Conditions · Nephrology and urology
Lupus nephritis !
Lupus nephritis is kidney inflammation caused by systemic lupus. It can cause blood and protein in the urine and, without treatment, kidney failure.
Updated 2026-11-01
Structures involved
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In the clinical exam
Why it happens
- Mediators of inflammation: the table to know
- Innate and adaptive immunity: overview
- Glomerular filtration: the barrier and its determinants
- Glomerulus and the filtration barrier: podocytes, mesangium, JGA
What it is
Kidney involvement in systemic lupus erythematosus, mainly an immune-complex glomerulonephritis. It ranges from mild urinary changes to nephritic or nephrotic syndrome and rapidly progressive kidney failure, and is one of the main causes of death and disability in lupus.
Who gets it
About a third to a half of adults with lupus develop nephritis, usually within the first five years of the disease. It is more frequent and more severe in women of childbearing age and in people of Hispanic/Latin American, African and Asian ancestry, so it is a common cause of glomerular disease and of dialysis in young women in Colombia and Latin America.
Causes
- Systemic lupus erythematosus with autoantibodies (anti-dsDNA) and immune-complex deposition in the glomeruli
- Genetic susceptibility combined with hormonal and environmental triggers
- Flares often triggered by infections, pregnancy or stopping treatment
Risk factors
- Female sex and age 15–45 years
- Hispanic, African or Asian ancestry
- Early-onset lupus and childhood lupus
- High anti-dsDNA titres and low complement (C3, C4)
- Antiphospholipid antibodies
- Poor adherence to treatment
Pathophysiology
Immune complexes formed by antibodies against nuclear antigens (such as anti-dsDNA) deposit in the mesangium and in subendothelial or subepithelial sites of the glomerulus. They activate complement and recruit inflammatory cells, which damages the capillaries and causes haematuria, proteinuria and loss of filtration. Subendothelial deposits produce proliferative lesions (classes III–IV, the most aggressive), while subepithelial deposits give a membranous pattern (class V) with nephrotic-range proteinuria.
Classification
- ISN/RPS classes: I minimal mesangial, II mesangial proliferative
- Class III focal and class IV diffuse proliferative (diffuse is the most common and severe)
- Class V membranous (nephrotic syndrome)
- Class VI advanced sclerosing (more than 90% sclerosed glomeruli)
Symptoms and signs
- Often silent at first: found as proteinuria or haematuria on routine urine tests
- Foamy urine and swelling of the legs, face or around the eyes
- Dark or cola-coloured urine
- New or worsening high blood pressure
- Weight gain from fluid retention
- Other lupus features at the same time: rash, joint pain, fever, mouth ulcers, serositis
Diagnosis
- Clinical
- Screening every person with lupus regularly with blood pressure and urinalysis; looking for oedema, hypertension and signs of a systemic flare.
- Tests
- Urinalysis with active sediment (dysmorphic red cells, red cell casts); urine protein-to-creatinine ratio; creatinine and eGFR; anti-dsDNA rising with low C3 and C4 during activity; antinuclear antibodies and antiphospholipid antibodies. Kidney biopsy is the key test: it gives the ISN/RPS class and the activity and chronicity, which guide treatment.
- Imaging
- Kidney ultrasound to assess size and guide the biopsy; Doppler if renal vein thrombosis is suspected.
Differential diagnosis
- Other glomerulonephritides (IgA nephropathy, post-infectious, ANCA vasculitis)
- Primary membranous nephropathy (anti-PLA2R positive)
- Drug-induced acute interstitial nephritis
- Thrombotic microangiopathy from antiphospholipid syndrome
- Pre-renal or acute tubular injury in a sick patient with lupus
Goal of treatment
Achieve complete renal remission (low proteinuria with stable kidney function), prevent flares and progression to kidney failure, and limit the adverse effects of immunosuppression.
Treatment
- Medical
- Hydroxychloroquine for every patient with lupus unless contraindicated, as background therapy that lowers flares.
- Medical
- Classes III–IV (± V): induction with glucocorticoids plus mycophenolate or cyclophosphamide, sometimes with newer agents such as belimumab or calcineurin inhibitors; maintenance with mycophenolate or azathioprine for years.
- Medical
- ACE inhibitors or ARBs for proteinuria and blood pressure; statins, diuretics and anticoagulation when indicated (for example with antiphospholipid syndrome).
- Lifestyle
- Low-salt diet, sun protection, vaccination before immunosuppression and planning of pregnancy during disease remission.
- Follow-up
- Monitoring and nursing care: blood pressure, weight and oedema, urine protein, creatinine and complement on a schedule; watching for infection, cytopenias, glucose rise and other drug adverse effects; supporting adherence.
Drugs for this condition
Complications
- Chronic kidney disease and end-stage kidney disease needing dialysis or transplant
- Hypertension and accelerated cardiovascular disease
- Thrombosis, especially with antiphospholipid antibodies or nephrotic syndrome
- Infections and other adverse effects of immunosuppression
- Pregnancy complications: preeclampsia, fetal loss, flare
Prognosis
With modern treatment most patients reach partial or complete remission, but relapses are common. Proliferative classes, delayed treatment, high creatinine at diagnosis, persistent proteinuria and poor adherence predict progression; about one in ten patients with lupus nephritis eventually needs kidney replacement therapy.
Prevention
- Regular urine and blood pressure screening in everyone with lupus
- Continuous hydroxychloroquine and adherence to treatment
- Early biopsy and treatment when proteinuria or active sediment appear
Test yourself
Think of the answer, then tap the question to see it.
Which kidney biopsy class is the most common and most severe form of lupus nephritis?
Class IV, diffuse proliferative lupus nephritis.
Which blood tests rise and fall when lupus nephritis is active?
Anti-dsDNA antibodies rise while complement C3 and C4 fall.
Which lupus nephritis class presents mainly with nephrotic syndrome?
Class V, membranous lupus nephritis, from subepithelial immune deposits.
Which two drugs are classic options for induction in proliferative lupus nephritis together with glucocorticoids?
Mycophenolate or cyclophosphamide.
Which test is essential to classify lupus nephritis and guide treatment?
Kidney biopsy, interpreted with the ISN/RPS classification.
Related conditions
- Systemic lupus erythematosus
- Nephrotic syndrome
- Rapidly progressive glomerulonephritis (anti-GBM, ANCA)
- Antiphospholipid syndrome
- Acute kidney injury
- Chronic kidney disease
- Arterial hypertension
- Kidney transplant rejection
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Lupus nephritis: MedlinePlus Medical Encyclopedia (MedlinePlus (U.S. National Library of Medicine), 2024); Lupus & Kidney Disease (Lupus Nephritis) (NIDDK (National Institutes of Health), 2024).
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