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Protein in Urine Causes

Protein in Urine Causes

The elevated levels of protein in urine could be attributed to medical conditions such as polycystic kidney disease, kidney infection, diabetes, hypertension, etc. The following write-up provides information on the reasons behind a temporary or persistent rise in the protein levels in urine.
Bhakti Satalkar
Last Updated: May 6, 2018
The term 'proteinuria' refers to the presence of excessive protein in urine. While an insignificant increase in the protein levels may occur occasionally, it is the persistently high levels of serum proteins that is actually a cause of serious concern. Albumin and globulin are two major types of protein that are present in the blood. Serum albumin, which is a water-soluble protein that helps to regulate the osmotic pressure of the blood, accounts for more than 50% of the protein present in the blood plasma.

Since albumin and globulin are big-sized, these usually don't pass through the glomeruli, which are small clusters of capillaries that filter the blood and play a vital role in the formation of urine. Under normal circumstances, only traces of albumin and globulin are found in the urine. Under normal circumstances, the reference range for protein in a urine sample should be less than 10 mg/deciliter.

If urinalysis reveals elevated levels of protein, other diagnostic tests need to be conducted so as to identify the causes of protein in urine. Though proteinuria is not a disease in itself, consistently high protein levels could be an indicator of malfunctioning kidneys or other systemic diseases.
Causes and Types of Proteinuria
Proteinuria could occur due to defects in the glomeruli, elevated levels of plasma proteins, or an existing systemic disease that affects the kidneys' ability to reabsorb the protein. Proteinuria could be transient or persistent. Here are some of the common reasons behind the elevated levels of protein in the urine.

◘ Transient Proteinuria
There are some conditions which may cause a temporary rise in protein levels. Transient proteinuria is not considered to be a cause of concern, as it is not associated with serious medical conditions. Moreover, it usually resolves on its own. This condition may occur due to:

► Exposure to extreme cold
► Exposure to heat
► High fever
► Intense physical activity
► Stress

More often than not, a slight increase in the levels of protein in urine doesn't give rise to symptoms. Moreover, the protein levels decrease once the underlying condition has been resolved.

◘ Orthostatic Proteinuria
Orthostatic proteinuria, which is also called postural proteinuria, is another type of proteinuria wherein the amount of protein that is present in the urine is higher when the person is sitting in an upright position. The cause of this type of proteinuria is not known. This condition is mostly observed in children and young adults who are tall and thin. The secretion of protein is more during the day when the level of activity is high, which is why, the urine sample that is collected in the morning doesn't contain protein.

◘ Persistent Proteinuria
Consistently high levels of protein in the urine are usually indicative of certain medical conditions. Abnormal protein levels could be indicators of systemic diseases such as:

► Polycystic kidney disease is a condition that is characterized by the development of multiple cysts in the kidneys that causes them to enlarge. It often gives rise to hypertension. People affected by this kidney disease may have elevated levels of protein in their urine.
► Kidney infection, glomerulonephritis (inflammation of glomeruli), Goodpasture's syndrome (autoimmune disease affecting the kidneys), and chronic kidney failure could also cause proteinuria.
► Diabetes, which is a medical condition that is marked by elevated blood glucose levels, could damage the kidneys, thereby affecting the kidneys' ability to filter blood or reabsorb the protein into the bloodstream.
► High blood pressure is one of the leading causes of kidney diseases. Hypertension damages the arteries that are located in and around the kidneys, thereby affecting the kidney function in an adverse manner.
► Prolonged use of certain non-steroidal anti-inflammatory drugs could cause proteinuria.
► Amyloidosis, which is a medical condition that is characterized by protein buildup in tissues and organs, could also be a contributing factor.
► Preeclampsia is a complication of pregnancy that may develop after the twentieth week of pregnancy. It is characterized by proteinuria and hypertension.
► Rheumatoid arthritis, heart conditions, Hodgkin's lymphoma, multiple myeloma, lupus, sarcoidosis, etc., could also be responsible for causing proteinuria.
Symptoms and Diagnosis of Proteinuria
Though the presence of traces of protein in the urine may not cause any symptoms, certain symptoms may appear when the protein levels are high.

A person who has high protein levels in the urine is likely to experience the following symptoms:

Foamy Urine
Swelling in the hands and ankles
Facial swelling

The symptoms could also vary, depending on the underlying medical condition that is responsible for causing proteinuria.

◘ Diagnosis
The protein levels can be determined with a dipstick test, wherein a strip of chemically treated paper is dipped in urine. If the urine contains large amounts of protein, a change in color would be observed. In case of healthy individuals, the amount of protein in a random urine sample doesn't exceed 10 mg/deciliter of urine. The results are graded as trace when the protein levels lie in the range of 10 to 20 mg/deciliter of urine. The protein concentration of 30 mg/deciliter and 100 mg/deciliter is graded as 1+ and 2+ respectively. Protein concentration of 300 mg/deciliter, and 2,000 mg/deciliter is graded as 3+ and 4+ respectively. While 1+ and 2+ values reveal significant proteinuria, 3+ and 4+ values signify nephrotic range proteinuria.

Tests could also be conducted on a random urine sample or a sample that is collected over a period of 24 hours. Since dipstick tests may not always give accurate results, a 24-hour urine protein test may be recommended. This test is considered to be more reliable. Normal range for protein in case of a 24-hour sample is less than 80 mg. A protein to creatinine ratio (PCR) can also help in diagnosing proteinuria. For healthy individuals, PCR value is less than 2 mg/mmol.
If urinalysis shows elevated protein levels, urine tests must be conducted frequently to rule out the possibility of persistent proteinuria. Consistently high levels of protein in the urine could be indicative of systemic diseases. While transient proteinuria usually resolves on its own, medical assistance must be sought for treating persistent proteinuria.

Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.