Differences and characteristics of COVID-19 and atypical pneumonia

Abstract

<b>Introduction:</b> Since COVID-19 is newly defined, the differences between COVID-19 and other microorganisms causing atypical pneumonia have not been fully expressed yet. We aimed to make clinical comparison of cases with COVID-19 and atypical pneumonia. <b>Method:</b> “Non-COVID-19 atypical pneumonia” group included patients with both radiological and clinical confirmation of atypical pneumonia by radiologist and clinician. Patients with positive Polymerase Chain Reaction test formed "COVID-19 pneumonia" group. <b>Results:</b> A total of 177 patients (46:non-COVID, 131: COVID-19) were included. The mean age of COVID group was significantly lower (p=0.040).Ground-glass density and peripheral involvement were more common in thoracic CT of patients with COVID-19 (p=0.017 and 0.019). Fever and fatigue in COVID (p&lt;0.001 and p=0.040), and shortness of breath and gastrointestinal complaints in non-COVID group were significantly higher as presenting symptoms (p&lt;0.001 and p=0.031). Impairment in liver function tests in COVID-19 (p &lt;0.001), impairment in kidney function tests, increased C-reactive protein(CRP) and procalcitonin(PCT) in non-COVID patients were more common (p=0.003, 0.042 and 0.023, respectively). Serum PCT, CRP and lymphocyte levels were significantly lower in cases with COVID-19 (p&lt;0.001, p=0.048 and 0.016). There was no significant difference in prognosis of both groups(p=0.556). <b>Conclusions:</b> With COVID-19 pandemic, there has been an increase in atypical pneumonia cases in which viral strains play role. Symptomatic, laboratory and radiological differences between two groups detected in our study may help in differential diagnosis.