Chronic kidney disease, or decreased kidney function, affects more than 20 million adults, reports the Centers for Disease Control and Prevention. The kidneys are essential organs that help regulate blood pressure and filter wastes from the body. Diabetes and high blood pressure are the most common causes of chronic kidney disease, or CKD. In its early stages, CKD often does not cause symptoms. Since the kidneys perform so many vital functions, however, decreased kidney function can eventually lead to a number of symptoms.
Chronic kidney disease typically progresses over several years, and initial symptoms may not be obvious. Fatigue is one of the first symptoms people notice. Researchers are not entirely sure why people with CKD experience fatigue, but slow accumulation of waste products normally filtered by the kidneys likely plays a role. Anemia related to CKD may also be a contributing factor. As CKD progresses, the urge to urinate more frequently may develop. This may be particularly noticeable at night.
Many people with chronic kidney disease note a decrease in appetite. Some people report a sour or metallic taste in their mouth that makes eating less appetizing. The buildup of urea, a substance that would normally be filtered by the kidneys, likely contributes to this unusual taste. Accumulation of urea may also trigger nausea, another common symptom of decreased kidney function.
As chronic kidney disease progresses, the kidneys become less able to regulate the body's water balance. As a result, people with CKD often retain fluid, especially in the legs and feet. In advanced CKD, fluid can accumulate in the lungs, leading to difficulty breathing. If too much fluid builds up, hemodialysis may be required to remove fluid and restore normal breathing. CKD also causes anemia and an associated decrease in the oxygen-carrying capacity of the blood, which can contribute to difficulty breathing. People with profound anemia often develop a rapid breathing rate to compensate for decreased blood oxygen.
When the kidneys become less able to filter waste products, including urea, the lining around the heart can become inflamed. This condition, known as uremic pericarditis, can cause intense chest pain and trouble breathing. Hemodialysis may be necessary to address a severe buildup of urea. In addition to filtering waste products, the kidneys also maintain normal electrolyte levels in the blood. Electrolytes, such as potassium, are essential for heart muscle function. If CKD progresses to kidney failure, potassium levels can rise dangerously high. Without treatment, palpitations, dizziness and even death due to heart muscle weakness can occur.
- Kidney International: Definition and Classification of Chronic Kidney Disease -- A Position Statement From Kidney Disease -- Improving Global Outcomes
- National Kidney Foundation: KDOQI Clinical Practice Guidelines for Chronic Kidney Disease -- Evaluation, Classification, and Stratification
- American Family Physician: Chronic Kidney Disease -- Prevention and Treatment of Common Complications