Kidney disorders in the PICU: Thrombotic microangiopathies and glomerulonephritis

Abstract

Renal diseases presenting in the Pediatric Intensive Care Unit are diverse. Amongst the most severe lesions are the thrombotic microangiopathies (TMA) and the glomerulonephritides. Both clinical scenarios necessitate nephrology consultation to facilitate diagnosis and timely treatment initiation in order to limit renal mobidity. TMAs are represented by intravascular platelet aggregation, red blood cell shearing and thrombus formation. The resultant microangiopathic hemolytic anemia and thrombocytopenia are the clinical markers that suggest a risk for the ischemic loss of renal function. The broad differential for TMA includes typical hemolytic uremic syndrome (HUS), atypical hemolytic uremic syndrome (aHUS), and thrombotic thrombocytopenic purpura (TTP). Though histologically similar, typical HUS, aHUS, and TTP have different causal mechanisms and diverse treatments may be warrented. In contrast to the TMAs, glomerulonephritis is an inflammatory process leading to direct glomerular injury and loss of renal filtering function. The differential for glomerulonephritis can be broad with etiologies ranging from collagen abnormalities (e.g., Alport Syndrome) to antibody-mediated disease (e.g., antiglomerular basement membrane disease). Acute renal replacement therapy and/or plasmapheresis may be required for successful treatment of disease due to TMA as well as glomerulonephritis.