom is temporary, usually the olfactory function is fully restored after the end of the course of treatment. Anosmia is provoked by the following groups of drugs:
- Nasal drops with alpha-adrenomimetics: pharmazoline, naphthyzine, oxymetazoline.
- ACE inhibitors: enalapril, lisinopril, fosinopril.
- Hormonal drugs: utrozhestan, tamoxifen, mifepristone.
Rare causes
- Congenital diseases: Kallman syndrome (olfactogenital syndrome).
- Endocrine pathology: type 1 and type 2 diabetes mellitus, hypothyroidism.
- Deficient conditions: zinc deficiency, hypovitaminosis.
- Iatrogenia: damage to olfactory structures during surgical interventions on the brain, nerve ruptures during the reposition of fractures of cranial bones.
- Burns of the nasal mucosa: thermal and chemical.
Diagnostics
Patients with complaints of loss of sense of smell often turn to an otolaryngologist. Since anosmia can be associated with both damage to the upper respiratory tract and pathology of the brain, a comprehensive diagnosis is carried out. The examination plan includes functional tests, instrumental and laboratory studies aimed at determining the degree of olfactory sensitivity reduction and identifying the root cause of the symptom. In diagnostic terms , the most informative:
- Olfactometry. A qualitative assessment of the ability to distinguish flavors is carried out using a special device — an olfactometer. The use of test tubes with various strong aromas in combination with performing tests alternately for both nasal passages allows you to detect a one- or two-way decrease in the perception of odors. On the one hand, anosmia is of great diagnostic importance.
- ENT examination. Examination of the paranasal sinuses and upper respiratory tract is carried out to exclude the rhinogenic nature of olfactory disorders. During rhinoscopy, the nasal mucosa is studied in detail. When a purulent discharge is detected, it is collected for further investigation. An “adrenaline test” is done to differentiate catarrhal and hypertrophic rhinitis.
- Instrumental inspection. The standard method is radiography of the bones of the skull, which is prescribed if traumatic damage to nerve structures is suspected. To exclude sinusitis, X-ray images of the paranasal sinuses are shown. In neurological diseases, computed tomography is a more accurate method, in some cases, an MRI of the brain is prescribed.
- Laboratory examination. Nonspecific signs of inflammatory processes are detected using general and biochemical blood tests. In the presence of nasal discharge, bacteriological seeding is performed. Specific highly sensitive blood tests for toxins and narcotic substances help to exclude poisoning as a cause of loss of smell perception.
After excluding the organic prerequisites of anosmia and physiological age-related changes in the receptor apparatus, additional examination methods are prescribed according to indications – allergy tests, angiography of cerebral vessels. In case of possible functional disorders of the sense of smell caused by disorders of the emotional sphere, a consultation with a neurologist or psychiatrist is necessary.
Treatment
In most cases, anosmia is transient, the ability to smell is restored after treatment of the underlying disease. To eliminate the accompanying unpleasant symptoms (dryness, burning) with physiological anosmia in the elderly, rinsing and irrigation of the nasal cavity can be used. Specific therapy of inflammatory, neurological and psychogenic disorders is prescribed by a specialist after a comprehensive examination of the patient.
