# Applied RPGN: ANCA Disease, IgA Vasculitis, and Dialysis

Use the clinical syndrome to recognize urgency, then tissue and serology to distinguish ANCA from IgA disease and choose the appropriate treatment pathway.

![Infographic: Applied RPGN: ANCA Disease, IgA Vasculitis, and Dialysis](https://urinenephrology.org/visual-reference/images/rpgn-cases.png?v=20261003c)

## Same emergency, different mechanism

Both cases combine rapid kidney decline with inflammatory urine findings. Obtain creatinine/urine-output trajectory, protein burden, sediment, complements, ANCA, anti-GBM, and targeted infection testing. Escalate immediately; do not wait for a fixed percentage GFR loss.

## Case 21: ANCA disease plus dialysis need

Treat refractory potassium, acid–base, volume, or uremic complications with KRT when indicated while investigating the vasculitis. Dialysis supports physiology; it does not treat vessel inflammation. Kidney biopsy activity/chronicity and systemic disease help frame recovery prospects.

## Interpret ANCA with tissue

PR3/MPO specificity and a pauci-immune necrotizing/crescentic pattern support AAV in context. Infection can produce misleading serology or overlapping findings. Rituximab/cyclophosphamide-based induction is a disease-specific decision; plasma exchange is reserved for selected severe presentations or anti-GBM overlap.

## Case 22: IgA vasculitis clues

Palpable purpura, abdominal pain, arthralgia, and kidney findings suggest IgA vasculitis. IgA-dominant skin deposits support the systemic diagnosis, but do not show kidney activity or scarring. Rapidly progressive renal disease requires renal assessment and often kidney tissue.

## Do not transfer chronic IgAN trials

A drug studied in stable primary IgA nephropathy is not automatically validated for rapidly progressive IgA vasculitis. Use the current disease-specific pathway and specialist input. Both cases need BP/volume management, infection prevention, and repeated electrolyte/kidney review alongside immunotherapy.

## Reassess response and harm

Track urine output, creatinine, proteinuria, pulmonary/systemic symptoms, CBC, and drug toxicity. New deterioration may mean ongoing inflammation, infection, thrombosis, or treatment harm. ADVOCATE’s 2026 retraction must remain explicit wherever historical avacopan results are discussed.

## Supporting evidence

- [Official clinical guidance](https://kdigo.org/wp-content/uploads/2024/05/KDIGO-2024-ANCA-Vasculitis-Guideline-Update.pdf)
- [Official clinical guidance](https://kdigo.org/guidelines/iga-nephropathy/)
- [Retraction notice for the ADVOCATE avacopan report (2026)](https://pubmed.ncbi.nlm.nih.gov/42377355/)

## Source lessons

- [case21 rpgn dialysis](https://urinenephrology.org/2025_UDPA_Lectures_Live/cases/case21_rpgn_dialysis.html)
- [case22 rpgn iga](https://urinenephrology.org/2025_UDPA_Lectures_Live/cases/case22_rpgn_iga.html)

Read alongside the full lessons; the findings and decisions shown here require the stated clinical context.