In December 2019, a novel coronavirus (CoV) epidemic, caused by the severe acute respiratory syndrome coronavirus – 2 (SARS-CoV-2) emerged from China (7). As the virus continues to be a global threat, scientists and researchers all across the world have accelerated their efforts to know more about the clinical presentation of COVID-19 in a bid to combat the disease more effectively (8). As the main harboring site of the virus is the oropharyngeal and nasopharyngeal mucosa, widespread symptoms in relation to ear nose and throat persist(9). While most of the present studies focus on presence of lower respiratory tract infections and other generalized symptoms like fever and myalgia, very little is known about the prevalence of ENT manifestations in covid patients . ENT-related symptoms of the patients were loss of smell (53.5%), loss of sense of taste (51.2%), hearing loss (50.2%), sore throat (47.1%), and tinnitus (38.5%). With the spread of SARS-CoV-2 especially to European countries and the USA, the number of patients developing loss of sense of smell has been shown to increase. The American Ear Nose and Throat Academy stated that STL is one of the symptoms of COVID-19 disease, and the COVID-19 disease screening test should be performed in patients with newly developed STL (10). During the same period, Hopkins argued that there is strong evidence that SARS-CoV-2 causes STL (11,12). Frequency of both generalised and specific ORL symptoms was significantly high in our study. Most patients although presented with cough, breathlessness and fever; patients gave history of ENT related symptoms 6.25+/-1.25 days before the actual diagnosis of COVID 19 or hospital referral. While most patients reported complete recovery from ORL symptoms, hearing loss was seen to appear after the actual diagnosis.
The fig 1 denotes the presence of general symptoms in the entire sample size. Amongst which fever and cough were the most prominent symptoms followed by breathlessness and diarrhea.
The fig 2 denotes the presence of ORL symptoms in the entire sample size. Amongst which sore throat and hyposmia were the most prominent symptoms followed by loss of taste and hearing loss.
In our study, all the ENT symptoms identified were non specific in nature and did not involve any emergencies . No laryngeal involvement suggested by change in voice or hoarseness was documented. Similar results were stated earlier . As stated in other published articles, No reported sneezing, epistaxis, or post nasal discharge suggesting a meager role of nose in disease transmission, as compared to that of the throat (4,13). The results of the current study resonate with other studies that fever (reported in 95% of the included patients), and cough (reported in 83.33%) are the dominant symptoms of COVID-19 whereas gastrointestinal symptoms were less common, proposing the difference in viral predilection as compared with influenza, SARS-CoV, and MERS-CoV (14). However, recent studies suggest multiple CNS involvement by the virus making ENT symptoms an integral part of the clinical presentation (15). The most common ENT manifestations for COVID-19 in the current study were loss of smell and taste sensation (26%), sore throat (47.22%), hearing loss (54.44%) and headache (37.77%), co relating with past studies showing similar results (31) However, it is clear that their incidence is much less than the incidence of fever and cough in COVID-19 patients.
Fig 3 denotes Comparison between ENT and non ENT symptoms
Kaye et al. report on 237 US patients with COVID-19 and found that 73% reported anosmia, and that loss of sense of smell was the initial symptom in 26.6% (16). While Mao et al. found out anosmia in 5.1% of their studied cases several studies also recommend that presence of anosmia or hyposmia without nasal blockage or nasal congestion should be considered as a high index of suspicion for COVID-19 (10).
The pathogenesis of STL caused by SARS-CoV-2 virus is not yet clear. However, direct extension through the nasal mucosa via angiotensin-converting enzyme 2 receptor and extension to the olfactory bulb of SARS-CoV-2 are thought to be involved (17). Despite all the unknown factors regarding the pathogenesis of STL caused by SARSCoV- 2, our study showed that SARS-CoV-2 can cause STL in infected patients, that STL may be the first and only symptom independent of other upper respiratory complaints in SARS-CoV-2-positive patients, and that majority of the patients developing STL due to SARS-CoV-2 show rapid improvement.
Auditory manifestation was not reported in the studies on COVID-19 and auditory complication due to coronavirus is little mentioned in the literature. In a previous report on other coronavirus infection, brainstem involvement was observed and the neuro auditory problem is a possible (18). The study by Mustafa et al, stated that COVID-19 infection could have deleterious effects on cochlear hair cell functions despite being asymptomatic as reduction of high frequency pure-tone thresholds as well as the TEOAE amplitudes were detected . Likewise, a positive association with diagnosis of COVID 19 with the onset of sudden sensorineural hearing loss was noted in our study(18).
To further confirm the subjectively reported complaints of the patients, an ENT examination was performed that confirmed the data that was obtained after thorough history taking. 13 out of 18 patients complaining of sore throat had signs suggestive of either local pharyngeal inflammation or dryness without any evidence post nasal discharge. A substantial percentage of patients (12%) were proven to have mild to moderate sensorineural hearing loss when subjected to tuning fork tests. On a careful otoscopic examination, none of the patients showed any major abnormalities in EAC or tympanic membrane. Absence of sinus tenderness on palpation and no signs of nasal discharge or congestion suggest no interplay of nasal cavity in the pathogenesis of the disease thus helping it differentiate from other maladies like acute rhinosinusitis or allergic rhinitis.
While several papers and research manuscripts mention about neuro invasive nature of the virus causing neuropathy in humans thus explaining extensive multi systemic involvement of the disease, it was impressive to note that a similar result was obtained in our study signifying a poly neuropathic damage caused by the virus resulting in varied manifestations and severe inflammatory response as seen in (19).
Since the study was conducted on admitted patients, each symptom was studied in detail with respect to its onset duration and progression. An average duration of symptoms and their onset before the actual diagnosis of the disease or admission to the hospital was plotted. As shown in Fig 4 and 5
Fig 4 Denotes distribution of ORL symptoms.
While the major symptoms of fever, cough and breathlessness have a shorter duration before the actual diagnosis of the disease, ENT symptoms like sore throat, hearing loss and loss of smell and taste tend to show an earlier onset and a longer persistence.
In our population there was an alteration of the sense of taste, of the sense of smell, dryness of oral cavity and an auditory discomfort, symptoms probably linked to the neurotropism of the virus. Thus, anosmia, dysgeusia and xerostomia are early symptoms of COVID-19, which can be exploited for an early quarantine and a limitation of viral contagion.