6. Acute nephritis syndrome

Question 1

What is glomerulonephritis?

Answer 1

• A common cause of ESRD in adults
• Classified according to histological characteristics or to the presenting clinical syndrome
  
  • Primary renal disease
  • Systemic disease
• GN means inflammation of the glomeruli and nephrons that may damage glomerulus and result in:
  
  • Restriction of blood flow (==> increased BP)
  • Damage to the filtration mechanism ( ==> proteinuria or hematuria)
  • Loss of usual filtration capacity (==> AKI)

Question 2

What is the spectrum of disease of glomerulonephritis?

Answer 2

Depending on the degree of inflammation, damage and the underlying condition, patients present with a spectrum of disease

Question 3

What are the immune mechanisms of injury?

Answer 3

• Antibody against local antigen
• Deposition of circulating immune complexes
• No immune complex but with immune mechanism (Pauci immune - autoimmune)

Question 4

What are the different proliferative and non-proliferative GN?

Answer 4

Question 5

What is the acute nephritic syndrome?

Answer 5

It is a clinical complex, usually of acute onset, characterized by:

• Hematuria with dysmorphic RBC and RBC casts in the urine
• Some degree of oliguria and azotemia
• HTN
• Proteinuria and edema may be present, but very mild compaired to nephrotic syndrome

Question 6

What is the pathophysiology of acute nephritic syndrome?

Answer 6

• Proliferation of cells within glomeruli with leukocytic infiltration
  
  • The inflammation severely injures the capillary walls ==> hematuria ==> decreased GFR
    
    • Oliguria, fluid retention, azotemia
• HTN is probably the result of both fluid retention and increased renin release from ischemic kidney

Question 7

What are the causes of acute nephritic syndrome?

Answer 7

• Systemic disorders (e.g. SLE)
• Following a primary glomerular disease (e.g. IgA nephropathy)

Question 8

What is IgA nephropathy? Pathophysiology? Treatment? Prognosis?

Answer 8

• It is the most common GN in the developed world.
• May present with micro- or macrohematuria, but occasionally with nephritic syndrome
• Typically seen in young men with episodic macroscopic hematuria
  
  • Rapide recovery between attacks

Pathophysiology:

• Increase plasma IgA due to infection ==> formation of immune ocmpelxes and deposition on mesangial cells
  
  • This leads to complement activation ==> damage
• Renal biopsy demonstrates mesangial proliferation and immunofluorescence shows deopists of IgA and C3

Treatment:

• BP control with ACEI
• Immunosuppression ==> slows decline of renal function

Prognosis

• Worse if increased BP, male, proteinuria or renal failure at presentation
• 20% of adults develope ESRD over 20 years

Question 9

What is post-streptoccal GN?

Answer 9

• It is a diffuse proliferative GN that occurs typically 1-12 weeks after a streptoccocal throat infection or skin infection
• A strep antigen is deposited in the glomerulus ==> immune reaction ==> immune complex deposition
  
  • Patients usually present with nephritic syndrome

Diagnosis:

• Renal biopsy is not usually done unless atypical presentation but may demonstrate inflammatory reaction affecting mesangial and endothelial cells
• Immunofluorescence: shows IgG and C3 deposition
• Serology: increased ASAT and C3

Treatment:

• Supportive treatment and >95% of renal function is recovered