- Clinical science
Nephritic syndrome is characterized by glomerular damage leading to hematuria, pyuria, water retention, and subsequent hypertension and edema. It can be caused by a variety of conditions including autoimmune, hereditary, and infectious diseases. This learning card provides an overview of nephritic syndrome; underlying conditions are discussed in more detail in other learning cards. Nephritic diseases can present in varying degrees of severity, ranging from asymptomatic hematuria to systemic involvement as in rapidly progressive glomerulonephritis. The urine sediment is typically characterized by red blood cell (RBC) casts, mild to moderate proteinuria (< 3.5 g/day), and sterile pyuria. Diagnosis of the underlying disease is often based on presentation and laboratory values, although renal biopsy may be indicated for confirmation.
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|Small vessel vasculitis|| |
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|LM = light microscopy, IM = immunofluorescent microscopy, EM = electron microscopy|
Inflammation → cytokine release → glomerular capillary damage
- Porous glomerular basement membrane → leakage of proteins and RBCs → (all blood components are detectable on urinalysis)
- Oliguria: inflammatory infiltrates reduce fluid movement across the membrane (↓ GFR)
- Azotemia: inflammation prevents sufficient filtering and excretion of urea
- Salt retention → intravascular volume expansion → hypertension and edema
- Renal biopsy: sometimes indicated in patients with a nonspecific disease pattern to confirm diagnosis
- Blood tests
Glomerular hematuria is a typical finding in nephritic syndrome. It is characterized by acanthocytes, RBC casts, and mild to moderate proteinuria! (Nonglomerular hematuria is characterized by bright red or pink urine, the occurrence of blood clots, normal RBC morphology, and the absence of RBC casts.)
- See .
The differential diagnoses listed here are not exhaustive.
- Supportive therapy
- Low-sodium diet
- Water restriction
- Medical therapy
- If severe renal insufficiency or kidney failure: renal replacement therapy (e.g., hemodialysis, possibly transplantation)
- For management of specific diseases: See the “Therapy” sections of the respective learning cards.