Adult Nephrotic Syndrome Management
On this page
Direct answer
More than 3.5 g of urinary protein per day (or per 1.73 m²), serum albumin under 3 g/dL, and oedema define the nephrotic syndrome in an adult — and the first task is excluding secondary causes (diabetes, lupus, hepatitis B and C, HIV, drugs such as NSAIDs and lithium, and solid malignancy in older patients) before labelling it a primary glomerulopathy. Membranous nephropathy is the commonest pattern in older adults, minimal change disease in younger ones, and FSGS figures prominently in Indian biopsy registries. Management rests on four pillars: salt restriction (under 5 g/day) with loop diuretics for oedema, ACE inhibitor or ARB for proteinuria, statin for hyperlipidaemia, and anticoagulation consideration when serum albumin falls below about 2.5 g/dL; immunosuppression (steroids, calcineurin inhibitors, rituximab) is chosen by histology rather than applied blindly.
What you must remember
- Definition: proteinuria over 3.5 g/day/1.73 m², hypoalbuminaemia under 3 g/dL, generalised oedema, hyperlipidaemia and lipiduria (oval fat bodies, fatty casts, "Maltese cross" under polarised light).
- Histology-age map: minimal change disease dominates under 40 (and causes most childhood nephrotic syndrome); membranous nephropathy peaks in older adults; FSGS is the commonest pattern in several Indian and South Asian biopsy registries; membranoproliferative GN enters with hepatitis C and cryoglobulins.
- Secondary screen before "primary": fasting glucose and HbA1c, ANA and dsDNA, hepatitis B and C serology, HIV, complement C3-C4, and in over-50s a malignancy review (membranous association with solid tumours).
- PLA2R antibody: anti-phospholipase A2 receptor antibodies mark primary membranous nephropathy, correlate with activity and allow monitoring without repeated biopsies.
- Edema strategy: salt under 5 g/day, loop diuretic (furosemide, adding a thiazide for resistance), gentle fluid restriction — under-perfusion of the kidney in "overfilled" nephrotic states makes over-diuresis a recognised cause of AKI.
- Thrombosis risk: renal vein thrombosis and venous thromboembolism rise steeply when albumin is under 2.5 g/dL (membranous disease worst); anticoagulation is strongly considered at that threshold, balanced against bleeding risk.
- Infection susceptibility: urinary losses of IgG and complement-related factors predispose to pneumococcal peritonitis and cellulitis — vaccinate (pneumococcal, influenza) and have a low threshold for cultures.
Managing a new adult presentation
A 45-year-old presents with a month of progressive leg swelling and frothy urine; albumin 2.0 g/dL, proteinuria 6.8 g/day, cholesterol high, creatinine near normal, no diabetes, serology negative. The sequence: exclude secondary causes with the panel above, check PLA2R while awaiting biopsy (which shows membranous nephropathy with spike-and-dome basement membrane changes on silver stain), and start the four-pillar baseline — salt restriction, furosemide for oedema, an ACE inhibitor titrated to blood pressure and proteinuria, and a statin. Because the albumin is under 2.5 g/dL, thromboprophylaxis is discussed; sudden loin pain with haematuria during the illness is renal vein thrombosis until proven otherwise and earns a CT renal venogram.
Immunosuppression then follows the histology. Minimal change disease in a younger adult gets prednisolone 1 mg/kg/day for a minimum of four weeks (children-classic 8-12 week schedules adapted), with relapsers moving to calcineurin inhibitors or rituximab. Membranous disease at high risk (proteinuria persistently over 4 g/day despite six months of conservative care) moves to rituximab, cyclophosphamide plus steroids, or a calcineurin inhibitor per current KDIGO guidance. FSGS gets steroids first in the steroid-naive, calcineurin inhibitors next — and every one of these paths keeps the ACE inhibitor running underneath, because reducing intraglomerular pressure protects regardless of mechanism.
Where students slip
The examinable trap is treating the oedema aggressively in a child or adult with minimal change disease: brisk diuresis in a hypoalbuminaemic, intravascularly dry patient precipitates AKI and thrombosis, so the viva answer pairs "salt restriction plus judicious loop diuretic" with daily weight, not a diuresis target. The second slip is forgetting the hypercoagulable state — a stem describing nephrotic syndrome with sudden flank pain and haematuria is renal vein thrombosis, and the expected answer is anticoagulation with imaging, not antibiotics for "pyelonephritis". Indian viva boards also probe the steroid regimens by name (daily versus alternate-day prednisolone, duration before declaring steroid resistance) and expect the candidate to distinguish steroid-dependent, frequently relapsing and steroid-resistant labels precisely.
Frequently asked questions
What proteinuria level defines the nephrotic syndrome in adults?
More than 3.5 g per day per 1.73 m² body surface area, accompanied by hypoalbuminaemia under 3 g/dL, oedema and hyperlipidaemia.
Which antibody distinguishes primary membranous nephropathy?
Anti-phospholipase A2 receptor (PLA2R) antibodies, which support a primary (autoimmune) cause, track disease activity and obviate repeat biopsies for monitoring.
At what albumin level is anticoagulation considered in nephrotic syndrome?
Below about 2.5 g/dL, particularly in membranous disease, where renal vein and venous thromboembolism risk rises steeply — weighed against individual bleeding risk.
Which infections are nephrotic patients prone to, and why?
Pneumococcal peritonitis, cellulitis and urinary infections, from urinary losses of IgG and factor B — hence pneumococcal and influenza vaccination as standard care.
What is first-line therapy for minimal change disease in an adult?
Daily prednisolone at 1 mg/kg (commonly for up to 16 weeks before taper, per typical regimens), with calcineurin inhibitors or rituximab for frequent relapses or steroid dependence.