Kidney failure can be a gradual process and symptoms may not be seen until the disease is very advanced. Kidney failure occurs when the kidneys are no longer able to remove waste and maintain fluid balance in the body. Without some form of treatment, this would result in death.
The two types of treatment for kidney failure are dialysis or transplantation.
There are two different kinds of dialysis: hemodialysis or peritoneal dialysis. During hemodialysis, tubes connect the patient to a machine that filters the blood.
Hemodialysis is usually done three times a week for 3-4 hours each time. It is usually done at a dialysis center, although in some cases families can be trained to do the treatment at home.
People on hemodialysis must adhere to a strict diet, restrict their fluid intake and may feel unwell especially after dialysis.
Peritoneal dialysis uses the abdominal cavity membrane called the peritoneal membrane to filter the blood. During this type of dialysis, a tube is placed permanently into the abdomen.
During treatment, a fluid called dialysate is infused into the abdominal cavity. Waste and extra fluid move into the dialysate and after a few hours, the fluid is drained out.
This is called an exchange. Patients can do 4-5 exchanges per day, or the exchanges may be done at night with the help of a machine that cycles the exchanges while the person is sleeping.
Kidney transplantation is the third option for people with chronic kidney failure. In a kidney transplant, the donated kidney is surgically placed in the lower abdominal area and replaces the function of the natural kidneys.
The patient’s own kidneys are usually left in place. The recipient of a kidney transplant must take medicine for the life of the transplanted kidney to prevent rejection.
Kidney transplant recipients must alsofollow strict schedules for lab testing and doctor visits.
What are the kidneys?
The kidneys play key roles in body function, not only by filtering the blood and getting rid of waste products, but also by balancing the electrolyte levels in the body, controlling blood pressure, and stimulating the production of red blood cells.
The kidneys are located in the abdomen toward the back, normally one on each side of the spine.
They get their blood supply through the renal arteries directly from the aorta and send blood back to the heart via the renal veins to the vena cava.
(The term “renal” is derived from the Latin name for kidney.)
The kidneys have the ability to monitor the amount of body fluid, the concentrations of electrolytes like sodium and potassium, and the acid-base balance of the body.
They filter waste products of body metabolism, like urea from protein metabolism and uric acid from DNA breakdown.
Two waste products in the blood usually are measured; 1) blood urea nitrogen (BUN), and 2) creatinine (Cr).
When blood flows to the kidney, sensors within specialized kidney cells regulate how much water to excrete as urine, along with what concentration of electrolytes.
For example, if a person is dehydrated from exercise or from an illness, the kidneys will hold onto as much water as possible and the urine becomes very concentrated. When adequate water is present in the body, the urine is much more dilute, and the urine becomes clear.
This system is controlled by renin, a hormone produced in the kidney that is part of the fluid and blood pressure regulation systems of the body.
Kidneys are also the source of erythropoietin in the body, a hormone that stimulates the bone marrow to make red blood cells. S
pecial cells in the kidney monitor the oxygen concentration in blood. If oxygen levels fall, erythropoietin levels rise and the body starts to manufacture more red blood cells.
Urine that is made by each kidney flows through the ureter, a tube that connects the kidney to the bladder. Urine is stored within the bladder, and when urination occurs, the bladder empties urine through a tube called the urethra.
Causes of kidney failure
Kidney failure may occur from an acute situation that injures the kidneys or from chronic diseases that gradually cause the kidneys to stop functioning.
In acute renal failure, kidney function is lost rapidly and can occur from a variety of insults to the body. Since most people have two kidneys, both kidneys must be damaged for complete kidney failure to occur.
Fortunately, if only one kidney fails or is diseased it can be removed, and the remaining kidney may continue to have normal kidney (renal) function. If a both patient’s kidneys are injured or diseased, a donor kidney(s) may transplanted.
The list of causes of kidney failure is often categorized based on where the injury has occurred.
Prerenal causes (pre=before + renal=kidney) causes are due to decreased blood supply to the kidney. Examples of prerenal causes of kidney failure are:
- Hypovolemia (low blood volume) due to blood loss
- Dehydration from loss of body fluid (for example, vomiting, diarrhea, sweating, fever)
- Poor intake of fluids
- Medication, for example, diuretics (“water pills”) may cause excessive water loss
- Abnormal blood flow to and from the kidney due to obstruction of the renal artery or vein.
Renal causes of kidney failure (damage directly to the kidney itself) include:
- Sepsis: The body’s immune system is overwhelmed from infection and causes inflammation and shutdown of the kidneys. This usually does not occur with simple urinary tract infections.
- Medications: Some medications are toxic to the kidney including:
- Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen (Advil, Motrin, and others), and naproxen (Aleve, Naprosyn)
- Antibiotics like aminoglycosides gentamicin (Garamycin), tobramycin
lithium (Eskalith, Lithobid)
- Iodine-containing medications such as those injected for radiology dye studies
- Rhabdomyolysis: This is a situation in which there is significant muscle breakdown in the body, and the damaged muscle fibers clog the filtering system of the kidneys. Massive muscle injury may occur because of trauma, crush injuries, and burns. Some medications used to treat highcholesterol may causerhabdomyolysis.
Acute glomerulonephritis or inflammation of the glomeruli, the filtering system of the kidneys. Many diseases can cause this inflammation including:
- Systemic lupus erythematosus
- Wegener’s granulomatosis
- Goodpasture syndrome.
- Hemolytic uremic syndrome: This condition results from abnormal destruction of red blood cells. It most often occurs in children after certain infections, but also may be caused by medications, pregnancy, or can occur for unknown reasons.
Post renal causes of kidney failure (post=after + renal= kidney) are due to factors that affect outflow of the urine:
- Obstruction of the bladder or the ureters can cause back pressure because the kidneys continue to produce urine, but the obstruction acts like a dam, and urine backs up into the kidneys. When the pressure increases high enough, the kidneys are damaged and shut down.
- Prostatic hypertrophy or prostate cancer may block the urethra and prevents the bladder from emptying.
- Tumors in the abdomen that surround and obstruct the ureters.
- Kidney stones. Usually, kidney stones affect only one kidney and do not cause kidney failure. However, if there is only one kidney present, a kidney stone may cause the remaining kidney to fail.
Chronic renal failure develops over months and years. The most common causes of chronic renal failure are related to:
- poorly controlled diabetes,
- poorly controlled high blood pressure, and
- chronic glomerulonephritis.
Less common causes of chronic renal failure include:
- Polycystic kidney disease
- Reflux nephropathy (damage caused by urine backflow from the bladder into the ureters and kidney)
- Nephrotic syndrome
- Alport’s disease
- Interstitial nephritis
- Kidney stones
- Prostate disease
Signs and Symptoms
Initially, kidney failure may be not produce any symptoms (asymptomatic).
As kidney function decreases, the symptoms are related to the inability to regulate water and electrolyte balances, clear waste products from the body, and promote red blood cell production.
If unrecognized or untreated, the following symptoms of kidney failure may develop into life-threatening circumstances.
- Shortness of breath
- Generalized swelling (edema)
- Generalized weakness due to anemia
- Loss of appetite
- Congestive heart failure
- Metabolic acidosis
- High blood potassium (hyperkalemia)
- Fatal heart rhythm disturbances (arrhythmias) including ventricular tachycardia and ventricular fibrillation
- Rising urea levels in the blood (uremia) may lead to brain encephalopathy, pericarditis (inflammation of the heart lining), or low calcium blood levels (hypocalcemia)
Prevention is always the goal with kidney failure. Chronic diseases such as hypertension (high blood pressure) and diabetes are devastating because of the damage that they can do to kidneys and other organs.
Lifelong diligence is important in keeping blood sugar and blood pressure within normal limits. Specific treatments depend upon the underlying diseases.
Once kidney failure is present, the goal is to prevent further deterioration of renal function. If ignored, the kidneys will progress to complete failure, but if underlying illnesses are addressed and treated aggressively, kidney function can be preserved, though not always improved.
In chronic kidney disease (CKD), doses and dosing intervals of drugs that are excreted or metabolized renally should be adjusted according to the residual glomerular filtration rate (GFR).
Some drugs are contraindicated in moderate to severe renal impairment because of potentially serious effects from drug or metabolite accumulation.
Routine consultation of the appropriate references should be undertaken when prescribing any new drug to a patient with CKD.
For patients undergoing dialysis, it is extremely important to carefully check dosing guides or monitor levels when possible. These modalities differ in their clearance of drugs.
Hospitalized patients undergoing other types of continuous renal replacement therapy also require close monitoring. An experienced clinical pharmacist can be invaluable in assisting to design individualized dosing regimens.
Treatments for the pathologic manifestations of CKD include the following:
- Hyperphosphatemia: Dietary phosphate binders and dietary phosphate restriction
- Hypocalcemia: Calcium supplements and possibly calcitriol
- Hyperparathyroidism: Calcitriol or vitamin D analogues
- Anemia: Iron replacement therapy and erythropoiesis-stimulating agents