- Nephrotic range proteinuria can be the result of many processes, but “the nephrotic syndrome” refers to proteinuria >3.5g/day, albumin ❤ and peripheral edema
- Nephrotic range proteinuria without nephrotic syndrome features (hypoalbuminemia and edema) is more likely to be due to secondary FSGS than other causes
- Albumin is the main protein lost in urine in nephrotic syndrome, but other proteins lost include clotting factors (especially proteins C&S), transferring, immunoglobulins and vitamin D binding protein
- Hyperlipidemia is theorized to be due to the hepatic response to decreased plasma oncotic pressure, and many patients with have lipiduria with fatty casts (remember those maltese crosses under polarized light on step 1?)
- Among diabetic patients, there is a close relationship between albuminuria and hypertension for reasons that are not well understood
- The combination of uncontrolled DM and HTN accelerates renal disease (and other vascular damage), which was likely the etiology of this patient’s macroalbuminuria
- 10-40% of patients with nephrotic syndrome will have venous or arterial thromboses most often DVTs, PEs and renal vein thrombosis).
- Risk is especially high in membranous nephropathy
- The albumin level corresponds more closely with clot risk than the amount of proteinuria in studies of membranous nephropathy patients
- No routine anti-coagulation is recommended in nephrotic syndrome in general, though it may be reasonable in patients with membranous nephropathy and very low serum albumin
Parving HH, Hommel E, Mathiesen E, et al. Prevalence of microalbuminuria, arterial hypertension, retinopathy and neuropathy in patients with insulin dependent diabetes. Br Med J (Clin Res Ed) 1988; 296:156.