Kidney damage can occur through various ways, from trauma and infections to autoimmune diseases and diabetes. These kidney diseases can be acute or chronic. As a person gets older the risk of chronic kidney disease increases. As many as 7 in 10 Americans over the age of 70 have some degree of chronic kidney disease whereas it affects only about 1 in 20 Americans in their thirties.
Read more on kidney damage.
As with any other organ damage, the signs and symptoms of kidney disease and damage are due to disturbances in kidney function. It is therefore important to first understand the functions of healthy kidneys:
- Maintains the water and electrolyte balance.
- Removes wastes and other toxic substances from the body.
- Controls the production of red blood cells and one form of vitamin D.
- Regulates the blood pressure.
The extent to which these kidney functions are disrupted depends on the type and severity of the kidney disease. The duration of kidney disease is also a factor in determining the symptoms that become evident. However, many people with varying degrees of kidney damage and disease are not aware of the underlying cause of the kidney problem. Therefore relying solely on the signs and symptoms of kidney disease can lead to a delayed diagnosis.
Nevertheless it is important to be aware of the signs of kidney damage and disease. Seeking medical attention as early as possible can significantly improve the outcome. Various diagnostic investigations like a urea and electrolyte (U&E) blood test are better indicators of kidney disease than the clinical presentation.
Read more on signs of kidney failure.
Abnormal Urine Volume and Urination
One of the most obvious signs of kidney failure is changes in the amount of urine produced and the number of times a person urinates in a day. With kidney failure there is reduced urine output (oliguria) and sometimes no urine altogether (anuria). Since the kidneys are not functioning properly it can therefore not produce sufficient urine.
However, the opposite may occur in certain kidney diseases like interstitial nephritis and pyelonephritis. In these instances there may be increased urine production (polyuria) as water cannot be reabsorbed and preserved. Polyuria leads to frequent urination.
Fluid Retention and Swelling of Legs
In kidney damage and diseases where urine production is reduced, the fluid that is not passed out with urine is retained within the body. It is first noticeable in the lower extremities. There may be swelling of the feet and ankles and eventually of the lower legs.
If this fluid retention worsens then there may also be swelling of the abdomen (ascites) and even throughout the body (anasarca). A person may appear bloated as the fluid accumulates in the tissue spaces. There may also be a rapid albeit moderate increase in body weight due to the retention of fluid.
Fatigue, Drowsiness and Weakness
Apart from disturbances in the fluid levels within the body, there is also disruptions in the levels of electrolytes and waste substances. As a result these substances accumulate in the body and can affect various biochemical processes. It may present as symptoms such as fatigue and even drowsiness.
There may also be muscle weakness. Initially these symptoms appear as lethargy and gradually worsens if the kidney damage or disease persists. To some extent and depending on the severity of kidney dysfunction, the symptoms may be mistaken for intoxication.
Shortness of Breath and Chest Pain
As fluid retention worsens, fluid may also accumulate in cavities. The increased fluid volume strains the heart which now has to receive and push a greater blood volume. Pressure on the chest and even chest pain may occur as a result. These chest symptoms are more prominent in people with pre-existing heart disease. Some of the fluid then seeps into the lung and even around the lung thereby hampering gas exchange.
Collectively the effects on the heart and lungs leads to symptoms like shortness of breath. Furthermore the kidney releases a hormone known as erythopoietin which controls red blood cell production. Depending on the type of kidney disease and duration, there may be a reduction in red blood cells (anemia) which can also cause shortness of breath and anemia.
Nausea and Vomiting
Nausea, the feeling of wanting to vomit, is a non-specific symptom that can arise with kidney damage. It is usually a result of the accumulation of wastes in the body that would normally be excerted by the kidneys. The higher level of waste and substances in the bloodstream can then stimulate nausea and vomiting centers in the brain. Depending on the severity of the nausea, it may lead to vomiting although this does not always occur.
Itching, Twitching and Cramps
The accumulation of waste substances in the body may eventually lead to symptoms that are not typically associated with kidney damage or disease. One of these symptoms is in itching and this is known as uremic pruritus. However, itching may also occur when the waste levels are not high like in patients who are undergoing dialysis. This is known as renal pruritus and the exact substance responsible for the itching in these cases is not known.
Other symptoms that are not typically associated with kidney damage and disease are muscle twitching and cramps. This can occur as a result of the electrolyte imbalance that arises with kidney problems. There may also be muscle pain (myalgia). Any muscle can be affected including the skeletal muscles (muscles under voluntary control) and even smooth muscles (muscles in organs that are not under voluntary control).
Confusion, Seizures and Coma
Kidney damage or disease can be severe to the extent that kidney function shuts down almost completely. Wastes cannot be removed from the body and the fluid and electrolytes levels become disrupted. When it reaches dangerously high levels then it can disrupt brain function.
The alterations in blood pressure and even blood oxygen levels are other contributing factors to the neurological symptoms in kidney disease. Confusion may arise as well as other disturbances in cognitive functions. It may also result in seizures (fits). Eventually a person may lose consciousness and ultimately this can result in death.