Chronic kidney disease, also known as chronic renal failure, chronic renal disease, or chronic kidney failure, is a slow progressive loss of kidney function over a period of several years. Eventually the patient has permanent kidney failure.
Chronic kidney disease is much more common than people realize, and often goes undetected and undiagnosed until the disease is well advanced and kidney failure is fairly imminent. It is not unusual for people to realize they have chronic kidney failure only when their kidney function is down to 25% of normal.
As kidney failure advances and the organ's function is seriously impaired, dangerous levels of waste and fluid can rapidly build up in the body. Treatment is aimed at stopping or slowing down the progression of the disease - this is usually done by controlling its underlying cause.
If chronic kidney failure ends in end-stage kidney disease, the patient will not survive without dialysis (artificial filtering) or a kidney transplant.
According to the NHS (National Health Service), UK, approximately 1 to 4 in every 1,000 British people are affected by chronic kidney disease. The average age of a British person with the disease is 77. In the UK, health authorities report that people of South Asian, African and Afro-Caribbean descent are at a higher risk of developing the disease, compared to other people.
Risk factors for chronic kidney disease
A risk factor is a condition, situation or environment which raises the risk of developing a disease or condition. For example, obese people have a higher risk of developing Diabetes Type II. Therefore, obesity is a risk factor for Diabetes Type II.
The following conditions or situations are linked to a higher risk of developing kidney disease:
- A family history of kidney disease
- Age - chronic kidney disease is much more common among people over 60 years of age
- Bladder obstruction
- Chronic glomerulonephritis
- Congenital kidney disease (kidney disease which is present at birth)
- Diabetes - the most common risk factor in Europe, Japan, North America, and probably most other parts of the world.
- Hypertension (high blood pressure)
- Lupus erythematosis
- Overexposure to some toxins
- Sickle cell disease
- Some medications
Symptoms of chronic kidney disease
A symptom is something the patient feels and reports, while a sign is something other people, including a doctor or a nurse may detect. For example, pain may be a symptom while a rash may be a sign.
Chronic kidney failure, as opposed to acute kidney failure, is a slow and gradually progressive disease. Even if one kidney stops functioning, the other can carry out normal functions. It is not usually until the disease is fairly well advanced and the condition has become severe that signs and symptoms are noticeable; by which time most of the damage is irreversible.
It is important that people who are at high risk of developing kidney disease have their kidney functions regularly checked. Early detection can significantly help prevent serious kidney damage.
The most common signs and symptoms of chronic kidney disease include:
- Blood in urine
- Dark urine
- Decreased mental alertness
- Decreased urine output
- Edema - swollen feet, hands and ankles
- Fatigue (tiredness)
- Hypertension (high blood pressure)
- Itchy skin, can become persistent
- Loss of appetite
- Male inability to get or maintain an erection (erectile dysfunction)
- More frequent urination, especially at night
- Muscle cramps
- Muscle twitches
- Pain on the side or mid to lower back
- Panting (shortness of breath)
- Protein in urine
- Sudden change in bodyweight
- Unexplained headaches
Causes of chronic kidney disease
Our kidneys carry out the complex system of filtration in our bodies - excess waste and fluid material are removed from the blood and excreted from the body. Our kidneys get their blood and oxygen supply from the renal arteries, which are branches of the abdominal aorta (another artery). When it enters the kidneys, blood goes through smaller and smaller blood vessels - the smallest ones being the glomeruli (tiny capillary blood vessels which are arranged in tufts).
It is in the glomeruli that blood is filtered - waste, fluids and other substances are extracted and cross into miniscule tubules, from which the bloodstream reabsorbs what the body is able to reuse. What the body cannot reuse - waste - is excreted in our urine.
In most cases our kidneys are able to eliminate all waste materials that our body produces. However, if the blood flow to the kidneys is affected, of the tubules or glomeruli are not working properly because of damage or disease, or if urine outflow is obstructed, problems can occur.
In the majority of cases progressive kidney damage is the result of a chronic disease (a long-term disease), such as:
- Diabetes - chronic kidney disease is linked to both Diabetes Types I and II. If the patient's diabetes is not well controlled, excess sugar (glucose) can accumulate in the blood. Glucose can damage the glomeruli.
The risk of chronic kidney disease is higher among patients with Diabetes Type I. Doctors say that approximately 20% to 40% of patients with Diabetes Type I develop kidney disease by the time they are 50 years of age.
Kidney disease is not common during the first ten years of diabetes; it more commonly occurs between years 15 to 25 after diagnosis (of diabetes). However, as treatment methods improve, experts say that the number of diabetes patients developing kidney disease is falling.
- Hypertension (high blood pressure) - high blood pressure can damage the glomeruli.
- Obstructed urine flow - if urine flow is obstructed it can back up into the kidney from the bladder (vesicoureteral reflux). Blocked urine flow increases pressure on the kidneys, and undermines their function. Possible causes include an enlarged prostate, kidney stones, or a tumor.
- Kidney diseases - including polycystic kidney disease, pyelonephritis, or glomerulonephritis.
- Kidney artery stenosis - the renal artery narrows or is blocked before it enters the kidney.
- Certain toxins - including fuels, solvents (such as carbon tetrachloride), and lead (and lead-based paint, pipes, and soldering materials). Even some types of jewelry have toxins which can lead to chronic kidney failure.
- Fetal developmental problem - if the kidneys do not develop properly in the unborn baby while it is developing in the womb.
- Systemic lupus erythematosis - an autoimmune disease. The body's own immune system attacks the kidneys as though they were foreign tissue.
- Malaria and yellow fever
- Some medications - overuse of, for example, NSAIDs (non-steroidal anti-inflammatory drugs), such as aspirin or ibuprofen.
- Illegal drug abuse - such as heroin or cocaine.
- Injury - a sharp blow or physical injury to the kidney(s)
On the next page we look at the diagnosis of chronic kidney disease. On the final page we discuss treatments for chronic kidney disease and prevention.