This book describes Proteinuria, Diagnosis and Treatment and Related Diseases.
Proteinuria indicates the leakage of protein in the urine.
It is often defined as a quantity in excess of 300 mg per day.
Proteinuria is linked with cardiovascular and renal disease and is an indicator of end organ damage in patients with hypertension.
The detection of a rise in protein excretion is believed to have both diagnostic and prognostic effect in the early detection and confirmation of renal disease
Protein should not normally pass out in the urine in detectable quantities.
Micro-albuminuria
Micro-albuminuria is protein between 30 and 300 mg per 24 hours.
This may occur with diabetes.
Bence-Jones protein
Because it may occur with multiple myeloma, this may also not be detectable on standard dipstick testing.
These are the light chains of immunoglobulins.
Albuminuria
This is often the same as proteinuria:
While plasma contains both albumin and globulin, the latter tends less likely to appear in the urine.
If the filtration system of the glomeruli may be regarded as like a sieve or a mesh then small holes or tears will allow larger particles than normal to pass through.
The smaller rather than the larger of the particles will normally be retained back, unless damage is severe.
With mild or moderate damage, smaller proteins such as albumin will pass and only with severe injury will globulins pass.
Causes
With a healthy kidney, when the body removes waste, protein is kept in the blood stream.
This is because protein in the blood is too large to pass through the tiny holes in the kidney filters.
When the filter is damaged in kidney disease, protein can pass into the urine.
Protein in the urine can be a marker of almost any type of kidney disease, so investigations are always required if the cause of proteinuria is to be confirmed:
1.High blood pressure
2.Infection
3.Reflux nephropathy
4.Diabetes
5.Glomerulonephritis
6.Minimal change nephritis
Some people get more protein into urine while standing than while lying down.
That is called orthostatic proteinuria.
Symptoms
Normally there are no symptoms, but protein can be found by a routine urine test.
Patients with asymptomatic proteinuria normally have no physical signs
In more serious cases (nephrotic syndrome) there may be:
1.Edema,
2.Ascites,
3.Hydroceles
4.Pleural effusions
Diagnosis
A urine sample is analysed the levels of protein and creatinine (protein-creatinine ratio or PCR for short)
It is more usual to test for albumin so the result is an albumin-creatinine ratio (ACR).
An ACR of 3-30 does not normally require action
An ACR of higher than 30 indicate considerable leakage of protein through the kidneys, and the higher the level the more concern, particularly if it is over 100
The size and shape of the kidneys may be measured in the X-ray department with an ultrasound
Finally, to make a firm diagnosis of the cause of proteinuria, it is required to perform a kidney biopsy
Treatment
Proteinuria is not a specific disease.
So its treatment is dependent on identifying and treating its underlying cause.
In mild or temporary proteinuria, no treatment may be required
Medicines are given for high blood pressure:
1.ACE inhibitors
2.ARBs
Treatment is also given for Diabetes to avoid the progressive kidney damage causing the proteinuria
Water retention can be treated by reducing the amount of salt
If proteinuria is high >1.5 g a day, this is likely to need treatment by a specialist from the outset and further investigation may be:
1.Urine microscopy.
2.Glomerular filtration rate.
3.Renal ultrasound.
4.Possible intravenous urography.
5.Possibl