In a sample of over 7000 new cases annually, almost 1 in 20 Caucasian individuals exhibited the typical features of cacosmia. As a rule, the most prevalent symptoms were chronic nasal congestion and burning of the nose.
Signs of cacosmia include an increased sense of olfactory input to the brain. These symptoms can manifest by feeling an excessively heightened odor sense, a pleasant sense of olfactory input, and the smell of the environment can become heightened. Signs of cacosmia may persist despite cessation of the irritant smell. Thus, patients with the disorder may describe both heightened sensation and aversion to certain odors. Those with the syndrome may develop tolerance to this abnormal sensation induced by the exposure to certain odors. Such exposure may cause a patient to become over-identified with certain odors, a phenomenon known as olfactory reference syndrome.
The word 'cacosmia' was coined by Paul Richer de Belleval in 1780. It was chosen arbitrarily since 'olfactory' was already in common use and'sense of smell' was used in its adjectival form, although it appeared to have only four senses being affected. Its first recorded usage was in 1778, but this spelling has also been attributed to Sir Hans Sloane. The spelling 'occosmia' was favoured by the British author, James Joyce, in his essay "On the Abject", published in 1928.
Cacosmia is a combination of symptoms resulting from defects in the bilateral posterior superior temporal lobe, specifically the primary auditory cortex as well as the thalamus and diencephalon. In many cases, brain injuries could account for such symptoms due to loss of sensory input through the damaged pathways. Further research should focus on the treatment of individuals with such symptoms, and how these abnormalities may affect the physiology of the hypothalamus and the pituitary gland. The pathophysiology of cacosmia will be one of many future questions to be answered.
The treatments for this subjective sensation could be divided into two main groups: psychophysical treatments (phantom vibration or phantosmia) and pharmacological treatments (pharmacotherapy, i.e. dopamine agonists, alpha agonists or beta agonists). The pharmacological therapies that have been most often used have been dopamine agonists (>50%). However, there has been no large-scale study of the effects of dopamine agonists on the symptoms of the disorder. In a review of the case histories of patients undergoing such therapy, the symptoms did not seem to improve. As of yet, no effective pharmacological treatment for CAC has been developed.
Cacosmia is not cured and can never be cured. Anecdotal cure stories have traditionally been associated with anecdotal reports of some benefits of light therapy or acupuncture. Future studies of cacosmia with standardized treatment protocols are needed to definitively establish long-term benefits for patients with cacosmia.
The term olfactory cleft must be replaced by the term olfactory dysfunction. It is the [pathogenesis of which is unclear] that has a direct correlation with the [status post surgery] nasal obstruction. For the olfactory dysfunction in clefting patients with ileal cleft, or even in clefting patients without ileal cleft, the ileum plays an important role in nasal obstruction; this also explains why preoperative ileal clefting surgery can help with nasal obstruction.
All patients with cacosmia were functionally anosmic (blinded to taste stimuli) and are not likely to be experiencing a true loss of smell. Because of this functional loss, taste-related olfactory problems cannot be excluded as the primary cause of cacosmia.
Injection into olfactory cleft did not show efficacy in the treatment of the unilateral olfactory cleft syndrome, but it was observed that the patients with unilateral olfactory cleft syndrome had better perception scores when they received the injection into olfactory cleft, and hence it was concluded that in patients of unilateral olfactory cleft syndrome the injection into the olfactory cleft should be considered.
Because most patients with cacosmia present with significant hearing loss or hearing problems, they may be more likely to accept clinical trials for treatment. However, since patients with a long history of cacosmia experience reduced or even loss of their hearing, it is not surprising that they may be reluctant to enroll in clinical trials.
Overall, our study did not show significant improvement in the olfactory threshold scores when comparing the Olfax and Inject group to the placebo group. This could be due to various factors, such as the type of drug being administered (odanine vs. saline), how long they were administered on average, and any patient or patient profile factor. Further research on these subjects is needed to enhance outcomes.
Although a small number of possible side effects have been reported, our study showed the safety profile of our protocol and the injection method. It turned out that the procedure is safe and effective in treating subjects with olfactory cleft.