Overview

Focal segmental glomerulosclerosis (FSGS) describes the injury of podocytes and scarring of the glomerulus leading to proteinuria and nephrotic syndrome. It may progress to end-stage renal failure.

Epidemiology

  • FSGS is most commonly seen in people aged 18-45 years, however, all ages can be accepted
  • FSGS is more common in men
  • FSGS is more common in Black people

Risk Factors

  • Male sex
  • Black ethnicity
  • Family history
  • HIV
  • Heroin use – thought to be directly toxic to podocytes
  • Obesity
  • Kidney transplants

Presentation

Patients present with nephrotic syndrome:

  • Proteinuria (>3.5 g/24hr)
  • Hypoalbuminaemia
  • Oedema

Other features that may also be seen in nephrotic syndrome include:

  • Hyperlipidaemia
  • Hypercoagulability
  • Immunodeficiency

Differential Diagnoses

Minimal change disease (MCD)

  • More common in children
  • Light microscopy is normal in MCD
  • Electron microscopy shows diffuse podocyte effacement

Membranous nephropathy

  • Both present similarly
  • Immunofluorescence microscopy shows IgG, C3, kappa and lambda light chains on a biopsy

Membranoproliferative glomerulonephritis

Investigations

  • Urinalysis:
    • Proteinuria is seen – generally intermediate-sized proteins (e.g. albumin or transferrin)
    • No significant haematuria is generally seen
  • Urine microscopy and culture:
  • 24-hour urinary protein or urine protein:creatinine ratio:
    • Shows proteinuria
  • Urea and electrolytes (U&Es) and estimated glomerular filtration rate (eGFR):
    • Urea and creatinine may be elevated
    • Estimated glomerular filtration rate (eGFR):
    • May be reduced
  • Serum albumin:
    • May be low (<30 g/L)
  • Serum lipids:
    • Shows hypertriglyceridaemia/hypercholesterolaemia
  • C3 and C4 complement levels:
  • Liver function tests (LFTs):
    • To rule out chronic liver disease as a cause of hypoalbuminaemia
  • Renal ultrasound:
    • To rule out structural abnormalities
  • Kidney biopsy:
    • Light microscopy shows focal segmental areas of mesangial sclerosis
    • Immunofluorescence microscopy is unremarkable

Management

Management involves initially using corticosteroids. If this is insufficient, other immunosuppressants may be used, such as ciclosporin.

Complications

The main complication is chronic kidney disease and its associated complications (e.g. hypertension and cardiovascular disease (CVD). CVD can also occur due to hyperlipidaemia due to nephrotic syndrome.

Prognosis

The prognosis of FSGS varies significantly depending on factors including the degree of proteinuria, serum creatinine, and response to therapy.

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