Recombinant factor-viia

Abstract

A 7-year-old developed renal thromboembolism while receiving recombinant factor-viia.The boy, who had a history of haemophilia B, was hospitalised with severe haematuria. He started receiving a single daily dose of IV recombinant factor-viia 285 µg/kg. In spite of treatment, his haematuria worsened with a rapid decline of RBC. Subsequently, the dose of recombinant factorviia was increased to 105 µg/kg four times a day and his haematuria improved with a stabilised RBC count. Afterwards, the recombinant factor-vi dose was reduced and he received 285 µg/kg once daily for the following 2 days. On the fifth day of therapy, he experienced left lumbar colic pain with visible blood clots in his urine.Recombinant factor-viia was discontinued and the boy received hyper-hydration and spasmolytic therapy. His renal ultrasound revealed renal colics, enlarged left kidney with hyperechogenic inhomogeneous parenchyma with partial loss of corticomedullary differentiation and dilated pelvicalyceal system with hyperechogenic inhomogeneous content consistent with clots. His renal scintigraphy revealed a vascular bed on his left kidney without visualization of the parenchyma and a very pale left kidney. A renographic curve of his left kidney revealed obstruction over the third phase of the renogram. A multi-slice CT renal angiography showed severe left kidney damage with 3 independent unobstructed arteries. At 9 months follow-up, a repeated renal scintigraphy revealed normal findings.Author comment: "[T]his is the first case of tromboembolic event connected with [recombinant factor viia] therapy with this set of symptoms presented exclusively on kidney with underlying vascular anomalies." Milosevic D, et al. Renal thromboembolism during treatment with recombinant activated factor VII (rFVIIa) in a child with hemophilia B with factor IX inhibitors. BMC Pediatrics 14: No. 315, 17 Dec 2014. Available from: URL: http://