Lupus attacks the kidney in roughly half of people who have it. When it does, the kidney is usually the organ that determines the outcome.
It is also treatable. The difference between early treatment and late treatment is the difference between preserved kidney function and dialysis.
How it gets missed
Silently, and then through a urinalysis nobody chased.
Protein appears in the urine and creatinine rises before anything is felt. The urine gets checked, something is abnormal, and it is attributed to a urinary tract infection, or to the lupus generally, or to nothing in particular. Antibiotics, sometimes. A recheck in six months, sometimes.
If you have lupus and your only kidney monitoring is a creatinine, your kidneys are not being monitored. Creatinine rises late — it moves after nephrons are already gone. What is needed is a urinalysis with microscopy and a urine protein-to-creatinine ratio, together, regularly.
Red cell casts and dysmorphic red cells on microscopy mean active glomerular inflammation right now. That finding changes the urgency of everything that follows, and it is invisible on a dipstick and absent from a metabolic panel.
Waiting for symptoms means treating scar tissue.
Board-certified nephrology at Remix Medical in Houston. Call (713) 597-5131 or book online.
The biopsy is not optional
Lupus nephritis has six histologic classes, and the class determines the treatment.
Class I and II are mild and often need no immunosuppression. Class III and IV are proliferative, aggressive, and require aggressive therapy. Class V is membranous, presents with heavy proteinuria, and follows a different course. Class VI is scarred and does not respond to immunosuppression at all.
These cannot be distinguished by blood tests, urine findings, or serologies. A patient with Class IV and a patient with Class V may look identical on paper and need entirely different drugs.
We determine whether a biopsy is needed, confirm it is safe to perform, coordinate the procedure, and interpret the pathology. Treating lupus nephritis without a biopsy means guessing, and the cost of guessing wrong is the kidney.
Treatment
Induction brings the inflammation under control. Mycophenolate mofetil or low-dose intravenous cyclophosphamide, with corticosteroids.
Belimumab and voclosporin are both approved as additions and improve renal response rates meaningfully. Both are underused.
Maintenance continues for years, usually mycophenolate or azathioprine, because relapse is common and each relapse takes function.
Hydroxychloroquine for everyone with lupus, unless there is a reason not to. It reduces flares, reduces renal damage, and improves survival. Some patients stop it because they feel fine on it, which is precisely the point.
Alongside all of it: ACE inhibitors or ARBs to reduce proteinuria, blood pressure to target, and increasingly SGLT2 inhibitors.
| Class | What it means | General approach |
|---|---|---|
| Class I–II | Mild, confined to the mesangium | Monitor; treat the lupus itself |
| Class III–IV | Active inflammation (focal or diffuse) | Immunosuppression — the classes that most threaten the kidney |
| Class V | Membranous pattern, heavy protein loss | Immunosuppression plus protein-lowering therapy |
| Class VI | Advanced scarring | Focus shifts to kidney-failure planning |
What determines the outcome
How quickly treatment starts. How completely proteinuria resolves in the first year. Whether relapses are caught early. Whether hydroxychloroquine is continued.
Black and Hispanic patients develop lupus nephritis more often, progress faster, and respond less well to standard therapy. This is documented and it is not fully explained by access to care.
Pregnancy requires planning. Mycophenolate is teratogenic and must be stopped and replaced months in advance. This conversation should happen before a pregnancy, not during one.
If you have lupus and nobody has looked at your urine under a microscope, that is the appointment. Not a creatinine. The sediment.
Call (713) 597-5131 or book online.