Discussion
Phantosmia is an olfactory sensation that occurs when there is no odor source. These phantom odors can be strong or weak, familiar or unfamiliar, and cannot be detected by anyone in the immediate vicinity. Phantosmia was defined as a qualitative disruption of smell function and it was not observed in Bangladesh during the COVID-19 pandemic. Persistent rhinosinusitis, craniofacial injury, cerebrovascular disease, seizure disorders, psychological symptoms, brain radiotherapy, neurologic disorders, iatrogenic causes, and neurologic and neurodegenerative disorders are some of the causes of phantosmia. The conductive or sensorineural underlying mechanism of this specific symptom is still unknown (8). In patients with olfactory disorders, phantosmia has been observed to occur up to 25% of the population, and the incidence is higher in the elderly than in the younger population (9). However, in our situation, the patient was a young one. COVID-19 patients, on the other hand, frequently report a lack of taste or smell without nasal congestion or discharge (10, 11).It was clear that late-onset symptoms like qualitative alterations (phantosmia) can develop. In some situations, phantosmia developed after months of no other symptoms (11). In a population-based survey, Sjolund et al. (12) found that phantom odors were encountered fewer than once a month (54 %) and that the most commonly reported phantom smell was smokey or burnt (46%). The odor of onion and garlic was present in our case, which was unusual.
SARS-CoV-2 involves the spike protein, which is found in the angiotensin-converting enzyme (ACE)-2 protein, to attach to a membrane receptor complex and the proteolytic activities of host proteases such as TMPRSS2 to invade cells (13, 14). ACE-2 is not generated by olfactory nerve cells or olfactory epithelium mitral cells, according to recent single-cell RNA-sequencing and immunostaining investigations, but it is represented at a substantial level by other supporting cells in the olfactory mucosa, such as sustentacular and microvillar cells (13, 15). The Olfactory disorder has also been linked to viral illness of vascular pericytes (which express ACE-2) and/or immunologically vascular destruction in the olfactory epithelium and olfactory bulb; indeed, magnetic resonance microscopy research discovered microvascular injury in the olfactory bulbs of COVID-19 patients (16).
In SARS-CoV-2 positive patients in Europe and America, the prevalence of smell and taste impairment ranges from 18.6% to 90% (17, 18). In one sub-group study, they discovered that Chinese and Bangladeshi participants were more likely than other South East Asian ethnicities to have Olfactory and Taste Dysfunction (OTD) (19). Unfortunately, treating these disorders is difficult. The use of systemic and local glucocorticoids (20), as well as olfactory therapy (21) and carbamazepine (5), has been shown to be beneficial. However, no data on the efficacy of these strategies in post-COVID-19 STD is currently available. However, due to safety concerns, existing evidence does not support the usual prescription of systemic corticosteroids in this circumstance.
On December 1, 2021, the Omicron variant of COVID 19 was discovered for the first time in Dhaka, Bangladesh. Persons who had completed the whole main immunization series and booster doses using mRNA vaccines for COVID-19 can become infected with Omicron variant illnesses. In this period, the Omicron variant may contribute as new symptoms and kinds of compliance, thus we are also conscious of these unexpected COVID-19 symptoms as the variant change’s day by day.
Limitation, there was no endoscopy or rhinoscopy to examine the nasal cavity and evaluate for disorders that could explain phantosmia. Imaging techniques, such as Computed tomography, Magnetic resonance imaging (MRI) and electroencephalogram (EEG) scans, were used to search for problems in the nasal cavity, brain, or nervous system, which were also not performed.
Although phantosmia or olfactory hallucinations have not previously been linked to COVID-19 disease commonly, the onset of phantosmia due to olfactory impairment is a known occurrence. Albeit the pathogenic cause is unknown, phantosmia occurred following infection with COVID-19 and subsided after the disease was resolved. Despite the small duration of follow-up, this case report revealed the presence of a novel, unique.