Identifying Kidney Failure

Perhaps most frightening, kidney failure can exist for long periods of time before making itself known. It is possible, for instance, to lose as much as 75% of your normal kidney function before becoming aware that kidney failure is present.

Below, experts Dr. Jai Radhakrishnan and Dr. Leonard Stern discuss how kidney failure is identified.

Could you describe the kidney's function in the body, and what happens when it can't do its job?
LEONARD STERN, MD: The kidney is an organ that regulates homeostasis, or the body's equilibrium. It is directly responsible for controlling the acidity of blood, and as the kidney fails, our blood becomes more acid. The kidney makes a hormone that regulates our red blood cells, and during the process of chronic kidney failure, the hormone fails and we don't make enough red blood cells.

The symptoms of this red blood cell deficiency are anemia, fatigue, sleepiness and poor concentration, none of which are unique to kidney disease. So we have troubles with these symptoms because they overlap. Anemia symptoms and kidney disease symptoms look alike. We can treat the anemia symptoms by replacing the hormone. Once we do that, many of the symptoms of kidney disease largely disappear until the illness is very far advanced.

Why is kidney failure so difficult to diagnose?
JAI RADHAKRISHNAN, MD: You have a tremendous amount of reserve in the kidneys before any symptoms manifest, and typically we don't see patients come in with any problems until they're down to about 25 or 30% of normal kidney function. The second issue is that the symptoms that accrue from kidney damage are so vague that you might easily ascribe it to something like depression or fatigue from working too hard, and in reality there's a lot of damage being done in the kidney that could lead to a lot of problems like high blood pressure and anemia. Again, it's basically difficult to detect.

What are some basic screening tests that a general practitioner might use to screen for kidney problems?
LEONARD STERN, MD: The general practitioner will typically do screening blood work. We use a marker called the serum creatinine, which is a general gauge of kidney function. When that number is elevated, then the general practitioner might suspect that there is something awry with the kidneys. The BUN is a widely used index. The serum potassium. The bicarbonate is an index of the acidity of blood.

Another screening test the general practitioner could use would be urinalysis, where they look for the presence of protein or inflammatory cells. Sometimes the blood work, in addition to the creatinine, might give the practitioner a clue that there's a problem. The serum protein level, the albumin, might be reduced, or the lipid levels or cholesterol might be elevated. All could be features of subtle kidney disease.

These are routine screening tests. The standard blood work done in a regular check-up should look for an index of kidney function, as well as liver function and the blood count and things of that sort.

What are some of the most dramatic kidney failure symptoms that people might experience?
JAI RADHAKRISHNAN, MD: If a person feels perfectly and suddenly feels run down, tired, or weak, they should definitely seek help from a practitioner. Kidney failure could be the cause for all this.

If there's pain in the flanks where the kidneys are, if you have pain down there and it's recurrent and disabling, you should definitely go to a doctor, because there could be a stone sitting there, causing progressive kidney damage.

If you have a burning of the urine, if you feel scratching in the skin, these are some of the signs, or you've lost your appetite out of the blue, for no reason, or you're not able to concentrate, your mind's wandering.

All these symptoms could relate to a kidney problem.

What are some of the more subtle symptoms of a kidney problem?
LEONARD STERN, MD: A person might urinate more frequently at night, or their ankles might be swollen, or the screening test will have shown that their blood pressure is mildly elevated. Those could be the first presentations of some subtle form of kidney disease.

There are certain people who definitely need to keep a close eye on their kidney function, and those are people who have hypertension or diabetes. Both are very strongly linked to impaired kidney function. Who else needs to be especially mindful of their kidneys?
LEONARD STERN, MD: A group that has an inherited disorder called polycystic kidney disease. The patient who has this will develop kidney failure, typically in their 40s or 50s, and this is an inherited disorder, so there would be a strong family history.

What about people who have recurrent urinary tract infections or the incidence of kidney stones? Are they more susceptible to developing serious kidney disease that might lead to kidney failure?
JAI RADHAKRISHNAN, MD: Yes. People who get an infection of the upper urinary tract, especially if there's blockage -- like a stone, for example -- could certainly lead to kidney failure if not treated and managed.

But if it is treated and managed, is that an indicator that they are then more susceptible to other forms of kidney disease?
JAI RADHAKRISHNAN, MD: No. Essentially, it's directly related to direct damage because of the infection. So if you manage to treat the reason why the patients are getting frequent infections, you're basically okay.

LEONARD STERN, MD: Or you manage to figure out why the patient is making frequent stones, and if we could prevent that, then we could largely prevent the kidney failure related to stones and infection.

What happens when you have kidney failure?
LEONARD STERN, MD: Unfortunately, the kidneys are essential organs for life, and if left untreated, a patient would die. But in the last 30 years we have techniques called dialysis or transplant that act in place of our own kidneys. With dialysis, patients can maintain life with reasonable quality, but not normal quality, because they're dependent on an artificial means of kidney replacement. Still, they can live reasonable lives.

Transplantation is the treatment of choice for kidney failure, but unfortunately, because of organ shortages, we can't provide transplants for everyone. At this point, the number of transplants done in the United States has been stable for a decade. About 9,000 per year and that's dependent on a shortage of kidney donors. And despite public awareness programs, we're really unable to raise that number.