This chapter deals only with the total loss of smell. Are excluded hyposmia (decrease) cacosmia (perception of an unpleasant odor from the subject himself), parosmia (erroneous olfactory sensation) and phantosmia (olfactory hallucination).
Smell of modern man is in decline (microsmatique animal) and its loss is not without consequence.
In people anosmic the risk of domestic accidents would double, since they no longer smell like warning signal to an incident of everyday life (cooking, fire, gas leak, etc.).
Moreover the perception of body odor and perfume plays a key role in the relational and sexual life.
The olfactory mucosa is located at the posterior part of the nasal cavity over an area extending over the upper cone and the upper third of the nasal septum.
Axonal tracks traverse the cribriform plate of the ethmoid and then form the olfactory nerve that goes to the olfactory bulb, located in the lower part of the frontal lobe. From here depart the connections with centers of smell located in the rhinencephalon.
This scheme allows to classify and understand the various types of anosmia: transmission and perception.
During a consultation, in the presence of a person complaining of anosmia, it is quite easy to do simple tests of olfaction, making feel various products. Explores a nostril after another.
For example, the alcohol test: Normally, one is able to feel a pad impregnated with alcohol at a distance of 20 cm; if the subject feels no less than 10 cm, there anosmia. In our practice everyday, this type of testing is sufficient.
There are olfactometry equipment, exploration reflexes related to olfaction, olfactory measuring potentials, functional MRI. These examinations have currently an interest in research and in very special cases (such as expertise).
The review search obstruction, sneezing, rhinorrhea before or after (its type: purulent, aqueous or mixed), pain in the sinus cavities, spontaneous or palpation.
The mucous membranes of the clinical examination is done with a speculum or an otoscope. It allows to check the state of the mucous membranes, to see a bloody or purulent discharge.
If necessary the examination is completed by an endoscopy performed in ENT.
If clinical examination and normal endoscopy, we must do a CT scan to search for a sinus lesion or tumor pathology pathways and centers of olfaction.
The odor molecules are unable to reach the sensory receptors or by inflammation of the nasal mucosa, or by obstacles.
Outrages like common cold, flu syndrome, or other viral diseases, are often accompanied by anosmia, but this is usually transient.
In a few cases, they persist after healing of the initial episode. The mechanism may also be achieved by perception of the olfactory bulbs. The recovery is not certain.
The management uses the local or systemic corticosteroids whose schema seems poorly codified.
We must seek an allergic individual or family.
Clinically there is significant rhinorrhea, nasal congestion, sneezing, nasal itching, sometimes associated conjunctivitis.
It should also look for triggers.
It may be interesting to do an allergy assessment when considering treatment of desensitization.
Treatment is based on the eviction to allergens whenever possible, local antihistamines and / or general, local cortisone.
It is a nasal hyperactivity syndrome, but arises without etiology: lack of allergy, infection, or hormonal imbalance.
Rather, it occurs in people of a certain age.
We find precipitating factors such as temperature changes, the rising of the morning, irritants (aerosols). The evolution is long and capricious.
Treatment is difficult because anticholinergics and cortisone are not working. It is based on antihistamines as drying rhinorrhea, e.g., Ipratropium (Atrovent) local.
Rhinitis nonallergic eosinophilic:
The non-allergic rhinitis with eosinophilia (NARES) represent 15 to 20% of chronic rhinitis.
Rather, it affects children and young adults.
It manifests as allergic rhinitis with sneezing fits, runny nose and a front and rear. But anosmic disorders are much more common.
Allergy testing is negative.
On examination the nasal cavity are normal. We find a significant proportion of eosinophils in the nasal secretions.These rhinitis changing very often to sinonasal polyposis, and it is permissible to make a scanner for the search.
Treatment is based on the local long-term corticosteroid.
The formation of polyps is due to chronic inflammation of the mucous membranes.
Anosmia is part of the clinical picture. We research on clinical examination and CT.
Treatment is cortisone. At the start: a cure systemically 1 mg / kg / day for one week, then local for three to six months associated with washing with salt solutions (saline sea water, etc.).
In case of failure and severe discomfort, one can consider surgical treatment. This one is tricky, and does not guarantee a complete and permanent cure (60% improvement on the various symptoms).
In case of failure and also to prevent recurrence, we can consider treatment with sulfur waters spa.
They are accompanied by anosmia especially in chronic forms and when all the sinuses are achieved: it is the pansinusitis. It complicates an anatomical abnormality (deviated septum, turbinate hypertrophy) or polyposis.
The examination may reveal pus welling at the osmiums. CT is essential to diagnose and find a cause.
Treatment relies on antibiotics for ten days and corticosteroids in short course. If unsuccessful surgical treatment may be necessary.
The perception of anosmia are fewer, but often final.
Traumatic brain injury :
When a head injury (TC), the olfactory fibers can undergo shear phenomenon through the target plate of the ethmoid causing anosmia.
Recoveries are rare and often late.
There is no real treatment. But it is perhaps in these cases we can try rehabilitation of smell developed in recent years: daily memorization of simple odors, scented games odorisations exhibitions, etc.
Toxic and iatrogenic causes:
The main drugs and toxic anosmia perception of responsible concern:
– Drugs: methotrexate, codeine, morphine, gold salts, D-penicillamine, L- dopa, clofibrate, angiotensin-converting enzyme, aminoglycosides, hormonal;
– Chronic exposure to certain substances in the workplace: cement, acetophenone, chrome, asphalt, gasoline, lead, zinc, sulfur dioxide, etc.
Pregnancy is a provider of disorders of smell, with hyper- or hyposmia.
Earlier tumors skull base can cause anosmia.
essentially three etiologies include: epilepsy, Alzheimer’s disease, Parkinson’s disease wherein anosmia can appear first.