[Two patients with renal medullary hyperechogenicity].

History And Admission Findings: We report two patients with medullary nephrocalcinosis and nephrolithiasis. The first patients had unspecific symptoms of a systemic inflammatory disease, the second patient was asymptomatic.

Investigations: Both patients had normocalcemia and normal parathyroid hormone levels, very high 1,25(OH)(2)-vitamin D and normal to low 25-OH-vitamin D levels. On renal ultrasound, both patients displayed nephrocalcinosis and nephrolithiasis.

Diagnosis: Both patients showed dysregulation of the 1α-hydroxylase activity. The first patient suffered from a systemic inflammatory disease with consecutive activation of macrophages with extrarenal α-hydroxylase activity. The second patient had a "loss of function" mutation of the calcium sensing receptor with - for the situation - inadequatly high parathyroid hormone levels and consequently a renal dysregulation of the 1α-hydroxylase.

Treatment And Course: After immunosuppressive treatment with prednisolone and hydroxychloroquin there was complete remission of the systemic inflammatory disease in the first patient. In consequence the 1,25-(OH)(2)-vitamin D levels regressed and renal function stabilized. The second patient was completely asymptomatic with normal renal function, so far we did not initiate any treatment.

Conclusions: Nephrocalcinosis and nephrolithiasis can result from hypercalciuria due to dysregulated hydroxylation of vitamin D. For both renal and extrarenal sources causal treatment is available.