A multi-center retrospective cohort study defines the spectrum of kidney pathology in Coronavirus 2019 Disease (COVID-19).

Kidney failure is common in patients with Coronavirus Disease-19 (COVID-19), resulting in increased morbidity and mortality. In an international collaboration, 284 kidney biopsies were evaluated to improve understanding of kidney disease in COVID-19. Diagnoses were compared to five years of 63,575 native biopsies prior to the pandemic and 13,955 allograft biopsies to identify diseases that have increased in patients with COVID-19. Genotyping for APOL1 G1 and G2 alleles was performed in 107 African American and Hispanic patients. Immunohistochemistry for SARS-CoV-2 was utilized to assess direct viral infection in 273 cases along with clinical information at the time of biopsy. The leading indication for native biopsy was acute kidney injury (45.4%), followed by proteinuria with or without concurrent acute kidney injury (42.6%). There were more African American patients (44.6%) than patients of other ethnicities. The most common diagnosis in native biopsies was collapsing glomerulopathy (25.8%), which was associated with high-risk APOL1 genotypes in 91.7% of cases. Compared to the five-year biopsy database, the frequency of myoglobin cast nephropathy and proliferative glomerulonephritis with monoclonal IgG deposits was also increased in patients with COVID-19 (3.3% and 1.7%, respectively), while there was a reduced frequency of chronic conditions (including diabetes mellitus, IgA nephropathy, and arterionephrosclerosis) as the primary diagnosis. In transplants, the leading indication was acute kidney injury (86.4%), for which rejection was the predominant diagnosis (61.4%). Direct SARS-CoV-2 viral infection was not identified. Thus, our multi-center large case series identified kidney diseases that disproportionately affect patients with COVID-19 and demonstrated a high frequency of APOL1 high-risk genotypes within this group, with no evidence of direct viral infection within the kidney.

Abdominal compartment syndrome and acute kidney injury due to excessive auto-positive end-expiratory pressure.

Abdominal compartment syndrome is an under-recognized cause of acute kidney injury in critically ill patients. We report a case of a patient with severe obstructive lung disease who, while intubated for respiratory failure, developed abdominal compartment syndrome and oliguric acute kidney injury due to air-trapping and excessive auto-positive end-expiratory pressure (auto-PEEP; also known as intrinsic PEEP). When chemical paralysis was initiated and the auto-PEEP resolved, the patient's intra-abdominal hypertension rapidly improved and kidney function recovered immediately. Abdominal compartment syndrome secondary to excessive auto-PEEP appears to be unreported in the literature; however, any process that significantly increases intrathoracic pressure conceivably could cause increased pressure to be transmitted to the abdominal compartment, resulting in organ failure. Patients undergoing mechanical ventilation, which puts them at risk of airflow obstruction and the development of intra-abdominal hypertension, should be evaluated for air-trapping and excessive auto-PEEP.