Why PKD Patients Have Protein in Urine

Protein in urine is called proteinuria in clinical and it is one of the dominant symptoms of kidney damages. For most polycystic kidney disease patients, persistent foamy urine usually means that their renal tissues have been damaged and that their kidney functions are declining.

Different from foamy urine in nephrotic syndrome, usually PKD patients will not have too much foams in urine and their 24-h urine protein is usually 1-2g when foamy urine first appears. This is because in the early stage of PKD, it is the renal tubules that are damaged.

Generally, for a normal person, there is only a little amount of protein leaking out every day because protein belongs to bigger molecules which should not leak out. With time passing by, cysts which have grown up began to press the renal intrinsic cells and tissues around them, thus causing damage in the renal cells, including renal glomerular basilar membrane and filtration membrane, in which there are pores. If the pores are bigger than the normal range, there will be bigger molecules which leaks out, such as protein, red blood cells, which form proteinuria and hematuria in clinic. The protein in urine looks foam in the urine, which does not disappear for a long time.

Though PKD patients lose protein in urine, they should not have too much protein and meat foods which will add more burdens to their kidneys and worsen renal damages. High-quality proteins such as egg, lean meat, milk can produce less nitrogen-related wastes and they are good for PKD patients, but also they should not have too much.