INCIDENCE AND RECOVERY OF CHEMOSENSITIVE DYSFUNCTION IN COVID-19 POSITIVE PATIENTS

Background: the objective of this study is to �nd the incidence of chemosensitive dysfunction in COVID-19 positive patients and its recovery. We collected the data from Sixty-ve patients, all Covid-19 positive, quarantined in hospital between 5.4.2020 and 17.5.2020, by a questionnaire distributed the quarantine ward. Results: Smell dysfunction appeared in (89.23%) with or without other symptoms of COVID-19. (39.66%) had the sense of smell recovered. Taste dysfunction was found in (83.08%) patients with other COVID-19 symptoms. only (29.63%) of them recovered. The recovery took 1-3 weeks, most cases within 1 week or less. As the only symptom before COVID-19 con�rmation, (18.46%) and (15.38%) had smell dysfunction and taste dysfunction respectively. Most of the chemosensitive dysfunction affected the 4 th decade of age. Conclusion: Chemosensitive dysfunction is associated with COVID-19, and may be the only presenting symptom of the disease. This makes the ENT doctors in the �rst line of contact with corona virus. Further objective studies are required to cover chemosensitive dysfunctions, as the recognition of this dysfunction may help the diagnosis of COVID-19, and prevent the spread of this disease.


Background
There are three types of presentations in COVID-19: asymptomatic, mild upper respiratory tract infection (URTI), and severe systemic disease such as bilateral interstitial pneumonia. 1factory dysfunction (OD) is already recognized in ENT practice after many viral infections, which can cause OD by in ammation in the sinonasal mucosa and rhinorrhea; the most common viruses being rhinovirus, parain uenza Epstein-Barr virus, and some coronavirus. 2 2018, Dubé et al, found that the previous form of human coronavirus HCoV OC43 invades the central nervous system through the olfactory epithelium and initiates neuropropagation at olfactory bulbs. 3ny other recent studies found that smell and taste dysfunctions represent common clinical ndings in COVID-19 patients. 4erefore, it is logical to consider the relationship between OD and the novel COVID-19.
In Iraq, the COVID-19 affected the public life, as in all other affected countries, and since the pandemic, there was an increase in the reported cases of OD and taste loss in hospitals and private clinics.Therefore, we are investigating the incidence in OD and taste disorders as an isolated symptom of COVID-19 in Iraqi patients.

Methods
We collected the data from Sixty-ve patients, all Covid-19 positive, quarantined in quarantine hospital between 5.4.2020 and 17.5.2020,by a questionnaire distributed the quarantine ward.
The patients were included if they were proved positive for COVID-19, and they are fully conscious and had willingly given the formal consent of being enrolled in the research.
We excluded patients who had olfactory problems before January 2020.Insert Figure 2 here.
(23/58, 39.66%) patients had the sense of smell recovered.The recovery took 1-3 weeks to occur.The time taken to recover the smell distributed as 21.74% recovered within less than a week, 52.17% 1 week, 21.74% within 2 weeks and 4.35% 3 weeks.
Insert Figure 4 here.
The time for taste recovery distributed as 25% recovered within less than a week, 50% a week, 18.75% within 2 weeks and 6.25% 3 weeks.
Insert Figure 5 here.
(Figure 6) show the percentage of different patients' complaints.
Insert Figure 6 here.

Discussion
Viral infections are common causes of olfactory loss, and tran sient loss is likely under-reported. 5Over the last 2 months, an increase of sudden isolated anosmia incidence, with or without taste loss, was reported.In this study chemosensitive dysfunction appeared in high percentage of the COVID-19 positive patients, 89.23% of patients had smell dysfunction and 83.08 had taste dysfunction. 2,6dden Isolated chemosensitive dysfunction appeared in 18.46% and 15.38% for anosmia and taste loss respectively.Interestingly, that percentages were reported in patients who were tested because of only contact with COVID-19 relative; two of them reported the loss of smell as the rst symptom, while other 10 patients reported no rst complaint except contact with COVID -19 positive patient, and when it comes for the symptoms questionnaire, they had reported only chemosensitive dysfunction.
Females gender was more affected in this study, although little difference.This may be because many male patient refused giving consent to participate.[7][8] Most cases were mild, followed by moderate, then total anosmia and or taste loss.There must recognition of the patient felling to have chemosensitive disorders and the real presence of such dysfunction, i.e. the subjective and objective chemosensitive dysfunction.More subjective studies that investigate the taste and smell dysfunction are needed, although it is di cult to conduct such study because the risk of spread of infection.
The age group distribution shows most chemosensitive dysfunctions were in the fourth decade and around it. 9garding timing of chemosensitive dysfunctions with con rmation of COVID-19, more than half of patients the dysfunction appeared one week or less before con rmation, which may give a clue to the cause of this dysfunction.
Recovery of chemosensitive dysfunction occurred within 1-3 weeks, most of them recovered within the rst week. 2 This means the dysfunction is transient in most of the cases and reversible.Most of them did not take speci c treatment for the chemosensitive dysfunction.
Majority of patients were nonsmokers as shown by other studies. 2,10The relation of smoking to COVID-19 is interesting and need to be investigated in further studies.

Conclusion
Chemosensitive dysfunction is associated with COVID-19, and may be the only presenting symptom of the disease.This makes the ENT doctors in the rst line of contact with corona virus.Further objective studies are required to cover chemosensitive dysfunctions, as the recognition of this dysfunction may help the diagnosis of COVID-19, and prevent the spread of this disease.The percentage of smell and taste loss in general and as a presenting symptom of COVID-19.

List Of Abbreviations
The percentage of smell loss severity in the different age groups.
Page 10/13 The percentage of taste loss severity in the different age groups.
Page 11/13 The percentage of smell recovery in the corresponding periods.

Table 2 :
Taste loss severity in relation to gender distribution.