The kidneys are two bean-shaped organs that lie in the abdominal cavity. They are an essential part of the urinary system. The key function of kidneys is to filter blood and form urine. This process removes water-soluble metabolic waste products from the body.
In addition to formation of urine, the kidneys also play a key role in maintaining homeostasis in the body. Homeostasis means maintenance of certain constant conditions in the body that make biochemical life processes possible. Maintenance of electrolyte balance, acid-base balance, fluid balance and regulation of blood pressure – all depend on properly functioning kidneys.
The cells of kidneys also produce some critical hormones, such as erythropoietin. Erythropoietin stimulates the production of red blood cells in bone marrow. Cells in kidneys also secrete the renin enzyme, which is a critical part of the system that maintains proper blood pressure in the circulatory system.
What is kidney failure?
Kidney failure is where the function of the kidney declines and eventually ceases. As can been surmised from the variety of functions that the kidneys perform, it isvital to the survival of human body. Any injury or disease that adversely affects kidney function can affect waste disposal, homeostasis and other vital functions of body. Kidney failure is a life-threatening condition.
Depending on the time it takes for kidney damage to occur, cases of kidney failure can be classified into acute and chronic conditions. Acute kidney failure occurs suddenly, and results in intense signs and symptoms. The presence of these obvious signs and symptoms prompt the affected individual to seek medical treatment. Due to prompt diagnosis and treatment, cases of acute kidney failure can be treated in time, and the condition may be reversible.
Chronic kidney failure, on the other hand, happens over a long period of time. The onset of chronic kidney failure may be difficult to identify because the early stages of the condition may not display any obvious signs and symptoms. Signs and symptoms of chronic kidney failure only become evident when the disease worsens and affects kidney functions drastically.
By this time, the condition may have progressed to end stage renal disease. Chronic kidney failure is mostly irreversible. The patient needs to be kept on dialysis till a kidney transplant can be arranged. End stage renal disease is mostly seen in people above 65 years of age.
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Signs of Kidney Failure
Kidney failure can occur due to a variety of causes. Disruption of kidney function usually occurs as a result of damage to nephrons in kidneys, impairment of blood flow through kidneys, and obstruction to urine outflow from the kidneys. The causes include both acute and chronic conditions, such as trauma, infections, autoimmune disorders, high blood pressure, and uncontrolled diabetes. Kidneys may also get damaged due to toxic effects of certain drugs and metals.
Reduced urine output
The key function of kidneys is to remove water-soluble metabolic waste from the body. Metabolic waste products are generated in different tissues of the body as a result of normal biochemical life processes. The metabolic wastes from different parts of the body find their way into the bloodstream. The blood carrying these metabolic wastes then flows through multiple tiny filtration units present in kidneys. These tiny filtration units, known as nephrons, are the basic functional units of kidneys.
Filtration of blood through nephrons results in the formation of urine, which is composed of metabolic waste products meant for excretion from the body. During the process of urine formation, the nephrons also reabsorb some substances that are useful to the body (such as amino acids, glucose, salts and water) and return them to the blood.
When the kidneys fail, urine output may decrease dramatically (a condition known as oliguria), or stop altogether (a condition known as anuria). Also, damage to the filtration units of kidneys may result in excretion of useful substances that are normally reabsorbed by the kidneys.
Swollen hands and feet
Retention of fluid in the body is a characteristic sign of kidney failure. However, it is important to note that fluid retention may also occur in other diseases that do not involve kidneys. The most obvious signs of fluid retention in the body can be seen in the form of swelling in the peripheral regions (such as hands, feet, and legs). Swelling is not restricted to the extremities though, and may also occur in other regions of the body. Fluid may accumulate in abdomen (technically called ascites), lungs (technically called pulmonary edema), or throughout the body (technically called anasarca).
Shortness of breath
Excessive fluid accumulation throughout the body may also affect the lungs. Fluid accumulation in the lungs hamper the process of gaseous exchange that occurs during the process of breathing. This would reduce the amount of oxygen that gets into the blood. The consequence of such a state is breathlessness. The extent of breathlessness depends on the extent of fluid accumulation in lungs. In some cases, an individual may feel breathless only upon lying down. In severe cases, abnormal breathing sounds may also be present.
Nausea and vomiting
Both acute and chronic kidney failure can result in nausea and vomiting. Due to kidney dysfunction, accumulation of wastes and toxins occurs throughout the body. Stimulation of certain regions of the brain by these accumulated wastes and toxins elicits feelings of nausea. In severe cases, vomiting may also occur. Vomiting is especially seen in cases of acute kidney failure.
Widespread accumulation of wastes and toxins in body also result in an itchy feeling all over the body. This condition is known as generalized pruritis. The itching that results from kidney failure is not accompanied by rashes on the skin. Scratching the itch furiously may lead to damaged skin and infections. Widespread itching also results in disturbed sleep during night.
Kidney failure is also accompanied by signs of fatigue. Tiredness in this condition is not due to physical exertion, and happens even at rest. The affected person may feel drowsy all the time, and display an unwillingness to move around. It is important to mention here that fatigue is not specific to kidney failure, and can occur in a variety of other medical conditions.
High blood pressure
Kidneys play a critical role in the regulation of blood pressure. Blood pressure can increase to abnormally high levels in kidney failure. This rise in blood pressure is difficult to manage with anti-hypertension drugs.
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