Multicenter Clinicopathologic Correlation of Kidney Biopsies Performed in COVID-19 Patients Presenting With Acute Kidney Injury or Proteinuria.

RATIONALE & OBJECTIVE: Kidney biopsy data inform us about pathologic processes associated with infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We conducted a multicenter evaluation of kidney biopsy findings in living patients to identify various kidney disease pathology findings in patients with coronavirus disease 2019 (COVID-19) and their association with SARS-CoV-2 infection. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: We identified 14 native and 3 transplant kidney biopsies performed for cause in patients with documented recent or concurrent SARS-CoV-2 infection treated at 7 large hospital systems in the United States. OBSERVATIONS: Men and women were equally represented in this case series, with a higher proportion of Black (n=8) and Hispanic (n=5) patients. All 17 patients had SARS-CoV-2 infection confirmed by reverse transcriptase-polymerase chain reaction, but only 3 presented with severe COVID-19 symptoms. Acute kidney injury (n=15) and proteinuria (n=11) were the most common indications for biopsy and these symptoms developed concurrently or within 1 week of COVID-19 symptoms in all patients. Acute tubular injury (n=14), collapsing glomerulopathy (n=7), and endothelial injury/thrombotic microangiopathy (n=6) were the most common histologic findings. 2 of the 3 transplant recipients developed active antibody-mediated rejection weeks after COVID-19. 8 patients required dialysis, but others improved with conservative management. LIMITATIONS: Small study size and short clinical follow-up. CONCLUSIONS: Cases of even symptomatically mild COVID-19 were accompanied by acute kidney injury and/or heavy proteinuria that prompted a diagnostic kidney biopsy. Although acute tubular injury was seen among most of them, uncommon pathology such as collapsing glomerulopathy and acute endothelial injury were detected, and most of these patients progressed to irreversible kidney injury and dialysis.

Disseminated cryptococcosis associated with administration of eculizumab.

PURPOSE: A case report of fatal disseminated cryptococcosis in a patient treated with eculizumab is presented along with a review of literature suggesting a possible etiologic mechanism. SUMMARY: A 23-year-old man with a history of minimal change nephrotic syndrome was hospitalized for acute kidney injury and abdominal pain and swelling. He was found to have disseminated pneumococcal disease, including peritonitis, bacteremia, and pulmonic endocarditis. The patient developed evidence of microangiopathic hemolytic anemia, leading to a diagnosis of atypical hemolytic uremic syndrome, and was started on eculizumab. The patient initially improved but developed septic shock 18 days after the first dose of eculizumab. All subsequent blood, respiratory, and intraabdominal cultures grew Cryptococcus neoformans. Twenty-eight days after the initial dose of eculizumab, the patient died. Autopsy findings demonstrated disseminated cryptococcosis, with infection noted in lung, myocardial, kidney, and liver tissues. Considering the complement-dependent nature of host defenses against Cryptococcus species and available evidence regarding C. neoformans pathogenicity from studies of murine models, it was hypothesized that the patient's cryptococcosis and death were secondary to administration of eculizumab and consequent blockage of the C5 component of the complement cascade. Eculizumab is known to predispose recipients to infections with encapsulated organisms; however, this was believed to be the first reported case of infection with an encapsulated yeast possibly due to eculizumab use. Patients receiving eculizumab should be monitored closely for invasive cryptococcal infections. CONCLUSION: A 23-year-old man developed fatal disseminated cryptococcosis after treatment with eculizumab.

Giant cell tubulitis with tubular basement membrane immune deposits: a report of two cases after cardiac valve replacement surgery.

This paper presents two elderly patients who had normal baseline renal function and had stenotic valvular lesions secondary to rheumatic fever and underwent aortic valve replacements with mechanical valves. Both patients developed acute renal failure after cardiac valve replacement procedures. The renal biopsies revealed acute granulomatous tubulointerstitial nephritis. The unique histologic features were tubular basement membrane (TBM) immune complex deposition detected by both immunofluorescence and electron microscopy and prominent multinucleated giant cells surrounding intact TBM. The temporal relationship to the surgical procedure and the subsequent recovery of the patients' renal functions upon therapy suggested that the renal failure may have been due to an allergic drug reaction from the perioperative exposure to unknown agents, such as prophylactic antibiotics and furosemide. The literature on TBM immune complex deposition was reviewed, and the pathophysiologic mechanisms that may account for the similarities between the clinicopathologic features of these two cases were examined. These two cases expand the histopathologic spectrum of previously described cases of putative drug-induced acute tubulointerstitial nephritis.