A. Tubular Proteinuria
- Little albumin in UPEP analysis
- Low molecular weight compounds including ß2-microglobulin, lysozyme, Ig Light Chains
- Urinary protein in 24 hours usually 1-3gm
- Usually due to hereditary tubular defects, other tubular damage
- In absence of casts or hematuria, usually benign
- Medications toxic to tubules (or interstitium): gold, NSAIDs, heavy metals
- Bence-Jones Proteins are immunoglobulin light chains, usually due to multiple myeloma
B. Glomerular Proteinuria
- Significant quantities of albumin in urine signify glomerular damage
- Nephrotic Range Protein Excretion:
- >3.5gm protein / 24 hour urine in person with normal serum albumin
- With abnormal >0.4mg protein/mmol (3.5gm/dL) creatinine
- Microalbuminuria
- Urinary albumin excertion 20-199µg/min
- Also defined as >25µg/dL of glomerular filtration rate
- Non-Nephrotic Glomerular Proteinuria
- Absence of hematuria, casts, azotemia
- Hereditary Syndromes (usually benign)
- Diabetes mellitus
- Amyloidosis
- Rheumatoid Arthritis
- Malignancy
- Primary Glomerular Diseases
- Membranous Glomerulonephritis
- Proliferative Glomerulonephritis
- Minimal Change Disease (mostly children)
- Focal and Segmental Sclerosing Glomerulonephritis (FSGS)
- Glomerular Dysfunction Secondary to Multisystem Disease
- Diabetes Mellitus
- Hypertension, hypercholesterolemia, smoking tobacco [1]
- Immune Complex Diseases: Systemic Lupus Erythematosus, Polyarteritis Nodosa
- Infection: Bacterial, Viral including HIV
- Malignancy: Leukemia, Lymphoma, Carcinoma
- Allergic Reactions
- Hypothyroidism
- Renal Vein Thrombosis
- Primary and Scleroderma Renal Crisis (hypertensive emergency)
- Proteinuria is a weak risk factor for all cause mortality and for cardiovascular disease [2]
References
- Cirillo M, Senigalliesi L, Laurenzi M, et al. 1998. Arch Intern Med. 158(17):1933
- Culleton BF, Larson MG, Parfrey PS, et al. 2000. Am J Med. 109(1):1