Probenecid-Induced IgA Nephropathy Is Reversible

Introduction: IgA nephropathy is usually idiopathic in nature but can have a genetic predisposition & it can also be secondary to autoimmune diseases, vasculitis, infections, liver disease, or anti-VEGFdrugs like bevacizumab, & covid vaccine. We present a case of probenecid-induced IgA nephropathy. Case Description: A 65-year-old male with chronic gout developed progressive chronic kidney disease over a 3-year period. He had been on probenecid 1 g twice daily for his gout for 15 yrs. His sodium iothalamate clearance deteriorated to 58 mL/min, with a serum creatinine of 1.5 mg/dL. All other serologic tests were negative. His 72-hour lead level was also normal. He did not have SLE, granulomatous disease, or systemic rheumatic disorders. Suprisingly he did not have proteinuria or hematuria. Renal biopsy revealed IgA nephropathy, with segmental mesangial hypercellularity, mild arterial sclerosis, & tubular atrophy. Cytoplasmic lipofuscin pigment was noted on PAS stain capillary loops with focal thickening of the glomerular basement membrane, engorged capillary loops, & thickened tubular basement membrane. Immunofluorescence studies showed diffuse segmental paramesangial granules of IgA [3+] & fibrinogen as well as paramesangial granules of IgG [2+], Kappa & lambda. Electron microscopy showed swollen podocytes with increased cytoplasmic organelles and vacuolization, focal foot process effacement, & electron-dense deposits in the paramesangium & mesangium. His MEST score was zero. 6 months after discontinuation of probenecid, the patient's iothalamate GFR significantly improved to 79 mL/min, followed by 82 mL/min 6 months later. He never had proteinuria, hematuria, or casts throughout his disease course. Five years later his GFR was 88 ml/min with a serum creatinine of 1.1 mg/dl. Discussion(s): Probenecid has pleiotropic effects on the human immune system. It inhibits Pannexin-1 channels which are known to modulate T-cell function. Probenecid also regulates TRPV -2 channels as an agonist. These channels are also present on human immune B and T cell lymphocytes. Probenecid inhibits VEGF in retinal endothelial cells, & bevacizumab, an anti-VEGF monoclonal antibody, has been shown to cause IgA nephropathy. We conclude that probenecid can be a cause of IgA nephropathy which is reversible upon drug discontinuation.

Extracorporeal cytokine reduction using oxiris blood purification in COVID-19

Introduction: Severe COVID-19 infection can cause 'cytokine storm' and endorgan dysfunction. OXIRIS, a blood-purification filter, was recently approved by the FDA under emergency use authorization for this indication due to its ability to remove cytokines and endotoxin through its AN-69ST membrane. We describe our experience with the first two cases treated at our institution. Case Description: Case 1: 58 year-old female patient with a baseline creatinine of 0.8 mg/dL & history of hemoglobin SC disease was admitted with respiratory failure due to COVID-19 infection. She deteriorated on hospital day (HD) 6 and was intubated. She received broad-spectrum antibiotics and convalescent plasma. On HD 15 she had increasing vasopressor requirement, anuric AKI and was started on continuous renal replacement therapy (CRRT). Due to worsening clinical status on HD18 she was started on the OXIRIS hemofilter through the CRRT circuit for 48 hours. Oxygenation improved and there was some improvement in inflammatory markers (IM) (table 1), however, the family withdrew care on HD 20. Case 2: 29-year-old male with no prior past medical history apart from morbid obesity presented with fever and dry cough in the setting of recent COVID-19 exposure. He was found to be COVID-19 positive and rapidly deteriorated with resultant intubation on HD4. He received hydroxychloroquine, doxycycline, remdesivir and convalescent plasma. OXIRIS hemoperfusion was initiated on HD8 due to worsening hypoxia despite high FiO2. Oxygenation improved by HD10 (table 1) and he was successfully extubated on HD16. Discussion: We present our first 2 cases using the OXIRIS hemofilter. We treated the patients for 48 hours with a scheduled filter exchange at 24 hours. We used a blood flow of 250 ml/min and dialysate flow of 25 ml/kg/hour with either systemic heparin or regional citrate anticoagulation along with 1L/hr of pre-filter saline. For hemoperfusion we used the same parameters without dialysate. We observed rapid improvements in oxygenation (Figure 1). The findings are hypothesis generating though more data is needed to determine optimal timing and efficacy of this filter.

SARS COV-2 continuous quality improvement program: Initiation of a standardized protocol for AKI prevention

Background: During the initial phase of the SARS CoV-2 pandemic our institution had high rates of acute kidney injury (AKI) requiring renal replacement therapy (RRT). Nephrocheck (NC), a renal biomarker, indicating renal stress was the basis of a continuous quality improvement (CQI) program to identify patients at risk for AKI & RRT. Methods: Patients admitted from 4/17-5/15/2020 were all tested for SARS CoV-2. All positive patients ≥ 18 years old & with a creatinine <2.0 mg were tested with NC. Values ≥ 0.7 led to nephrology consults & utilization of a renal-protective strategy including monitoring volume status, scrutinizing nephrotoxic medications & urine studies. A 'Plan-Do-Study-Act' approach was used to increase utilization of NC and the resulting protocol for positive results. Intervention was biphasic with a follow up maintenance phase, each lasting 10 days. Phase 1 was adding NC to the SARS CoV2 admission order set & Phase 2 was educating hospitalist providers about using and interpreting NC to increase appropriate nephrology consults. Education was reinforced with protocol cards & reminders via encrypted text services. Additionally, intervention team members reviewed charts daily & reminded providers in real time. Results: In Phase 1, 58% of the SARS CoV-2 positive patients had a NC but only 48% of NC positive patients had a renal consult. In Phase 2, 79% of SARS CoV-2 positive patients had a NC with 80% of positive patients getting a renal consult. In the maintenance phase, 67% of SARS CoV-2 positive patients had NC with 59% of NC positive patients getting a renal consult. Conclusions: During our CQI project, efforts to mitigate severe AKI by using a biomarker-based alert for nephrology consultation saw the number of SARS CoV2 positive patients screened with NC & the number of positive NC patients seen by nephrologists rise significantly. Barriers to implementation included the weekly turn-over of house staff & a reliable alert system to ensure adequate screening. The multidisciplinary team reviewing charts and reminding hospitalists of the protocol also helped significantly but was difficult to sustain.