Abdominal Neonatal Emergencies Considering Prenatal Diagnosis

Fig. 5.1

Typical prenatal US aspect of a duplication cyst. Axial US scan on the abdomen of a 30-week-old fetus, showing a cystic right pelvic structure with a multilayered wall (arrow)

Potential complications are: bleeding due to the presence of ectopic gastric mucosa, torsion (in cases of pediculate lesions), intussusception, and occlusion responsible for acute abdominal pain and vomiting.

These complications may lead to abdominal emergencies.

For instance, major neonatal distension may be encountered in communicating duplication cysts. The lesion that appeared cystic in utero will progressively and sometimes massively get inflated due to the progressive digestive tract aeration. In such situation, a plain radiograph of the abdomen (potentially associated with an opacification of specific parts of the digestive tract to confirm the presence of a communication) (Fig. 5.2) will establish the diagnosis and confirm the need for immediate surgery.

Fig. 5.2

Acute neonatal distension of a communicating duplication cyst. (a) Abdominal radiograph showing a large distended digestive structure, which corresponds to an acute aeration of a communicating duplication cyst. (b) Surgery confirms the presence of a distended duplication cyst (Courtesy P. Lingier MD)

In some other cases, the lesion may be responsible for acute abdominal distension due to intestinal occlusion secondary to digestive tract compression [5–7] (Fig. 5.3). Sometimes, the duplication cyst (even small) can also be the leading point of a secondary intussusception. These complications are generally diagnosed at surgery.

Fig. 5.3

Neonatal digestive occlusion by a tubular duplication cyst. (a) Abdominal radiograph shows a distended loop in the right flank (arrow) and evidence for intestinal occlusion. (b) The US performed at the same time shows a typical multilayered walled cystic structure corresponding to a duplication cyst responsible for the occlusion

In very rare cases, rectal duplication may prolapse through the perineum and appear like a large external mass developing in the buttocks potentially diagnosed in utero (Fig. 5.4). As usual, a prenatal detection has the advantage of inducing the consideration of all differential diagnosis including other pelvic and external masses such as teratomas and prompting neonatal management and surgery.

Fig. 5.4

Neonatal large external mass corresponding to a rectal duplication diagnosed prenatally (Courtesy C. Fayard MD). (a) Large extraperineal soft mass. (b) The left lateral decubitus radiograph shows a partially aerated mass. (c) The sagittal T2 weighted MR imaging confirms that the mass corresponds to a duplicated rectum prolapsed through the perineum

In most of these uncommon situations, thanks to the prenatal diagnosis, the neonatal investigations are limited to abdominal plain radiograph and US. Still, in more complex or rare cases, opacification or MR Imaging can be useful [8, 9].

5.2.2.2 Ovarian Cysts

Ovarian cysts are the most common pelvic cystic masses encountered in female fetuses. They‑ occur in 1/2600 pregnancies. These cysts would classically appear in the third trimester in relation with the hormonal environment associated with the gestation. Most appear as a unilocular thin walled cystic structure with anechoic content developed within the fetal pelvis. Rarely the cysts may appear during the second trimester or develop bilaterally. After birth, the influence of maternal hormones decreases rapidly leading to spontaneous progressive involution of the cyst. Sometimes, the cyst can persist a few months in particular in case of breast-feeding. Still, most commonly, it should have disappeared before the age of 6 months. Complications like bleeding or torsion can occur in utero or after birth and modify the aspect of the content of the cyst which then would appear more echogenic with possible sedimentation confirming the blood content.

No therapeutic procedure or early delivery is advised in case of prenatal diagnosis.

Classical presentation: In the neonate, ovarian cysts detected in utero should be imaged by US only. The examination confirms the diagnosis mostly by identifying peripheral small daughter cysts that are pathognomonic for the ovarian origin of the cystic lesion (Fig. 5.5). If the cyst measures less than 4 cm, a simple monthly US monitoring is advised because many cysts will stay clinically silent and will regress spontaneously. In some cases, neonatal complications can occur leading to urgent (celioscopic) surgery.

Fig. 5.5

Very large ovarian cyst. (a) Axial US abdominal scan of a third trimester fetus showing a large cystic mass filling almost entirely the abdomen. The differential diagnosis with other etiologies is difficult because of the size of the cyst. (b) The postnatal US is pathognomonic of an ovarian cyst, thanks to the demonstration of peripheral daughter follicle (arrow)

Noteworthy, an ovarian hemorrhagic lesion can appear like an echogenic “solid type” mass with worrisome differential diagnosis. A rapid postnatal involution would favor the diagnosis of a (complicated) ovarian cyst [10].

An ovarian cyst is rarely an abdominal emergency in the neonate. Yet, acute bleeding, torsion, or mass effect can occur in the neonatal period. In such case, an important increase in size or ischemic insult (torsion) is responsible for acute abdominal pain. Complications occur more frequently in big cysts (larger than 5 cm) and therefore cyst aspiration has been advocated to reduce the risk of torsion. In such presentation, US is the best diagnostic tool to confirm the ovarian origin of the lesion and exclude other causes of acute abdominal symptoms. Complicated ovarian cysts appear like heterogeneous structures with intracystic echogenic clots or debris, fluid/fluid levels, and septations (Fig. 5.6) [11]. The presence of vascular flow on Doppler imaging does not exclude ovarian torsion or auto-amputation [12], as the presence of flow may be secondary to vascular proliferation in the fibrotic walls. Urgent surgery or celioscopic cystectomy/fenestration is required in order to preserve functional ovarian tissue [13]. Cases of ovarian cysts associated with bowel obstruction have been described as well (Fig. 5.7). Two mechanisms are suggested: adhesions caused by twisted necrotic ovary or mass compression in case of large cysts [14]. In this context, immediate surgery is also required. When calcifications are present, even if they may suggest auto-amputation, the differential diagnosis with a teratoma should be raised. In this context, evaluation by MR imaging can be useful.

Fig. 5.6

Acute neonatal hemorrhage in an ovarian cyst. (a) Prenatal US abdominal sagittal scan of a 36-week-old fetus displaying a completely hypoechoic ovarian cyst. (b) The neonatal (Day 1) abdominal US shows a complex echogenic content corresponding most probably to hemorrhage within the cyst

Fig. 5.7

Acute intestinal obstruction secondary to compression by bilateral ovarian cysts. (a) Prenatal US at 33 weeks demonstrating bilateral huge ovarian cysts (between crosses) (Courtesy C. Coulon MD). (b) Neonatal abdominal US confirming the prenatal diagnosis of bilateral ovarian cysts. (c) Abdominal radiograph (Day 1) shows an intestinal obstruction that was confirmed to be secondary to external compression of the small bowel by the bilateral ovarian cysts

5.2.2.3 Choledocal Cyst (See Also Chap. 8)

Choledocal cyst is a difficult prenatal diagnosis. Only 15% of the cases are accurately diagnosed in utero. In fetuses with subhepatic cysts, the differential diagnoses are hepatic cysts, cystic biliary atresia, and duodenal duplication cyst. In the fetus, the demonstration of intrahepatic biliary ducts dilatation connected with the cyst is the only sign ascertaining choledochal cyst. When this sign is absent, there is no absolute criterion to exclude intrahepatic biliary atresia with intrahilar cyst.

The etiologies suggested for such a malformation are an abnormal bilio-pancreatic junction-leading to biliary reflux and secondary distension of the common bile duct- or a failure of bile duct recanalization during the embryologic development.

Classical presentation: A prenatal suspicion of choledochal cyst requires a neonatal US to confirm the nature of and exact localization of the cyst. An MR Imaging can also help to rule out biliary atresia by showing other specific malformations and to classify the type of the cyst [15]. In case of persisting neonatal cholestasis or inconclusive examinations, exploratory surgery is needed and peri-operative cholangiogram should be performed. If a conservative approach is decided, in early life. The newborns are carefully followed up clinically, biologically, and by means of US; 50% of the patients will be free of symptoms. Still, the prognosis is uniformly poor if left untreated (cholangitis, obstructive jaundice, liver dysfunction, pancreatitis, etc.) progressing to biliary cirrhosis and portal hypertension. The surgical treatment in asymptomatic patients should optimally be planned within the first 6 months in order to avoid progressive hepatic fibrosis [16].

Rarely, acute complications such as stomach outlet compression or cyst rupture may occur leading to vomiting and feeding difficulties [17, 18]. In this context, the newborn presents acute abdominal discomfort and peritoneal fluid due to biliary ascites. The diagnosis relies on the previous prenatal diagnosis of a subhepatic cyst and on the biological analysis of the peritoneal fluid. The treatment is urgent surgery with cyst resection peritoneal lavage and Roux en Y hepatico-jejunostomy.

5.2.3 Solid Masses

5.2.3.1 Renal Masses

Renal masses are rare in the fetus. The most common mass is mesoblastic nephroma. It appears on US like a solid or mixed type well-circumscribed mass of the kidney and is associated with polyhydramnios [19] (Fig. 5.8). The differential diagnoses include rare Wilms’ tumor and intrarenal neuroblastoma [20], the final diagnosis relies on histological data.

Fig. 5.8

Pre- and postnatal assessment of a mesoblastic nephroma. (a) Sagittal T2 weighted MR imaging of a 35-week-old fetus with hydramnios demonstrating a very large heterogeneous abdominal mass. (b) Neonatal US confirms the heterogeneous mass that almost completely fills the abdominal cavity. (c) Axial enhanced CT scan of the newborn demonstrates more accurately the limits of the mass and the relation with the displaced abdominal vessels

Classical presentation: In newborns with prenatal diagnosis of a renal mass, a clinical and biological close monitoring has to be performed with regular evaluation of blood pressure and calcemia [21]. An abdominal US is performed to confirm the mass, its limits, and content. Renal masses are usually well delineated. If adenopathies or calcifications are present, a diagnosis of neuroblastoma should be raised [20]. An abdominal MR imaging examination or CE-CT is mandatory to better define the extension of the lesion before surgery.

Mesoblastic nephroma has an excellent oncological outcome but a high risk of perinatal life-threatening complications. Besides the hemodynamic instability (hypertension), and the respiratory distress, these tumors may induce unusual acute clinical complications due to tumor rupture and massive hematuria leading to hemorrhagic shock [22, 23]. Furthermore, the mass effect of very large tumors on the digestive tract can lead to (sub)occlusion and vomiting. These exceptional situations lead to urgent surgical resection of the affected kidney, and this can be anticipated, thanks to the prenatal diagnosis.

5.2.3.2 Suprarenal Masses

Suprarenal masses may be of variable origins. They are very often detected in the fetus. The main diagnoses are infradiaphragmatic sequestration, adrenal hemorrhage, and neuroblastoma. Infradiaphragmatic extralobar pulmonary sequestration is rare [24]; it corresponds to non-functional lung without any connection with the bronchial tree; its blood supply derives from systemic vessels. The prenatal diagnosis is generally made in the second trimester and relies on a well-circumscribed lesion with similar echogenicity compared to the lung parenchyma. The demonstration of the systemic vascular supply, which is not always obvious, confirms the diagnosis. The vessel may be more evident on fetal MR imaging. Adrenal hemorrhage and the suprarenal neuroblastoma are most often depicted in the third trimester like heterogeneous or solid suprarenal masses. Their differential diagnosis may be difficult, both can present with cystic components. The main differentiating criterion is the rapid changes of echogenicity in cases of hemorrhage (Fig. 5.9). Noteworthy, both may involute spontaneously. MR imaging may help in detecting blood within the lesion, which is more in favor of a hemorrhage.

Fig. 5.9

Suprarenal neonatal mass. (a) Axial US neonatal scan on the left kidney showing a heterogeneous suprarenal mass that could correspond to a suprarenal hemorrhage or to a neuroblastoma. (b) US performed at 1 month shows the partial involution of the lesion favoring the diagnosis of a hemorrhage

Classical presentation: In newborns with prenatal diagnosis of a suprarenal mass, a neonatal ultrasound is performed to confirm the diagnosis. The US criteria are the same as in the fetus. In case of sequestration (in the absence of clinical symptoms), a CE-CT scan is performed preferably between the third and sixth month of life in order to precise the vascular anatomy before surgery. In case of the suspicion of a neuroblastoma, MR imaging is the most useful imaging modality for the staging; it shows bone marrow infiltration and intraspinal extension much more accurately than CE-CT. Urinary catecholamines levels and I-MIBG scintigraphy are also mandatory in this context.

Very rarely, a suprarenal lesion may be life threatening and represent a neonatal emergency. A sequestration with high blood flow may lead to neonatal cardiac failure (Fig. 5.10), a cardiac support therapy should be initiated before surgery. Cases of severe respiratory distress have been reported; they are related to the upward displacement of the diaphragm secondary to huge bilateral adrenal cystic neuroblastoma requiring urgent debulking surgical procedure. This abdominal involvement can be rapidly confirmed by abdominal US [25].

Fig. 5.10

Sequestration (the lesion was detected antenatally). (a) Axial neonatal US scan on the upper abdomen showing hyperechogenic mass with a systemic feeding vessel (arrow) confirming the diagnosis of sequestration. (b) 3D reconstruction of the CE-CT scanner performed after birth shows the highly vascularized lesion with two arterial feeding pedicles (arrow) arising from the aorta and one large vein draining in the dilated azygos vein. This vascular shunting has been responsible for a transitory cardiac failure

5.2.3.3 Hepatic Masses (See Also Chap. 8)

Hepatic masses are rare in the perinatal period. The three most frequent are hemangioendothelioma, mesenchymal hamartoma, and hepatoblastoma. Many are detected in utero. Hemangioendothelioma is a benign vascular tumor. Prominent US features include an intrahepatic mass with a complex heterogeneous pattern associated with dilated hepatic artery and veins indicating intratumoral arteriovenous shunting. Mesenchymal hamartomas are also complex intraparenchymal lesions that can be mostly cystic or with a mixed pattern but without vascular components demonstrable on US examination. Hepatoblastoma, the most common malignant liver tumor of infancy, appears like a solid hepatic mass.

Classical presentation: After birth, these lesions will be confirmed by an US with Doppler analysis. An associated abdominal MR Imaging or CE-CT is required in order to better characterize the lesion and precise its topography within the liver. A raised alpha-fetoprotein level is suggestive of hepatoblastoma. In case of massive hemangioendothelioma, corticotherapy generally leads to progressive involution of the tumor. Mesenchymatous hamartoma should be operated as these tumors do not regress spontaneously. Hepatoblastoma should be treated by chemotherapy and surgery as appropriated. A Beckwith-Wiedemann syndrome has to be excluded in babies with hepatoblastoma or mesenchymal hamartoma, as they can be associated features.

On rare occasions, these hepatic lesions may induce acute neonatal complications. The hemangioendothelioma may lead to cardiac failure and hydrops due to the important vascular intratumoral shunting (Fig. 5.11). Cases of rupture and hemorrhage in case of large mesenchymatous hamartoma or hepatoblastoma leading to hypovolemic shock have also been reported [26–28]. In cases of very large masses, babies may present with jaundice and respiratory distress, respectively, due to hepatic infiltration and upward displacement of the diaphragm [29].

Fig. 5.11

Hepatic mass. (a) Axial US scan of the abdomen of a 20-day-old neonate presenting abdominal deformation without prenatal diagnosis. It shows a huge solid aspect lesion of the left hepatic lobe. (b) The lesion seems moderately vascularized on Doppler imaging. (c, d) The enhanced T1 weighted MR sequences show characteristic progressive centipede filling of a vascular tumor: hemangioendothelioma

It is important to differentiate vascular tumors from vascular malformations like portosystemic shunts (Fig. 5.12). The latter correspond to abnormal communications between the ombilicoportal and caval system and can be intra or extrahepatic (see Chap. 15) [30]. Most of them will close spontaneously but possible high vascular flow may lead to cardiac failure. Therefore, a close hemodynamic follow-up should be initiated before and after birth. In some cases, embolization will be necessary to prevent cardiac and hepatic failure (see also Chap. 8).

Fig. 5.12

Intrahepatic portosystemic shunt. (a) Axial US scan of the liver of a 36-week-old fetus showing the wide anastomosis between the left portal and one suprahepatic vein (arrow). (b) The same aspect is observed at birth; the shunt closed spontaneously within the first month of life

5.2.3.4 Congenital Sacrococcygeal Teratomas

Sacrococcygeal teratoma (SCT) is the most common location for teratoma. The tumor arises from the anterior part of the coccyx and may extend externally or within the pelvis and abdomen. It originates from Hensen’ nodes and comprises all cell layers. Most fetal teratomas are benign; consequently, their prognosis relies mainly on their intrapelvic/abdominal extension and spinal canal invasion [31]. Therefore, fetal MR imaging is performed as a complementary tool to US to better define the topography of the lesion and its impact on adjacent organs [32]. Some tumors can be huge, necessitating drainage of their large cystic components before delivery to prevent tumor or uterine rupture. The tissular part of the tumor is also important for the prognosis, as it can be highly vascularized and responsible for blood shunting leading to cardiac failure and hydrops. Fetal hemodynamic status should be carefully monitored.

Classical presentation: The postnatal management consists in neonatal US and MR imaging in order to define the tumoral extent before surgery. The prognosis relies on the consequences of the mass on the surrounding organs and on the hemodynamic and respiratory status of the newborn. It should be carefully monitored in specialized neonatal units.

Sometimes, an SCT can present, already in utero, acute symptoms necessitating urgent C-section and rapid surgical management [33]. Fetal cardiac failure secondary to high vascular output or to massive bleeding increases perinatal morbidity and mortality. Furthermore, the compressive tumor may interfere with renal or digestive tract function. Tumoral bladder outlet compression may lead to urinary retention and secondary renal failure (Fig. 5.13). Intramedullar infiltration may also be responsible for irreversible damage to the splanchnic or hypogastric nerves with the potential associated consequences as neurogenic bladder and fecal incontinence as well as reduced lower limbs mobility. All these complications render a rapid neonatal management mandatory.

Fig. 5.13

Sacrococcygeal teratoma with intrapelvic development. (a) Sagittal T2 weighted MR imaging on a third trimester fetus showing a large mostly solid mass with microcysts infiltrating the spinal canal (arrow) and responsible for the distension of the genital tract (arrow head). (b) The coronal T2 weighted image shows the compression of the urinary tract by the pelvic mass that induces bilateral hydronephrosis (arrow)

5.2.3.5 Lymphatic Malformations

Lymphatic malformations are not real neoplasms. They are composed of distended cystic lymphatic channels and are generally diagnosed in the second or third trimester of pregnancy. They are mainly located in the cervico-facial and mediastinal regions but some can develop in the chest or abdomen. They appear as heterogeneous cystic and septated masses (Fig. 5.14a). The cystic components appear anechoic but sometimes they display an echogenic content suggesting intracystic hemorrhage. These lesions typically infiltrate or displace the surrounding organs.

Fig. 5.14

Lymphatic malformation. (a) Sagittal T2 weighted MR image performed on a 29-week-old fetus showing a massive retroperitoneal lymphatic malformation presenting the typical cystic and septated aspect. (b) Post-natal T2 weighted coronal image demonstrates the extraabdominal extension with pelvic and left limb infiltration. The newborn died of acute sepsis

Classical presentation: The postnatal management includes neonatal US and MR imaging in order to better define the loco-regional extension (Fig. 5.14b) and to differentiate intra- from retroperitoneal lymphangioma as well as to define the relation of the malformation with the intra- abdominal vessels. The treatment may generally be delayed except in cases with important compression of intraabdominal organs and vessels. Whenever elected, surgery should be as complete as possible as these tumors may recur.

Uncommonly, it can happen that these lesions bleed and become therefore a surgical emergency for obvious hemodynamic reasons. They may also be infected and lead to acute septic situations. Some other will need rapid surgery because of infiltration of adjacent structures (Fig. 5.14). Rarely, like every large intraperitoneal mass, lymphatic malformations may interfere with digestive tract transit and lead to acute situations like (sub)occlusion or even volvulus [34].

5.3 Newborns with (Suspected) Antenatal Intestinal Occlusion

5.3.1 Introduction

Thanks to prenatal diagnosis, many neonatal digestive tract occlusions can be anticipated and the neonatal work-up is therefore simplified. In a newborn presenting signs of occlusion such as abdominal distension, bilious vomiting, delayed or absent meconium emission, it is mandatory to first refer to the prenatal data (hydramnios, digestive tract distension, colonic content, associated malformations, etc.) and second to be informed about the family history (cystic fibrosis, maternal diabetes, etc.).

Only gold members can continue reading. Log In or Register to continue