Thanks for your question on Healthcare Magic.
I can understand your concern.
Your aunt is having end stage
Renal disease (ESRD). So her kidney is noted functioning properly.
Hence she is not excreting urine out of the body.
So there is positive fluid balance in her body. Hence excessive fluid is accumulating in her body.
Now excess fluid in the body tend to accumulate in body cavities like
peritoneal cavity,
pleural cavity etc.
Fluid in the pleural cavity is known as
pleural effusion.
On chest x ray, pleural effusion and pleural thickening look similar.
So for confirmation, ultrasound examination of chest is needed.
She is also having cardiomegaly and
pulmonary congestion. These favour pleural effusion more.
So get done ultrasound examination of chest.
Hope I have solved your query. I will be happy to help you further. Wishing good health to your aunt. Thanks.