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Low type imperforate anus, a small and irregular ‘high-low-high’ concentric circular echo similar to ‘target sign’
Source publication
Background
The prenatal diagnosis of foetal imperforate anus is difficult. Most previous studies have been case reports. To provide useful information for diagnosing foetal imperforate anus, a retrospective review of diagnostic approaches was conducted. Ultrasonography was performed in 19 cases of foetal imperforate anus from 2016 to 2019 at our pr...
Citations
... У систематичному огляді Hannah, et al [55] мали на меті узагальнити та оцінити наявні дані щодо результатів аноректальної манометрії у дітей після лікування аноректальної вади розвитку та оцінити використання протоколів манометрії, включаючи обладнання, підхід до оцінки та інтерпретацію. У огляді підкреслено поширену відсутність стандартизації в процедурі аноректальної манометрії, яка використовується для оцінки аноректальної функції у дітей після відновлення аноректальної вади розвитку. ...
Anorectal malformations include a wide range of conditions that can affect both sexes and involve the distal anus and rectum, as well as the urinary and genital tracts. An imperforate anus is a common birth defect that results from defects or delays in the development of the hindgut. The diagnosis of nonperforation of the anus is usually made shortly after birth through a routine medical examination. Patients have the best chance for a good functional outcome if the disease is diagnosed early and effective anatomic repair is started immediately. Most malformations in girls can only be correctly diagnosed on physical examination. An anus visible in the perineum with a normal vagina and urethra suggests a perineal fistula. A rectovestibular fistula occurs when the opening is in the posterior vestibule and beyond the hymen. If only one opening is visible between the labia, it is very likely a cloaca. Rectovaginal fistulae may initially appear as a non-perforating anus without a fistula (a normal-looking vagina and urethra, but no visible anus). Close examination usually reveals the presence of an opening in the back wall of the vagina or inside the hymenal ring. Radiological evaluation of a newborn with non-perforated anus should include abdominal ultrasound, using it to detect urological abnormalities. Sepsis, aspiration, abdominal distention, colonic perforation, respiratory distress, electrolyte imbalance are complications that can result from delayed diagnostic and therapeutic treatment of anorectal malforations. Accurate preoperative identification of an internal fistula between the distal part of the genitourinary tract is very important for optimal surgical treatment and prevention of possible damage to the genitourinary tract. Staged surgery, the most common approach for treating anorectal malformations, consists of three operations: a colostomy at birth, a definitive operation at 2–3 months of age, and closure of the colostomy at approximately 6 months of age.
... Based on the prenatal image of the anal structure in this case, the anal mucosa appeared smaller and had lower echogenicity in comparison to the normal mucosa, and the peripheral anal sphincter was shallow. Screening for anal atresia of appropriate for gestational age (AGA) fetuses around 20 weeks is challenging, as a result, making it even more difficult in severe IUGR cases with the fetal size too small to allow delineation of these structures on the scan [11,17]. ...
Objectives: The study aimed to demonstrate the performance of anal atresia ultrasound screening in the second trimester and to describe associated experiences in a primary care fetal medicine clinic.
Materials and methods: We retrospectively analyzed the medical records of fetuses who underwent a second-trimester screening at the Taiji clinic between November 2019 and May 2022. Fisher's exact test was conducted to investigate potential risk factors.
Results: There were 28 459 fetuses screened in our clinic during the study period; eventually, 6 cases were diagnosed with anal atresia after birth. The incidence of anal atresia in our sample was 2.11 in 10 000. Based on our findings, potential risk factors significantly associated with anal atresia included: multiple pregnancies (p-value ¼ 0.0185) and in-vitro fertilization (p-value ¼ 0.038). Half of the anal atresia cases were associated with abnormalities affecting other organ systems, most frequently the genitourinary system (66.7%) and cardiovascular system (66.7%), especially persistent left superior vena cava (2 cases).
Conclusion: Anal atresia is a malformation that requires extensive care; the clinical management after the prenatal discovery of its signs should include testing for chromosomal abnormalities and close monitoring of the amniotic fluid volume. Therefore, prenatal ultrasound screening for anal atresia in the second trimester is critical, particularly in the cases of multiple and IVF pregnancies, and multiple abnormalities. The fetuses with ultrasound signs of anal atresia should be followed at a later gestational period and referred to a specialized institution for postnatal management planning and parental counseling.
... concentric circle echo (Fig. 2a). Further, a part of fetuses with a diagnosis of high-type anal atresia has only a visible hyperechoic line consisting of the bottom skin fold with an absent anal structure [5,6]. To ensure diagnostic quality and test reproducibility it is crucial to follow a uniform diagnostic protocol. ...
... Yin et al. in a previous study pointed out that in cases of low-type anal atresia, the rectal wall was thinner than the sphincter of the anal canal. Therefore, the hypoechoic ring formed by the rectal wall is thinner and it could appear as the pseudo "target sign" in the perineum [5]. The authors considered it a clue of low-type anal atresia. ...
... However, the appearance of perianal tissue could be used as a secondary point for screening. The peripheral anal tissue is presented as a hyperechoic ring due to the reflection of the interface between the outer layer of the anal sphincter and the surrounding tissue [5] (Fig. 1a). Compared to the hyperechoic perianal tissue in Fig. 1a, bilateral perianal tissue in Fig. 3b seem crowded, thick, and asymmetric. ...
Objective:
We present prenatal ultrasound images of two high anal atresia cases. The main screening tool used in our clinic is the "target sign" in the tangential view of the fetal perineum. In the current report, we discuss some challenges in the existing screening practices.
Case report:
CASE 1: A 28-year-old woman (gravida 1, para 0) with a twin pregnancy underwent ultrasound screening at 21 weeks of gestation when an absent "target sign" in twin A was discovered. At the same time, we were able to present evidence that if the wrong plane was visualized, other structures could be mistaken as the "target sign". Eventually, high-type anal atresia was confirmed postnatally in Twin A. CASE 2: A 29-year-old woman (gravida 1, para 0) came to our clinic for routine screening at 23 weeks of gestation. In the standard tangential view at the level of the perineum, a low-high concentric circle structure resembling a "target sign" was visualized during a prenatal scan. However, anal atresia was discovered postnatally. A retrospective review of prenatal images revealed discrepancies from the typical "target sign".
Conclusion:
High-type anal atresia may present as a pseudo "target sign" on prenatal ultrasound. Visualization of a "target sign" on fetal ultrasound does not always exclude the diagnosis of anal atresia. It is crucial to evaluate the size, shape, level, and position of the "target sign". The appearance of the bilateral hyperechoic perianal tissue is a hint for the screening of anal atresia.
... (5) En cuanto a su diagnóstico, este puede ser prenatal sin embargo este aun significa un reto, cabe mencionar que la mayoría de estudios previos han sido reporte de casos, sin embargo, actualmente se ha logrado identificar diferentes métodos diagnósticos como es el caso de las ecografías prenatales. (2,6) La Atresia Anal es una complicación que debe ser tratada inmediatamente, por lo general se puede encontrar en algunos casos anomalías congénitas que acompañan al cuadro. Dependiendo de la fistula y su ubicación se puede dirigirse al tratamiento más oportuno para cada caso (7). ...
INTRODUCCION: La Atresia Anal es una malformación anorrectal, el cual es identificado en el examen físico al momento del nacimiento en la cual se destaca la ausencia del ano, se estima que su incidencia esta alrededor de 1 de cada 5000 nacimientos, en cuanto a su manejo se considera de carácter urgente la intervención quirúrgica con la finalidad de evitar complicaciones que aumenten el riesgo de mortalidad el cual el éxito de la misma se valorara con el transcurso de los años. CASO CLINICO: Paciente Masculino recién nacido en hospital básico quien posterior a examen físico se le diagnostica ano imperforado más fistula es referido a hospital de tercer nivel en donde tras exámenes complementarios se encuentran alteraciones cardiacas que incrementaron el riesgo de mortalidad del paciente lo cual tras varios días de hospitalización con mala evolución provoco la muerte inminente del paciente. CONCLUSION: El ano imperforado es una patología que en la mayoría de los casos se acompaña de alteraciones cardiacas o renales, lo cual provocara un incremento en el riesgo de mortalidad de estos pacientes, por tal motivo es necesaria la prioridad quirúrgica en su patología de base con la finalidad de incrementar la esperanza de vida, por consiguiente, es necesario el seguimiento adecuado en estos cuadros clínicos proporcionando el apoyo necesario para la familia y el paciente.
