Pathophysology of nephritic syndrome

Nephritic syndrome is a collection of specific signs/symptoms frequently occurred as a manifestation of Acute Postinfections Glomerulonephritis. The specific signs and symptoms are:

• haematuria
• azotemia
• hypertension
• oliguria
• proteinuria
• edema
  

Formation of antigen-antibody complex in circulation following Streptococcal infection (or any other certain infection) and the complex get trapped within glomeruli. Inflammatory reaction occurs and cytokines are released. This leads to capillary wall damage and increased in capillary permeability. As a result, RBC escaped into urine and present with HAEMATURIA.

The inflammation also leads to proliferation of glomerular cells (endothelial and mesangial cells) as a result of Growth Factor released. Reduction in capillary lumen occurs and result in reduced GFR. Less is urea being filtered and leads to AZOTEMIA.

Reduced GFR will activate RAAS mechanism (renin-angiotensin-aldosterone) resulting from reduced sodium delivery to distal tubules. Sodium and water retention cause HYPERTENSION and also OLIGURIA.

In addition, small amounts of selective proteins also escaped through injured glomeruli leads to PROTEINURIA. Reduced plasma protein levels will reduce plasma oncotic pressure, so water escaped into interstitium and results in EDEMA.