The aim of the study is to demonstrate the difficulties in instrumental diagnosis of acute respiratory distress syndrome (ARDS) in a patient with coronavirus disease (COVID-19) in the presence of certain clinical signs of its development and progression.

Results. We present a case of severe COVID-19 in a 79-year-old unvaccinated patient with comorbidities (stage II hypertension and psoriasis). The diagnosis of COVID-19 was confirmed by RNA detection with PCR; treatment was in accordance with the Order of the Ministry of Health of Ukraine No. 762. On the 3rd day of the disease, despite the presence of physical signs such as shortness of breath in the lower parts of the lungs and dry rales, as well as oxygen dependence, no pathology was detected by X-ray. The coronavirus disease course worsened during the period of hospital treatment, which was manifested by an increased supplemental oxygen requirement and the need to enhance the oxygen level and its partial pressure.

On the 9th day of hospitalization, the patient was transferred to the intensive care unit. Instrumental imaging methods (radiography and ultrasound examination of the lungs) were repeated, showing left-sided interstitial edema of the lung parenchyma with the formation of superficial consolidations, that progressively worsened. That same day, acute myocardial infarction was diagnosed. The level of consciousness decreased to 9 points on the Glasgow Coma Scale due to hypoxia, necessitating the patient’s transfer to mechanical ventilation. On the 24th day of hospitalization, the patient died due to the development of severe ARDS and acute myocardial infarction.

Conclusions. This clinical observation of an ARDS case in a patient with COVID-19 indicates that the emergence of this complication might occur without the typical radiological and sonographic signs of infiltrative lung injury. Alternatively, this could be attributed to the limitations of the equipment employed, while, conversely, the clinical manifestations might be influenced by the pathophysiological characteristics of ARDS development, prompting researchers to identify its distinct subphenotypes.