Urogenital ImagingCryoglobulinaemia, renal involvement
Cryoglobulins are a group of immunoglobulins that have the common and unusual property of reversibly precipitating or forming a gel when cooled. Cryoglobulinaemia may be idiopathic, or secondary to a wide variety of conditions, including infections (especially chronic viral
hepatitis), connective tissue diseases (such as
systemic lupus erythematosus,
rheumatoid arthritis, polyarteritis nodosa, Sjogren's syndrome, and
scleroderma), and lymphoproliferative diseases (such as myeloma,
Waldenstroms macroglobulinaemia,
lymphoma, chronic lymphatic leukaemia). Clinical features of cryoglobulinemia include purpura, weakness, and arthralgia.
Renal involvement has been reported in 1060% of patients, and may be due to glomerulonephritis, vasculitis, or a combination of the two. Renal disease may manifest clinically as haematuria, proteinuria, renal impairment or nephrotic syndrome. The course of renal involvement is variable, but only 10% of patients progress to end-stage renal disease. Imaging findings are nonspecific.
Ultrasound may demonstrate increased echogenicity of the renal parenchyma, renal swelling in the acute phase, or renal atrophy in the chronic phase. Possible CT findings include poor renal parenchymal enhancement, with a persistent faint or increasingly dense nephrogram, renal swelling, or renal atrophy. MRI may demonstrate swelling or atrophy, loss of corticomedullary differentiation on T1-weighted images, and reduced enhancement after intravenous gadolinium administration.
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