Proteinuria

WikiDoc Resources for Proteinuria
Articles
Most recent articles on Proteinuria Most cited articles on Proteinuria Review articles on Proteinuria Articles on Proteinuria in N Eng J Med, Lancet, BMJ
Media
Powerpoint slides on Proteinuria Images of Proteinuria Photos of Proteinuria Podcasts & MP3s on Proteinuria Videos on Proteinuria
Evidence Based Medicine
Cochrane Collaboration on Proteinuria Bandolier on Proteinuria TRIP on Proteinuria
Clinical Trials
Ongoing Trials on Proteinuria at Clinical Trials.gov Trial results on Proteinuria Clinical Trials on Proteinuria at Google
Guidelines / Policies / Govt
US National Guidelines Clearinghouse on Proteinuria NICE Guidance on Proteinuria NHS PRODIGY Guidance FDA on Proteinuria CDC on Proteinuria
Books
Books on Proteinuria
News
Proteinuria in the news Be alerted to news on Proteinuria News trends on Proteinuria
Commentary
Blogs on Proteinuria
Definitions
Definitions of Proteinuria
Patient Resources / Community
Patient resources on Proteinuria Discussion groups on Proteinuria Patient Handouts on Proteinuria Directions to Hospitals Treating Proteinuria Risk calculators and risk factors for Proteinuria
Healthcare Provider Resources
Symptoms of Proteinuria Causes & Risk Factors for Proteinuria Diagnostic studies for Proteinuria Treatment of Proteinuria
Continuing Medical Education (CME)
CME Programs on Proteinuria
International
Proteinuria en Espanol Proteinuria en Francais
Business
Proteinuria in the Marketplace Patents on Proteinuria
Experimental / Informatics
List of terms related to Proteinuria

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Cafer Zorkun, M.D., Ph.D. [2]; Sapan Patel M.B.B.S; Ogheneochuko Ajari MB.BS, MS

Synonyms and keywords: Urinary protein levels raised; urine protein raised

Overview

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.

Causes

Proteinuria may be a feature of the following conditions:

• 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
• 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.
• 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.
• Ebola hemorrhagic fever
• Nail Patella syndrome
• Familial Mediterranean fever

Causes of Proteinuria by Classification

Glomerular Proteinuria

• Allergins
• Glomerulonephritis

• Minimal change GN
• Membranous GN
• Focal segmental GN
• Membranoproliferative GN
• Mesangioproliferative GN
• Fibrillary glomerulopathies
• Crescentic GN

• Collagen Vascular Disease

• Henoch-Schonlein Syndrome
• Kidney amyloidosis
• Mixed cryoglobulinemia
• Multiple Myeloma
• Other vasculitis
• Polyarteritis Nodosa
• Sarcoidosis
• Sickle Cell Disease
• Systemic lupus erythematosus
• Wegener's Granulomatosis

• Drugs
• Hereditary

• Anticonvulsants
• Captopril
• Gold
• Heavy metals
• Heroin
• NSAIDs
• Penicillamine

• Infections

• Bacterial
• CMV
• EBV
• Helminthic
• Hepatitis B
• HIV
• Leprosy
• Malaria
• Poststreptococcal glomerulonephritis
• Toxoplasmosis

• Miscellaneous

• Hypothyroidism
• Preeclampsia
• Nephritis of Pregnancy
• Nephritic syndrome
• Diabetes Mellitus

Tubular Proteinuria

• Connatal tulbulopathies
• Hypokalemic nephropathy
• Interstitial nephropathy
• Renal Vein Thrombosis
• Renal tubular acidosis
• Toxic nephropathy

Prerenal and Overflow Proteinuria

• Bence-Jones Proteinuria
  • Waldenstrom's macroglobulinemia
  • Chronic lymphocytic leukemia
  • Amyloidosis
  • Malignancies (e.g., lymphoma, other cancers)
  • Multiple myeloma
• Hemoglobinura
• Increased formation of polyclonal free light chains
• Myoglobinuria

Renal Parenchymal and Post Renal Proteinuria

• Hemmorhage in the urinary tract
• Local infections
• Nephrolithiasis
• Prostitis
• Tamm-Horsfall protein

Miscellaneous Causes of Proteinuria

• Arteriolar nephrosclerosis
• Chronic Pyelonephritis
• Constrictive Pericarditis
• Genitourinary Tuberculosis
• High Fever
• Malignant Hypertension
• Massive Obesity
• Orthostatic proteinuria
• Preeclampsia
• Renal Neoplasm
• Renal Vein Thrombosis
• Tricuspid insufficiency
• Unilateral kidney

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.

Diagnosis

Laboratory Findings

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.

Reference Range
Physiologic protien elimination	<150mg protien/24 hours
Proteinuria	>150mg protein/24 hours
Microalbuminuria	<30mg albumin/24 hours

Treatment

Treating proteinuria mainly needs proper diagnosis of the cause. The most common cause is diabetic nephropathy; in this case, proper glycemic control may slow the progression. Medical management consists of angiotensin converting enzyme (ACE) inhibitors, which are typically first-line therapy for proteinuria. In patients whose proteinuria is not controlled with ACE inhibitors, the addition of an aldosterone antagonist (i.e., spironolactone) or angiotensin receptor blocker (ARB) may further reduce protein loss. Caution must be used if these agents are added to ACE inhibitor therapy due to the risk of hyperkalemia. Proteinuria secondary to autoimmune disease should be treated with steroids or steroid-sparing agent plus the use of ACE inhibitors.

Related Chapters

• Albuminuria
• Microalbuminuria
• List of terms associated with diabetes