Renal Monomorphology in COVID-19 with Acute Renal Insufficiency Abstract. A 78-year-old ventilator-dependent COVID-19 patient developed severe renal failure with an estimated glomerular filtration rate of 20 ml/min per 1.73 m2 and nephrotic proteinuria. Sonography showed echo-dense and enlarged kidneys with high resistance indices (>0.8). Echocontrast sonography showed a delayed renal perfusion. In the further course of the disease renal function recovered, kidney size decreased and the renal perfusion normalized. An acute COVID-19-associated interstitial nephritis is postulated.