Hypoproteinemia is a pathological condition that is characterized by a decrease in the plasma concentration of total protein less than 64 g / l. The causes are starvation, kidney and liver diseases. The clinical picture can be varied - from an asymptomatic course to the appearance of peripheral edema, effusion in the abdominal, thoracic, pericardial cavities, and increased susceptibility to infections. The protein level is examined in plasma on an empty stomach. To eliminate hypoproteinemia, protein deficiency is compensated and the underlying disease is treated.
Low protein content can also be observed in healthy people (physiological hypoproteinemia), for example, in children under the age of 3 months or women in the third trimester of pregnancy. Also, the concentration of total protein may be reduced during prolonged hospitalization in bedridden patients. By origin, pathological hypoproteinemias are divided into:
1. Hemodilutional (false). A decrease in the protein level occurs due to its “dilution” with an excess of the liquid part of the blood (hypervolemia) during water intoxication, oligo- or anuria, primary hyperaldosteronism, and the syndrome of inappropriate secretion of antidiuretic hormone.
2. True . With this variety, hypoproteinemia develops due to a decrease in protein synthesis, increased loss in the urine, or accelerated decay. In turn, they are divided into:
According to the decrease in the content of a separate protein fraction, the following are distinguished:
The most common cause of hypoproteinemia is kidney disease, accompanied by nephrotic syndrome, one of the key components of which is hypoalbuminemia. A drop in protein levels is pathogenetically directly related to proteinuria. Due to damage to the glomerular apparatus of the kidneys, glomerular podocytes lose their negative charge, which disrupts the main filtration barrier for albumins and they are excreted in the urine. As a result, the level of protein in the blood decreases. Diseases associated with nephrotic syndrome include:
In most cases of nephrotic syndrome, there is either a slight or moderate decrease in the amount of protein in the blood. With monoclonal gammopathy, especially with amyloidosis, protein values can reach quite low numbers. Hypoproteinemia occurs slowly, progresses in parallel with the development of the underlying disease. After achieving remission under the influence of specific treatment, the protein level quickly returns to normal.
nephrotic syndrome
The main organ where the formation of almost all proteins of the human body occurs is the liver. With massive death of hepatocytes, the synthetic function of the organ, including protein formation, is disrupted. First of all, the albumin fraction decreases. Hypoalbuminemia, along with other indicators, is one of the criteria for assessing the severity of liver failure. Liver diseases associated with hypoalbuminemia:
Depending on the degree of progression of liver failure, hypoproteinemia can occur either acutely, within a few hours (for example, with acute viral hepatitis or toxic liver damage), or gradually, over weeks or months (with liver cirrhosis). The level of protein drop can be either insignificant or drop to very low levels, which sometimes requires, in addition to treating the underlying disease, additional administration of albumin.
Losses of protein through the gastrointestinal tract are much less common. Hypoproteinemia can develop due to a violation of the absorption of protein that enters the body with food. This occurs when there is a deficiency of pancreatic and intestinal enzymes that break down proteins (chronic pancreatitis), or an inflammatory lesion of the intestinal wall that prevents the absorption of amino acids from the lumen of the small intestine into the bloodstream (ulcerative colitis or Crohn's disease).
Also malabsorption with malabsorption of nutrients, incl. proteins, occurs with atrophy of the intestinal villi due to their damage by autoantibodies (gluten celiac disease). Hypoproteinemia in these diseases can be severe, especially in pancreatitis and celiac disease, which often requires additional compensation for protein deficiency.
Transient malabsorption can be observed in acute intestinal infections - salmonellosis, dysentery, yersiniosis, etc. However, in order to achieve normalization of protein levels, in these cases, antibiotic therapy and re-feeding of the patient are sufficient.
Unlike the other reasons listed above, a low protein level in immunodeficiency states occurs due to the fraction of globulins, or rather, immunoglobulins (antibodies), which actually serves as the main link in the pathogenesis of humoral immunity disorders. Mutations in the genes that regulate the production of immunoglobulins (primary immunodeficiencies) can be the cause of a drop in protein concentration - this is Wiskott-Aldrich syndrome, Job syndrome.
Of the acquired immunodeficiencies, hypoproteinemia most often occurs with HIV infection at the stage of acquired immunodeficiency syndrome (AIDS), as well as with malignant lymphomas, chronic lymphocytic leukemia. The degree of hypoproteinemia in these diseases is quite significant, the total protein indicators can remain below the reference values for quite a long time even after treatment.
In these pathological conditions, a drop in blood protein concentration is observed rarely and in severe cases. The main links in the pathogenesis of hypoproteinemia are the increased transition of albumins from the vascular bed to the interstitial space (due to a sharp increase in the permeability of capillary walls) and accelerated protein catabolism. These reasons include:
Due to the large number of causes of hypoproteinemia, its detection requires detailed differential diagnosis. When receiving a biochemical blood test with a high protein content, you must first consult a general practitioner. During a physical examination of the patient, attention is paid to the clinical signs of hypoproteinemia - peripheral edema or pastosity of the lower extremities, an increase in the volume of the abdomen due to ascites, muffled heart tones.
When collecting an anamnesis, they clarify what chronic diseases the patient suffers from, whether he is registered with a specialist. This information can help in the diagnostic search for the reasons for the deviation in the analysis. The following additional methods of examination are assigned:
Albumin infusion to replace protein losses
Hemodilutional and physiological hypoproteinemias resolve spontaneously and do not require any medical intervention. The treatment of hypoproteinemia has two main goals - the correction of protein deficiency and the treatment of the underlying disease. To do this, the following activities are carried out:
Severe hypoproteinemia can lead to adverse consequences for the patient. A drop in the level of albumin reduces the oncotic pressure of the blood plasma, which leads to leakage of fluid in the body cavity (abdominal, pleural, pericardial). Also, at a low concentration of protein, the level of cholesterol in the blood rises, fatty degeneration of the liver occurs and the production of anti-infective proteins - immunoglobulins, proteins of the complement system is disrupted. Therefore, the detection of hypoproteinemia requires a visit to a doctor.