Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (530 page)

The clinical spectrum of GN comprises:

   Asymptomatic subnephrotic proteinuria without hematuria.

   Asymptomatic proteinuria with hematuria: the coexistence of asymptomatic proteinuria and hematuria substantially increases the risk of significant glomerular damage, hypertension, and progressive renal dysfunction in comparison to the situation of isolated asymptomatic proteinuria.

   Nephrotic syndrome: proteinuria in excess of 3.5 g in 24 hours, accompanied by edema, hypoalbuminemia, hyperlipidemia, and lipiduria.

   Nephritic syndrome: nonnephrotic proteinuria, hematuria, and appearing tendency to GFR lowering.

   Course of rapidly progressive glomerulonephritis, including non-nephrotic proteinuria, hematuria with rapid GFR decline, and acute renal failure.

   Macroscopic hematuria associated with glomerular diseases, appearing mainly in children and young adults as a symptom of IgA nephropathy and postinfectious GN. The characteristic feature of IgA nephropathy is episodic frank hematuria occurring simultaneously with an upper respiratory tract infection, whereas in postinfectious GN, there is a 2- to 3-week period of latency between infection and hematuria.

   See Figure
12-3
.

Figure 12–3
Algorithm for evaluation of glomerulonephritis.

Suggested Reading

Klinger M, Mazanowska O. Primary idiopathic glomerulonephritis: modern algorithm for diagnosis and treatment.
Pol Arch Med Wewn.
2008;118(10):567–571.

GLOMERULONEPHRITIS, MEMBRANOPROLIFERATIVE

   Definition

   Membranoproliferative GN (MPGN) accounts for approximately 10% of all cases of biopsy-confirmed glomerulonephritis and ranks as the third leading cause of end-stage renal disease among the primary glomerulonephritides.

   MPGN can be primary or secondary to systemic diseases (e.g., SLE), neoplasms, monoclonal gammopathy, or infections (especially HCV with cryoglobulinemia).

   MPGN most commonly presents in childhood but can occur at any age. Patients can present with a variety of findings ranging from microscopic hematuria to severe glomerulonephritis associated with hypertension and nephrotic syndrome. The clinical course may be clinically active, or there may be periods of remission. Approximately 50% of untreated patients have chronic renal insufficiency in 10 years.