Kidney failure occurs when one or both kidneys are not able to perform their usual functions. The kidneys are two bean-shaped organs in the lower back. Their main function is to remove waste from the body and to balance the water and electrolyte content of the blood by filtering the salt and water in the blood. The waste and water excreted by the kidneys combine to form urine.
Kidney failure is divided into acute and chronic.
Acute Kidney Failure – sudden loss of kidney function
Chronic Kidney Failure – slow, gradual loss of kidney function
If kidney function is reduced to 20% of normal function, serious health problems develop. When kidney function decreases to 10% to 15% of normal, dialysis or a transplant is needed to maintain life.
Kidney diseases cause the tiny filters in the kidneys (called nephrons) to lose their filtering ability. Damage to the nephrons may occur suddenly after an injury or poisoning. However, many kidney diseases take years or even decades to cause damage that is noticeable.
The two most commons causes of kidney failure are:
- Diabetes – longstanding high blood sugar that results from diabetes damages the nephrons
- High blood pressure – longstanding high blood pressure damages the capillaries in the kidneys
Others causes of kidney failure may include:
- Polycystic kidney disease
- Birth defects
- Severe trauma
- Long-term use of medicines that contain:
- Blockage of the urinary tract due to:
- Bladder or colon tumor
- Large kidney stone(s)
- Enlarged prostate
- Build-up of abnormal substances within the kidneys, such as:
- Protein buildup
- Toxic reaction to drugs or x-ray dyes
- Systemic diseases, including:
- Systemic lupus erythematosus (lupus)
- Wegener's and Goodpasture's granulomatosis
- Conditions that severely decrease circulating fluid/blood volume, such as:
- Severe blood loss
- Heart failure
- Liver disease
- Shock (due to any of the above conditions or a sudden and severe drop in blood pressure)
A risk factor is something that increases your chance of getting a disease or condition. Risk factors for kidney failure include:
- High blood pressure
- Long-term use of painkillers containing aspirin or NSAIDs in high doses
- Liver failure, jaundice
- Respiratory failure
- Recent open heart surgery
- Recent surgery on an abdominal aortic aneurysm
Some kidney diseases begin without any symptoms at all. As kidney failure progresses, some of the following symptoms may develop:
- Fluid retention
- Swollen hands and feet
- Numbness of hands and feet
- Itchy skin
- Low urine output
- Frequent urination
- Loss of appetite, malnutrition
- Sores, bad taste in the mouth
- Muscle cramps and twitches
- Shortness of breath
- Swelling throughout the body
- High blood pressure
- Weak, brittle bones
- Yellowish-brownish skin tone
The doctor will ask about your symptoms and medical history, and perform a physical exam.
Tests may include:
Blood Tests – to see if the kidneys are working properly. If they are not working properly, blood levels of creatinine and blood urea nitrogen will increase.
Urine Tests – to see if the kidneys are working properly. If they are not working properly, urine may contain elevated amounts of protein. You may be asked to collect urine in a special container over a 24-hour period. In addition to finding out if you are losing protein in your urine, your doctor can determine how your kidneys are functioning by measuring if your kidneys are clearing creatinine at a normal rate. In severe kidney failure, the amount of urine produced may be quite low, and can even be completely absent.
Renal Imaging – use of ultrasound, magnetic resonance imaging (MRI), or computed tomography (CT scan) to take a picture of the kidneys. These pictures will show whether there is a blockage in the flow of urine or a growth on the kidney.
Biopsy – removal of a tiny piece of kidney tissue to see how kidney cells are functioning.
Most chronic kidney diseases are not reversible, but the following are treatments that may be recommended to help preserve as much kidney function as possible, and to try to reverse some of the ill effects of kidney failure.
- Fluid restriction
- Daily weight checks
- High carbohydrate diet
- Low protein diet
Use of all medications, both prescribed and over-the-counter, should be carefully reviewed. Medications that rely on the kidney for excretion need to be carefully dosed and monitored, or avoided entirely.
Medications used in acute or chronic kidney failure may include:
- Diuretics, such as furosemide or mannitol – help to flush out the kidneys, increase urine flow, and rid the body of excess sodium
- Dopamine, atrial natriuretic peptide (ANP) – dilates blood vessels in the kidneys, increases urine flow, flushes out sodium
- Angiotensin-converting enzyme inhibitors
- Blood pressure medications
Dialysis – dialysis is a process that takes over for the kidneys and filters potentially toxic waste from the blood. Dialysis may be done temporarily, until kidney function improves, or until a kidney transplant is available.
Balancing of Electrolytes, Anemia, and Low Platelet Counts– blood levels of sodium, potassium, calcium, and phosphate, as well as hematology measures such as red blood cells, hematocrit, and platelets should be monitored regularly. Injections of erythropoietin, a hormone normally produced by the kidney to stimulate production of red blood cells, may be given to manage the anemia of kidney disease.
Kidney Transplant – for some people, receiving a kidney transplant may be the right option. Success of a kidney transplant depends on multiple factors, including whether the underlying cause of the kidney damage is still present, and general state of health of the person receiving the transplant.
The following are steps to help your kidneys stay healthy longer:
- Have your blood pressure checked regularly and use appropriate medication to control high blood pressure.
- If you are diabetic, control your blood sugar carefully. Ask your doctor or dietitian for help.
- Avoid the chronic use of pain medications.
- If you have chronic kidney disease, you may need to limit your intake of protein. A dietitian can help you adjust your diet.
- Limit cholesterol intake. Cholesterol is present in foods that come from animals, such as meat and dairy products, including eggs.
- Limit sodium intake.
- If you have severe kidney disease, limit your potassium intake (found in fruits, vegetables, nuts, and seeds). Help from a dietitian is crucial if your kidneys are failing.
In some cases, you cannot prevent kidney failure. But there are some steps you can take that will lower your risk of kidney failure:
- Maintain normal blood pressure.
- If you are diabetic, control your blood sugar.
- Avoid long-term exposure to toxic substances such as lead and solvents.
- Do not abuse alcohol or over-the-counter pain medication.
- If you have chronic kidney failure, consult your doctor before you become pregnant.