Protein In Urine

Protein in urine (proteinuria) can be a symptom of many diseases. Becasue proteinuria itself often has no symptoms, it can be accidentally found during a routine urine examination.

Causes

Urinary tract infections

Inflammatory processes in urinary tract are usually associated with presence of protein in the urine. Another typical symptom is a burning sensation when urinating or finding blood in urine. These infections can affect even kidney tissue and such kidney infection is also known as pyelonephritis. Kidney infections have often a serious course accompanied by high fever and strong headache. A transition into sepsis is common as kidneys are very well with blood perfused organs. Urinary tract infections are also often connected with urinary tract stones.

Stress situations

We often find protein in urine by patients whose body is in stress conditions like more serious acute infections or abnormal physical exertion by an untrained person. In these cases proteinuria is only a temporary sign. It is therefore advisable to examine the urine again after such stress situation has ended.

High blood pressure

Chronic and untreated high blood pressure leads to progressive kidney damage and one of its manifestations may be the discovery of protein in urine. Antihypertensive agents are the best way of treatment.

Diabetes

Long years of diabetes leads to damage of kidney blood vessels and to reduction of kidney filtering capacity. Damaged kidney tissue allows leaking proteins into urine and at the same time there is a gradual deterioration of kidney functions. This is why diabetics should have regular urine testing. The loss of a small amount of protein is called microalbuminuria and it is a warning sign that the condition can worsen. Careful and regular controls are needed with cautious treatment of high blood pressure. Antihypertensive agents, especially ACE-inhibitors, have a protective effect on kidneys.

Glomerulonephritides

This is a whole group of non-infectious inflammatory diseases of so-called glomeruli, the kidney filtration units. Their classification is complex and in this article shall not be mentioned. They have different course and prognosis – some are relatively inconspicuous, others may completely withdraw, but others lead to sudden or progressive renal failure.

Tumors of urinary tract

Any tumor of the urinary tract may be associated with presence of protein in urine. Another very important symptom in this case is also a discovery of blood in urine. Most commonly found tumors are urinary bladder cancer and kidney cancer.

Multiple myeloma

This is obviously a rarer cause of protein in urine, but it really should not be forgotten. Multiple myeloma is a special form of cancer developing from white blood cells that produce antibodies (B-lymphocytes). Tumor cells also produce antibodies, but these are defective and non-functional. Small portions of these protein antibodies penetrate into urine and professionally they are labeled as Bence-Jones protein.

Preeclampsia

This condition emerges especially in second half of pregnancy and is also associated with high blood pressure. Its complications can endanger the life of pregnant woman and fetus. More information can be found in relevant article.

Symptoms

Perhaps the only direct clinical manifestation of proteinuria is a tendency of urine to foam. Indirect symptoms appear when there is a deficiency of proteins in our body because of their excessive losses. Swelling of tissues is the main symptom. Classic swelling emerges around the eyes and also swollen lower extremities are typical. People with reduced level of blood proteins tend to be tired and they are susceptible to infections. If there is a loss of protein greater than three grams per day, it is called as nephrotic syndrome.

Diagnostic approach

Diagnosis should begin with medical history and physical examination. Urinal proteins can be found by urine examination using special test strips or by more specific examination of urine sample in a biochemical laboratory. Sometimes we want to examine a sample of urine collected for 24 hours that allows us to count the protein loss in one day. Further examination depends on our suspicion – we can examine urine for bacteria, urinary tract is examinable by an X-ray (urinary stones) or by ultrasound including kidney tissue. The inside of urinary bladder may be viewed by cystoscopy. When there is a suspected primary kidney disease like glomerulonephritides, a nephrologist should treat the patient. Nephrologists have special investigative procedures that may include a kidney biopsy (i.e. a puncture of a kidney by long needle to obtain a sample for histological examination).