Kidney Disease

If your physician has told you that you have chronic kidney disease or CKD, this means that you have decreased function of your kidneys. At the very early stages, this may be apparent only as an increase in the excretion of albumin in the urine, termed microalbuminuria, or an increase in the excretion of total protein, termed proteinuria.

These changes can usually be detected by a dipstick test performed in the clinic. However, a more accurate test that is usually required is a 24-hour urine collection.

Blood tests also may indicate some reduced kidney function as an increase in blood urea nitrogen (BUN) or serum creatinine concentration (Cr). The more accurate test of kidney function requires a 24-hour urine collection (see patient handout: How 10 Collect a 24-Hour Urine).

Your kidney disease may be a primary problem in your kidneys, such as glomerulonephritis or a kidney complication of a generalized disease such as high blood pressure (hypertension) or diabetes (diabetic nephropathy). The primary kidney diseases that cause glomerulonephritis are too numerous to describe individually. Their severity and progression are very variable.

If you have protein in your urine, this implies that the filtration barrier at the glomerulus has become leaky. Treatment that reduces the amount of protein that is excreted is likely also to reduce the damage to your kidney over time. Therefore, your physician may adjust your treatment to reduce your protein excretion by about one-half, but it is not likely to be reduced to normal levels.

It may become important to diagnose precisely the category of glomerular nephritis that you have. Your nephrologist will order a wide range of blood and urine tests to assess your immune system, any past or present viral infections, perhaps other systems that could be abnormal and a renal ultrasound to assess the size of your kidneys.

Your nephrologist may recommend a biopsy of your kidneys as the most precise way of forming the diagnosis. A kidney biopsy requires current blood tests that are undertaken to insure that you are not anemic and have no bleeding condition. The biopsy is booked by the Division of Nephrology on the sixth floor of the Pasquerilla Health Care Building at Georgetown University Medical Center (tel: 202-444-9183). The staff there will complete the necessary paperwork and coordinate with the Department of Radiology. Once all required paperwork and results are received, the biopsy nurse will call you to schedule your biopsy. It is usually undertaken by a radiology ultrasound technician and a nephrologist, together. You will be asked to lie on your front on a table while a radiology technician locates your kidneys using ultrasound. Some freezing solution (local anesthetic) will be injected into the skin of your flank and a needle passed on three or more occasions into your kidney to take a small segment of the kidney for examination in the Pathology Department. You will be given instructions for your care after the biopsy. If you have blood in the urine, low blood pressure, or are feeling faint, come to the emergency room without delay.

The biopsy is examined in the Pathology Department and reviewed with your nephrologist. This process typically takes about two weeks to be complete. Thereafter, a report will be issued which your physician can discuss with you.

Other causes of chronic kidney disease include a narrowing of the artery to the kidney termed renal artery stenosis, which, over time, can damage the function of the kidney and lead to a condition called ischemic nephropathy. This is associated with high blood pressure and various other changes (please see patient handout: Secondary Hypertension).

Other conditions that can cause chronic kidney disease include any that obstruct the flow of urine from your kidneys. This is sometimes due to stones in your kidney, tumors in the bladder, or to an enlarged prostate that prevents passage of urine from the bladder. These conditions, once suspected, often require referral to a urological surgeon for management.

About half of patients with diabetes and about one tenth of patients with severe hypertension eventually develop some damage in their kidney. The first sign of this is the appearance of albumin or protein in the urine. Typically, this does not occur for about 10 years after first diagnosis. The finding of albumin in the urine is important because it is the first step in kidney disease. In diabetic patients, this can progress to excretion of large amounts of protein in the urine, a fall in the protein level in your blood, and swelling of your ankles, termed nephrotic syndrome. This leads to progressive loss of kidney function, ultimately to end-stage renal disease (ESRD). Before you are at danger of developing ESRD, your physician will discuss with you the options available to you. Typically, this loss of kidney function is slow.

Any damage to your kidney can cause high blood pressure. Moreover, prolonged high blood pressure itself can damage the kidney. Therefore, this can represent a vicious cycle of increasing blood pressure leading to increased kidney damage. Chronic kidney damage from high blood pressure can cause loss of function of the kidneys, but typically this does not occur for many years, and it may be preventable by adequate treatment. It shows up as a rise in the BUN and creatinine and a modest increase in protein excretion in the urine.

There are a number of diseases which affect many organs of the body (multi-system disease) that can cause damage to your kidney as part of the underlying problem. Examples of these are collagen vascular diseases such as systemic lupus erythematosus (SLE). These are diseases due to the formation of antibodies against the natural constituents of your body. The kidney disease that can complicate SLE is important because it has a specific treatment. Therefore, if you have SLE and protein in the urine, your physician may suggest a kidney biopsy.

Another set of causes of chronic kidney disease are hereditary conditions such as autosomal-dominant polycystic kidney disease or ADPKD. If you have ADPKD, it is likely that one of your parents also had it. If you are diagnosed with it, on average about half of your children will also suffer from the condition. It is caused by a genetic abnormality that leads to progressive increase in cysts in both your kidneys. Damage to the kidney shows up as a rise in BUN and creatinine that usually does not occur until middle age. Unfortunately, many patients eventually develop ESRD.

If your physician has diagnosed you with chronic kidney disease, this will likely mean that you will be advised to optimize your lifestyle. You may well be advised to reduce your blood pressure, which can help to reduce the amount of protein you excrete, and to follow a specific diet. Since chronic kidney disease also causes damage to blood vessels and increases the risk of a subsequent heart attack or a stroke, it is important for you to have excellent control of your blood pressure and blood cholesterol, refrain from smoking and adopt a healthy lifestyle, including a healthy diet and regular exercise. You should discuss this with your physician (see patient handout: Instructions/or a Healthy Diet to Help Lower Your Blood Pressure and to Prevent Cardiovascular Disease: The DASH Diet).

If you are excreting much protein in your urine, your physician may assist you to reduce your systolic blood pressure to a value of 120-125 mmHg. This is lower than is required for most people, but has been found to reduce kidney damage. You may also be advised to reduce the amount of potassium or sodium in your diet (see patient handouts: Dietary Potassium and Dietary Salt Restriction).

It is important to accept that if you have chronic kidney disease, it is unlikely to go away. Indeed, chronic kidney disease usually gets slightly worse over time. Therefore, you must make plans for prolonged followup with your physician who will chart the progress of your kidney disease and help you adjust your lifestyle and treatment to delay its’ progression.

Kidney Disease

Further Reading