Light Chain Cast Nephropathy in Multiple Myeloma: Prevalence, Impact and Management Challenges

Abstract

“Cast nephropathy” (CN) is a pathological feature of myeloma kidney, also seen to a lesser extent in the context of severe nephrotic syndrome from non-haematological diseases. The name relates to obstruction of distal tubules by “casts” of luminal proteins concentrated by intensive water reabsorption resulting from dehydration or high-dose diuretics. Filtered proteins form complexes with endogenous tubular Tamm-Horsfall glycoprotein. The resulting gel further slows or stops luminal flow upon complete obstruction of distal convoluted tubules and collecting ducts. Thus, a tubular obstructive form of acute kidney injury (AKI) is a common consequence of CN. The pathogenesis of CN will be reviewed in light of recent advances in the understanding of monoclonal disorders of B lymphocytes, leading to the release of immunoglobulin components (free light chains, FLC) into the bloodstream and their filtration across the glomerular basement membrane. Treatment aiming at reduction of the circulating burden of FLC may help recovery of renal function in a fraction of these patients, besides filling the void between the onset of AKI, histopathological diagnosis, and full response to pharmacologic treatment.

Cranial versus Caudal Direction Technique of Native Percutaneous Kidney Biopsy: A Randomized Controlled Trial

“…Ideally, the biopsy core should be predominately contained cortical tissue because this is the location of glomeruli. 2 However, the juxtamedullary junction and medulla portion remained necessary to diagnose some kidney diseases such as myeloma cast kidney, 21 FSGS, 22 or polyoma nephropathy. 23 Additionally, the needle was fired transverse to the kidney cortex and medulla directly in the CD PKB technique ( Figure 2 ).…”