Nephrotic Syndrome - Specialists and Information

Kidney damage in nephrotic syndrome triggers several typical symptoms. These are primarily caused by the loss of proteins that are essential for the body. Therefore, the following symptoms are particularly common in nephrotic syndrome:

• Proteinuria (protein in the urine, which often causes it to foam)
• Edema (fluid retention in the tissues, especially in the face, feet, ankles, and lower legs)
• Hypoproteinemia (low protein levels in the blood)
• Elevated blood lipid levels
• Hypertension (high blood pressure)
• Increased susceptibility to infections
• Formation of thrombi (blood clots)

Nephrotic syndrome occurs as a result of kidney damage. A distinction is made between primary kidney disease and secondary kidney disease. In primary kidney disease, the condition originates in the kidneys themselves, whereas secondary kidney disease arises as a consequence of another illness.

The kidneys filter the blood and remove metabolic waste products. Larger particles, such as sugar and proteins, normally remain in the blood. In addition, the kidneys also control blood pressure by regulating fluid balance and maintaining the correct ratios of certain electrolytes.

The filtering function in the kidney is carried out by the glomeruli and the renal tubules. Together, these two structures form the smallest unit of the kidney, the nephron.

Nephrotic syndrome is caused by damage to the glomeruli. As a result of this damage, the glomeruli become increasingly permeable until, at some point, they can no longer filter properly. Consequently, many important blood components, such as proteins, are no longer retained. Consequently, the symptoms mentioned above develop. Impaired kidney function can be caused by various diseases:

• chronic inflammatory disease of the glomeruli (for example, membranous glomerulopathy, in which antibodies deposit on the glomeruli)
• diabetes mellitus (a condition in which the formation of deposits disrupts the filtering function of the glomeruli)
• minimal glomerular lesions (dysfunction of certain immune cells that cause damage to the glomeruli)
• certain autoimmune diseases (for example, amyloidosis, in which protein deposits form in the organs)

Anatomy of the kidney: 6: Renal pelvis. 7: Ureter. 12: Glomerulus. 13: Nephron

If nephrotic syndrome is suspected, a doctor must evaluate the symptoms. The typical symptoms often provide important clues for the diagnosis.

In addition, a urine test is performed, in which a test strip is dipped into the urine for a few minutes. If the results are abnormally high, a second test is usually conducted. This test involves a more precise measurement of protein levels, which is why it is performed using a 24-hour urine collection sample. Normally, a healthy person excretes no more than 150 milligrams of protein per day. In nephrotic syndrome, this value can reach 3,500 milligrams or more per day.

In addition to the urine test, a blood test is performed, and a tissue sample is taken from the kidney during a minor surgical procedure and examined histologically. This allows the cause of the disease to be determined.

Treatment is not directed at the nephrotic syndrome itself, but rather at the underlying condition. If this condition responds well to treatment, the nephrotic syndrome usually resolves on its own after some time. In many cases, the kidneys’ filtering function remains intact. However, if the kidneys are too severely damaged by nephrotic syndrome, chronic kidney disease or kidney failure may develop over time.

If the underlying condition cannot be treated, the goal of therapy is to address the symptoms of nephrotic syndrome and alleviate them.

To normalize high blood pressure, doctors often prescribe medications such as ACE inhibitors. High blood pressure must be lowered in all cases, as it causes additional damage to the kidneys.

In addition to treating high blood pressure, medication is also used to treat edema. The excess fluid is flushed out of the body using diuretics. To prevent new edema from forming, the patient must not drink more than the amount prescribed by the doctor. The same applies to sodium intake (no more than six grams per day). It is also important to regularly monitor the mineral salt levels in the blood, as diuretics cause increased excretion of electrolytes.

Since nephrotic syndrome increases the risk of blood clots, patients are also given medications that inhibit blood clotting. Compression stockings also help prevent the formation of blood clots.