You may start to have symptoms only a few months after your kidneys begin to fail. But most people don't have symptoms early on. In fact, many don't have symptoms for as long as 30 years or more. This is called the "silent" phase of the disease.
How well your kidneys work is called kidney function. As your kidney function gets worse, you may:
- Urinate less than normal.
- Have swelling and weight gain from fluid buildup in your tissues. This is called edema (say "ih-DEE-muh").
- Feel very tired or sleepy.
- Not feel hungry, or you may lose weight without trying.
- Often feel sick to your stomach (nauseated) or vomit.
- Have trouble sleeping.
- Have headaches or trouble thinking clearly.
Your doctor will do blood and urine tests to help find out how well your kidneys are working. These tests can show signs of kidney disease and anemia. (You can get anemia from having damaged kidneys.) You may have other tests to help rule out other problems that could cause your symptoms.
Your doctor will do tests that measure the amount of urea (BUN) and creatinine in your blood. These tests can help measure how well your kidneys are filtering your blood. As your kidney function gets worse, the amount of nitrogen (shown by the BUN test) and creatinine in your blood increases. The level of creatinine in your blood is used to find out the glomerular filtration rate (GFR). The GFR is used to show how much kidney function you still have. The GFR is also used to find out the stage of your kidney disease and to guide decisions about treatment.
Your doctor will ask questions about any past kidney problems. He or she will also ask whether you have a family history of kidney disease and what medicines you take, both prescription and over-the-counter drugs.
You may have a test that lets your doctor look at a picture of your kidneys, such as an ultrasound or CT scan. These tests can help your doctor measure the size of your kidneys, estimate blood flow to the kidneys, and see if urine flow is blocked. In some cases, your doctor may take a tiny sample of kidney tissue (biopsy) to help find out what caused your kidney disease.