In the beginning, kidney failure may be asymptomatic (not producing any symptoms).

As kidney function decreases, the symptoms are related to the inability to regulate water and electrolyte balances, to clear waste products from the body, and to promote red blood cell production. Lethargy, weakness, shortness of breath, and generalized swelling may occur. Unrecognized or untreated, life-threatening circumstances can develop.

• Metabolic acidosis, or increased acidity of the body due to the inability to manufacture bicarbonate, will alter enzyme and oxygen metabolism, causing organ failure.
• Inability to excrete potassium and rising potassium levels in the serum (hyperkalemia) is associated with fatal heart rhythm disturbances (arrhythmias).
• Rising urea levels in the blood (uremia) can affect the function of a variety of organs ranging from the brain (encephalopathy) with alteration of thinking, to inflammation of the heart lining (pericarditis), to decreased muscle function because of low calcium levels (hypocalcemia).
• Generalized weakness can be due to anemia, a decreased red blood cell count, because lower levels of erythropoietin do not adequately stimulate the bone marrow. A decrease in red cells equals a decrease in oxygen-carrying capacity of the blood, resulting in decreased oxygen delivery to cells for them to do work; therefore, the body tires quickly. As well, with less oxygen, cells more readily use anaerobic metabolism (an=without + aerobic=oxygen) leading to increased amounts of acid production that cannot be addressed by the already failing kidneys.
• As waste products build in the blood, loss of appetite, lethargy, and fatigue become apparent. This will progress to the point where mental function will decrease and coma may occur.
• Because the kidneys cannot address the rising acid load in the body, breathing becomes more rapid as the lungs try to buffer the acidity by blowing off carbon dioxide. Blood pressure may rise because of the excess fluid, and this fluid can be deposited in the lungs, causing congestive heart failure.

HOW IS KIDNEY FAILURE DIAGNOSED?

Diagnosis of kidney failure is confirmed by blood tests measuring the buildup of waste products in the blood. BUN and creatinine become elevated, and the glomerular filtration rate decreases. This is the rate with which blood is filtered through the kidneys and can be calculated based upon the creatinine level, age, race, and gender.

Urine tests may be done to measure the amount of protein, detect the presence of abnormal cells, or measure the concentration of electrolytes. Protein in the urine is not normal and can be a clue that damage to the kidneys has occurred. Abnormal aggregations of red and white blood cells called casts can be seen in the urine with kidney disease. Comparing the concentrations of electrolytes in the blood and urine can help decide whether the kidneys are able to appropriately monitor and filter blood.

Other tests are used to diagnose the type of kidney failure. Abdominal ultrasound can assess the size of the kidneys and may identify whether any obstruction exists. Biopsy of the kidney uses a thin needle that is placed through the skin into the kidney itself to get bits of tissue to examine under the microscope.