Fibrillary glomerulonephritis

Other Names: Non-amyloid fibrillary glomerulopathy; Congo red-negative amyloidosis-like glomerulopathy; Non-amyloid fibrillary glomerulonephritis

Fibrillary glomerulonephritis is an uncommon cause of glomerular disease. A more rare disorder known as immunotactoid glomerulpathy is a very similar condition. Both disorders probably result from deposits derived from immunoglobulins but in most cases the cause is idiopathic (unknown).

Cause

Both fibrillary glomerulonephritis and immunotactoid glomerulopathy have been associated with hepatitis C virus infection and with malignancy and autoimmune disease. Because of this, patients should be screened for these conditions.

Signs and symptoms

The signs and symptoms include blood (hematuria) and protein (proteinuria) in the urine, kidney insufficiency and high blood pressure.

Diagnosis

The diagnosis is made with a kidney biopsy and by electron microscopy. Fibrillary glomerulonephritis and immunotactoid glomerulopathy can be differentiated from each other by electron microscopy; the fibrils in fibrillary glomerulonephritis are smaller and randomly oriented as opposed to the larger and often organized fibrils of immunotactoid glomerulopathy.

Treatment

Treatment is generally determined by the severity of the kidney problems. The most common form of treatment was steroids, with or without a second agent, including most notably cyclophosphamide or rituximab. A benefit of immunosuppression could not be detected in these small, retrospective studies in which patients with more severe disease were more likely to have been treated.

Prognosis

The prognosis for patients with FGN remains poor, with limited data to suggest optimal therapy.

NIH genetic and rare disease info

• NIH info on Fibrillary glomerulonephritis

Fibrillary glomerulonephritis is a rare disease.