By Jay B. Wish, MD

Patients with chronic kidney disease (CKD) should be aware of signs and symptoms that their kidney function may be deteriorating, which may warrant further evaluation and treatment by their nephrologist. There is no level of kidney function or glomerular filtration rate (GFR) at which all patients with CKD can be expected to develop symptoms of kidney failure. Patients with additional complications, such as anemia, diabetes or heart disease, may be expected to develop symptoms at higher GFR levels than patients without these other conditions.

The decision to start a CKD patient on dialysis is usually based on the GFR level, symptoms the patient is experiencing, and other laboratory values such as serum albumin that reflect the patient’s nutritional status. The average GFR at which patients in the United States are started on dialysis is 15 ml/min, which corresponds to the National Kidney Foundation’s (NKF) definition of stage 5 CKD. However, since this is an average, it means half the patients starting dialysis in the United States have a GFR greater than 15 ml/min, meaning they are experiencing enough symptoms of kidney failure to require dialysis. However, there are many patients who have a GFR as low as 5 to 10 ml/min who may have virtually no symptoms and do not necessarily require dialysis based on GFR alone.

Nonspecific Symptoms

Most symptoms of kidney failure are nonspecific, meaning they occur in a variety of conditions, including kidney failure. For example, the most common symptoms are loss of appetite, nausea and vomiting. However, these symptoms can occur in patients with a flu-like syndrome totally unrelated to kidney disease, with food poisoning, or a variety of other common conditions. Loss of appetite, even before nausea and vomiting may occur, is a significant problem since it may lead to inadequate dietary protein intake, protein malnutrition and muscle wasting. It is very clear from a variety of clinical studies that patients who develop protein malnutrition prior to starting dialysis have worse outcomes during the first year of dialysis, so it is important for patients with noted loss of appetite to seek prompt medical attention before protein malnutrition occurs.

For Your Information

You are at an increased risk of kidney disease if you have diabetes, high blood pressure (hypertension), a family history of kidney disease, or you are of older age.

Constitutional Symptoms

The second most common group of symptoms, called constitutional symptoms, are very subjective and are not confined to one part of the body or organ system. These include fatigue (which may be constant or represent a low tolerance for physical activity), difficulty concentrating, memory loss and sleep disorders. Many of these symptoms may be related as much to anemia as to the accumulation of toxins resulting from the diseased kidney’s failure to excrete them. Accordingly, many of these symptoms will respond to anemia treatments and will not require dialysis therapy. Of course, these symptoms can occur in a variety of other non-kidney, non-anemia-related conditions and should be thoroughly evaluated by the patient’s physician to determine their cause. If the anemia is corrected, but causes eliminated by these constitutional symptoms persist, dialysis may be the treatment of choice.

Fluid Retention

The third most common symptom is fluid retention leading to high blood pressure, swelling and shortness of breath. Patients with kidney disease, even advanced kidney disease, maintain their ability to urinate well after starting dialysis. Because of what appears to be a normal urine volume, many patients are surprised when they are told their kidneys are not working normally because they expect this to be associated with a decreased production of urine. However, even a small imbalance between salt and water intake, and the amount of salt and water excreted in the urine, can lead to progressive accumulation of fluid over time. In its early stages, this is treated with dietary sodium restriction and diuretic drugs. However, in advanced stages of kidney disease, these treatments may no longer be sufficient and dialysis may be the only effective option. Therefore, any patient with CKD who notices the development of tissue swelling, shortness of breath, or an increased difficulty with blood pressure control should promptly seek medical attention to determine the most appropriate treatment.

There are a variety of signs and symptoms that often occur in patients with kidney failure. These include itching, which tends to affect the whole body and may be related to high blood phosphorus and calcium levels. This may respond to lowering of serum phosphorus levels with the use of a phosphate binder and dietary phosphate restriction.

However, in some patients, itching persists despite correction of serum calcium and phosphorus levels, and is thought to represent irritation of the small nerves in the skin (neuropathy) due to the accumulation of toxins not being eliminated by the damaged kidneys. In this situation, dialysis may be the only effective treatment. Another form of neuropathy may lead to tingling in the hands and feet, a symptom that is also not specific for kidney disease and which may be seen in patients with neuropathy due to diabetes, chronic alcoholism and certain vitamin deficiencies. If these other causes of neuropathy have been eliminated, dialysis is the treatment of choice for the peripheral neuropathy associated with kidney failure.

In summary, most of the signs and symptoms of kidney failure are not specific to patients with kidney disease and may be seen in a variety of other conditions. Therefore, it is recommended that should any of these symptoms appear, the patient promptly seek medical attention to determine the cause rather than assuming it is due to kidney failure. In many situations, these symptoms can be effectively treated with medications and other forms of medical management, and do not necessarily indicate the need for dialysis. The decision to start dialysis is based on the combination of symptoms and laboratory values. When any of these symptoms appear, the patient should discuss the implications and therapeutic alternatives thoroughly with his or her nephrologist and, based on each patient’s unique clinical, laboratory and lifestyle issues, a fully informed decision can be made regarding the best treatment plan.

Jay B. Wish, MD, is professor of medicine in the Division of Nephrology at University Hospital in Cleveland. He is also a member of the AAKP Medical Advisory Board.

This article originally appeared in the September/October 2005 issue of Kidney Beginnings: The Magazine, Vol. 4, No. 3.

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