Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (543 page)

   Focal nephritic: generally associated with inflammatory regions in less than one half of glomeruli. Patients often present with asymptomatic hematuria and proteinuria.

   Diffuse nephritic: heavy proteinuria, edema, and hypertension may be observed.

   Causes

   Renal: can be postinfectious (due to certain nephritogenic strains after streptococcal, staphylococcal, or pneumococcal infections, mumps, measles, chickenpox, hepatitis B and C) or due to MPGN or anti–glomerular membrane disease.

   Systemic: due to SLE, vasculitides, IgA nephropathy, or Henoch-Schönlein purpura.

   Laboratory Findings

   Urinalysis: oliguria (<400 mL/day), proteinuria (usually <3.5 g/day), and hematuria, with RBC casts.

   Uremia and azotemia.

   Complement C3 level is usually decreased. Immunologic tests (e.g., anti-GBM antibodies, ASO) can help in the differential diagnosis.

   Renal biopsy establishes the diagnosis.

NEPHROTIC SYNDROME

This syndrome presents as heavy proteinuria, hypoalbuminemia, hyperlipidemia, lipiduria, and edema.

   Causes

   Primary glomerular diseases are responsible for >50% of all nephrotic syndrome cases. Systemic diseases such as diabetic glomerulosclerosis, SLE (14% of all cases), and amyloidosis (6% of cases) can also be associated with nephrotic syndrome. Other causes include infections, neoplasms (10% of adult cases), and drugs or toxins (see Table
12-5
).

TABLE 12–5. Major causes of Nephrotic Syndrome