Mitigated Clinical Course of Crescentic Glomerulonephritis with Positive Anti-Glomerular Basement Membrane Antibodies in a 14-Year-Old Girl

Abstract

Introduction: Anti-glomerular basement membrane (anti-GBM) glomerulonephritis is associated with severe kidney failure and high morbidity and is exceedingly rare in children. The few pediatric studies published about this condition report dependency of kidney replacement therapy at presentation and partial or complete response in kidney function in a minority of cases.

Case presentation: We describe the case of a 14-year-old girl with crescentic glomerulonephritis based on double positive anti-GBM and myeloperoxidase-antineutrophil cytoplasmic antibodies with a mitigated clinical course presenting with fatigue, anemia, and an estimated glomerular filtration rate range between 34 and 42 mL/min/1.73 m². Response to treatment with daily therapeutic plasma exchanges, corticosteroids, and oral cyclophosphamide was prompt.

Conclusion: This ultrarare presentation highlights the need to consider determining anti-GBM antibodies and/or obtaining a kidney biopsy even in children with less severe presentations of unexplained glomerulonephritis and underlines the clinical treatment dilemma in this disease for children due to the potential long-term sequelae.

Keywords: Anti-glomerular basement membrane glomerulonephritis; Antineutrophil cytoplasmic antibody-associated vasculitis; Chronic kidney disease; Cyclophosphamide; Pediatric nephrology.

Fig. 1.

Course of estimated glomerular filtration rate (eGFR), anti-GBM, and MPO-ANCA antibodies. eGFR is estimated using the Schwartz equation (0.413 × height [cm]/serum creatinine [mg/dL]). Day 0 is the starting day of treatment according to the 2021 KDIGO glomerular diseases guideline (total follow-up time 102 days). Therapeutic plasma exchange (TPE; green) was continued for 2 weeks when anti-GBM and MPO-ANCA antibodies became undetectable. Oral cyclophosphamide (CPO; red) was discontinued after 18 days and switched to oral mycophenolate mofetil (MMF; black; current treatment). Corticosteroids (CS; blue) were given as three pulses of methylprednisolone and continued for 4 weeks of oral prednisolone in a 1 mg/kg daily dosage and then tapered to 0.6 mg/kg (total duration: 2 weeks), 0.5 mg/kg (total duration: 2 weeks), and 0.3 mg/kg (current treatment).

Fig. 2.

Histological images of the kidney biopsy. a Representative microphotograph (PAS staining; original magnification ×20) of two glomeruli, with segmental destruction of the capillary tuft by fibrocellular crescents. The surrounding parenchyma shows interstitial fibrosis and interstitial inflammation. b Immune fluorescence image (IgG staining, DAPI background staining; magnification ×20), showing weak-to-moderate linear staining of IgG.