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.



中文翻译：

---

疑似肾钙质沉着症婴儿大面积血栓形成：病例报告及文献复习

简介
围产期的特点是血栓形成的风险增加，这是由于资源不足和生命早期凝血系统的代偿能力有限。

案例报告
我们报告一例39周剖宫产女婴，因产前胎膜破裂，体重3570γ，Apgar评分10分。妊娠合并甲状腺功能减退、子宫肌瘤、泌尿道感染和母亲在 16 Hbd 时的阑尾切除术。3个月时，女孩因B超时偶然发现肾脏钙化而入院。在实验室检查中，未检测到钙和磷酸盐稳态异常。然而，在超声扫描中，在两个肾脏中都可以看到沿着金字塔的线性钙化。由于肾钙质沉着的位置不典型，进行了多普勒扫描，显示缺乏从肾静脉到下腔静脉 (IVC) 的可见血流，有从肾静脉到椎旁丛的代偿性血流，和 IVC 闭塞，肝脏部分有大量钙化。磁共振证实 IVC 和髂总静脉闭塞，IVC 节段性扩张，以及从肾脏和下肢流向椎旁神经丛的代偿性血流。临床表现和侧支循环形成提示宫内血栓形成。实验室检查排除先天性易栓症。

结论
肾实质钙化（肾钙质沉着症）的鉴别诊断应包括肾静脉血栓形成。由于在生命早期形成侧支循环的能力很高，因此大量胎儿和围产期血栓形成可能是无症状的。