Fibrillary glomerulonephritis

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The fibrillary glomerulonephritis is a rare disease of the renal corpuscle , which is found in about 1% of the cases in which a tissue sample of the kidney was removed. The disease is characterized by the deposition of fibrils in a random arrangement in the kidney corpuscle. The fibrils are thread-like , unbranched structures that are only visible with an electron microscope . These fibrils are similar to the deposits found in amyloidosis , but are larger and do not stain with Congo red .

Pathogenesis

The pathogenesis of fibrillary glomerulonephritis is unknown. Immunoglobulin G , complement component C3 and amyloid component P were detected in the fibrils . However, it has not been clarified whether the fibrils consist of IgG or whether the IgG is secondary to a previously unknown protein that makes up the fibrils.

clinic

Fibrillar glomerulonephritis usually occurs in middle age (frequency peak 55–60 years of age). The disease is rare in children. Usually there is an increased excretion of protein in the urine (proteinuria) , in half of the cases there is a nephrotic syndrome with protein excretion over 3.5 g / day, reduced protein content in the blood (hypoproteinemia) , water retention in the tissue (edema) and lipid metabolism disorders (Hyperlipoproteinemia) . In 60% of the cases red blood cells (erythrocytes) can be detected in the urine ( hematuria ), in approx. 75% of the cases there is high blood pressure . So far, no specific laboratory test is known with which the diagnosis could be confirmed. Chronic hepatitis C has been demonstrated in isolated cases in patients with fibrillary glomerulonephritis .

diagnosis

The diagnosis can only be made by histological examination of a tissue sample from the kidney .

In the light microscope , deposits of an amorphous material can be found in the structures of the kidney corpuscles . Inflammatory cells are generally absent. The deposits can not be stained with Congo red , the histochemical evidence for amyloid is negative.

The immunohistological examination usually shows deposits of polyclonal IgG and light chains ; monoclonal IgG or light chain deposits are rarely detectable.

In the electron microscope , unbranched fibrils are found in a random arrangement. The thickness of these filamentous structures is typically 12–24 nm , mostly 18–20 nm. In contrast, the diameter of amylodifibrils is typically 8–15 nm, mostly 8–12 nm.

therapy and progress

The therapy consists in the treatment of the secondary diseases of chronic kidney failure . No specific treatment for fibrillary glomerulonephritis is known. Formal therapy studies have not yet been carried out.

The prognosis for fibrillary glomerulonephritis is often poor. In around half of the cases, the disease leads to a complete loss of kidney function within a few years, necessitating dialysis treatment . After kidney transplantation, fibrillary glomerulonephritis in the transplanted kidney can recur (recurrence) and lead to the loss of the transplant.

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