Uremia: Signs, Symptoms and Causes of Kidney Failure

Uremia is defined as malfunctioning of kidneys and subsequent accumulation of urea in blood. The chief component of mammalian urine is urea. Urea is the chief excretory product in ureotelic animals like human beings.

• Generally, urea is found in urine, but sometimes its quantity is elevated in blood also.
• Urine in the blood is simply described as uremia (urine + haima, where haima is blood).
• This condition leads to renal or kidney failure.
• The term uremia was first used by Pierre Adolph Perry.

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Key Words: Uremia, Kidney, Kidney Failure, Urea, Symptoms, Blood, Disease.

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What is Kidney Failure? 

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The unwanted waste materials of our body that are by-products of metabolism are removed by the kidney. Here, urea is a very significant by-product of metabolism.

• Kidneys play an integral role in filtering out the unwanted waste from the bloodstream.
• It sends the waste product further to the bladder and ureter for excretion.
• Consequently, when the kidneys fail to do so, the waste materials accumulate in the bloodstream that lead to azotemia.

The condition in which blood contains less quantity of urea due to less damage to kidneys is called azotemia. Uremia cannot be detected at this stage, because symptoms are hardly manifested.

• The glomerulus is a cup-shaped apical part of a nephron.
• Ultrafiltration of blood takes place here. Nephrons are microscopic functional units of kidneys.
• Clinically glomerular filtration rate (GFR) is taken as a criterion to look at the functioning of kidneys.
• A healthy kidney has GFR between 100-120 mL/min (milliliters per minute).
• A diseased kidney shows 60 mL/min. A failed kidney shows 15 mL/min.
• So, if a patient with a GFR of 15 mL/min or below can be regarded as suffering from uremia.

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Uremia or Uremic Syndrome

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When azotemia becomes serious, then we call it uremia. In other words, uremia is the condition in which excess amounts of urea are found in the blood.

• Uremia can also be described as a uremic syndrome, as the disorder is accompanied by a set of symptoms.
• It generally happens to patients over 30 years old, and with less than 50% kidney function.
• So kidney or renal failure is the final result of uremia.

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Symptoms of Uremia

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The general symptoms of uremia include weakness, fatigue, headache, nausea, loss of appetite, shallow respiration, muscle cramps, and mental retardation.

• Ammonia smell in the mouth is also a common symptom.
• White plaques in the mouth and on the skin also indicate uremia.
• In children, dental problems may occur.
• Low blood sugar levels (hypoglycemia) may also occur.
• As the condition becomes worse, the patient may suffer from a coma and eventually faces death. 

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Causes of Uremia

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Uremia is caused due to several reasons. There may be increased production of urea in the liver, low blood pressure (hypotension), heart failure, excessive loss of fluid substances and minerals from the body (dehydration), etc. Ultimately, it is due to decreased functioning or failure of kidneys. Chronic kidney disease (CKD) or acute kidney failure (AKF) leads to uremia.

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Clinical Diagnosis of Uremia

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Increased levels of urea nitrogen and creatinine in the blood indicate uremia. Medical experts suggests following tests to diagnose uremia

• Test for GFR- GFR levels indicate the condition of the kidney.
• Urine, radioisotope tests, and ultrasonography can also be conducted to diagnose uremia. 
• One can go for creatinine and BUN blood test as well.

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Mechanism Leading to Uremia

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The kidney is the chief excretory organ in the body. It eliminates harmful waste substances from the body.

• When the kidney fails to filter out harmful substances, there will be chances of retention of these compounds in the body and blood system.
• These compounds are called uremic toxins.
• Some of these harmful compounds are urea, creatinine, cyanates, beta2-microglobulin, dimethylamine, parathyroid hormone (PTH), etc.
• These toxins affect the regulatory functions of the body.
• Excretion of both acidic and nitrogenous compounds will be affected.
• There will be an imbalance in fluids, electrolytes, and hormones.
• There will be a failure in the functioning of different body systems such as excretory and digestive systems. 

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Effect of Uremia

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Chronic renal failure is followed by recurring kidney diseases. Stones or cysts in kidneys (nephrolithiasis and polycystic kidney disease), enlarged prostate gland, inflammation of kidney parts, type1 or type 2 diseases will be the other effects.

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Treatment of Uremia 

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There are three ways of treating a uremic patient - medication, dialysis, and kidney transplant. 

Dialysis

Dialysis is the chief treatment for kidney or Renal Failure.

• Uremia patients must need this. Dialysis is a procedure to remove harmful substances from the blood when the kidneys stop working properly.
• It controls blood pressure and balances levels of minerals and vitamins in the body.
• The process of dialysis is again of two kinds - peritoneal dialysis and hemodialysis.

Peritoneal Dialysis (PD)

The serous membrane that lines the abdominal cavity is called the peritoneum. In peritoneal dialysis, the peritoneal membrane is used to exchange fluid and dissolved substances like electrolytes and harmful substances with the blood of the person.

• This procedure is useful during the initial stages or patients with heart problems.
• In this method, a tube called a catheter is introduced into the lower abdomen.
• Dialysate solution containing sodium chloride, hydrogen carbonate, and glucose is introduced into the abdomen.
• This solution absorbs the majority of harmful substances into it.
• Finally, the fluid will be drained out of the body to get rid of harmful substances.

Haemodialysis

It is used during end-stage kidney failure. It is a clinical procedure where a dialysis machine and dialyzer are used. Dialyzer acts as an artificial kidney.

• It consists of a coiled cellophane tube surrounded by dialyzing fluid having the same composition as that of blood plasma except for blood cells.
• The porous cellophane acts as a semipermeable membrane.
• Procedure involves the diffusion of solutes across a semipermeable membrane.
• During the treatment, two needles are inserted into a convenient artery in the arm.
• Each needle in turn is connected to a plastic tube.
• plastic tubes are connected to the dialyzer.
• An anticoagulant like heparin is used during the process.
• Blood cells and plasma proteins remain in the blood, whereas urea, creatinine, and other harmful substances pass through the membrane and are removed. 

Kidney transplant

A kidney transplant or renal transplant is a surgical procedure, where a healthy kidney is placed in the place of a failed kidney.

• A healthy kidney is collected from a living person or a person in a coma.
• The kidney from a close relative has more chances of successful grafting (more chances of compatibility).
• This is the ultimate procedure to save a person's life.
• A kidney transplant is generally done on a patient with end-stage renal disease (ESRD).
• Through a modern technique of regenerative medicine, the damaged kidney can be healed.

Prevention of Uremia

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Prevention is better than cure.

• Anything that affects the proper functioning of the liver, heart, and kidney should carefully be avoided.
• Uremia can be prevented by healthy lifestyles.
• Regular exercise, taking in healthy food and regular testing for diabetes and blood pressure prevent uremia to a greater extent.
• Reduce consumption of spicy food, red meat, and cheese.
• Abstain from smoking and alcohol to avoid damage to the liver, heart, and kidneys. 

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Things to Remember

• The chief component of mammalian urine is urea.
• Urine in the blood is called uremia.
• The term uremia was coined by Perry.
• Less severe uremia is called azotemia.
• Uremic syndrome is a collection of many symptoms due to high levels of urine in blood.
• Uremia is generally reported in persons of more than 30 years of age.
• Glomerular Filtration Rate (GFR) of less than 50% results in uremia.
• Less than 15% means kidney failure.
• Diabetes and cardiovascular diseases may be the root causes of uremia.
• Uremic toxins include urea, beta2-microglobulin, and parathyroid hormone.
• Almost all body systems will be affected due to uremia.
• Uremia can be treated through medication, dialysis, and kidney transplant.
• Peritoneal or hemodialysis are used as per the condition of uremia.
• A kidney transplant is a must for ESRD (end-stage renal disease).
• Uremia can be prevented by regular exercise, a healthy lifestyle, and timely treatment of diabetes and cardiovascular diseases.