The impact of COVID-19 on the clinical course of acute mastoiditis - analysis of children hospitalized in the University Department in years 2018-2022.

<b>Introduction:</b> Serious intracranial complications of acute mastoiditis seem to be reduced due to vaccine prophylaxis and antibiotics, but recently, after the COVID-19 era, we observe its significant growth.<b>Aim:</b> Due to this observed growth, especially regarding central venous thrombosis, we decided to investigate the patterns of infections within our patients.<b>Materials and methods:</b> We retrospectively analyzed patients hospitalized in our clinic in the years 2018-2022 with the diagnosis of acute mastoiditis. We gathered and analyzed data concerning patients' characteristics and the course of illness. We divided our data into 2 groups: pre- and post-COVID-19-era cases.<b>Results:</b> We found 97 records of 86 patients treated due to acute mastoiditis. As many as 54 cases were classified as pre- and 43 as post-COVID-19 cases. We noted a definite decline in hospitalizations from March 2020 to September 2021 (to 0), which reflects the lockdown period. In the year 2022 we had surprisingly more cases in spring and summer months than in winter. We observed male predominance (p>0.5). Most cases in the pre-COVID group received no treatment before hospitalization in our clinic (p<0.05). We observed higher WBC and CRP levels in the post-COVID group (p<0.05). We found no statistically significant differences in microbiological results between the groups. We found more serious complications in the post-COVID group, with statistical significance only for nerve abducens palsy. We observed a higher need for the use of Vancomycin alone (p = 0.04), mostly as a corrected treatment, or in combination with Ceftriaxone (p = 0.04) in the post-COVID group. The mean time of hospitalization between the 2 groups seems to be similar and was about 13 4 days.<b>Conclusions:</b> We presume that the children's isolation, together with post-infection immunosuppression led to the observed growth of severe complications.