Synopsis
Distinguish biopsy-proven IgA nephropathy from mimics, assess progression risk from proteinuria and eGFR trajectory, and apply contemporary supportive and specialist disease-modifying care.
- IgA nephropathy is defined by kidney-biopsy evidence of dominant or co-dominant mesangial IgA deposition in a compatible clinical setting; serum IgA is neither sensitive nor specific enough for diagnosis.
- Visible haematuria often begins during or within days of an upper-respiratory infection, unlike the longer latent interval typical of classic post-streptococcal glomerulonephritis.
- Presentation ranges from incidental microscopic haematuria to proteinuric CKD, nephrotic syndrome or rapidly progressive kidney failure, so the familiar young-adult vignette is incomplete.
- Sustained proteinuria and eGFR slope are central modifiable prognostic signals; haematuria supports activity but cannot alone determine treatment intensity.
- After biopsy, the International IgA Nephropathy Prediction Tool can inform shared prognostic discussion, but it does not prescribe a particular medicine.
- Optimised supportive care includes blood-pressure control, a single ACE inhibitor or ARB when appropriate, dietary sodium reduction, smoking cessation and cardiovascular-risk management.
- SGLT2 inhibition is considered for eligible CKD according to NICE and renal guidance, with sick-day, ketoacidosis and genital-infection counselling.
- Targeted-release budesonide and sparsentan now have NICE technology-appraisal routes for defined adults; selection, contraindications and funding criteria require specialist confirmation.
- Sparsentan replaces rather than accompanies ACE inhibitor or ARB therapy because of overlapping renin–angiotensin effects and requires pregnancy and liver-safety controls.
- Systemic glucocorticoid benefit must be weighed against substantial infection and metabolic toxicity; it is not a reflex response to crescents or persistent microscopic haematuria.
- Rapid eGFR decline with extensive crescents represents a distinct emergency and is managed through a specialist rapidly progressive GN pathway after excluding other causes.
Key red flags
Prolonged heavy haematuria can cause tubular obstruction and pigment injury, especially in older adults; a creatinine rise still requires exclusion of obstruction and crescentic disease.
A substantial eGFR fall over weeks with active sediment and crescents is uncommon but time-critical; urgent biopsy-led nephrology treatment is required.
Investigation priorities
Document haematuria, quantify albumin and total protein and identify an active glomerular sediment.
Management branches
Persistent glomerular haematuria, proteinuria or recurrent infection-associated visible haematuria raises IgA nephropathy.
- Check blood pressure, kidney trajectory, quantitative proteinuria and urine microscopy, and assess for systemic vasculitis, liver disease, infection and alternative immune disease.
- Refer according to urgency and NICE kidney criteria; discuss biopsy when results would define diagnosis, prognosis or treatment and control bleeding risk before the procedure.
- After histological confirmation, document MEST-C, baseline eGFR slope and protein burden and agree an individual monitoring and supportive-care plan.
Key medicines
ACE inhibitor or ARBUse one licensed agent, beginning cautiously and titrating to the highest tolerated dose with biochemical monitoring.Check creatinine and potassium after changes; avoid dual blockade and do not use in pregnancy, severe hyperkalaemia or unstable hypovolaemic AKI.
SGLT2 inhibitorUse the licensed once-daily CKD dose only when current NICE eligibility and eGFR criteria are met.Counsel about temporary withholding during serious illness or fasting, genital infection and rare euglycaemic ketoacidosis; specialist advice may be needed at low eGFR.