Kidneys are the most significant component of the human renal system. They are indispensable to our body for they act as a multi-functional unit performing a wide variety of bodily functions. These are relatively small organs but receive about 20% to 25% of the heart’s output. It is quite likely the kidneys may get affected by various diseases or even fail. Read more about the kidneys here.
Kidney failure is the last and most severe stage of chronic kidney disease also known as end-stage renal disease or ESRD, in short.
There are five different types of kidney failures :
Acute prerenal kidney failure:
Kidneys fail due to a sudden reduction in blood flow causing hypoperfusion. Kidneys play no part in their own failure. Various causes include severe blood loss, dehydration, pancreatitis, etc.
Acute intrinsic kidney failure:
This type of failure can result from a direct physical impact on the kidneys, insufficient oxygen supply, and toxin overload. It can be treated by diagnosing and correcting the failure.
Chronic prerenal kidney failure:
Insufficient blood flow through kidneys over a long period of time causes the kidneys to shrink and eventually fail.
Chronic intrinsic kidney failure:
This happens when there’s long-term damage to the kidneys due to intrinsic kidney disease developing from direct trauma to the kidneys, such as severe bleeding or a lack of oxygen.
Chronic post-renal kidney failure:
It is caused by the blockage of the urinary tract over a long period of time exerting pressure on kidneys and eventually damaging them.
Why do kidneys fail?
Kidney failure may occur due to numerous reasons, most prominent amongst all being diabetes and hypertension (high blood pressure).
Diabetes mellitus is a condition with high blood glucose (sugar) levels. Over time, persistent high sugar levels in the blood damage the tiny filtering units within each kidney, eventually causing kidney failure. Around 20-30% of people with diabetes develop kidney disease (diabetic nephropathy) whether they use insulin or not. Diabetics are also susceptible to other kidney problems such as renal artery stenosis which causes the narrowing of the arteries to the kidneys.
Hypertension or high blood pressure is the second leading cause of kidney failure. Kidneys use blood vessels to extract waste and extra fluids from the blood. They need a proper supply of oxygen and nutrients to function well. But hypertension affects the blood vessels causing them to narrow, weaken or harden. Thus, kidneys lose their ability to filter blood and regulate body fluids properly.
Other common causes:
Though there are other causes of kidney failure one should be aware of which are as follows:
- Autoimmune diseases (the anomaly in which the immune system destroys its own cells and tissues) such as Lupus, IgA nephropathy.
- Genetic diseases that you are born with may also cause kidney failure.
- A nephrotic syndrome due to which excess protein is excreted through urine may also cause serious kidney problems and failure after an extent.
- Urinary tract problems
- Various environmental factors may cause functional and structural problems leading to kidney diseases or outright failure.
Causes of acute renal failure:
Acute renal failure occurs when kidneys suddenly stop filtering excess salt, fluids and waste materials from your blood. Sudden failure of kidney or acute renal failure may occur due to the following reasons:
- Heart attack causes consequential damage to the veins connected to kidneys and eventually affects the functioning of kidneys as well
- Chronic abuse of drugs and alcohol may lead to severe kidney damage
- Insufficient blood flow through the kidneys
- Severe or sudden dehydration
- Acute tubular necrosis (ATN), where these small tubules inside the kidneys undergo sudden injury
Symptoms of kidney failure:
Symptoms usually are not evident in the initial stages of kidney failure. They surface only after significant damage has been incurred due to excessive fluid and waste accumulation. Various symptoms among these may be experienced in case of kidney failure-
- Fluid retention causing swelling in feet and ankles.
- Insufficient or excessive urination and at times change in urine colour.
- Abdominal and back pain
- Persistent nausea and vomiting.
- Significant loss of appetite.
- Itching and rashes
- Nose bleeding and muscle cramps
- Diarrhea, fever and consistent fatigue.
- Pain or pressure in the chest.
- Frequent seizures
- Even coma under extreme circumstances
Occasionally there are no warning symptoms in case of acute renal failure. It is detected by running lab tests such as creatinine test and treated by either dialysis or transplant depending upon what stage it has reached and if the patient is eligible or not.