Proteinuria

Bergstein classification

Proteinuria classification according to J. Bergstein (1992):

• Nonpathological proteinuria
  • Postural (orthostatic)
  • Febrile
  • Physical exercise

• Pathological proteinuria
  • Glomerular
    • Persistent asymptomatic
    • Nephrotic syndrome
    • Idiopathic nephrotic syndrome (minimal changes, mesangial-proliferative focal sclerosis )
    • Glomerulonephritis
    • Tumors
    • Drug disease
    • Congenital diseases (e.g., Fabry disease )
  • Tubular hereditary
    • Cystinosis
    • Wilson-Konovalov disease
    • Low syndrome
    • Proximal Renal Tubular Acidosis
    • Galactosemia
  • Tubular acquired
    • Drug abuse
    • Hypervitaminosis D
    • Hypokalemia
    • Antibiotics
    • Interstitial jade
    • Acute tubular necrosis
    • Cystic disease
    • Sarcoidosis
    • Penicillamine
    • Heavy metal salt poisoning

Robson classification

Classification of proteinuria depending on the underlying pathophysiological mechanism according to A. Robson (1987)

Persistent proteinuria

• Increased glomerular permeability for plasma proteins
  • Damage to the basement membranes: glomerulonephritis.
  • Loss of glomerular polyanion: nephrotic syndrome with minimal changes.
  • Other possible mechanisms: an increase in the filtration fraction, a decrease in the mass of nephrons with an increase in the permeability of the remaining nephrons.

• Decreased calcium reabsorption of filtered proteins

Fanconi syndrome , Balkan nephropathy , hereditary tubular disorders, the effect of nephrotoxic drugs.

• Proteinuria by the overflow mechanism
  • Normal kidney function: large plasma proteins - repeated transfusions of albumin or blood; small plasma proteins - myeloma , macroglobulinemia (fragments of immunoglobulins), leukemia (lysozyme), bronchial carcinoma (orozomukoid).
  • Lowering the renal threshold: administration of albumin in nephrotic syndrome.

• Secretory proteinuria
  • Tamm-Horsfall proteinuria: neonatal period, pyelonephritis.
  • Renal-specific antigens: analgesic nephropathy, heavy metal poisoning, rapidly progressive glomerulonephritis.
  • Other proteins: pathology of the prostate gland, other secondary sex glands.

• Histuria
• Tissue antigens: urothelial carcinoma , melanoma , neuroblastoma ;
• Nonspecific antigens: diseases that cause damage to the basement membrane or collagen.

Postural proteinuria

Recurrent proteinuria

• Accidental detection - the cause is unknown.
• Emergency disorders - fever, stress, physical activity, stay in the cold.
• Renal pathology (in rare cases, isolated disorders) - urinary tract infection, obstruction.
• Urine pollution - vaginal secrets.
• False positive test - sulfonamides , penicillins , butamide , chlorhexidine , radiopaque substances.

There is physiological secretion of protein from the urinary tract, prostate gland, but it does not exceed 150 mg / day. Such a small concentration is not detected in single servings.

Methods for determining protein in urine can be divided into:

• Quality
  • Geller's ring test
  • sample with 15–20% sulfosalicylic acid
  • boiled sample, and others
• Semi-quantitative
  • Brandberg-Roberts-Stolnikov method,
  • Determination of protein in urine using diagnostic test strips.
• Quantitative
  • Turbidimetric
  • Colorimetric

Physiological proteinuria:

• in single servings of urine - up to 0.033 g / l.
• daily urinary protein excretion of 30-50 mg \ day (in children up to 1 month 240 mg \ m2; in children older than 1 month - 60 mg \ m2 \ day).

Increase proteinuria: fever , stress , exercise, the introduction of norepinephrine .

Protein in the urine during pregnancy:

• up to 30 mg - normal;
• 30 - 300 mg - microalbuminuria;
• from 300 mg - macroalbuminuria.

During pregnancy, an indicator of protein that exceeds 300 mg per day is often an indicator of preeclampsia. In women who are expecting a baby, the protein count in urine tests for 12 hours correlates with the readings per day. Scientists have proven that 300 mg of protein in a daily urine test is not an indicator of complications during pregnancy (hypertension, premature birth, low birth weight). Therefore, the researchers proposed moving the daily rate to 500 mg. ^[3]

Mild proteinuria is 150-500 mg / day. Reasons - acute post-streptococcal glomerulonephritis ; chronic glomerulonephritis, hematuric form; hereditary nephritis ; tubulopathy ; interstitial nephritis ; obstructive uropathy.

Moderately expressed proteinuria 500-2000 mg / day. Reasons - acute post-streptococcal glomerulonephritis; hereditary nephritis; chronic glomerulonephritis.

Severe proteinuria more than 2000 mg / day. The reasons are nephrotic syndrome , amyloidosis .

Prerenal proteinuria - increased protein breakdown in tissues and hemolysis .

Renal proteinuria - glomerular or tubular.

Postrenal proteinuria - associated with pathology of the urinary system ( ureter , bladder , urethra , genitals).

Permanent proteinuria - with kidney disease.

Transient proteinuria - with fever, orthostatic.

• M.V. Erman - Nephrology of childhood in charts and tables, St. Petersburg, 1997, pp. 14-15.
• A.V. Papayan, N.D. Savenkova - Clinical Nephrology of Children, St. Petersburg, 1997.

• Semiotics proteinuria
• Proteinuria
• Pathogenesis of proteinuria
• Hereditary Proteinuria Syndromes