Patients are sometimes confused about the difference between acute kidney failure and chronic kidney failure. Chronic kidney failure is a condition where the kidneys’ ability to filter waste from the bloodstream becomes worse over time, generally a period of years.
Acute kidney failure is the sudden loss of this important ability. Although the condition can be life threatening, it can also be reversible. Patients whose kidneys have suffered from a direct injury or an obstruction are at risk. According to American Family Physician, 5 percent of hospitalized patients develop this condition.
Acute kidney failure is the sudden and dramatic loss of kidney function. This condition develops rapidly, often in just a few days.
Healthy kidneys filter and remove wastes and excess fluid from blood and turn it into urine. When one experiences acute kidney failure, the kidneys are operating at less than 10 percent of normal function. This means wastes such as creatinine and urea nitrogen build up in the bloodstream. If this waste is not removed, a person will feel extremely ill.
Acute kidney failure may occur for a variety of reasons. A “crush-” type injury may damage internal organs, including the kidneys. An over-exposure to metals, solvents and certain antibiotics and medication can also lead to this condition. An infection in the kidneys may cause them to shut down.
Obstructions in the urinary tract or renal artery can start acute kidney failure. Tumors, kidney stones or an enlarged prostate can block the flow of urine in the urinary tract. A blockage in the renal artery can cut off the supply of oxygen to the kidneys. Oxygen is necessary for kidney function. When the kidneys are starved for oxygen, a condition called Acute Tubular Necrosis (ATN) sets in.
Shock or trauma to the body can lead to low blood pressure. Sometimes the stress of surgery on the body can lower blood pressure to dangerous levels. Extremely low blood pressure means there is a decrease in blood flow. Kidneys will not receive oxygen or filter blood as efficiently as before.
The most obvious symptom of acute kidney failure is a decrease of urine. This symptom occurs in 70 percent of cases. Patients who fall into this category are said to be oliguric. Their urine output is less than 16 ounces a day.
When urine output is low, fluid retention will occur. Excess fluid will cause swelling in the legs, feet and ankles. Because wastes are not being removed from the body, patients will feel ill. In addition, many patients report:
- feeling nauseated
- feeling drowsy
- having difficulty paying attention
- experiencing numbness or decreased sensation in the hands and feet
Doctors can easily diagnose acute kidney failure with blood and urine tests. Increased amounts of creatinine and urea nitrogen in the blood are causes for concern.
Doctors will first treat any reversible illnesses that caused the kidney failure. Infections can be treated with medication. Blockages such as tumors or kidney stones may need to be removed.
Since treating the causes of the acute kidney failure takes time, the body will be unable to remove the waste from the bloodstream. The patient will undergo dialysis. Dialysis will remove the toxins from the bloodstream and help the patient feel better.
Sometimes patients develop high levels of potassium in their blood as a result of acute kidney failure. This is condition is called hyperkalemia. Doctors can prescribe medication to bring an elevated potassium level under control.
In order to help keep the wastes and electrolytes at acceptable levels, patients may be placed on a special diet that is low in protein, salt and potassium. Their fluid intake may also be restricted.
Staying healthy is the best way to prevent acute kidney failure. If you are going to be hospitalized for surgery or an illness, be aware of the risks and complications of any procedure you may undergo. Immediately report any changes in your urine output. And, as always, follow any instructions your doctors and nurses give you.
Keeping an open channel of communication with your healthcare team can help you get the treatment you need if acute kidney failure occurs.
Kidneys don’t always get the respect they deserve. Maybe, it’s because they’re relatively small. Maybe, it’s because when they’re functioning normally, we simply take them for granted. But, kidneys are truly impressive and the more you learn, the more you’ll understand why you want to help keep them healthy.
Another word for kidney is renal. You may hear your doctor talk about renal function or read materials that mention renal failure. Whenever you see or hear the word renal, you will know the subject is about kidneys.
The kidneys are two bean-shaped organs about five-inches long, three-inches wide and one-inch thick located in your back on each side of your spine. Each kidney is about the size of a fist and weighs from four to six ounces. They are situated above your waist, with the left kidney a little higher and a little larger. The right kidney is a little lower and smaller to make room for the liver. The lower ribs protect your kidneys.
Inside the kidneys are nephrons. These are tiny units where the filtering of excess fluids and dissolved particles occurs. There are between 1.0 and 1.3 million nephrons in each kidney.
Most people think their kidneys are just responsible for producing urine, but there’s a lot more to it. In addition to removing extra fluid and water from your body, kidneys:
- Filter the blood
- Balance fluid content in the body
- Produce the enzyme renin that helps control blood pressure
- Produce the hormone erythropoietin to help make red blood cells
- Activate vitamin D to maintain healthy bones
- Adjust levels of minerals and other chemicals to keep the body working properly
The basic function of kidneys begins when you eat and drink. After the body takes the nutrients it needs, the extras become wastes. Some of the waste winds up in the blood and needs to be filtered out. The blood gets circulated through the body with every beat of the heart. It’s the job of the kidneys-with their millions of nephrons-to filter and clean out the blood and remove the extra fluids. The extra fluid and waste becomes urine and travels from the kidneys down the ureters to the bladder until eliminated through the urethra.
Removing waste is only one job of the kidneys. In addition to filtering, the kidneys monitor the levels of chemicals, salts and acids in the blood. Inside the nephrons are sensors that keep track of sodium, phosphorus, calcium and potassium. When levels are high, the kidneys signal to remove the excess from your blood for elimination.
Another important job of the kidneys is to monitor and regulate certain body functions. An enzyme called renin is secreted by the kidneys to control blood pressure. A hormone called erythropoietin tells the bone marrow to make red blood cells, and one called calcitriol helps to keep bones strong.
Inside each kidney is approximately one million tiny filtering units called nephrons. Each nephron has a glomerulus and tubules. The glomerulus is a series of specialized capillary loops where water and small particles are filtered from the blood. The waste and extra fluids then travel through the tube-like structure of the tubules where several processes take place to turn those fluids into urine. The tubules lead to the collecting duct where the urine is drained into a funnel-shaped sac called the renal pelvis. Each kidney has a ureter that connects the renal pelvis to the bladder. The urine from the kidneys flows down the ureters into the bladder and is then passed out of the body through the urethra.
It is amazing when you think of everything the kidneys do for the body. It’s even more amazing that some people are born with only one kidney and it does a fine job of filtering blood, producing urine and regulating certain functions all by itself. There are situations when kidneys can no longer perform their job, which leads to kidney failure. We are fortunate, however, to live in a time when treatments such as dialysis and kidney transplant will keep the body alive after kidneys stop functioning