A 35-year-old man presents with macroscopic hematuria coinciding with an upper respiratory tract infection (synpharyngitic hematuria). Urine shows dysmorphic red blood cells and red cell casts. Kidney biopsy shows mesangial IgA deposits on immunofluorescence. Which histological finding on the Oxford MEST-C score predicts the worst long-term renal outcome?

• A Mesangial hypercellularity (M1)
• B Endocapillary hypercellularity (E1)
• C Segmental glomerulosclerosis (S1)
• D Crescents (C2: >25% glomeruli with crescents) ✓

Explanation

The Oxford MEST-C classification for IgA nephropathy includes: M (mesangial hypercellularity), E (endocapillary hypercellularity), S (segmental sclerosis), T (tubular atrophy/interstitial fibrosis), and C (crescents). The T score (T1/T2) and C score (C2) carry the worst prognosis for progression to ESRD. C2 (crescents in >25% glomeruli) indicates aggressive disease warranting immunosuppression. T score (tubular atrophy) reflects irreversible damage.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.