Proteinuria

Proteinuria (from "protein" and "urine") means the presence of anexcess 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), [http://www.pathguy.com/lectures/urine.htm Retrieved 2007-01-20] retrograde ejaculation, [http://www.medhelp.org/forums/urology/archive/195.html Retrieved 2007-01-20] pneumaturia (air bubbles in the urine) due to a fistula, [GPnotebook|1161101335|Pneumaturia Retrieved 2007-01-20] or drugs such as pyridium. [http://www.pathguy.com/lectures/urine.htm Retrieved 2007-01-20]

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. [http://medlib.med.utah.edu/WebPath/TUTORIAL/URINE/URINE.html Retrieved 2007-01-20] cite journal |author=Simerville JA, Maxted WC, Pahira JJ |title=Urinalysis: a comprehensive review |journal=American family physician |volume=71 |issue=6 |pages=1153–62 |year=2005 |pmid=15791892 |doi= |url=http://www.aafp.org/afp/20050315/1153.html] 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. [http://www.pathguy.com/lectures/urine.htm Retrieved 2007-01-20] [http://www.answers.com/topic/protein-electrophoresis Retrieved 2007-01-20]

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 of >30 mg/mmol) with very high levels of nephrotic syndrome being for PCR > 100 mg/mmol. [cite web |title=Identification, management and referral of adults with chronic kidney disease: concise guidelines |url=http://www.renal.org/CKDguide/full/Conciseguid141205.pdf |format=PDF |date= 2005-09-27 |publisher=UK Renal Association - see Guideline 4 Confirmation of proteinuria, on page 9]

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. The most common cause of proteinuria is diabetes and in any person with proteinuria and diabetes the etiology of the underlying proteinuria should be separated into two categories: diabetic proteinuria versus the field.

With severe proteinuria, general hypoproteinemia can develop which results indiminished 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:cite journal |author=Simerville JA, Maxted WC, Pahira JJ |title=Urinalysis: a comprehensive review |journal=American family physician |volume=71 |issue=6 |pages=1153–62 |year=2005 |pmid=15791892 |doi= |url=http://www.aafp.org/afp/20050315/1153.html]
* Nephrotic syndromes (i.e. intrinsic renal failure)
* Pre-eclampsia
* Eclampsia
* toxic lesions of kidneys
* Collagen vascular diseases(e.g., systemic lupus erythematosus)
* Dehydration
* Glomerular diseases, such as membranous glomerulonephritis, focal segmental glomerulonephritis, minimal change disease (lipoid nephrosis)
* Strenuous exercise
* Stress
*Obsessive Compulsive Disorder
* Benign Orthostatic (postural) proteinuria
* Focal segmental glomerulosclerosis (FSGS)
* IgA nephropathy (i.e., Berger's disease)
* IgM nephropathy
* Membranoproliferative glomerulonephritis
* Membranous nephropathy
* Minimal change disease
* Sarcoidosis
* Alport's syndrome
* Diabetes mellitus
* Drugs (e.g., NSAIDs, nicotine, penicillamine,gold, ACE inhibitors, antibiotics, opiates especially heroin.cite journal |author=Dettmeyer RB, Preuss J, Wollersen H, Madea B |title=Heroin-associated nephropathy |journal=Expert opinion on drug safety |volume=4 |issue=1 |pages=19–28 |year=2005 |pmid=15709895|doi=10.1517/14740338.4.1.19]
* Fabry's disease
* Infections (e.g., HIV, syphilis, hepatitis,post-streptococcal infection)
* Aminoaciduria
* Fanconi syndrome
* Heavy metal ingestion
* Hypertensive nephrosclerosis
* Interstitial nephritis
* Sickle cell disease
* Hemoglobinuria
* Multiple myeloma
* Myoglobinuria
* Organ rejection- kidney transplant patients may have gamma-globulins in their urine if the kidneys start to reject.cite journal |author=Hermann G, Zühlke V, Faul P |title=Gamma globulin fragments in urine of kidney transplant patients in relation to rejection crisis |journal=European surgical research. Europäische chirurgische Forschung. Recherches chirurgicales européennes |volume=2 |issue=1 |pages=55–63 |year=1970 |pmid=4131420 |doi=]
* Ebola hemorrhagic fever
*Nail Patella Syndrome
* Familial Mediterranean fever
* HELLP Syndrome

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

* Waldenstrom's macroglobulinemia
* Chronic lymphocytic leukemia
* Amyloidosis
* Malignancies (e.g., lymphoma, other cancers)
* multiple myeloma

ee also

*Albuminuria
*Microalbuminuria
*List of terms associated with diabetes

Footnotes