A better test is the glomerular filtration rate (GFR), which can be calculated from the blood creatinine test value, the patient’s age, gender and body size.
A low level, less than 90, usually indicates that the kidneys are not functioning normally. Patients at risk for CKD should request that this test be determined by their physician.
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.
Nonetheless, CKD causes many chemical changes in the body, and may affect many parts of the body. As kidney function falls, symptoms appear and sometimes worsen, eventually leading to the need for a kidney transplant or dialysis.
High Blood Pressure (Hypertension): High blood pressure is present in more than 70 percent of people whose kidney function falls below 60 percent of normal. It can cause faster loss of kidney function.
Hypertension can also cause heart and blood vessel disease, including enlargement of the heart, congestive heart failure, heart attacks and strokes. Most people with high blood pressure have no symptoms of this dangerous disorder. When blood pressure is severely elevated, headaches, dizziness, confusion, double or blurred vision and even seizures and unconsciousness can result.
All patients with CKD should work with their doctors to monitor blood pressure results frequently, and follow diet and medication advice to maintain blood pressure at less than 130/85. Many powerful blood pressure medicines are now available to lower blood pressure and at the same time help preserve kidney function.
Low Red Blood Cells (Anemia): Kidneys make a hormone called erythropoietin (EPO), that travels in the blood stream to the bone marrow, and increases production of red blood cells.
When CKD damages the kidneys, this hormone secretion is reduced, and normal red blood cell production reduces. This results in a low red blood cell count or anemia. Anemia is sometimes associated with reduced iron in the body.
In general, the worse the kidney disease, the worse the anemia becomes. Low blood counts are associated with higher rates of hospitalizations, heart and blood vessel disease and impaired thinking processes. Several studies have shown that anemia is associated with higher chances of death.
Anemia can cause a pale complexion, weakness, reduced exercise ability and a general feeling of poor well-being. Some patients say, “I feel cold all the time.” Anemia can also cause thickening of the heart muscle, and lead to congestive heart failure (CHF).
Patients with CKD and anemia need frequent measures of their blood hemoglobin, a measure of the red blood cell mass. Treatment with injections of EPO, and with oral or intravenous iron, can correct the anemia and improve many if not all of these symptoms and complications. Patients with CKD should work with their doctors to follow and treat anemia.
Heart and Blood Vessel (Cardiovascular) Disease: CKD increases the chance for heart disease, stroke and narrowing of blood vessels in the legs. Patients with CKD have a higher chance to develop chest pain (angina) and heart attacks.
In addition, CKD patients have a higher incidence of heart muscle thickening, leading to congestive heart failure (CHF). Symptoms of CHF include shortness of breath, particularly with exercise or when lying down. Swelling of the feet or ankles (edema) may develop.
Strokes are more common in CKD, the result of narrowing of arteries to the brain. Recent studies also show that postmenopausal women with CKD and heart disease also are at higher risk for artery narrowing to the legs, called peripheral arterial disease. This complication can cause pain, inability to walk and tissue breakdown.
Abnormalities of lipid metabolism (cholesterol and triglyceride) are common in CKD, and may add to the risk of heart and blood vessel disease.
In addition, smoking adds to this risk, and may speed the decline of kidney failure in patients with diabetes, high blood pressure and other kidney diseases. Patients need to find effective ways to stop smoking. They should work with their doctors to reduce the level of cholesterol with diet and medications.
Nutrition: Poor intake of protein and calories during the course of CKD is common in many patients, particularly as the level of kidney function drops below 60 percent of normal.
This leads to malnutrition, and is associated with poor outcomes. Patients experience a decrease in appetite, lower protein levels in the blood, weight loss and reduction in body fat and muscle.
It is recommended that the nutritional status of CKD patients be monitored every six to 12 months when the kidney function is less than 60 percent of normal, and every one to three months when function falls to less than 30 percent of normal. Patients with CKD and malnutrition should get nutritional counseling, and receive dietary modification, education or specialized nutrition therapy.
Many CKD patients have protein loss in the urine, which can lead to low body protein.
In addition to making the malnutrition worse, this protein loss can lead to swelling of the feet, ankles or the whole body (edema). Medications, such as angiotensin converting enzyme (ACE) inhibitors, can sometimes reduce the level of protein excretion and improve the kidney’s function.
Bone Disease and Calcium: Bone disorders are common in patients with CKD. In some patients, an increased level of phosphorus in the blood reduces vitamin D production in the body, which reduces the intestine’s absorption of calcium from food.
The combination of low calcium absorption and high phosphorus can cause the growth of the tiny parathyroid glands in the neck, causing high levels of the hormone they produce (parathyroid hormone, or PTH). PTH stimulates increased cell turnover in the bones, causing abnormal bone structure, decreased bone strength and increased risk of fracture.
Other patients develop low turnover bone disease, with reduced ability of the bones to reshape. Some patients with this disorder have pain in their bones. Patients and their doctors should work together to measure calcium, phosphorus and PTH in the blood, and to assess bone structure with X-ray tests or a bone density test.
Medicines to reduce phosphorus levels and several forms of vitamin D have helped treat this bone disease. Newer medicines are being tested that may help improve this condition.
Diseases of the Nervous System (Neuropathy): Neuropathy is a common complication of CKD. The brain is sometimes affected (encephalopathy), resulting in fatigue, impaired memory, confusion, disorientation or poor thinking processes.
Severe kidney failure can cause hallucinations, delirium, convulsions and coma. Sleep disorders are common, causing restlessness, frequent awakening and fatigue.
The nerves of the arms, hands, legs and feet can be affected, causing decreased sensation, itching, burning, muscle irritability, cramps or weakness.
Neuropathy effects on the autonomic nerves can cause abnormal responses of the pulse and blood pressure. When patients experience symptoms of neuropathy, specialized laboratory tests should be performed.
Functioning and Well-Being: CKD can affect the ability to function normally or the sense of one’s well-being.
CKD is associated with increasing symptoms such as tiring easily, low energy, weakness, cramps, bad taste in the mouth, poor odor perception and hiccups.
These symptoms, along with the effects of CKD on the heart, bones, blood vessels and nervous system, reduce well-being and the ability to function well.
