The kidneys filter the blood, control salt and water balances in the body, and help control blood sugar levels. Each kidney contains millions of nephrons--the functional units of the kidney that process and filter blood. Kidney disease develops due to damage to the cells in nephrons responsible for preserving blood filtration. If allowed to progress, kidney disease can lead to unpleasant and damaging symptoms.
Proteinuria
A common symptom of kidney disease is proteinuria, or the presence of protein in the urine. Each nephron in the kidney contains structures called glomeruli that form a filtration barrier that prevent chemicals from the blood from leaking into the urine. During kidney disease, disruption of the filtration barrier allows protein to leak out of the blood to get expelled in the urine. The Penn State Children's Hospital indicates that proteinuria alone does not cause many noticeable symptoms, but may be diagnosed by analysis of a urine sample.
Blood in the Urine
Another common symptom of advanced kidney disease is the noticeable presence of blood in the urine, also called hematuria. This condition develops due to damage to the filtration barrier within the nephron that allows small cells in the blood, such as red blood cells, to leak though the barrier and into the urine. In the earlier stages of kidney disease small numbers of cells may pass through, and with blood only detected by microscopic analysis. In advanced kidney disease, so much blood leaks into the urine that it lends a pink or red color to the urine. Visible blood in the urine indicates kidney failure and requires immediate medical attention, reports the University of Maryland Medical Center.
Anorexia and Nausea
Anorexia--loss of appetite--and nausea occur in very advanced kidney disease and in kidney failure. Patients with advanced kidney disease often experience a metallic taste in the mouth that reduces the desire to eat. Severe kidney damage and a lack of filtration also leads to the accumulation of toxins within the body, which causes nausea. Patients suffering from anorexia and nausea require immediate medical attention, and likely require dialysis to artificially filter the blood, according to NetWellness, a program associated with the University of Cincinnati. If left untreated, the accumulation of toxins in the body can lead to organ failure and eventually prove fatal.
