Kidney biopsy in patients with antineutrophil cytoplasmic antibody-associated vasculitis with mild renal abnormality

An unusual complication of kidney biopsy: a case report

BACKGROUND

The kidney biopsy is a routine procedure. Once an indication has been established, the benefit-risk balance may be considered. Sometimes, even with effective treatment, a severe complication may develop.

CASE PRESENTATION

We present the case of a Caucasian 20-year-old young woman admitted to investigating and treating acute kidney injury. Renal involvement was characterized by kidney damage requiring hemodialysis treatment, positive immunologic testing, 0.5 g/day proteinuria, and microscopic hematuria. Contraindications were excluded, so an ultrasound-guided kidney biopsy was performed. To reduce the bleeding complication, Octostim (desmopressin) was administered. There were no direct complications following the kidney biopsy, so we continued the immunosuppressive treatment. Histologically founded thrombotic microangiopathy. However, 1 week later, severe bleeding developed with the need for urgent surgical left kidney removal.

CONCLUSION

Kidney biopsy can be considered a routine procedure, and various bleeding episodes are most common in terms of complications, the detection of which is essential. Delayed bleeding complications are rare and can be caused by minor injuries. Our young patient had no injury during the hospitalization. We hypothesized that the developed serious and delayed bleeding complication resulted from effective immunosuppressive treatment. To the best of our knowledge, this is the first such case to date. However, renal biopsy in the case of thrombotic microangiopathy requires caution.

The correlation of interstitial change with renal prognosis in patients with myeloperoxidase-ANCA-associated glomerulonephritis: a single-center retrospective analysis

OBJECTS

We aim to explore the correlation between active/chronic tubulointerstitial injury and renal survival, and to compare their predictive value in patients with myeloperoxidase (MPO)-anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (AAGN).

METHOD

A total of 225 patients with MPO-AAGN diagnosed between February 2004 and December 2020 were included. Survival and univariate/multivariate Cox regression analyses were used to analyze the prognostic value of interstitial inflammation and interstitial fibrosis/tubular atrophy (IF/TA).

RESULTS

Of the 225 patients, 73 (32.4%) patients developed end-stage renal disease (ESRD) requiring maintenance dialysis. Interstitial inflammation>50% and IF/TA>50% were important predictors for ESRD in MPO-AAGN in multivariate Cox regression analysis adjusted by age, gender, estimated glomerular filtration rate (eGFR)≤15 ml/min/1.73m2, and normal glomeruli% (classified by <25%, 25-50%, >50%). Furthermore, we conducted stratified Cox regression analysis and found different results in the subgroups of eGFR>15 ml/min/1.73m2 and eGFR≤15 ml/min/1.73m2. Interstitial inflammation>50% and IF/TA>50% were significant risk factors for ESRD in the subgroup of eGFR>15 ml/min/1.73m2, but not or less significant in the subgroup of eGFR≤15 ml/min/1.73m2. Similarly, the survival analysis according to interstitial inflammation>50%/≤50% and IF/TA>50%/≤50% showed significant differences in the subgroup of eGFR>15 ml/min/1.73m2, but not or less significant in the subgroup of eGFR≤15 ml/min/1.73m2.

CONCLUSIONS

Interstitial inflammation>50% and IF/TA>50% were prognostic factors for renal survival in MPO-AAGN. In particular, interstitial inflammation and IF/TA had a better predictive ability in the subgroup of eGFR>15 ml/min/1.73m2. Key Points • Interstitial inflammation>50% and IF/TA>50% can help to predict renal survival in MPO-AAGN. • Both interstitial inflammation and IF/TA had a better predictive ability in the subgroup of eGFR>15 ml/min/1.73m2 than those in the subgroup of eGFR≤15 ml/min/1.73m2.