Dysproteinemias and Amyloidosis

The most common histologic diagnosis, found in 80% of patients with myelonaa, is cast nephropathy or myeloma kidney. Light-chain deposition disease, occurring in 5% to 10%, and amyloidosis, occurring in 10%, can present as the nephrotic syndrome, which is present in up to 25% of the cases.

Patients with cast nephropathy usually present with proteinuria and renal insufficiency. Renal failure can evolve rapidly despite stable paraprotein production and large The typical light microscopic findings include tubular casts ated giant cells located in by multinucleated giant cells located in the distal and collecting tubules.

The casts are composed of light chains and Tamm-Horsfall protein and are strongly and periodic acid-kgooSchiff positive. Light chain deposition disease is a gammopathy characterized by deposition of light chains in the kidney and other vital organs(liver, heart, peripheral This disorder predominantly affects men, with a ser ratio of 2:1 to 4:1 and an age range between 35 and 75 years. The primary renal presentation is impairment, ent by an elevated serum creatinine level and proteinuria, with nephrotic-range proteinuria being detected in 25%. Extrarenal manifestation of light chain deposition may be noted at presentation with abnormal results of liver function tests. The characteristic light microscopic findings vary from normal glomeruli to degrees of mesangial expansion along with thickened tubular basement membranes outlined by continuous deposits. One third of the biopsy lar to Kimmelstiel-Wilson glomerulopathy seen with diabetic nephropathy. Immunofluorescence shows deposits type). Systemic amyloidosis is classified into four types according to the chemical composition of fibrillar deposits which correspond to clinical patterns termed primary secondary, hereditary, and dialysis associated. The most common form in the United States is primary or AL, which develops after chronic inflammatory or infectious disease, has deposits composed of AA proteins. There are several autosomal dominant hereditary forms, of the most well known is familial amyloidotic polyneuropathy. The fourth form occurs in chronic hemodialysis patients, and the amyloid fibril is a B2-microglobulin. Up to 80% of patients with AL or AA forms of amyloidosis have renal involvement.

Nephrotic syndrome is the initial feature in patients with secondary amyloidosis and in approximately 25% of patients with primary amyloidosis and is a rare complication of familial amyloidosis.

Renal insufficiency is present in approximately 50% at diagnosis, and the most common cause of death is cardiac failure with a median survival of 4 months.

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