2.1 Clinical manifestations of COVID-19
Being one of severe airway diseases, COVID-19 patients usually show
typical symptomatic respiratory presentations, such as cough, tiredness,
muscle aches, headache, sore throat with sometimes fever and chills
(Singhal, 2020). In such cohort, some patients may suffer from other
worsened symptoms, such as profound acute shortness of breath combined
with persistent chest pain, increasing the emergency need for oxygen
therapy and mechanical ventilation (Yang et al., 2020). On the contrary,
there are asymptomatic carrier states, who experience no symptoms or
even only very mild symptoms; increasing thereby the risk of disease
transmission (Lai et al., 2020).
Case reports declare that some people may display other unusual
non-respiratory manifestations such as diarrhea which is recognized to
be an initial sign of COVID-19 infection, in addition to taste or
olfactory disorders which are especially identified in young people
infected with SARS-CoV-2 (Luërs et al., 2020; Song et al., 2020).
Early clinical studies report that critically ill COVID-19 patients may
associate with cardiovascular insults including myocardial injury,
myocarditis, cardiac arrhythmias and heart failure with increased risk
for thromboembolism as pulmonary embolus because of COVID-19-induced
hypercoagulable state (Driggin et al., 2020).
Other cases with COVID-19 may also exhibit some neurological symptoms
including dizziness, ataxia, altered mental state or even seizures (Mao
et al., 2020). As well, some common COVID-19-related complications have
been detected involving elevated liver enzymes, acute kidney injury
(AKI) as well as an increased risk of developing fatal bacterial
infections (Cox et al., 2020; Yang et al., 2020). Lately, ocular
abnormalities such as conjunctival hyperemia, chemosis, and increased
secretions are additionally reported in COVID-19 infected patients (Wu
et al., 2020).