The glomeruli are the kidney's filters — about a million of them per kidney, each a tuft of capillaries that lets water and waste through while holding protein and blood cells back.
When they become inflamed, protein and blood leak into the urine. Most patients feel nothing at all.
The biopsy that comes too late
Glomerular disease is usually found on a urinalysis and then watched. Protein is noted. The creatinine is normal, so there is no urgency. Blood pressure medication is adjusted. Everyone waits to see what happens.
What happens is scarring. Inflamed glomeruli do not stay inflamed indefinitely — they sclerose. A glomerulus that has scarred does not come back, and no immunosuppression recovers it. A rapidly progressive glomerulonephritis can take the kidney in weeks.
The biopsy is what names the disease, and the disease determines whether you need nothing, steroids for six weeks, or rituximab for two years. Deferring the biopsy does not defer the decision. It makes the decision by default, in favor of doing nothing, while nephrons are lost.
If you have protein in your urine, or protein and blood together, and the plan has been to recheck in six months — ask what is being waited for.
Board-certified nephrology at Remix Medical in Houston. Call (713) 597-5131 or book online.
Why the specific diagnosis matters
These diseases look alike from the outside. Protein in the urine. Sometimes blood. Sometimes swelling. Sometimes a rising creatinine.
They behave nothing alike. One resolves on its own. One responds to steroids within weeks. One requires immunosuppression for years. One does not respond to immunosuppression at all, and treating it that way causes harm without benefit.
A kidney biopsy is what separates them. The tissue is examined three ways — light microscopy, immunofluorescence, and electron microscopy — and the diagnosis often depends on all three. There is no blood test that substitutes.
| Glomerular disease | Hallmark |
|---|---|
| IgA nephropathy | Blood in the urine, often after an infection; the most common worldwide |
| Membranous nephropathy | Heavy protein loss; often linked to anti-PLA2R antibodies |
| FSGS | Scarring of the filters; a common cause of nephrotic syndrome in adults |
| Minimal change disease | Sudden nephrotic syndrome; most common in children |
| MPGN | Immune- or complement-driven; requires a hunt for the underlying cause |
IgA Nephropathy
The most common primary glomerular disease worldwide. IgA antibodies deposit in the glomerulus, often after a respiratory infection — classically, visible blood in the urine within a day or two of a sore throat.
Course varies enormously. Many never progress. Perhaps a quarter to a third reach kidney failure over decades. Proteinuria is the strongest predictor, and reducing it changes the trajectory. New targeted therapies have arrived in the last few years.
Nephrotic Syndrome
Not a disease but a pattern: heavy proteinuria above 3.5 grams daily, low blood albumin, swelling, and high cholesterol.
It carries its own dangers regardless of cause — blood clots, infection, severe edema. Several of the diseases below present this way, which is why identifying the underlying cause is the first task.
Membranous Nephropathy
A leading cause of nephrotic syndrome in adults. Antibodies, usually against the PLA2R receptor, deposit along the glomerular basement membrane.
Roughly a third remit spontaneously, a third remain stable, a third progress. The anti-PLA2R antibody can be measured in blood and helps decide who needs immunosuppression and who can be watched. Rituximab is now first-line for those who need treatment.
Focal Segmental Glomerulosclerosis (FSGS)
Scarring in parts of some glomeruli. Primary FSGS is an immune-mediated podocyte disease. Secondary FSGS results from obesity, prior nephron loss, viral infection, or medication — and it does not respond to immunosuppression, which is why the distinction is essential rather than academic.
APOL1 risk variants, present in a substantial minority of people of West African ancestry, markedly increase risk and accelerate progression.
Minimal Change Disease
The glomeruli look normal under a light microscope. Only electron microscopy reveals the abnormality.
The most common cause of nephrotic syndrome in children and a real cause in adults. Highly steroid-responsive — most remit within weeks. Relapse is common but the long-term kidney outlook is generally excellent.
Membranoproliferative Glomerulonephritis (MPGN)
A pattern rather than a single disease. Modern classification asks what is driving it: immune complexes from chronic infection, autoimmune disease, or monoclonal protein; or dysregulation of the complement system.
That classification is the treatment. Finding the underlying cause, particularly a hidden infection or a monoclonal gammopathy, is more important than any immunosuppressive protocol.
What we do
We quantify the protein, examine the urine sediment for red cell casts and dysmorphic red cells, run the serologies that identify autoimmune and infectious causes, and image the kidneys.
We determine whether a biopsy will change management and confirm it is safe to perform. We coordinate the procedure with an interventional radiologist, interpret the pathology, and build the treatment plan from what the tissue shows.
And we treat what is common to all of them: proteinuria reduction with ACE inhibitors or ARBs and SGLT2 inhibitors, blood pressure to target, and management of the clotting and infection risks that come with heavy protein loss.
Protein in the urine is not a finding to monitor indefinitely. It is a question with an answer, and the answer is in the tissue.
Call (713) 597-5131 or book online.