Urinary protein excretion greater than 150mg/day is considered proteinuria.
Proteinuria is the leading symptom of the nephrotic syndrome, which includes peripheral oedema due to low serum protein levels. Hypertension and haematuria my be present but are not the leading symptoms as in nephritic syndrome.
Molecular weight allows to distinguish glomerular and tubular proteinuria. The latter is also known as low molecular weight proteinuria. The former may be further divided into selective and unselective glomerular proteinuria. Pathological proteins, such as Bence Jones protein, happen in urine in the course diseases with protein overproduction.
Microalbuminuria is a highly slective glomerular proteinuria with virtually only traces of albumine excretion (30-300mg/d).
Dip sticks allow to measure proteinuria semiquatitatively:
traces 15-30mg/dL,
1+ 30-100mg/dL,
2+ 100-300mg/dL,
3+ 300-1000mg/dL,
4+ >1000mg/dL.
Nephrotic range proteinuria is above 3500mg/day.
Alport Syndrome | |
Proteinuria is seldom the leading symptom in Alport syndrome. It usually occurs after hematuria and almost never reaches nephrotic range. |
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CFHR5 Nephropathy | |
Proteinuria becomes apparent in young adults often accompanied by hypertension. |
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Dent disease | |
Proteinuria is an early symptom. It is the most consistent symptom and detected in obligate female carriers even. Typically at the beginning, it is a low-molecular-weight (tubular) proteinuria (LMWP) that pattern may change however with disease progression. |
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Diabetes mellitus | |
Microalbuminuria is an early symptom of renal damage in diabetes mellitus. In severe diabetic nephropathy proteinuria can reach the nephrotic range. |
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Fibronectin glomerulopathy | |
Proteinuria is the first symptom in patients with fibronectin glomerulopathy. |
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Hereditary FSGS type 6 | |
Proteinuria in FSGS6 is usually nephrotic. |
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Hereditary FSGS type 7 | |
Proteinuria, which may reach nephrotic range, is an important feature of FSGS caused by mutations of the PAX2 gene. |
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Nephrotic syndrome | |
All subtypes of congenital nephrotic syndrome are characterized by mostly nephrotic range (more than 3,5g/d) proteinuria. |
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Congenital nephrotic syndrome type 04 | |
Proteinuria in NPHS4 is accompanied by mesangial sclerosis and possibly abnormalities of sexual organ development. |
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Congenital nephrotic syndrome type 10 | |
Proteinurie often develops into nephrotic range, it response to immunosuppressive therapy, but often relapses. |
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Renal tubular acidosis with arthrogryposis | |
Proteinuria pattern in ARC syndrome indicates glomerular in addition to the pathognomonic tubular damage. |
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ATTR amyloidosis | |
Proteinuria might be only mild but signals renal involvement. |