Definition of Proteinuria

  • proteinuria is defined as urinary protein excretion of greater than 150 mg per day.
  • Urinary protein excretion in healthy persons varies considerably and may reach proteinuric levels under several circumstances.
  • Most dipstick tests that are positive for protein are a result of benign proteinuria, which has no associated morbidity or mortality

    Common Causes of Benign Proteinuria

    Dehydration, Emotional stress, Fever, Heat injury, Inflammatory process, Intense activity, Most acute illnesses, postural disorder

    Mechanisms of Proteinuria

    Normal barriers to protein filtration begin in the glomerulus, which consists of unique capillaries that are permeable to fluid and small solutes but effective barriers to plasma proteins.
    The adjacent basement membrane and visceral epithelial cells are covered with negatively charged heparan sulfate proteoglycans.

    Proteins cross to the tubular fluid in inverse proportion to their size and negative charge.
    Proteins with a molecular weight of less than 20,000 pass easily across the glomerular capillary wall.
    Conversely, albumin, with a molecular weight of 65,000 Daltons and a negative charge, is restricted under normal conditions.
    The smaller proteins are largely reabsorbed at the proximal tubule, and only small amounts are excreted

    The pathophysiologic mechanisms of proteinuria can be classified to:

  • Glomerular: Increased glomerular capillary permeability to protein
  • Tubular: Decreased tubular reabsorption of proteins in glomerular filtrate
  • Overflow :Increased production of low-molecular-weight proteins

    Proteinuria Management

  • Usage of antihypertensive drug, such as an angiotensin converting enzyme (ACE) inhibitor, help in reduce or eliminate proteinuria
  • Diet Recommendations

    Adequate protein intake is essential for body energy and avoid depletion

    A 1gm of protein for each body kg is good, a rough figure 1gm protein equal 4 gm of meat

    High protein diet may affect the kidney

    Low protein diet may lead to malnutrition and worsen kidney