Multidisciplinary consensus on the classification of antenatal and postnatal urinary tract dilation (UTD classification system)

The outcomes of favipiravir exposure in pregnancy: a case series

Purpose

As in vitro and in vivo studies reported antiviral efficacy against RNA viruses, favipiravir, a pyrazinecarboxamide derivative, has become one of the treatment options for COVID-19 in some countries including Turkey. Preclinical studies demonstrated the risk for teratogenicity and embryotoxicity. Hence, the drug is contraindicated during pregnancy. Although limited in numbers, case-based evaluations indicate that favipiravir might not be a major teratogen in human pregnancies. This study aimed to present and analyze the outcomes of favipiravir exposure during pregnancy.

Methods

In this case series, the outcomes of nine pregnancies that were referred to the Teratology Information Service of Dokuz Eylul University Faculty of Medicine, Department of Medical Pharmacology between 01 April 2020 and 30 November 2021 were retrospectively evaluated.

Results

One spontaneous abortion, two elective terminations, one preterm live delivery and five term live deliveries were detected. The premature newborn was reported dead on the 5th day of neonatal intensive care unit admission. Physiological jaundice and transient respiratory distress were recorded in two term infants. One term infant was antenatally diagnosed with renal pelviectasis, but the findings resolved postnatally without requiring intervention.

Conclusion

The data indicate that favipiravir is not likely to be a major teratogen. Yet, it is not possible to draw a definite conclusion due to methodological limitations. Favipiravir exposures during pregnancy should be followed up closely and the outcomes should be reported consistently.

ACR Appropriateness Criteria® Antenatal Hydronephrosis-Infant

Antenatal hydronephrosis is the most frequent urinary tract anomaly detected on prenatal ultrasonography. It occurs approximately twice as often in males as in females. Most antenatal hydronephrosis is transient with little long-term significance, and few children with antenatal hydronephrosis will have significant obstruction, develop symptoms or complications, and require surgery. Some children will be diagnosed with more serious conditions, such as posterior urethral valves. Early detection of obstructive uropathy is necessary to mitigate the potential morbidity from loss of renal function. Imaging is an integral part of screening, diagnosis, and monitoring of children with antenatal hydronephrosis. Optimal timing and appropriate use of imaging can reduce the incidence of late diagnoses and prevent renal scarring and other complications. In general, follow-up neonatal ultrasound is recommended for all cases of antenatal hydronephrosis, while further imaging, including voiding cystourethrography and nuclear scintigraphy, is recommended for moderate or severe cases, or when renal parenchymal or bladder wall abnormalities are suspected. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Validation of "urinary tract dilation" classification system: Correlation between fetal hydronephrosis and postnatal urological abnormalities

Aim to illuminate the correlation between fetal hydronephrosis and postnatal urological abnormalities by a new classification system-"urinary tract dilation (UTD)" grade.Of 659 pregnancies screened by ultrasound, 34 cases were found with isolated fetal hydronephrosis, and enrolled in our study from 2017 to 2019. These 34 infants had been prospectively followed up to 6 months after birth by 3 times of urinary tract ultrasound. Hydronephrosis was graded in accordance with the UTD classification system.Among 34 infants with isolated fetal hydronephrosis. Twenty-four (70.6%) were classified as UTD A1 grade (mild hydronephrosis), and the other 10 (29.4%) were UTD A2-3 grade (moderate to severe hydronephrosis) by antenatal evaluation. After birth, all of the 24 infants (70.6%) with UTD A1 grade had normal ultrasonic findings of urinary tract; while the other 10 cases with UTD A2-3 grade had persistent abnormalities of urinary tract by postnatal assessment, sorted as UTD P1 grade (mild hydronephrosis) in 6 cases (17.6%), UTD P2 grade (moderate hydronephrosis) in 2 cases (5.9%) and UTD P3 grade (severe hydronephrosis) in 2 cases (5.9%). The most common postnatal urological abnormality of isolated fetal hydronephrosis was vesicoureteral reflux. During the follow-up period, 7 infants (20.6%) had urinary tract infection episodes and very few obtained positive cultures of the urine. Only 2 infants (5.9%) with the diagnosis of ureterovesical junction obstruction required surgery intervention, who were both classified as UTD P3 grade. None of the children with UTD P1 and P2 grades needed operation.The UTD classification system described the urinary tract both antenatally and postnatally, which could point out the correlation between fetal hydronephrosis and postnatal urological abnormalities. This new classification system is expected to be a good prognostic marker for fetal hydronephrosis.

Classification of pediatric urinary tract dilation: the new language

The multidisciplinary consensus on the classification of prenatal and postnatal urinary tract dilation (UTD classification system) was created to unify the language used to describe urinary tract dilation on antenatal and postnatal ultrasound examinations and thereby facilitate communication among providers and improve outcomes research. The background and new classification system are described in this review, with imaging examples.

Imaging of the Pediatric Urinary System

Recent advances in pediatric urinary tract imaging include development of alternative imaging methods without use of ionizing radiation; evolving understanding of the relationship of urinary tract infection, vesicoureteral reflux, and renal scarring, including the important role of dysfunctional voiding; development of a consensus nomenclature and risk-based classification for fetal and antenatal urinary tract dilation; advances in the understanding of sporadic and inherited renal cystic disease; and a proposed modification of the Bosniak criteria for distinguishing complex renal cysts from cystic renal tumors in children.