Fibrillary Glomerulonephritis
Overview
Fibrillary GN is a disease which affects the millions of filtering units that make up the kidney. These filtering units are called glomeruli. Each individual glomerulus is composed of multiple layers of straining material.
In this condition, the body produces a large volume of unusual proteins. These proteins enter the filters. The proteins become trapped in the straining layers, disrupting filtration. In some instances these proteins activate the immune system. This causes swelling in these delicate structures.
Over time the swelling can damage the layers of the filters. The damage allows large amounts of proteins to spill into the urine. As the swelling progresses filtering units are damaged beyond repair. They are replaced by scar tissue.
With the loss of enough filters, the kidneys lose the ability to filter and clean the blood. This condition is known as end-stage kidney disease.
This disease has been found in patients age 10 to 89. It appears to affect Caucasians at a slightly higher rate. We cannot predict who will develop it. It appears there may be an association of this disease with conditions of immune system dysfunction, such as lupus. This disease can also be found in association with diseases causing chronic immune system activation, such as Hepatitis C.
SYNONYMS
fibrillary GN
non-amyloid fibrillary glomerulopathy
Congo red-negative amyloidosis-like glomerulopathy
don-amyloid fibrillary glomerulonephritis
SIGNS & SYMPTOMS
The most common symptoms of fibrillary glomerulonephritis include:
Blood in the urine (hematuria)
Protein in the urine (proteinuria) causing it to look “foamy”
Decreased kidney function (renal insufficiency)
High blood pressure (hypertension)
CAUSES
The causes of fibrillary glomerulonephritis are currently unknown and are being researched. Antibodies (immunoglobulins) build up in the glomerulus, often in patients with an underlying disease such as cancer (particularly leukemia, lymphoma and multiple myeloma), a monoclonal gammopathy or an autoimmune disease (Crohn’s disease, Graves’ disease, immune thrombocytopenia, etc.).
AFFECTED POPULATIONS
Patients with a history of cancer (particularly leukemia or multiple myeloma), a monoclonal gammopathy or an autoimmune disease (particularly Crohn’s disease, lupus, Graves’ disease, or immune thrombocytopenia [ITP]) are at risk for fibrillary glomerulonephritis.
DISORDERS WITH SIMILAR SYMPTOMS
Immunotactoid glomerulopathy – a similar disease in which antibodies (immunoglobulins) and microtubules affect the glomerulus rather than fibrils.
Fibronectin glomerulopathy – a similar disease in which a protein called fibronectin-1 affects the glomerulus rather than fibrils.
Collagenofibrotic glomerulopathy – a similar disease in which collagen affects the glomerulus rather than fibrils.
DIAGNOSIS
A diagnosis is made from a kidney biopsy to look at the fibrils under an electron microscope and immunofluorescence microscope. Routine lab tests may detect the blood and protein in the urine, but a biopsy is the only way to determine which proteins are affecting the glomerulus.
Clinical Testing and Work-up
Abnormal results from routine blood and urine tests are the first line of evidence for kidney damage. Kidney function tests can then detect the severity of kidney damage. After a kidney biopsy confirms the diagnosis of fibrillary glomerulonephritis, a physician will likely order more blood tests and imaging. These tests are important to find any underlying cancer, hepatitis or autoimmune disease which may be associated with the glomerulonephritis. In some patients, finding and treating the underlying condition can decrease the severity of the kidney disease. In the case when an underlying condition is not found, treatment focuses on controlling the hypertension, protein in the urine and progression of the kidney disease.
STANDARD THERAPIES
Treatment
There is currently no approved therapy to treat fibrillary glomerulonephritis with unknown cause. Many therapies have been tried with little success including steroids, plasmapheresis, cyclophosphamide and cyclosporine. Clinicians will likely focus instead on controlling the symptoms such as hypertension, proteinuria and kidney insufficiency. If an underlying condition is present (see Affected Populations), clinicians will instead focus on treating the underlying condition, which may improve symptoms of fibrillary glomerulonephritis.
Patients who progress to end-stage renal disease will likely need a kidney transplant and/or dialysis, although fibrillary glomerulonephritis can recur after a kidney transplant.
TYPE OF DOCTOR AND DEPARTMENT: Kidney Specialist and Nephrologist Specialist can diagnose these disease.
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