AskDefine | Define proteinuria

Dictionary Definition

proteinuria n : the presence of excessive protein (chiefly albumin but also globulin) in the urine; usually a symptom of kidney disorder [syn: albuminuria]

User Contributed Dictionary

English

Noun

proteinuria

Extensive Definition

Proteinuria (from protein and urine) means the presence of an excess of serum proteins in the urine. The protein in the urine often causes the urine to become foamy, although foamy urine may also be caused by bilirubin in the urine (bilirubinuria), retrograde ejaculation, pneumaturia (air bubbles in the urine) due to a fistula, or drugs such as pyridium.

Measurement

Proteinuria is often diagnosed by a simple dipstick test although it is possible for the test to give a false negative even with nephrotic range proteinuria if the urine is dilute. False negatives may also occur if the protein in the urine is composed mainly globulins or Bence-Jones Proteins because the reagent on the test strips, Bromphenol blue, is highly specific for albumin. Traditionally dipstick protein tests would be quantified by measuring the total quantity of protein in a 24-hour urine collection test, and abnormal globulins by specific requests for Protein electrophoresis.
Alternatively the concentration of protein in the urine may be compared to the creatinine level in a spot urine sample. This is termed Protein/Creatinine Ratio (PCR). The 2005 UK Chronic Kidney Disease guidelines states that PCR is a better test than 24 hour urinary protein measurement. Proteinuria is defined as a Protein:creatinine ratio >45 mg/mmol (which is equivalent to Albumin:creatinine ratio of >30 mg/mmol) with very high levels of nephrotic syndrome being for PCR > 100 mg/mmol.

Associated conditions

Proteinuria may be a sign of renal (kidney) damage. Since serum proteins are readily reabsorbed from urine, the presence of excess protein indicates either an insufficiency of absorption or impaired filtration. Diabetics may suffer from damaged nephrons and develop proteinuria.
With severe proteinuria, general hypoproteinemia can develop which results in diminished oncotic pressure. Symptoms of diminished oncotic pressure may include ascites, edema, and hydrothorax.

Conditions with proteinuria as a sign

Proteinuria may be a feature of the following conditions:

Conditions with proteinuria consisting mainly of Bence-Jones proteins as a sign

Footnotes

proteinuria in German: Proteinurie
proteinuria in Estonian: Proteinuuria
proteinuria in Spanish: Proteinuria
proteinuria in French: Protéinurie
proteinuria in Hebrew: פרוטאינוריה
proteinuria in Dutch: Proteïnurie
proteinuria in Japanese: タンパク尿
proteinuria in Polish: Białkomocz
proteinuria in Finnish: Proteinuria
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