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drainage may occur, resolution of the jaundice and reversibility of the liver disease may or may not occur.

Currently, approximately 60% of the patients with biliary atresia undergo a surgical repair.

However, only a little more than one half of these patients have a resolution of jaundice and a return to normal liver function.

One third of all patients with biliary atresia who undergo surgery will be treated successfully by current surgical techniques. (These results were obtained in the United States.)

Biliary atresia remains the primary indication for liver transplantation in the pediatric population.

More than 50% of the patients with failed hepaticoportenterostomies can be treated successfully with transplants. The limiting factor is the availability of donor organs.

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Recently, the use of split liver grafts has shown promise. This allows a donor liver to be anatomically divided and used in two recipients.

Living related liver transplants (using segments of the left lobe) have also been successful.

Because of these advancements, some transplant centers advocate transplant as the primary procedure.

C

Necrotizing enterocolitis (NEC) is an ischemic disorder of the intestine in the newborn.

Etiology. Although the etiology and underlying mechanism of NEC is not completely understood, it is probably multifactorial. Ischemic injury to an immature intestine in a host with an immature immune system in the presence of bacteria can result in NEC.

Clinical presentation

The basic defect is an ischemic or hypoxic insult, which causes intestinal mucosal sloughing. This may lead to bacterial invasion and subsequent intestinal gangrene and perforation.

The patients are usually born prematurely or have a low birth weight (75% weigh <2,000 g at birth). The disease usually occurs within the first 2 weeks of life.

The first signs are usually intolerance to formula and abdominal distention. These signs may be associated with the passage of either heme -positive or grossly bloody stools.

Associated perinatal problems include premature rupture of the membranes, prolonged labor, amnionitis, umbilical artery catheterization, respiratory distress, apneic episodes, cyanosis, or delivery -room resuscitation.

Diagnosis

Laboratory findings include leukopenia, thrombocytopenia, a low hematocrit, low serum sodium levels, metabolic acidosis, and coagulation defects.

Abdominal radiographs are used to aid in the diagnosis and to follow the patient's clinical course.

The initial findings include distended, edematous intestines; intramural air (pneumatosis); portal vein gas; an isolated persistent distended loop of bowel; or free intraperitoneal air, suggesting intestinal perforation.

Medical management. The primary management remains medical. This includes gastrointestinal decompression with a large oral or nasogastric tube, parenteral antibiotic therapy, treatment with fluids, and nutritional support.

Operative management. Although the disease is primarily a medical disorder, approximately 40% of all infants who develop necrotizing enterocolitis require surgery for its complications (e.g., perforation, gangrene, or intestinal stricture).

An absolute indication for surgery in the acute stage is intestinal perforation.

This perforation can usually be documented by the abdominal radiograph.

A cross-table lateral or left lateral decubitus position is used.

Films are obtained every 4–6 hours or as clinically indicated.

If perforation occurs, it is treated by resection of the involved intestine.

The gastrointestinal tract is diverted with either a jejunostomy or an ileostomy and colostomy.

Primary reanastomosis of the normal bowel is performed only in patients with limited disease or an isolated perforation.

In the severely ill patient with perforation or in the micropremature infant (<1,000 g), a major resective procedure may not be tolerated. In this situation, placement of peritoneal drains (using local anesthesia) at the bedside has proved successful. This can be either a stabilizing step or definitive therapy, depending on the clinical response of the patient.

Relative indications for surgery

Signs of peritonitis (erythema or edema of the abdominal wall) increase.

The patient fails to stabilize after 12 hours of optimal medical treatment (the patient shows persistent acidosis, apnea, or hypothermia).

A persistent distended loop of bowel is seen on serial radiographs.

An abdominal mass is palpated.

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A stricture with subsequent intestinal obstruction occurs in approximately 30% of cases.

This problem occurs usually 3–6 weeks after the acute episode.

Strictures are treated by resection and primary anastomosis once the patient is prepared nutritionally for surgery.

Postoperative management includes continued medical management of the primary disease as well as routine postsurgical care.

The infant is treated with antibiotics, gastrointestinal decompression, and hyperalimentation.

The disease may progress, requiring further surgery for additional perforations. Recurrent necrotizing enterocolitis occurs in approximately 4% of patients.

Oral feedings are not started until 10–14 days after the acute disease resolves. Dietary adjustments may be necessary until the mucosa has regenerated and undergone functional maturation.

The enterostomy can be closed during the initial hospitalization or later on.

Management of the stoma can be difficult.

Local problems include prolapse, degeneration of the surrounding skin, or mucosal irritation.

Physiologic problems include fluid losses, electrolyte abnormalities, and intolerance of the diet.

Early recognition and treatment of these difficulties are necessary to prevent further complications.

Prognosis

The mortality rate is 20% among patients who require only medical management for NEC.

The mortality rate among patients requiring surgery is up to 50%, reflecting the greater severity of the disease in this group.

Birth weight also affects outcome, and the overall mortality is 40% in patients weighing less than 1,500 g and 0%–20% in patients weighing more than 2,500 g.

Long-term morbidity is related to the quantity and function of the remaining intestine and other comorbidities related to prematurity after recovery from NEC.

A patient who has had an extensive bowel resection may develop a short-bowel syndrome (see Chapter 12, II E ) requiring a change of diet or nutritional support. This syndrome has been reported to occur in approximately 8% of all patients with NEC. However, NEC is the major cause of short-bowel syndrome in children (20%–50% of all patients).

Comorbidities include intraventricular cerebral hemorrhage, chronic pulmonary insufficiency, or associated cardiac problems.

X Solid Tumors

The two most common solid tumors of childhood are Wilms' tumor and neuroblastoma. Although other tumors occur (e.g., rhabdomyosarcoma, Ewing's tumor, osteogenic sarcoma, various brain tumors), neuroblastoma and Wilms' tumor illustrate the multidisciplinary approach that is currently used in the management of tumors that occur in childhood. They are also outstanding examples of successful management (Wilms' tumor) and the need for continued research to improve current poor results (neuroblastoma).

A

Wilms' tumor can involve either the entire kidney or a part of it. Bilateral involvement occurs in 3%–10% of the cases.

Etiology. Mesodermal, mesonephric, and metanephric origins have been proposed for this tumor.

Incidence. It has been estimated that 500 new cases of Wilms' tumor occur each year in the United States.

Clinical presentation

An asymptomatic flank mass is usually discovered by the parents or during a routine physical examination. The mass is smooth, lobulated, and commonly mobile.

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Other complaints or findings include abdominal pain, hematuria, and anorexia.

Hypertension occurs in approximately 10% of patients.

The patient is between 1 and 4 years of age at presentation; most patients are between 1 and 3 years of age.

The tumor rarely crosses the midline but may appear to cross because of its size.

Associated anomalies

Wilms' tumor has been associated with congenital anomalies, such as aniridia, hemihypertrophy, Beckwith's syndrome, sexual ambiguity, cryptorchidism, urinary tract anomalies, and abnormal karyotypes.

Congenital mesoblastic nephroma is a distinct renal tumor of infancy related to Wilms' tumor.

To date, approximately 70 cases have been reported.

The tumor usually presents soon after birth as an abdominal mass.

Nephrectomy alone is the current therapy and provides a cure.

Diagnosis. Imaging studies to aid in the diagnosis of Wilms' tumor should define the nature of the abdominal mass, the organ of origin, the status of the contralateral kidney, the presence of tumor in the renal vein or vena cava, and the presence or absence of distal metastases.

A chest radiograph will reveal metastasis to the lung, which is the most common site.

Ultrasonography with a Doppler examination can identify the organ of origin, the opposite kidney, and the presence of renal vein or vena cava involvement.

Venograms are useful if the ultrasound cannot define tumor involvement of the vena cava.

A computed tomography (CT) scan can identify both the tumor and lung metastasis, but the sensitivity for the metastasis is high and is not used currently in the staging of Wilms' tumor.

Staging of Wilms' tumor is as follows:

Stage I: The tumor is limited to the kidney and is completely excised. The surface of the renal capsule is intact. The tumor was not ruptured before or during removal. There is no residual tumor apparent beyond the margins of resection.

Stage II: The tumor extends beyond the kidney but is completely removed. There is regional extension of the tumor (i.e., penetration through the outer surface of the renal capsule into the perirenal soft tissues). Vessels outside the kidney substance are infiltrated or contain tumor thrombus. The tumor may have been biopsied, or there has been local spillage of tumor confined to the flank. There is no residual tumor apparent at or beyond the margins of excision.

Stage III: A residual nonhematogenous tumor is confined to the abdomen.

Lymph nodes on biopsy are found to be involved in the hulus, the periaortic chains, or beyond.

There has been diffuse peritoneal contamination by tumor, such as spillage or tumor beyond the flank before or during surgery or tumor growth that has penetrated through the peritoneal surface.

Implants are found on the peritoneal surface.

The tumor extends beyond the surgical margins either microscopically or grossly.

The tumor is not completely resectable because of local infiltration into vital structures.

Stage IV: Hematogenous metastases can occur with deposits beyond stage III (e.g., lung, liver, bone, or brain).

Stage V: Bilateral renal involvement is evident at diagnosis. An attempt should be made to stage each side according to the aforementioned criteria on the basis of the extent of disease before a biopsy.

Management of Wilms' tumor involves a multidisciplinary approach.

Surgery is the mainstay of treatment.

The timing of surgery depends on the stage of the tumor (i.e., stage IV or V).

The operation includes:

An exploratory laparotomy

Examination of the opposite kidney

Resection of the tumor

Periaortic node dissection or sampling

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Because of the relatively good prognosis, even with extensive disease, resection of other organs in an effort to remove the tumor is acceptable.

Venacaval extension requires the removal of the tumor thrombus. This operation may require a cardiopulmonary bypass to assist in the resection.

Chemotherapy currently involves the use of dactinomycin (actinomycin D) and vincristine.

Currently, chemotherapy is used in all stages (I–V) for varying cycles, depending on the histology (see X A 8).

Dactinomycin and vincristine are given preoperatively in stages IV and V disease.

Adriamycin is added to the chemotherapy regimen for patients with advanced disease.

Radiotherapy is used to treat extensive disease (stages III–V). The numerous complications after high-dose radiotherapy include secondary cancers in children; interference with growth and development of bones, joints, and muscles; radiation pneumonitis; radiation enteritis; and cardiotoxicity.

Prognosis. Survival appears to be related to the histology of the tumor, which is reported as favorable (FH) and unfavorable (UH) and dictates treatment protocols. Current 2-year survival rates by stage and histology are as follows:

Stage I (FH)—97%

Stage II (FH)—95%

Stage III (FH)—88%

Stage IV (FH)—85%

Stages I–III (UH) —80%

Stage IV (UH) —55%

Stage V —50%

B

Neuroblastoma is a neoplasm of adrenal and neural crest origin.

Incidence. It occurs in 1 of every 10,000 live births and is the most common extracranial solid tumor of childhood. It occurs in the early age group, with 50%–60% presenting by 2 years of age.

Types. The following are several major variants of neuroblastoma.

Classic neuroblastoma is a highly undifferentiated, immature malignant tumor that is unencapsulated and diffusely infiltrates the surrounding tissue.

Ganglioneuroma is a benign, well-encapsulated tumor containing fully differentiated mature ganglia cells.

Ganglioneuroblastoma is an intermediate or transitional form consisting of both primitive undifferentiated neuroblasts and mature differentiated ganglia cells. It can occur with or without encapsulation.

Etiology. Although they may occur anywhere along the sympathetic chain, the majority (65%) of these tumors arise from adrenal or nonadrenal retroperitoneal sites.

Clinical presentation

Most patients present with a complaint of an abdominal mass.

Neurologic symptoms may occur, resulting from compression of nerve trunks or from extension of the tumor into the extradural space (“dumbbell” tumor).

Horner's syndrome has been reported.

Other symptoms include acute cerebellar ataxia and opsoclonus (i.e., sustained, irregular multidirectional, spontaneous conjugate eye movements).

Metastatic spread can involve the liver, lungs, skin, bone marrow, and bone.

Skin lesions are firm, nontender, and bluish; a biopsy will provide the diagnosis.

The orbit is a common site of bony metastasis with consequent periorbital ecchymosis and proptosis.

More than 50% of patients have metastatic disease at presentation.

The diagnosis of the tumor may be obtained by various laboratory methods.

Bone marrow aspiration may reveal typical neuroblastoma cells.

Urinalysis. The tumor may synthesize various catecholamines.

The excretion products include vanillylmandelic acid (VMA) and homovanillic acid.

These acids can be checked in both spot urine samples and in 24 -hour urine collections. P.576

Radiologic studies

Skeletal surveys or bone scans may show metastatic lesions.

Chest radiographs will confirm or rule out pulmonary metastasis.

Ultrasonography acts as a screening tool to define the organ of origin and to rule out Wilms' tumor.

Calcifications are seen much more often on abdominal radiographs in neuroblastoma than in Wilms' tumor.

A CT scan gives complete details of the tumor as well as being sensitive to identifying metastatic disease.

If spinal cord extension of a paraspinal neuroblastoma, the presence of a “dumbbell” tumor, or neurologic symptoms are suspected, magnetic resonance imaging (MRI) is very helpful in defining the exact extent of cord involvement.

Liver function is documented, and routine blood studies are done. Anemia will be present in approximately 40%–60% of the patients at the time of diagnosis.

Age. The younger the child at diagnosis, the better will be the outlook; this variable is independent of staging.

Stage. The more advanced the disease, the worse will be the prognosis; however, stage D (S) has a relatively good prognosis (70% survival).

Location. An abdominal neuroblastoma has a worse outlook than has an extra-abdominal neuroblastoma.

Site of metastasis. Patients presenting with bony lesions have a mortality rate of almost 100%.

Presentation. Patients presenting with opsoclonus have a higher survival rate than do those who present without it.

Biologic markers are currently being used to define a study group as low risk in an effort to limit transplantation in order to reduce morbidity.

Overall survival rates are as follows:

Stage A—90%

Stage B—80%

Stage C—60%

Stage D—10%

Stage D (S)—70%

The two major pediatric cancer study groups (Pediatric Oncology Group and Children's Cancer Group) are currently merging into one unit. This merger will standardize study data and will result in an effort to improve therapy and general outcome.

Other studies now being undertaken in the long-term outcome for survivors relate to possible second malignancies and fertility as well as mental and physical development. These studies are confined not just to solid tumors but also to hematologic cancer.