Massive thrombosis in an infant with suspected nephrocalcinosis: case report and literature review

Introduction
Perinatal period is characterized by an increased risk of thrombosis due to low resources and limited compensatory capacity of the coagulation system in early stages of life.

Case report
We report a case of a second pregnancy female infant born at 39 weeks by caesarean section, due to pre-labor rupture of membranes, with body weight of 3,570 γ and Apgar score 10. The pregnancy was complicated by hypothyroidism, uterine myoma, urinary tract infections, and mother’s appendectomy at 16 Hbd. At 3 months, the girl was admitted to our hospital due to kidney calcifications, which were incidentally found during ultrasound scan. In laboratory workup, no abnormalities in calcium and phosphate homeostasis were detected. However, in ultrasound scan, linear calcifications along pyramids were visualized in both kidneys. Due to atypical location of nephrocalcinosis, Doppler scan was performed, showing lack of visible blood flow from renal veins to inferior vena cava (IVC), with compensatory flow from renal veins to paravertebral plexuses, and IVC obliteration with a massive calcification in the hepatic section. Magnetic resonance confirmed obliteration of IVC and common iliac veins, segmental dilatation of IVC, and compensatory blood flow from kidneys and lower limbs to paravertebral plexuses. Clinical picture and formation of collateral circulation suggested intrauterine thrombosis. Congenital thrombophilia was excluded in laboratory examination.

Conclusions
The differential diagnosis of calcifications in renal parenchyma (nephrocalcinosis) should include renal vein thrombosis. Massive fetal and perinatal thrombosis can be asymptomatic due to high ability to form collateral circulation at the early stage of life.