Etiology and Clinical features

Nephrotic syndrome may be caused by primary glomerular disorders (80–90% of cases) and/or systemic diseases and toxic exposures (10–20% of cases)

• Primary (idiopathic) forms: The following types of nephrotic syndrome are commonly associated with other conditions

  • Minimal change disease

  • Focal segmental glomerulosclerosis

  • Membranous nephropathy

  • Membranoproliferative glomerulonephritis (can manifest as nephrotic or nephritic syndrome)

• Secondary forms

  • Diabetic nephropathy

  • Amyloid nephropathy: can be associated with multiple myeloma (AL amyloidosis) or chronic inflammatory disease such as rheumatoid arthritis (AA amyloidosis)

  • Lupus nephritis (can manifest as nephrotic or nephritic syndrome)

• Massive proteinuria > 3.5 g/24 hours

• Edema

  • Typically starts with periorbital edema

  • Peripheral edema (pitting)

  • Pleural effusion

  • Pericardial effusion

  • Ascites

  • In severe cases, anasarca

• Hypoalbuminemia

• Hyperlipidemia

• Hypercoagulable state with increased risk of thrombosis and embolic events (e.g., pulmonary embolism, renal vein thrombosis)

• Increased susceptibility to infection

• Hypertension in some cases

• Possibly frothy urine

• Symptoms of hypocalcemia (e.g., tetany, paresthesia, muscle spasms)

• Symptoms of the underlying disease (e.g., malar rash in lupus nephritis)