Detecting foam in urine now and then is normal, since it can result from
rapid urination and other factors can affect this. However, if the symptom
doesn't go away for long time and exists persistently, this can signal the
possibility of excessive protein, known as proteinuria, in the urine. This may
indicate a serious kidney problem.
In kidney disease, the blood vessels of the kidneys are damaged, so protein
can leak from your blood into your urine. In normal condition, kidney filters
out waste products and restrain proteins, most of which are too big to pass
through the filtering membrane. Therefore, abnormal amounts of protein may
appear in the urine, your urine might look foamy and your may notice swelling in
the hands, feet, abdomen, or face.
The only way to eliminate proteinuria is to repair the damaged glomerular
filtration membrane and restore the kidney function. Then we can get rid of this
symptom.