Background

Various perinatal morbidities may adversely affect postnatal nephrogenesis in preterm infants. Kidney ultrasonographic findings following acute kidney injury (AKI) have not been well described in preterm infants. Herein, we describe three cases of extremely preterm infants who showed abnormal kidney ultrasonographic findings resembling dysplasia of the kidneys following AKI.

Case-diagnosis/treatment

Their median gestational age and birth weight were 25⁺⁶ (range 23⁺³–26⁺⁶) weeks and 620 (480–840) g, respectively. All infants suffered severe AKI during their third to seventh week of life. Their kidney function recovered with conventional management. Kidney ultrasonographies performed after AKI revealed increased kidney echogenicity, loss of corticomedullary differentiation, and multiple cortical cysts, which were similar to cystic dysplasia of the kidneys and were absent in previous kidney imaging. Three infants eventually developed at least one of the long-term kidney sequelae following AKI, including proteinuria, hypertension, and elevated levels of serum creatinine or cystatin C as determined during the last follow-up at the corrected age of 9–18 months.

Conclusions

Based on these cases, we can infer that AKI occurring during the early postnatal period may result in dysplasia of the kidneys with cortical cysts in extremely preterm infants, which may lead to chronic kidney disease in their later life. It is useful to follow up not only laboratory parameters but also kidney ultrasonographic findings in extremely preterm infants who suffered AKI during their early postnatal periods.

中文翻译：

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急性肾损伤后极早产儿肾脏囊性发育不良。

背景

各种围产期疾病可能对早产儿的出生后肾发生产生不利影响。急性肾损伤 (AKI) 后的肾脏超声检查结果尚未在早产儿中得到很好的描述。在此，我们描述了 3 例极早产儿，他们在 AKI 后表现出类似于肾脏发育不良的异常肾脏超声检查结果。

病例诊断/治疗

他们的平均胎龄和出生体重为 25 ⁺⁶（范围 23 ⁺³ –26 ⁺⁶) 周和 620 (480–840) g，分别。所有婴儿在出生后的第三至第七周都遭受了严重的 AKI。他们的肾功能通过常规治疗得以恢复。AKI 后进行的肾脏超声检查显示肾脏回声增加、皮质髓质分化丧失和多发性皮质囊肿，这与肾脏囊性发育不良相似，在之前的肾脏成像中不存在。3 名婴儿最终在 AKI 后出现至少一种长期肾脏后遗症，包括蛋白尿、高血压和血清肌酐或胱抑素 C 水平升高，这在矫正年龄 9-18 个月的最后一次随访中确定。

结论

基于这些病例，我们可以推断出生后早期发生的 AKI 可能导致极早产儿肾脏发育不良并伴有皮质囊肿，这可能导致他们晚年发生慢性肾病。对于在出生后早期遭受 AKI 的极早产儿，不仅要对实验室参数进行随访，还要对肾脏超声检查结果进行随访。