Diabetic nephropathy does not cause any symptom in the initial stages of kidney damage. In the initial stages, the patient is asymptomatic (without any symptom) and the only sign of kidney involvement may be the presence of small amounts of protein in the urine (microalbuminuria). Healthy kidney allows minimal amount of albumin to be excreted in urine (less than 150 mg in a 24-hour collection) except in certain conditions such as periods of high fever, strenuous exercise, pregnancy or infection.
Symptoms usually start 5 to 10 years after the kidney damage has begun. In type 1 diabetes, kidney damage or diabetic nephropathy usually develops a few years after the onset of diabetes (after about 5 to 10 years) whereas in type 2 diabetes, small amounts of albumin (microalbuminuria) may be detected in the urine at the time of diagnosis as many cases may have had diabetes for several years at the time of diagnosis.
The primary function of the kidney is to remove waste products from the body through the urine. As the damage to kidney progresses in cases with diabetic nephropathy, the kidneys cannot do their job efficiently and hence, you may develop signs and symptoms such as:
Protein in urine: Initially, small amount of protein (albumin) is found in the urine (microalbuminuria). As the functioning of the kidney/s declines, the amount of albumin increases and microalbuminuria becomes overt protein uria. The blood urea nitrogen (BUN) and serum Creatinine levels also increase gradually.
Rise in blood pressure: Blood pressure rises as kidney damage progresses. Furthermore, the increase in blood pressure increases the risk of kidney damage.
Swelling or edema: It usually starts in the feet and legs and may involve the entire body as kidney function declines.
Other non-specific symptoms are poor appetite or loss of appetite, fatigue or feeling tired most of the time, malaise or general ill feeling, headache, nausea and vomiting, weight loss, difficulty or trouble in sleeping etc.
Urinary symptoms such as the need to go to the bathroom more often at night, frothy appearing urine.
Decrease in need for insulin or anti-diabetic medications to maintain blood sugar. In case of severe kidney damage, the kidneys cannot remove the excess insulin or filter oral medicines that increase insulin production, such as glipizide (Glucotrol) or glyburide efficiently. This may lead to a fall in blood sugar levels and decrease in the need for insulin or anti-diabetic medications.
Paleness and anaemia: The kidneys secrete an important substance known as erythropoietin, which helps in the formation of haemoglobin. When the kidneys are damaged, they fail to form erythropoietin, which results in the fall of haemoglobin and thereby increases paleness and anaemia.
Itching: When the kidneys do not function well, waste products from the body are not removed efficiently. Accumulation of certain waste products in the blood results in itching.
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