Definition and Overview
Also referred to as renal insufficiency or renal failure, kidney failure refers to a medical condition in which the kidneys, a pair of vital organs, do not function the way they should.
The kidneys are an integral part of the urinary system. The bean-shaped organs found near the adrenal glands contain thousands of nephrons that filter blood and remove excess water and waste products, including those produced by the cells' metabolic processes. Their function can be likened to passing water with small stones onto a fine mesh. The waste products are then converted into urine that is eliminated by the body.
Aside from getting rid of excess water and sodium (salt), the kidneys also maintain the desired blood pressure and electrolyte balance. The organs also create erythropoietin, which activates the bone marrow to create red blood cells. These cells carry the much-needed oxygen to various parts of the body.
A variety of reasons, however, can make the kidneys ineffective. This simply means they cannot filter waste products efficiently and, in serious cases, they shut down. This can then lead to the buildup of toxic wastes in the body, harming other vital organs, and increasing blood pressure, which can potentially cause a severe heart condition or stroke. Kidney failure can lead to coma or death if not managed as soon as possible.
There are two types of kidney failure: acute and chronic. Acute kidney failure occurs suddenly usually due to trauma. Often, this case is reversible. Chronic renal failure, meanwhile, happens gradually and is often irreversible.
Depending on the severity of kidney failure, common treatment options are dialysis and kidney transplant.
Causes of Condition
Kidney failure can be caused by many factors. These include:
Injury – Injury to the kidneys (such as those due to an accident) can sometimes cause acute renal failure.
Chronic kidney disease (CKD) – CKD is a progressive kidney disease involving the decreased function of the kidneys. It may take months to years before the symptoms appear. In the majority of cases, the kidneys have already lost significant function by the time the symptoms appear or the patient is diagnosed.
Polycystic kidney disease (PKD) – PKD is an inherited kidney disease characterized by the formation of several non-cancerous cysts or sacs in the kidneys. Although they can be removed, they can also return. As the cysts keep on returning, they can cause undue damage to the kidneys. The cysts can also burst, leading to bleeding and pain.
Underlying conditions – Certain conditions such as liver failure or heart attack can impair the flow of blood through the kidneys, preventing them from working properly. Diseases like lupus and HIV may also complicate and cause kidney failure, as well as malignant tumors that grow on the organ.
Certain factors that can also increase the likelihood of kidney failure, include:
- Medication intake (certain components of the medicine may cause organ damage)
- Diabetes (the metabolic condition characterized by the presence of high insulin levels in the bloodstream can damage kidney nerves, leading to diabetic nephropathy)
- Sedentary lifestyle
- Heart disease
A common symptom of kidney failure is a change in urine output. Usually, there is a decreased production of urine, or the patient feels the urge to urinate often even at night. He may also feel as if he has not emptied his bladder. In certain situations, however, the kidneys can continue to produce same urine output even if they are already damaged.
Other signs and symptoms are:
- Flank pain (or pain in the lower back, where the kidneys are found)
- Edema or fluid retention that causes swelling of the arms and legs (this is due to the poor filtration of water)
- Itchiness of the skin (due to the buildup of toxic wastes in the body)
- Confusion or disorientation
- Shortness of breath
- High blood pressure
- Excessive amount of protein in the blood
- Difficulty in concentration
- Anemia (due to the decreased production of red blood cells that carry oxygen)
- Muscle cramps or paralysis
- Weight loss
- Slow or abnormal heart rate
Who to See and Treatments Available
People who have problems with their kidneys are referred to nephrologists, who specialize in kidney care. Different types of tests are performed to confirm kidney failure such as blood tests to see if there is a buildup of toxins or phosphates in the body and urinalysis to detect the presence and level of protein and blood in the urine.
A unique test called glomerular filtration test (GFR) measures how well the kidneys filter blood wastes. It is based on the creatinine level and factors such as weight, age, and gender. A score of 15 and below suggests the kidneys are failing and intervention is necessary.
In the event of kidney failure, the patient has to undergo either dialysis or kidney transplant. In dialysis, the patient is attached to a machine that substitutes for the kidneys. It filters the blood as it passes through the machine and goes back into the body.
There are two types of dialysis, namely, hemodialysis and peritoneal dialysis. Each has its own advantages and disadvantages, so it is essential the nephrologist is able to discuss them comprehensively to the patient.
Depending on the severity of the condition, the patient may go through dialysis for a few months to several years. Some people can be on dialysis for more than two decades.
If the kidneys are already irreparable and dialysis does not work, the patient may then proceed with kidney transplant, in which a kidney is obtained from either live or deceased donor.
The patient is signed up under the hospital’s kidney transplant program, and a coordinator helps the patient look for a donor. Because of the long wait list, it may take weeks to a year before a donor can be found. At least 90% of those who receive new kidneys live for 5 years or more. Nevertheless, as the new kidneys can be attacked by the body’s immune system, patients take lifelong medications like immunosuppressants, which may also cause damage to the body in the long term.
Molitoris BA. Acute kidney injury. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 122.
Sharfuddin AA, Weisbord SD, Palevsky PM, Molitoris BA. Acute kidney injury. In: Taal MW, Chertow GM, et al, eds. Brenner & Rector's The Kidney. 9th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 30.