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Currently filtering by tag: Proteinuria

AL Amyloidosis

A 70 year-old female presents with nephrotic range proteinuria and a creatinine of 1.2. She was in her normal level of health until about 6 months ago when she noticed foamy urine and swelling in her ankles. She has lost 30 lbs unintentionally during the last few months. Her cardiologist said that her proteinuria does not appear to be related to the heart. A kidney biopsy is performed. The glomerulus in figure 1 is distorted and has a “washed-out” or pale appearance on PAS stain. A silver stain shows material which is non-argyrophilic (figure 2). A Congo red stain shows...

Art of Medicine: Light Chain Proximal Tubulopathy

The painting above shows light chain proximal tubulopathy with crystals, which is one type of a monoclonal gammopathy of renal significance (MGRS).  MGRS, as defined by the International Kidney and Monoclonal Gammopathy Research Group, is a “clonal proliferative disorder that produces a nephrotoxic monoclonal immunoglobulin” (Leung N et al, 2019), and indicates end-organ damage resulting from a monoclonal gammopathy.   The most common MGRS manifestations include AL amyloidosis, monoclonal immunoglobulin deposition disease, light chain cast nephropathy, and light chain proximal tubulopathy.   In light chain proximal tubulopathy, a nephrotoxic monoclonal light chain induces acute tubular injury or proximal tubular dysfunction.  Proximal tubular...

Disease Week: Membranous Glomerulopathy

Membranous glomerulopathy: Looking forward Many excellent reviews are available that detail the current state of knowledge in membranous glomerulopathy so I will not attempt to round out this #DiseaseWeek by writing another. Instead, I would like to paint, with broad brush strokes, what I believe to be the near future of diagnostics in membranous glomerulopathy and discuss the techniques of discovery being applied today that are likely to similarly impact other types of immune complex-mediated glomerulonephritis. We live in exciting times for discovery in medicine as the tools available today are so powerful that the molecular pathogenic mechanisms of disease...

Twitter Poll (January 30, 2019)

ANSWER: B The medulla is the only compartment affected by AAPOAIV amyloidosis, sometimes with large amounts of amyloid. Glomeruli and vessels are spared and not affected by this type of amyloid. AAPOAIV Amyloidosis is a systemic amyloidosis reported from wild-type apolipoprotein AIV. When the kidney is involved the patient presents with gradual loss of renal function and proteinuria. It may also have cardiac involvement. References: Sethi S, Theis JD, Shiller SM, et al. Medullary amyloidosis associated with apolipoprotein A-IV deposition. Kidney Int 81: 201–206, 2012. Dasari S, Amin S, Kurtin P, et al. Clinical, biopsy, and mass spectrometry characteristics of...

Art of Medicine: Fabry

The image above shows myelinosomes, also known as “zebra bodies” for their appearance on tangential sectioning.  Myelinosomes are seen in Fabry disease, a rare x-linked recessive genetic disorder caused by the defective activity of the enzyme alpha-galactosidase A.   Renal, cardiac, and cerebrovascular involvement is common and can be fatal by the 4th decade without enzyme replacement therapy.   Alpha galactosidase A deficiency results in accumulation of globotriaosylceramide within podocytes of glomeruli, tubules, myocytes, and endothelium.  Globotriaosylceramide accumulation results in the formation of myelinosomes. Since myelinosomes are lipid-derived, they are maintained on osmium fixation, but are lost with exposure to xylenes in...

Twitter Poll (January 23, 2019)

ANSWER: A Although glomerular disease in patients with CLL/SLL is less common, the most frequent patterns of glomerular injury seen include MPGN (immune complex mediated), MCD, membranous GN, and monoclonal immunoglobulin deposition disease. The most common form of kidney involvement in patients with CLL/SLL is the presence of direct infiltration of the kidney parenchyma by leukemic cells. Although glomerular disease in patients with CLL/SLL is less common, they can be present.  The glomerular pattern of injury frequently seen in these group of patients include membranoproliferative glomerulonephritis (immune complex mediated), minimal change disease, membranous nephropathy, and monoclonal immunoglobulin deposition disease (nonamyloid...

Minimal Change Disease

A 70-year-old female presents with nephrotic range proteinuria. She had been in her regular state of health until 2 weeks ago when she noticed swelling in her ankles and that her shoes no longer fit. She went to her family practitioner who sent her to a cardiologist to rule out congestive heart failure. Her troponin levels were normal and her creatinine on routine examination was 7.5 mg/dL. She was admitted to the hospital and an emergent kidney biopsy was requested. Figure 1 shows a normal glomerulus. Figure 2 shows no significant interstitial fibrosis. Figure 3 shows severe arteriosclerosis. Figure 4...

Twitter Poll (January 16, 2019)

ANSWER: B The target of the circulating ABBA autoantibodies is LDL receptor-related protein 2 (LRP2) also known as “Megalin”. ABBA is a rare autoimmune disease associated with acute kidney injury and tubulointerstitial damage.  Histologically, IgG–positive immune deposits are found in tubular basement membranes by immunofluorescence (IF).  When indirect IF is done using patient’s serum and normal kidney controls, there is reaction of the autoantibodies with the proximal tubular brush borders. REFERENCE: Larsen CP, et al. LDL-Receptor Related Protein 2 (Megalin) as a Target Antigen in Human Kidney Anti-Brush Border Antibody Disease. J Am Soc Nephrol, 2018; 29:644-653    

KDIGO Connections: Membranous Glomerulopathy

Welcome to the first post in our new series KDIGO Connections, a series in which we are asking our nephrologist colleagues to educate us in real-world experiences treating kidney disease. In this series, Dr. David Bourne will be kicking it off with KDIGO guidelines for a kidney disease in visual abstract form. Our hope is that these posts will foster discussion regarding these diseases and how different providers approach them. Please share any points, pearls, questions, caveats, thoughts, or experience you have on the presented disease letting us all learn from your experience!