Hyperreninemia, Lysozymuria, and Erythrocytosis in Fanconi Syndrome with Medullary Cystic Kidney

Abstract

ABSTRACT. Adult onset Fanconi syndrome with medullary cystic kidney was diagnosed in a 30‐year‐old male with muscular weakness, hypokalemia, normal BP, hyperreninemia, and secondary aldosteronism. He also had non‐specific aminoaciduria, lysozymuria, and β2‐microglobulinuria. Urinary concentrating and acidifying capacity was impaired, and both sodium and potassium were lost into the urine. I. v. pyelography revealed medullary cystic kidney. Renal biopsy showed juxtaglomerular hyperplasia, heavy subintimal deposits and C3 and IgG in preglomerular arteriolar walls, and degenerative changes in the tubules, including loss of brush border and “macula densa‐like” lesions. Polycythemia with elevated serum erythropoietin levels, and raised blood ACTH values with features of cortisolism were also present. Indomethacin therapy decreased plasma renin activity (PRA), plasma aldosterone, and urinary loss of potassium and sodium, while serum potassium approached normal levels. Metoprolol, a β‐adrenergic blocking agent, caused similar effects. Insensitivity to the pressor effect of angiotensin II was reversed by indomethacin treatment. Somatostatin infusion lowered PRA and aldosterone without affecting BP. Several biochemical aberrations of this patient resemble Bartter's syndrome, including the effect of indomethacin.

Adult presentation of Bartter syndrome type IV with erythrocytosis

“…Although the etiology of such dysfunction cannot be fully understood, other case has already been reported in the literature consisting of an adult onset Fanconi syndrome with kidney medullary cystic disease, non-specific aminoaciduria, lysozymuria and beta2-microglobulinuria, hyperreninemia and polycythemia with elevated serum EPO levels resembling Bartter’s syndrome. ( 13 ) Another characteristic phenotype usually described in BS cases is the hypercalciuria, associated or not to nephrocalcinosis. Our patient did not show this phenotype, which agrees with other reports ( 2 , 3 ) possibly because of the low serum ionized calcium that led to a lower filtered load of calcium.…”

“…Apesar da etiologia dessa disfunção não estar completamente esclarecida, um outro caso de síndrome de Fanconi de início na idade adulta, associado a doença renal cística medular, aminoacidúria inespecífica, lisozimúria, perda de beta2-microglobulina, hiperreninemia e policitemia, com níveis elevados de eritropoetina sérica similares aos da SB, já foi descrito na literatura. ( 13 ) Outra característica fenotípica geralmente descrita nos casos de SB é a hipercalciúria, associada ou não a nefrocalcinose, que não foi detectada em nosso paciente, também corroborando outros relatos, ( 2 , 3 ) possivelmente devido ao cálcio sérico reduzido, que leva a menor carga filtrada.…”

Nephronophthisis and Medullary Cystic Kidney Disease in Children

“…Roentgenography contributes little to the diagnosis of the disease. Medullary cysts can sometimes also be demonstrated on magnetic resonance imaging or computed tomography [144,145]. Histology is characteristic but not pathognomonic in NPHP or MCKD, because cysts may be absent and tubulointerstitial disease can be relatively unspecific.…”