Pre-Renal Failure Treatment
Diseases intrinsic to the kidney tend to be progressive and ultimately result in kidney failure and the need for dialysis therapy or a kidney transplant. While there are effective treatments to slow or in some cases, arrest the progression, only a few such diseases can currently be reversed with treatment. Thus, most patients tend to progress with their kidney disease to ultimately arrive at renal failure. While the disease, itself may not be treatable, many of the complications are amenable to treatment which is often more effective if initiated early than after more severe and possibly irreversible damage has occurred.
The following paragraphs describe complications and their medical management.
Anemia: The normal kidney produces a hormone called erythropoietin. This hormone travels to the bone marrow to stimulate the production of red blood cells. Many patients with progressive renal disease are deficient in erythropoietin. This results in an anemia (low blood count) that can be severe. Treatment consists of periodic injections with artificial erythropoietin produced by DNA cloning technology. These shots are highly effective at maintaining a normal or near normal blood count. The advantage for the patient is a higher energy level and a greater sense of well being. Without erythropoietin, patients will often suffer from chronic fatigue, and a general feeling of lack of energy.
Bone Disease (Renal osteodystrophy): The normal kidney converts vitamin D to its active form. Vitamin D is important for calcium absorption and healthy bones. Patients with renal disease may not properly activate vitamin D and suffer a number of consequences. Treatment consists of pills containing activated vitamin D or one or its analogs to reverse the deficiency and prevent much of the damage to bones.
The failing kidney also has impaired excretion of phosphorus. This results in a high level of phosphorus in the blood which in turn causes calcium levels to be reduced. Along with other factors, the low calcium stimulates the parathyroid gland to produce excessive amounts of parathyroid hormone. This further aggravates the tendency for kidney patients to develop bone disease. The vitamin D deficiency mentioned above causes a condition similar to rickets. The high parathyroid levels cause an additional insult known as osteitis fibrosa cystica in which normal bone is replaced by scar tissue and cyst like lesions. Treatment of this later complication consists of reducing phosphorus intake in the diet and lowering phosphorus levels using "phosphate binders" that prevent absorption of phosphorus in the intestinal track thereby lowering blood phosphorus and reversing the pathologic process. Both of the above bone lesions are best managed by early treatment to prevent damage rather than to try to heal bone that has already been severely damaged.
Malnutrition: Kidney failure leads to a loss of appetite (anorexia) and patients with renal failure often become protein malnourished as a consequence. Less commonly they develop caloric malnutrition (weight loss). Dietary manipulations are available to prevent both types of wasting in most patients.
Hypertension: Severe hypertension, particularly in the black population, can cause renal damage and hypertension will hasten the progression of many intrinsic renal diseases. However, progressive renal disease is also associated with the onset of new hypertension or the worsening of already existing hypertension often to dangerous levels that are resistant to conventional blood pressure treatments. Special combinations of anti-hypertensive medications are often necessary to control blood pressure. Without such control, renal disease progresses more rapidly and the patient is at risk of other complications such as coronary artery disease and heart attacks as well as strokes.
Lipid abnormalities: Many patients suffer from high cholesterol or other abnormalities of lipid metabolism. Some forms of kidney disease, particularly those that cause large amounts of protein loss in the urine, are associated with a high blood cholesterol (hypercholesterolemia). Hypercholesterolemia further endangers the coronary vessels and the vessels to the brain. The current thinking in Nephrology is that lipid abnormalities are also deleterious to the diseased kidney. Thus, management of hyperlipidemia with diet and, when necessary, medications is particularly important in patients with early renal failure.
Diabetes mellitus: Patients with diabetes mellitus are particularly prone to developing kidney disease. Indeed, more than half of the patients in the United States currently on dialysis have their renal failure as a consequence of their diabetes. Optimal control of blood glucose has been shown to slow the progression of diabetic kidney disease and is thought to be beneficial to patients with diabetes who have other forms of progressive renal disease. (The presence of diabetes does not protect a patient from developing other forms of progressive renal disease). Careful control of blood glucose and optimal blood pressure control both slow the progression of renal disease. Two classes of anti-hypertensive medications seem to be beneficial beyond the simple lowering of blood pressure. These are angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARB’s)
Acidosis: Patients with progressive renal disease have problems excreting acid that is part of normal dietary intake. The result is too much acid in the blood (acidemia). Treatment consist of neutralizing agents such as sodium bicarbonate to reverse this process. Chronic acidosis is deleterious to bone and additive to the other abnormalities of bone that renal patients may develop.
Hyperkalemia: Patients with more advanced renal disease are at risk of developing high levels of potassium in the blood (hyperkalemia) because of the inability of the diseased kidney to excrete a potassium load (extra dietary potassium). Treatments are available to improve renal excretion of potassium. Dietary counseling can prevent much of the problem. In extreme cases, agents are available to bind potassium in the intestine and prevent its absorption into the blood stream thereby keeping potassium in the safe normal range. The treatment is often a balancing act, in part, because medications often required for the treatment of hypertension may affect potassium, either increasing or lowering blood potassium. Both low potassium (hypokalemia) and hyperkalemia are potentially lethal complications because of their effect on the heart.
The above complications may occur in different combinations and in varying degrees. Most of them are treatable and many are better treated by prevention than by later attempts to reverse damage. Nephrologists are particularly well trained to assist patients, monitoring them for early signs of these complications and administering therapy early. Penn State Hershey Nephrology has special clinics in which patients with early renal failure are followed. This has the added advantage of adequately preparing the patient for dialysis in advance of the actual need. Appropriate patients can also be referred from this clinic early in the course of their disease to facilitate their ultimately receiving a kidney transplant and thus obviate the need for dialysis or shorten the waiting period patients also must endure before receiving a kidney transplant.