Protein structures are the main building material in the human body. Protein molecules are present in biological fluids in certain amounts, and in case of a decrease or increase in their concentration, one can speak about the violation of certain functions of the body. On the rates and deviations of such an indicator as the protein in the urine, let's talk further.
Protein in urine - what does it mean?
Conducting a general laboratory analysis of urine, the protein is checked necessarily, as this is a very important diagnostic indicator. Urine formed in the kidneys by filtration from the blood can normally contain protein fractions only in trace amounts, that is, very small, which is at the limit of detection capabilities by analytical techniques. With the normal functioning of the filtering system of the kidneys, the protein molecules, because of their large size, can not penetrate into the urine, so the first thing that the protein in the urine means is a malfunction of the renal filtration membranes.
Protein in urine, whose norm is not more than 0.033 g / l (8 mg / dl) in healthy people, in pregnant women can be detected in amounts up to 0.14 g / l, which is considered normal. These values refer to the method of determination by sulfosalicylic acid. It is worth noting that the more reliable picture is provided not by the amount of protein compounds in a single portion of urine, but by the daily protein in the urine, determined in the entire volume of liquid produced by the kidneys in one day.
Proteinuria - types and mechanisms of development
A condition in which urine shows a protein at a concentration higher than the trace is called proteinuria. In this case, the body loses more than 150 mg of protein fractions per day. Syndrome of proteinuria can be physiological (functional) or pathological, and not always it is associated with a malfunction of the urinary system.
A temporary increase in the protein in the urine, which is passing benign, is sometimes observed in healthy people under certain conditions. To date, mechanisms for the development of functional proteinuria have not been fully explored, but it is believed that this is due to a small malfunction of the renal system without anatomical changes. Physiological proteinuria is divided into the following types:
- Orthostatic proteinuria (postural) - is noted in young people with asthenic physique after a long stay in standing or after walking, and after lying in the supine position is absent (therefore in the morning portion the protein is not detected).
- Feverish - is determined during periods of fever, accompanied by intoxication of the body.
- Alimentary - after consuming a large amount of food, saturated with proteins.
- Centrogenic - as a result of convulsive attack, concussion of the brain.
- Emotional - with a lot of stress, psychological shock.
- Working (proteinuria of tension) - arises from excessive physical exertion, training (due to a temporary violation of blood supply to the kidneys).
Elevated protein in the urine can be renal and extrarenal. The pathological processes taking place in the kidneys are based on different mechanisms, depending on which:
- Glomerular proteinuria - is associated with damage to peripheral glomeruli, increased permeability of the glomerular basal membrane (in large quantities from the blood in the urine filtered plasma proteins).
- Tubular proteinuria is due to abnormalities in the renal tubules due to anatomical or functional disorders, in which the ability to reabsorb proteins is lost, or the proteins are excreted by the tubular epithelium.
Based on the severity of damage to the glomerular filter, the glomerular proteinuria is divided into the following types:
- Selective proteinuria - occurs with a small lesion (often reversible), characterized by the penetration of proteins with a low molecular weight.
- Non-selective proteinuria - reflects a severe lesion, in which high or medium molecular weight fractions enter the glomerular barrier.
The following types of abnormalities are not associated with pathological processes in the kidneys:
- Proteinuria of overflow (prerenal), which arises from excessive production and accumulation in the blood plasma of proteins with low molecular weight (myoglobin, hemoglobin).
- Postrednaya - due to excretion in the urine, the renal filter, mucus and protein exudate with inflammation of the urinary or genital tract.
Isolate proteinuria, which is characterized by the presence of an increased number of protein compounds in urine without disturbing renal function, other symptoms or disorders. Patients with this diagnosis are at high risk for developing kidney failure after a few years. Often, the protein is released at a concentration of no more than 2 g per day.
Proteinuria - stages
Depending on the amount of protein in the urine, there are three stages of proteinuria:
- Slightly expressed (insignificant) - 150-500 mg per day;
- moderately expressed - 500-2000 mg per day;
- significant proteinuria (expressed) - over 2000 mg per day.
Protein in urine causes
Considering why the protein in the urine is found for a long time, we will list separately possible factors related to kidney damage and other pathologies. Probable renal causes of protein in the urine are as follows:
- ideopathic glomerulonephritis ;
- pyelonephritis ;
- polycystic kidney disease;
- amyloidosis of the kidneys ;
- tuberculosis of the kidneys;
- lupus nephritis;
- acute tubular necrosis;
- chronic rejection of the kidney transplant;
- thrombosis of the renal veins;
- kidney tumors;
- injury to the kidney.
Causes of extrarenal pathology:
- persistent hypertension;
- inflammatory and tumor diseases of the genitourinary system;
- sugar and diabetes insipidus ;
- malignant blood diseases;
- large-scale burns;
- lung cancer ;
- malignant tumors of the digestive system.
Urinalysis - Proteinuria
Carrying out of such research, as daily proteinuria, is recommended regularly to patients suffering from various kidney diseases. For the rest of the people, this analysis is prescribed if an increase in protein content is detected during the general urine test. At the same time, it is very important to correctly submit the material for research in order to avoid unreliable results.
Daily proteinuria - how to take the test?
If you want to know what daily proteinuria is like, how to take urine, the following rules will prompt:
- On the day of collection of material for analysis, drinking and food regimens should be familiar, unchanged.
- The collection container is used sterile, with a volume of at least three liters, hermetically sealed.
- The first morning portion of urine is not going.
- The last collection of urine is made exactly 24 hours after the first collection.
- Before each urination, you should wash your genitals with warm water with a means for intimate hygiene without fragrances and wipe dry with a cotton towel.
- At the end of the collection of urine, about 100 ml of the collected material is cast into a new sterile jar from the total capacity and delivered to the laboratory within two hours.
Proteinuria is the norm
It is believed that the norm of protein in the urine of an adult healthy person, collected during the day at rest, is approximately 50-100 mg. Exceeding the index of 150 mg / day is a serious reason to sound an alarm and find out the reason for the deviation, for which other diagnostic measures can be prescribed. If the collection of urine for the study is carried out against the background of physical activity, the limit level of the norm is set at 250 mg / day.
Protein in urine - treatment
Since the increased protein in the urine is not an independent pathology, but one of the manifestations of a disease, it is necessary to treat the pathology that leads to such a disorder. Methods of treatment can be very diverse, depending on the type and severity of the disease, concomitant illnesses, age. Often when the condition improves in the main pathology, proteinuria decreases or disappears.