*2.4.3 Diagnosis*

*Congenital Anomalies in Newborn Infants - Clinical and Etiopathological Perspectives*

Pyloric stenosis is not a surgical emergency and operative intervention is deferred until electrolytes have normalized, ideally, chloride >95, bicarbonate <30. As the primary metabolic derangements are caused by volume and gastric juice loss, resuscitation should be initiated with 10-20 cc/kg normal saline boluses. Once volume status has been adequately restored and urine output robust, potassium containing fluids (D5 1/2NS + 10 K/L) are administered at

The Ramstedt pyloromytomy was historically carried out through a right subcostal transverse incision however the laparoscopic approach is becoming preferred in current practice. A longitudinal incision along the anterior surface of the pylorus is carried down through the serosa and hypertrophied muscle until the submucosa protrudes, much like slicing the tough outer skin of a grape until the smooth inner flesh is encountered. The length of the myotomy extends from the antrum of the stomach proximally to the pyloric vein of Mayo distally, which designates the junction of the pylorus and proximal duodenum. Oral feeding may be initiated 6–8 h

Long term results from pyloromyotomy are excellent and few infants, if any, have residual complications. Incomplete myotomy can present with persistent feeding intolerance in the peri-operative period and requires re-operation.

The pathophysiology is unknown. Between 4 and 10 weeks of gestation, the extrahepatic biliary tract develops from the hepatic diverticulum. This occurs normally. In the post-natal period, there appears to be an inflammatory process that

**90**

*2.3.4 Surgical management*

*Diamond duodenoduodenostomy for duodenal atresia repair.*

**Figure 2.**

maintenance rate.

*2.3.5 Outcomes*

**2.4 Biliary atresia**

*2.4.1 Embryology*

post-operatively and advanced as tolerated.

causes fibrosis of the extrahepatic biliary ducts [2].

Hepatobiliary technetium-99 iminodiacetic acid scan (99-Tc IDA) has highest sensitivity and specificity [2]. Normally, the radiotracer is taken up by hepatocytes and readily excreted into the intestines via the biliary ducts. In biliary atresia, technetium will be taken up by the liver normally, but obstruction of the extrahepatic ducts prevents outflow of radiotracer into the duodenum. Abdominal ultrasound may reveal a small or obliterated gallbladder. Magnetic resonance cholangiopancreatography (MRCP) is also be helpful in ruling out intrahepatic atresia or choledocal cysts.

### *2.4.4 Surgical management*

Expeditious operative intervention is imperative as liver damage can be attenuated, even reversed, and chance of survival improved with early biliary decompression. Beyond 3–4 months, irreversible liver damage may preclude successful outcome. The Kasai portoenterostomy is the procedure of choice. First, an intraoperative cholangiogram is performed to delineate the anatomy of the biliary tree and confirm the diagnosis. A liver biopsy is obtained to document degree of liver damage. Next, the fibrotic common bile duct is dissected from the hepatoduodenal ligament up to the level of the porta hepatis and excised. An approximately 20 cm limb of jejunum is brought up in a retrocolic fashion and a Roux-en-Y hepaticojejunostomy is created.

### *2.4.5 Outcomes*

Successful, long term establishment of bile flow correlates with earlier surgical intervention. Infants aged <60 days at time of surgery have best results. Approximately one-third of children undergoing portoenterostomy have a 10-year or greater survival, while the rest will ultimately succumb to liver failure and require transplant. Other indications for liver transplant include presence of intrahepatic atresia, fat soluble vitamin deficiencies causing failure to thrive and variceal bleeding secondary to portal hypertension. 5-year survival following liver transplant ranges from 75 to 95% [2].

Apart from progressive liver failure, cholangitis is another major post-operative complication occurring in as much as 50% of patients who undergo portoenterostomy [2]. Decreased bile flow indicated by elevated total bilirubin in the setting of fever and leukocytosis is essentially diagnostic of cholangitis until proven otherwise. It is managed with IV antibiotics and fluid resuscitation.

#### **2.5 Choledochal cysts**

#### *2.5.1 Embryology*

Etiology is unknown. Aberrant pancreaticobiliary junction near the duodenal wall has been suggested [3].

#### **Figure 3.**

*Normal anatomy of the hepatobiliary tree and its relationship to the pancreas and duodenum. (A) Choledocal cyst type 1: fusiform dilation of the extrahepatic duct common bile duct. (B) Choledocal cyst type 2: isolated diverticulum off the common bile duct. (C) Choledocal cyst type 3: supraduodenal choledococele. (D) Choledocal cyst type 4: cystic dilation of intra- and extra-hepatic bile ducts. (E) Choledocal cyst type 5, dilation of intra-hepatic ducts only.*

**93**

*Congenital Anomalies of the Gastrointestinal Tract DOI: http://dx.doi.org/10.5772/intechopen.92588*

present with cholangitis or pancreatitis.

hepatic ducts are dilated (**Figures 3D, E**).

*2.5.4 Surgical management*

*2.5.5 Outcomes*

scopically, respectively.

**3. Midgut disorders**

*3.1.1 Embryology*

**3.1 Small intestine atresia**

Infants present with symptoms of biliary obstruction: progressive jaundice, dark urine, light colored stools. A tender abdominal mass may be palpated in the right upper quadrant. Laboratory values will be consistent with biliary obstruction and demonstrate elevated direct bilirubin and alkaline phosphatase. Patients may also

While abdominal ultrasound and hepatobiliary 99-Tc IDA scan are useful, MRCP best delineates the anatomy of the biliary tree and is the diagnostic test of choice. There are five types (**Figure 3**). Type 1 is the most common and presents as saccular or fusiform dilation of the common bile duct (CBD; **Figure 3A**).

Intrahepatic ducts are normal. Type 2 is an isolated CBD diverticulum (**Figure 3B**). Type 3 is a choledochocele, in which there is cystic dilation of the supra-duodenal CBD, prior to its junction with the pancreatic duct (**Figure 3C**). In type 4 disease, intra- and extra-hepatic bile ducts are dilated whereas in type 5 disease only intra-

Given the risk of cholangiocarcinoma, highest in types I and IV, surgical intervention is indicated at the time of diagnosis of any type of choledochal cyst. The approach depends on type of lesion. For type 1 cysts, primary cyst excision with cholecystectomy and roux-en-Y hepaticojejunostomy reconstruction is procedure of choice. Type 2 disease is managed by simple diverticulectomy. Type 3 is managed by transduodenal cyst excision or marsupialization and sphincteroplasty. Types 4 and 5 may be treated by anatomic hepatic resection based on the extent and location of

disease, however, liver transplantation is ultimately required in most cases.

Excision of choledocal cysts result in excellent long-term outcomes with few major complications. Biliary tract malignancy, the most feared complication, may occur with incomplete excision. Cholangitis, stricture formation and choledocolithiasis are lesser significant complications that are managed medically and endo-

Midgut development begins around the fifth week of gestation. The midgut starts as a vertical tube and has two connections: a ventral connection to the yolk sac via the omphalomesenteric (vitelline) duct and a dorsal attachment to the posterior abdominal wall, the mesentery [4–6]. The dorsal mesentery is the conduit for the superior mesenteric artery (SMA), which buds from the aorta, and delivers blood to the midgut. The lengthening gut tube outgrows the confines of the abdominal cavity and consequently herniates into the umbilical cord. As it elongates, it rotates

*2.5.2 Clinical presentation*

*2.5.3 Diagnosis*
