The results of the present study indicated a high and considerable prevalence of the typical symptoms (fever, cough, and respiratory distress) in patients with COVID-19. In this study, 56% of the hospitalized patients had neurological manifestations, including headache (34%), dizziness (25%), impaired consciousness (20%), taste impairment (17%), smell impairment (16%), and CVA (4.3%). In a similar study in Wuhan, China (n = 214), 45.5% of the patients with severe infection had neurologic symptoms of which the most common ones were dizziness (19.3%), headache (17%), impaired consciousness (14.8%), taste impairment (3.4%), smell impairment (3.14%), and acute cerebrovascular disease (5.7%) (
7). The comparison of the results of the two studies reveals that the prevalence of the neurologic symptoms is higher in the present study compared to the one in Wuhan, China.
The prevalence of the typical symptoms was higher in the present study compared to the study in Wuhan. While the prevalence of fever and cough in the present study was respectively 87% and 86.1%, the prevalence of these items in the study in Wuhan was 45.5% and 34.1% (
7). In another study in Wuhan, 80.3% of the patients had fever and 34.6% had cough (
3). In the present study, 77.8% of the patients experienced fatigue, 73% of them had myalgia, and 48.3% of them had anorexia, while in a study in Wuhan, which investigated cardiac injury and mortality in patients with COVID-19, fatigue (13.2%), myalgia (4.6%), headache (2.2%) and cerebrovascular diseases (5.3%) were reported (
12). The difference in the prevalence of the symptoms of the disease in the two studies might be due to the change in the virus genome caused by the passage of time and the genetic differences in the patients.
As shown in
Table 1, there is no significant difference between the two genders in terms of the general and the neurologic symptoms. Although the number of CVA cases was higher in women than in men, the difference was not statistically significant. However, the TIA cases were only observed in women, and the difference in this regard was statistically significant. These findings have not been inspected in the previous studies. The occurrence of CVA and TIA in patients with COVID-19 is probably caused by the incidence of vasculitis that follows this disease. Therefore, the higher prevalence of CVA and TIA cases in women compared to men can be suggestive of the idea that, COVID-19 causes vasculitis more in women than in men.
According to
Table 2, some clinical characteristics were statistically different among the age groups. For instance, the CNS symptoms were more prevalent in the age groups under 40 and over 60 compared to the middle-aged group. The CNS involvement might be caused by the virus reaching this area through the hematogenous or the retrograde neuronal route. In addition, headache was more common in the age groups under 40 and over 60 compared to the age group of 40-60, though this difference was not statistically significant. On the other hand, the prevalence of dizziness in the age groups under 40 and over 60 was significantly higher than the age group of 40-60. This discrepancy might be associated with the different behavior of the virus in different age groups considering their physiological status. The similar studies did not compare the incidence of headache and dizziness in different age groups.
As
Table 2 shows, the impaired consciousness increases significantly with the patients’ age, in a way that a notable increase can be seen among the elderly patients, which can be due to chronic diseases and the aging process. In other studies, too, it was shown that the prevalence of impaired consciousness was higher in the hospitalized elderly patients than in other age groups (
13,
14). The CVA cases were only seen among the patients over 60 years of age and were not reported in younger age groups. In the study of Coco et al., the relationship between the prevalence of stroke and old age was shown (
14).
The prevalence of ataxia was significantly lower in the age group of 40-60 compared to other age groups, especially the elderly ones. In another study, it was shown that the prevalence of ataxia increased with age (
15). In the present study, the lower prevalence of ataxia in the age group of 40-60 requires further studies in this regard.
Almost half of the patients with COVID-19 in the present study experienced anorexia, and it was significantly more prevalent in the age groups under 40 and over 60. In general, anorexia is a common symptom of many acute infectious diseases (
16). It requires further investigations to find the reason why anorexia was less prevalent in middle-aged patients compared to the other age groups. Taste impairment was more common in younger patients, and the prevalence decreased with age, but the difference was not meaningful. However, the incidence rate of smell disorder was significantly higher in younger patients compared to the older ones. In the study of Lechien et al., the prevalence of smell and taste impairment was respectively 85% and 88% in patients with the mild to moderate form of COVID-19 (
17). The study of Mao et al. showed that elderly people develop more severe forms of this disease (
7).
There was no evidence of encephalitis or transverse myelitis in the present study. Other similar studies have not reported these complications (
7,
12). In the study of Filatov, the analysis of the cerebrospinal fluid (CSF) of COVID-19 patients showed no trace of coronavirus. It seemed, COVID-19 probably cannot cross the blood-brain barrier (
18). However, other studies have reported these complications (
19,
20).
The rest of the clinical characteristics did not have any significant relationship with the age groups.
One of the strengths of the present study was that the medical records of the hospitalized patients were carefully reviewed. Moreover, the city of Babol in north of Iran was among the cities with a considerably high prevalence of COVID-19. At that time (peak outbreak of the disease), Rouhani Hospital in Babol only admitted COVID-19 patients from the nearby region and the western cities of the Mazandaran province. The limitation of this study was that some of the medical records were incomplete.
5.1. Conclusions
Based on the findings of the present study, the neurological manifestations, including headache, dizziness, taste impairment, and smell impairment, were substantially prevalent in COVID-19 patients. Some of the neurologic symptoms were more common in different age groups. For instance, the cases of CVA and TIA were more common in women than in men. Therefore, the medical staff should take these symptoms seriously and consider the patients’ age and gender in emergency centers and healthcare clinics to adopt appropriate preventive and therapeutic measures in time.