Nephrotic syndrome

Figure 1. Nephrotic edema.

Figure 2. Nephrotic edema.

NEPHROTIC SYNDROMENEPHROTIC SYNDROME Pathophysiology

- Proteinuria- Hypoalbuminemia- Edema- Hyperlipidemia

Cause (diagnosis and differential diagnosis)- Systemic renal disease

hepatitis B associated glomerulonephritis, Henoch-Schonlein purpura, systemic lupus erythematosus, diatetes mellitus, amyloidosis

- Idiopathic nephrotic syndrome Complications

- Infection- Coagulation disorders- Protein malnutrition and dyslipidemia- Acute renal failure

Pathophysiology

Proteinuria Proteinuria can be caused by systemic

overproduction, tubular dysfunction, or glomerular dysfunction. It is important to identify patients in whom the proteinuria is a manifestation of substantial glomerular disease as opposed to those patients who have benign transient or postural (orthostatic) proteinuria.

Heavy proteinuria (albuminuria)

Figure 3.

Hypoalbuminemia Hypoalbuminemia is in part a consequences of

urinary protein loss. It is also due to the catabolism of filtered albumin by the proximal tubule as well as to redistribution of albumin within the body. This in part accounts for the inexact relationship between urinary protein loss, the level of the serum albumin, and other secondary consequences of heavy albuminuria .

The salt and volume retention in the NS may occur through at least two different major mechanisms.

In the classic theory, proteinuria leads to hypoalbuminemia, a low plasma oncotic pressure, and intravascular volume depletion. Subequent underperfusion of the kidney stimulates the priming of sodium-retentive hormonal systems such as the RAS axis, causing increased renal sodium and volume retention, In the peripheral capillaries with normal hydrostatic pressures and decreased oncotic pressure, the Starling forces lead to transcapillary fluid leakage and edema .

Edema

In some patients, however, the intravascular volume has been measured and found to be increased along with suppression of the RAS axis. An animal model of unilateral proteinuria shows evidence of primary renal sodium retention at a distal nephron site, perhaps due to altered responsiveness to hormones such as atrial natriuretic factor. Here only the proteinuric kidney retains sodium and volume and at a time when the animal is not yet hypoalbuminemic. Thus, local factors within the kidney may account for the volume retention of the nephrotic patient as well.

Edema

Figure 4.

Hyperlipidemia

Most nephrotic patients have elevated levels of total and low-density lipoprotein (LDL) cholesterol with low or normal high-density lipoprotein (HDL) cholesterol . Lipoprotein (a) [Lp(a)] levels are elevated as well and return to normal with remission of the nephrotic syndrome. Nephrotic patients often have a hypercoagulable state and are predisposed to deep vein thrombophlebitis, pulmonary emboli, and renal vein thrombosis.

Cause

Table 2 CAUSES OF THE NEPHROTIC SYNDROME

Table 3a NEPHROTIC SYNDROME ASSOCIATED WITH SPECIFIC CAUSES (“SECONDARY” NEPHROTIC SYNDROME)

Table 3b NEPHROTIC SYNDROME ASSOCIATED WITH SPECIFIC CAUSES (“SECONDARY” NEPHROTIC SYNDROME)

Diagnosis and Differential diagnosis

Initial evaluation of the nephrotic patient includes laboratory tests to define whether the patient has primary, idiopathic nephrotic syndrome or a secondary cause related to a systemic disease.

Common screening tests include the fasting blood sugar and glycosylated hemoglobin tests for diabetes, and antinuclear antibody test for rheumatoid disease, and the serum complement, which screen for many immune complex-mediated disease (Table 3), In selected patients, cryoglobulins, hepatitis B and C serology, anti-neutrophil cytoplasmic antibodies (ANCAS), anti GBM antibodies, and other tests may be useful. Once secondary causes have been excluded, treating the adult nephrotic patient often requires a renal biopsy to define the pattern of glomerular involvement.

It leads to a multitude of other consequences , such as predisposition to infection and hypercoagulability. In general, the diseases associated with NS cause chronic kidney dysfunction, but rarely they can cause ARF. ARE may be seen with minimal change disease, and bilateral renal vein thrombosis.

ComplicationsInfectionCoagulation disordersProtein malnutrition and dyslipidemiaAcute renal failure

Treatment 1. General treatment

2. Symptomatic treatment (e.g.diuresis to relieve edema, treating dyslipidemias, anticoagulate treatment, etc.)

3. Immunosupressive treatment

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