Shaun Daly, M.D., Ai-Xuan L. Holterman, M.D.
1 Which of the following statements is true regarding daily fluid requirements?
A Premature infants weighing less than 2 kg require only up to 80 mL/kg/day of fluid.
B Neonates and infants weighing 2 to 10 kg require 200 mL/kg/day of fluid.
C Infants and children weighing 10 to 20 kg require 1000 mL/day plus 50 mL/kg/day of fluid for every kilogram over 10 kg.
D Children heavier than 20 kg require 1500 mL/day plus 30 mL/kg/day of fluid for every kilogram over 20 kg.
E All of the above.
Ref.: 1-3
Comments
See Question 2.
Answer
C
2 Which of the following is true in the pediatric population?
A The daily sodium requirement is 8 mEq/kg.
B The daily potassium requirement is 4 mEq/kg.
C The daily protein requirement is 2 to 3.5 g/kg/day in infants.
D The minimum daily carbohydrate requirement is 2 to 3 mg/kg/min in neonates.
E Fat infusions should be started at 1.5 g/kg/day and titrated up to 3.5 to 4 g/kg/day.
Ref.: 1
Comments
Free water maintenance requirements include replacement of insensible losses from the skin and lungs and the free water necessary to clear metabolic solutes in the urine. It does not include treatment of preexisting deficits or ongoing fluid losses. Numerous formulas are applicable to the calculation of maintenance requirements. Daily electrolyte requirements include sodium at 2 to 5 mEq/kg and potassium at 2 to 3 mEq/kg. Dextrose is administered to provide a glucose substrate at a minimum rate of 4 to 6 mg/kg/min. Fat infusions are started at 0.5 g/kg/day and advanced up to 2.5 to 3 g/kg/day. Protein requirements are 2 to 3.5 g/kg/day in infants, as opposed to requirements of about 1 g/kg/day in adults.
Answer
C
3 A 5-week-old boy has a 5-day history of vomiting and weight loss of 0.4 kg (from 4.0 to 3.6 kg). His anterior fontanelle is flattened and his mucous membranes are dry. Laboratory data are as follows (mEq/L): sodium, 132; potassium, 3.2; chloride, 91; and bicarbonate, 28. Which of the following statements about this infant is true?
A Characterization of the emesis as bilious is crucial to aid in the diagnosis.
B Palpation of the abdomen will not help with the diagnosis.
C Ultrasound imaging of the abdomen will not add to the diagnosis.
D The most likely diagnosis is intussusception.
E The condition should be corrected by emergency surgery.
Ref.: 1-3
Comments
Age is important in sorting out the differential diagnosis. Duodenal atresia is seen only in newborns. Pyloric stenosis typically produces symptoms in infants between 3 and 12 weeks of age. Intussusceptionmost commonly occurs in children between 3 and 18 months of age. Pyloric stenosis is usually manifested as nonbilious vomiting, which progressively becomes projectile as a result of the blockage occurring proximal to the ampulla of Vater. Duodenal atresia most commonly occurs distal to the ampulla of Vater and will be accompanied by bilious vomiting. The extent of dehydration and electrolyte imbalance depends on the duration of the symptoms. Early in the course, fluid and electrolyte levels can be normal. If the condition is diagnosed late, infants are more likely to have severe metabolic derangements and dehydration. Physical examination can reveal a palpable thickened pylorus manifested as a pathognomonic olive-sized mass in the upper part of the abdomen. Sometimes gastric waves are seen through the epigastrium. If the pyloric mass cannot be palpated by an experienced examiner, ultrasound imaging is the first choice for diagnostic study, but an upper gastrointestinal contrast-enhanced study can also be done. Correction of fluid and electrolyte abnormalities takes precedence over surgery, which can be undertaken electively.
Answer
A
4 For the infant in Question 3, which of the following is the most common electrolyte abnormality?
A Hypokalemia
B Hyperkalemia
C Hypocalcemia
D Hyperchloremia
E Hypercalcemia
Ref.: 1
Comments
The electrolyte imbalances commonly seen in infants with hypertrophic pyloric stenosis are those associated with gastric outlet obstruction, namely, hypokalemic, hypochloremic metabolic alkalosis and paradoxical aciduria. The electrolyte abnormalities reflect the extensive loss of gastric contents from emesis in hypertrophic pyloric stenosis. Paradoxical aciduria and hypokalemia result from the urinary loss of acid (H+) and potassium at the expense of sodium and water retention to preserve fluid volume. Hypochloremia is secondary to loss of bicarbonate from emesis with resulting contraction alkalosis. Disturbances in calcium are not classically a common electrolyte imbalance seen in infants with hypertrophic pyloric stenosis. Correction of fluid and electrolyte imbalances is essential before proceeding to surgery.
Answer
A
5 Which of the following solutions is appropriate for initial intravenous therapy in the infant in Question 3?
A Lactated Ringer’s solution at 25 mL/h
B Five percent dextrose in water (D5W) + 0.1% normal hydrochloride (HCl) at 30 mL/h
C D5W + 0.20% normal saline solution + KCl, 30 mEq/L at 25 mL/h
D D5W + 0.45% normal saline solution + KCl, 30 mEq/L at 16 mL/h
E D5W + 0.45% normal saline solution + KCl, 30 mEq/L at 24 mL/h
Ref.: 1-3
Comments
Appropriate fluid therapy requires the administration of maintenance fluid in addition to replacement for the estimated deficit and ongoing fluid losses. The estimated initial replacement volume for the first 24 hours includes maintenance of 100 mL/kg (400 mL/24 h, or 16 mL/h), plus replacement of approximately one half of the estimated deficit. Because weight loss is 40 g, or 10% of body weight, one half of this deficit would be 200 mL/24 h, or 8 mL/h. The initial rate of fluid replacement should be adjusted to maintain a urine output of 1 to 2 mL/kg/h. An initial bolus of isotonic saline solution at 20 mL/kg may be appropriate for severely dehydrated patients. Sodium, potassium, and chloride must be supplied for both maintenance and replacement of gastric losses as a 5% dextrose with 0.5% normal saline solution and KCl at 30 mEq/L. Ongoing assessment of fluid and electrolyte correction should be performed and adjusted as necessary by monitoring serum electrolytes and urine output. The operation should proceed only after appropriate fluid and electrolyte correction.
Answer
E
6 Major indications for the initiation of extracorporal membrane oxygenation (ECMO) in a newborn include all of the following except:
A Diaphragmatic hernia
B Meconium aspiration syndrome
C Sepsis
D Pulmonary sequestration
E Respiratory distress syndrome
Ref.: 1
Comments
Meconium aspiration syndrome, respiratory distress syndrome, persistent pulmonary hypertension, sepsis, and congenital diaphragmatic hernia are all major indications for the initiation of extracorporal membrane oxygenation. Meconium aspiration syndrome is the most common indication for neonatal ECMO. Selection criteria include failure of conventional therapy with an alveolar-arterial oxygen gradient of greater than 620 for 12 hours (or 6 hours in patients with extensive barotrauma and requiring high inotropic support) or an oxygen index higher than 40. Exclusion criteria include gestational age less than 34 weeks, birth weight less than 2 kg, irreversible pulmonary disease, uncorrectable cyanotic congenital heart disease, intractable coagulopathy or hemorrhage, intracranial hemorrhage, or a history of more than 10 to 14 days of high-pressure mechanical ventilation. Follow-up hematocrit, platelet count, fibrinogen, and activated clotting time values and daily cranial ultrasound are required.
Answer
D
7 Which of the following statement concerning pediatric trauma is true?
A Trauma is the second leading cause of death in children between 1 and 15 years of age.
B Acceptable indications for computed tomography (CT) include the presence of a painful distracting injury, significant head injury, or an unclear examination.
C Indications for operative intervention include documentation of injury to the spleen or liver on CT.
D Intraosseous access is the preferred means for delivering fluids or blood in a child younger than 10 years.
E Surgical cricothyroidotomy is an acceptable means of airway control for a child younger than 12 years.
Ref.: 1, 2
Comments
For children between the ages of 1 and 15 years, trauma is the leading cause of death. Motor vehicle accidents, falls, bicycle accidents, and child abuse are the most common causes of traumatic death. The priorities of resuscitationare airway, breathing, and circulation. Fluid resuscitation is given as 20-mL/kg boluses. If intravenous access cannot be obtained in a timely manner, a specially designed needle can be used to deliver fluids or blood through an intraosseous route in children younger than 6 years, most commonly via the tibia. The needle is placed 1 to 2 cm below the tibial tuberosity through the anteromedial surface of the tibia under sterile conditions. If hypovolemic shock is refractory to two crystalloid boluses, blood transfusion should be initiated. CT is commonly used to evaluate pediatric trauma patients. CT is indicated when there is an injury elsewhere causing pain, a significant head injury precluding a reliable examination, or if there is an equivocal examination in general. Even though injuries to the liver and spleen are common, the need for operative intervention is not absolute. Surgical cricothyroidotomy should not be attempted in a child younger than 12 years because of the risk of inadvertent airway injury.
Answer
B
8 A 6-month-old infant requires blood transfusion after injury. Which of the following regimens is the most appropriate initial replacement?
A 10 to 20 mL/kg of packed red blood cells (PBRCs)
B 30 to 40 mL/kg of PBRCs
C 10 to 20 mL/kg of PBRCs + 10 to 20 mL/kg of platelets
D 10 to 20 mL/kg of PBRCs + 10 to 20 mL/kg of fresh frozen plasma
E 40 to 60 mL/kg of whole blood
Ref.: 1, 2
Comments
Blood volume for infants is usually estimated at 80 mL/kg of body weight. When blood transfusions are required, PRBCs are typically used, and the initial volume replacement is 10 to 20 mL/kg body weight. Coagulation deficits can develop rapidly in infants requiring more blood replacement. Fresh frozen plasma at a volume of 20 mL/kg and platelets at a volume of 10 to 20 mL/kg can be given if necessary.
Answer
A
9 A 3-month-old child is admitted to the hospital for irritability and a 4-hour history of right scrotal fullness. Testicular torsion is suspected. Which of the following is false?
A Physical examination may reveal a horizontal testicular lie (bell clapper deformity).
B The chance of testicular salvage decreases after 6 hours of symptoms.
C Ultrasound is the test of choice to assist in the diagnosis.
D Contralateral orchiopexy is not indicated.
E Testicular scan may assist in the diagnosis.
Ref.: 1
Comments
Testicular torsion is a surgical emergency and must be diagnosed rapidly. Doppler ultrasound is the diagnostic test of choice to assess blood flow to the testicle. Rapid diagnosis is essential because longer than 6 hours of testicular ischemia significantly decreases the salvage rate. Contralateral orchiopexy is indicated to prevent future torsion of the contralateral testicle. The bell clapper deformity refers to the horizontal lie of a testicle as a result of the failure of normal posterior anchoring of the gubernaculum, epididymis, and testis to the tunica vaginalis, thereby predisposing the testis to torsion.
Answer
D
10 Which of the following is the indicated treatment for a noncommunicating hydrocele in a 2-month-old infant?
A Observation
B Needle aspiration
C Hydrocelectomy through a groin incision
D Hydrocelectomy through a scrotal incision
E Repair of the hernia and hydrocelectomy
Ref.: 1-3
Comments
Most noncommunicating hydroceles in young children are asymptomatic and will resolve as the fluid is absorbed. If the hydrocele persists past 12 months of age, peritoneal communication is likely, and hydrocelectomy with ligation of the patent processus vaginalis is indicated. In children, these operations are performed through the groin. Aspiration of the hydrocele is not recommended. If the hydrocele is noncommunicating, it will resolve and thus make aspiration unnecessary. If the hydrocele is communicating, the fluid will reaccumulate, and an operation will be necessary.
Answer
A
11 The following are true of inguinal hernias in the pediatric population except:
A Inguinal hernias are more common in females than in males.
B The most common structure found in an incarcerated inguinal hernia in girls are the ovaries.
C Laparoscopic evaluation of the contralateral groin is not always needed.
D High ligation of the hernia sac without repair of the inguinal floor is appropriate.
E Routine contralateral exploration is not indicated.
Ref.: 1-3
Comments
Repair of inguinal hernias in infants is recommended because the patent processus vaginalis does not close after birth and the risk for incarceration is high. In girls, the ovaries are the most common incarcerated organs in an inguinal hernia. High ligation plus excision of the hernia sac is adequate treatment, and routine repair of the inguinal floor is unnecessary. Inguinal hernias are more common in males than in females by a ratio of almost 6 : 1. The distal part of the hernia sac should be opened widely to prevent postoperative hydrocele. Operative management of a clinically normal contralateral groin has long been controversial. Many surgeons adopt a more selective approach over routine contralateral exploration. Laparoscopic examination through the hernia sac can identify a patent processus vaginalis of the contralateral groin but requires general anesthesia. Not all patients with a patent processus vaginalis will progress to a clinically significant hernia, but certainly patients without a patent processus vaginalis do not require contralateral exploration.
Answer
A
12 Which of the following statements is false in regard to branchial cleft remnants?
A Branchial fistulas are more common than external sinuses, which are more common than branchial cysts.
B First branchial cleft remnants are typically located along the anterior border of the sternocleidomastoid muscle.
C Second branchial cleft remnants are the most common branchial cleft remnants.
D Third branchial cleft remnants are typically located in the suprasternal notch or clavicular region.
E Second branchial cleft remnants are typically located along the anterior border of the sternocleidomastoid muscle.
Ref.: 1
Comments
Structures of the head and neck are derived from six pairs of branchial arches with intervening external clefts and internal pouches. Failure of these structures to regress leads to congenital branchial fistulas, sinuses, or cysts, with fistulas, sinuses, and cysts occurring in decreasing order of frequency. First branchial remnants are typically located in the front or back of the ear or in the region of the mandible. Second branchial remnants, which are the most common, are typically located along the anterior border of the sternocleidomastoid muscle. Third branchial remnants are typically located at the sternal notch or the clavicular region. Figure 32-1 shows a second branchial cyst in relation to the cranial nerves. The tract emerges superior to cranial nerve IX and will cross anterior to cranial nerves IX and XII. The cyst itself lies anterior to cranial nerves X and XII.
Figure 32-1 Second branchial cyst in relation to the cranial nerves.
Answer
B
13 Which of the following statements is most accurate regarding branchial cleft anomalies?
A Third arch anomalies are common.
B Type II first arch branchial anomalies are the most common overall.
C The glossopharyngeal nerve is associated with the third branchial arch.
D Second arch anomalies end in the piriform sinus.
E Second arch anomalies travel deep to the internal carotid artery.
Ref.: 4, 5
Comments
Branchial cleft anomalies can include cysts, fistulas, and sinus tracts, depending on the extent of development of the arch. Diagnosis depends mainly on understanding the associated anatomy of these structures. Treatment is surgical and may require a stair step incision, depending on the length of the tract. Branchial arch defects travel deep to the structures derived from its arch and superficial to the structures of the following arch. First arch anomalies are divided into type I and type II. The trigeminal nerve is derived from the first arch. Type I anomalies are duplications of the external auditory canal. Type II anomalies many times appear at the angle of the mandible and pass up through parotid gland. Both types can be intimately associated with the facial nerve, a second arch derivative. Second branchial arch anomalies are by far the most common and are characterized by a tract along the anterior border of the sternocleidomastoid muscle. They pass deep to the external carotid artery and superficial to the internal carotid artery and end at the tonsillar fossa. Third arch anomalies are rare and appear lower in the neck. They travel and enter the pharynx at the piriform sinus. They pass deep to third arch structures such as the internal carotid artery and glossopharyngeal nerve but superficial to the vagus nerve, a fourth arch analogue. Fourth arch anomalies are extremely rare.
Answer
C
14 A 12-month-old infant is admitted to the hospital for lower gastrointestinal bleeding. Which of the following is false regarding the probable admitting diagnosis for this infant?
A Most of the lesions are detected incidentally at autopsy or laparotomy.
B It is typically found on the mesenteric side of the bowel.
C It results from incomplete closure of the omphalomesenteric (vitelline) duct.
D Typically, gastric mucosa is indirectly responsible for the gastrointestinal hemorrhage.
E It occurs in 2% of the population.
Ref.: 1
Comments
A Meckel diverticulum is the most common congenital anomaly of the small intestine and occurs in 2% of the population. It is most commonly diagnosed at autopsy or found incidentally during exploratory laparotomy. It arises from incomplete closure of the omphalomesenteric (vitelline) duct. A Meckel diverticulum occurs on the antimesenteric border of the ileum, most commonly between 4 and 60 cm from the ileocecal valve. Gastric mucosa is commonly found in the diverticulum (in about 50% of cases) and can lead to ulcer formation and cause painless lower gastrointestinal bleeding as the most common initial symptom. Approximately 5% of Meckel diverticula contain ectopic pancreatic tissue.
Answer
B
15 Which of the following is the most common malignancy found in children?
A Lymphoma
B Leukemia
C Neuroblastoma
D Nephroblastoma
E Rhabdomyosarcoma
Ref.: 1-3
Comments
Malignancy is second only to trauma as the leading cause of childhood death. In infants, it is the third most frequent cause of death after prematurity and congenital anomalies. Approximately 40% of childhood malignancies are leukemia. The most common solid tumor in children younger than 2 years is neuroblastoma, which accounts for 6% to 10% of all childhood cancers. In children older than 2 years, the most common solid tumor is Wilms tumor.
Answer
B
16 Which of the following statements concerning biliary atresia is true?
A Without treatment, the average survival is 5 years.
B The hallmark pathologic findings in biliary atresia are giant cell transformation and hepatocellular necrosis.
C The Kasai procedure typically includes a choledochojejunostomy anastomosis.
D Ultrasound of the liver and gallbladder is an integral part of the diagnostic work-up for biliary atresia.
E Biliary atresia is the third most common indication for pediatric liver transplantation.
Ref.: 1, 2
Comments
Biliary atresia is characterized by progressive, irreversible fibrosis of the extrahepatic and intrahepatic bile ducts. There is no proved effective medical therapy. If surgical correction is not performed, the obliterative process progresses, and biliary cirrhosis and portal hypertension develop, followed by death by 2 years of age. Severe cholestasis, bile duct proliferation, and inflammatory cell infiltration are pathologic findings seen with biliary atresia. These findings are distinct from the hepatocellular necrosis and giant cell transformation seen with neonatal hepatitis. Biliary atresia is the most common indication for pediatric liver transplantation. The work-up for suspected biliary atresia includes ultrasound imaging of the liver and gallbladder, hepatobiliary iminodiacetic acid (HIDA) scanning, and percutaneous liver biopsy. In biliary atresia, the extrahepatic bile ducts cannot be seen on ultrasound imaging, and the gallbladder is diminutive or absent. Surgical diagnosis is made with an intraoperative cholangiogram demonstrating lack of opacification of the intrahepatic biliary tree. The goals of the Kasai procedure are to restore biliary flow by performing a Roux-en-Y portojejunostomy after resection of the gallbladder, extrahepatic bile ducts, and the fibrotic portal plate. A long-term successful outcome is generally low if the procedure is performed after 90 days of life. Cholangitis is the most common postoperative complication with the Kasai procedure.
Answer
D
17 With regard to the Kasai procedure for the treatment of biliary atresia, which of the following statements is true?
A It is most successfully performed after 3 months of age.
B Cholangitis rarely complicates a successful procedure.
C Portal hypertension remains problematic despite a successful operation.
D If hepatic transplantation is needed, an initial Kasai enterostomy is not indicated.
E Cholangitis is an infrequent late complication.
Ref.: 1-3
Comments
Biliary atresia occurs as part of a spectrum of anomalies of infantile obstructive cholangiopathy. In utero viral infection has been implicated as the cause, although the evidence for such has not been proven. A HIDA scan and ultrasound imaging of the bile ducts are the mainstays among imaging tests to support the diagnosis. Variable patterns of ductal involvement of the intrahepatic and extrahepatic biliary tree are seen, with 10% of patients initially having extrahepatic disease only. The goals of treatment are to establish biliary flow and prevent the late complications of biliary cirrhosis and hepatic failure. Hepatoportoenterostomy is most successful in establishing bile drainage when performed during the patient’s first 2 months of life. The success rate falls dramatically after 3 months of age. Cholangitis, biliary cirrhosis, hepatic failure, and portal hypertension remain late problems despite the fact that bile drainage is achieved. Attempts to reduce later cholangitic complications include prolonged use of antibiotics and steroids to minimize inflammation and infection. Hepatic transplantation has been successful in the treatment of this problem but has not replaced biliary enteric anastomosis as the initial procedure. An unsuccessful hepatoportoenterostomy does not preclude later hepatic transplantation.
Answer
C
18 Which of the following always requires surgical correction during infancy?
A Meconium ileus
B Umbilical hernia
C Meconium plug
D Hirschsprung disease
E All of the above
Ref.: 1-3
Comments
Large bowel obstruction cannot be differentiated from small bowel obstruction in infants on plain radiographs because of the lack of haustral markings. Classic Hirschsprung disease is characterized by aganglionosis of the rectosigmoid segment and should be suspected whenever an infant fails to pass meconium within the first 24 hours of life. Longer intestinal segments may be involved. Rarely, total colonic aganglionosis may be present. Infants with Hirschsprung disease have intestinal obstruction that requires surgical intervention. A meconium plug often occurs in the distal part of the colon and is frequently seen in infants of diabetic mothers. It can be treated with hypertonic water-soluble radiographic contrast–enhanced enemas. Patients with meconium ileus have distal ileal obstruction and microcolon from disuse. The diagnosis of cystic fibrosis must be considered in patients with meconium ileus. In the majority of cases, a Gastrografin enema relieves the obstruction without the need for surgery. Umbilical hernias are rarely an indication to operate during infancy unless the hernia is incarcerated or strangulated, has a large defect, or occurs in the setting of ventriculoperitoneal shunts.
Answer
D
19 Which of the following is true concerning Hirschsprung disease?
A More common in females
B Absent ganglion cells in both the Auerbach and Meissner plexuses
C Failure to pass meconium in the first 48 hours of life
D Best diagnosed by lower gastrointestinal contrast-enhanced study
E Atrophy of submucosal nerve endings seen on rectal biopsy specimens
Ref.: 2, 3
Comments
The primary clinical manifestation of Hirschsprung disease is intestinal obstruction with failure to pass meconium in the first 24 hours of life or chronic constipation in older infants and children. Hirschsprung disease is more common in males than in females. Affected infants are prone to the development of enterocolitis, which carries a high mortality rate if not recognized and treated promptly. In newborn babies in whom dilation of the bowel proximal to the aganglionic segment may not have developed, findings on barium enema may be normal. Anal manometric measurements demonstrate failure of relaxation of the internal sphincter in response to rectal distention. Definitive diagnosis is based on the rectal biopsy specimen demonstrating submucosal hypertrophied nerve endings, absent ganglion cells in the Auerbach and Meissner plexuses, and acetylcholinesterase staining. Full-term infants with Hirschsprung disease but without enterocolitis may be treated by single-stage pull-through. The remaining patients are managed mostly by serial intestinal biopsy to determine the level of normal ganglionated intestine and leveling colostomy followed by pull-through 3 to 6 months later. Anastomosis of the normally innervated colon to the anus is the basis of all three pull-through procedures (Swanson, Duhamel, and Soave).
Answer
B
20 A previously well 3-week-old infant exhibits a sudden onset of bilious vomiting. Which of the following is the most likely diagnosis?
A Pyloric stenosis
B Duodenal atresia
C Malrotation of the midgut
D Intussusception
E Tracheoesophageal fistula, H type
Ref.: 1-3
Comments
See Question 21.
Answer
C
21 For the scenario described in Question 20, which would be the most appropriate initial diagnostic test?
A Upper gastrointestinal contrast-enhanced study
B Abdominal ultrasound
C Barium enema
D Abdominal radiograph
E CT
Ref.: 1-3
Comments
Infants with intestinal obstruction exhibit bilious emesis. Fifty percent of children with malrotation have bilious emesis during the first few weeks of life. Infants with malrotation are at risk for midgut volvulus. Infants with a previous history of normal feedings in whom a sudden onset of bilious vomiting develops should be immediately evaluated for midgut volvulus. Midgut volvulus is demonstrated by upper gastrointestinal series showing an abrupt cutoff from failure of contrast material to pass beyond the distal duodenum or a corkscrew pattern of partial obstruction from the torsed intestines (or both), whereas malrotation is demonstrated by an aberrant course of the duodenum and duodenal-jejunal junction. A barium enema can be misleading in the diagnosis of malrotation because the position of the cecum cannot be relied on to rule in or rule out malrotation. As soon as a diagnosis is made, the infant should be taken immediately to surgery. Pyloric stenosis or tracheoesophageal fistula is not accompanied by bilious vomiting. The symptoms of infants with H-type tracheoesophageal fistula are usually feeding difficulties and recurrent pneumonia. The main symptoms associated with intussusception are colicky abdominal pain and bloody stools. Duodenal atresia may mimic malrotation in the first 24 to 48 hours of life, but at 3 weeks of age, duodenal atresia should already have been diagnosed and treated. Importantly, malrotation of the midgut is frequently associated with duodenal atresia and should be searched for at the time of repair of duodenal atresia.
Answer
A
22 All of the following are true of the Ladd procedure for midgut volvulus except:
A Midgut volvulus twists in a counterclockwise direction and needs to be untwisted in a clockwise manner.
B Ladd bands refer to congenital bands extending across the duodenum from the ascending colon to the retroperitoneum in the right upper quadrant.
C There is no proved benefit with pexis of the cecum, duodenum, or both.
D An incidental appendectomy is often performed to prevent confusing future signs and symptoms of appendicitis.
E Midgut volvulus twists in a clockwise direction and needs to be untwisted in a counterclockwise manner.
Ref.: 1
Comments
Operative management of malrotation involves counterclockwise reduction of the midgut volvulus when present. Nonviable bowel is resected. If viability is in question, second-look laparotomy should be performed in 24 hours to reassess and treat the intestine appropriately. The peritoneal bands (Ladd bands) between the ascending colon and the posterior abdominal wall in the right upper quadrant are divided, and the duodenum is mobilized so that the small bowel can be positioned in the right side of the abdomen and the colon in the left side of the abdomen. Pexis of the cecum or duodenum has not been proved to be of benefit in preventing midgut volvulus. Because of the abnormal position of the appendix, appendectomy is routinely performed to avoid future difficulty in the clinical diagnosis of appendicitis.
Answer
A
23 Which of the following is the most common anatomic type of tracheoesophageal malformations?
A Proximal atresia and distal tracheoesophageal fistula
B Complete esophageal atresia without fistula
C H-type esophageal fistula
D Proximal fistula and distal esophageal atresia
E Proximal and distal tracheoesophageal fistulas
Ref.: 1
Comments
There are five readily identified anatomic variants of esophageal atresia and tracheoesophageal fistula. Type A, with an incidence of 6%, is true esophageal atresia and no tracheoesophageal fistula. Type B, with an incidence of 2%, is distal esophageal atresia with a proximal tracheoesophageal fistula. Type C, the most common variant with an incidence of 85%, refers to proximal esophageal atresia with a distal tracheoesophageal fistula. Type D, with an incidence of 1%, is a proximal and distal tracheoesophageal fistula. Type H, with an incidence of 2%, refers to an intact esophagus with a single tracheoesophageal fistula. Other anatomic variants may be present, and tracheoesophageal fistula can occur in association with vertebral, anorectal, and renal and or radial anomalies, which together are components of the VATER syndrome.
Answer
A
24 A 1-month-old neonate has an umbilical hernia in which the defect is estimated to be 1 cm in diameter. Which of the following statements is true?
A The likelihood of spontaneous closure in this neonate is low, and the hernia should be repaired.
B Indications for early repair of an umbilical hernia include a history of incarceration, a large skin proboscis, and the presence of a ventriculoperitoneal shunt.
C Repair of the hernia defect should include the placement of mesh.
D Complete closure of the umbilical ring may be expected in only 30% of children by the age of 4 to 6 years.
E All of the above
Ref.: 1
Comments
Umbilical hernias occur as a result of persistence of the umbilical ring. By the age of 4 to 6 years, closure of this ring can be expected in 80% of children. In patients with umbilical hernias with greater than a 2-cm defect, spontaneous closure is less likely. Umbilical hernias are usually repaired early if the defect is greater than 2 cm, there is a history of incarceration, or a large skin proboscis or a ventriculoperitoneal shunt is present. Repair of an umbilical hernia involves an infraumbilical semicircular incision, separation of the hernia sac from the overlying skin, repair of the fascial defect, pexis of the base of the umbilicus to the fascia, and closure of the skin. The fascial closure is rarely under tension and does not require prosthetic mesh.
Answer
B
25 The most common cause of duodenal obstruction at birth is:
A Malrotation
B Duodenal atresia
C Annular pancreas
D Choledochal cyst
E Midgut volvulus
Ref.: 1-3
Comments
Vomiting within the first 24 hours of life in the absence of abdominal distention suggests duodenal atresia in a neonate. Malrotation with midgut volvulus is the most common and the most devastating cause of duodenal obstruction beyond the neonatal period. The duodenal obstruction can be caused by extrinsic compression by the peritoneal Ladd bands that extend from the abdominal wall to the anomalously located cecum in the right upper quadrant. Alternatively, the catastrophic complication of malrotation is midgut volvulus and intestinal infarction from torsion of the superior mesenteric vessels about the narrow mesenteric pedicle by which the midgut is suspended. An annular pancreas may cause duodenal obstruction as a result of duodenal stenosis. Choledochal cysts are rare and manifested as jaundice and an abdominal mass.
Answer
B
26 Regarding jejunal atresia, which of the following statements is false?
A It is caused by failure of embryologic recanalization of the gut.
B Associated anomalies are more common with duodenal atresia than with jejunal atresia.
C Cystic fibrosis may be present in roughly 10% of patients with jejunal atresia.
D The most common significant associated morbidity is short gut syndrome.
E It is not usually associated with trisomy 21.
Ref.: 1-3
Comments
Intestinal atresia is believed to arise from an in utero vascular accident. Multiple atresia occurs in approximately 10% of patients. Many forms exist, from a simple web or stenosis to long segments of atretic intestines or complete intestinal disruption with varying degrees of mesenteric defect. Intestinal atresia is usually accompanied by bilious vomiting and abdominal distention. Passage of meconium does not exclude the diagnosis. Cystic fibrosis may be present in approximately 10% of patients with jejunoileal atresia. Duodenal atresia is frequently associated with trisomy 21 (Down syndrome). The most common and significant morbidity associated with jejunoileal atresia is short gut syndrome.
Answer
A
27 An 8-hour-old newborn has mild respiratory distress and excessive drooling. An abdominal radiograph shows complete lack of air in the gastrointestinal tract. What is the most likely diagnosis?
A Bilateral choanal atresia
B Pyloric atresia
C Duodenal atresia
D Esophageal atresia with a distal tracheoesophageal fistula
E Esophageal atresia without a tracheoesophageal fistula
Ref.: 1-3
Comments
See Question 28.
Answer
E
28 The VACTERL association most commonly includes which of the following?
A Ankylosis
B Imperforate anus
C Eye deformities
D Congenital cystic lung malformation
E Choanal atresia
Ref.: 1
Comments
Neonates have a gasless gastrointestinal tract at birth. As they start to swallow soon after birth, air reaches the colon within 6 to 12 hours. In pure esophageal atresia without an associated fistula, swallowed or inspired air does not reach the distal end of the gastrointestinal tract and abdominal films demonstrate no air in the gastrointestinal tract. Esophageal atresia is suggested when an infant drools excessively because of esophageal obstruction or spits up during attempted feedings. When an orogastric tube is passed in an infant with esophageal atresia, a chest radiograph showing the tube coiled in a blind pouch helps in making the diagnosis. About 85% to 90% of patients with a tracheoesophageal malformation have a blind proximal pouch with a distal tracheoesophageal fistula, also known as esophageal type C. Respiratory symptoms are secondary to aspiration from the esophageal pouch or retrograde reflux of gastric contents from the fistula into the lung. In esophageal atresia with a tracheoesophageal fistula, inspired air reaches the stomach and small bowel through the tracheoesophageal fistula. Contrast-enhanced studies and bronchoscopy may be useful in select cases to confirm the diagnosis and demonstrate the location of the fistula. Recognition of the anatomy of the anomaly is important for establishing appropriate initial treatment and definitive repair. Air fails to pass from the stomach into the duodenum and small bowel in neonates with pyloric atresia, a rare congenital anomaly. Radiographic studies show extreme distention of the stomach with air-fluid levels. Neonates, being obligatory nasal breathers, have major respiratory problems when born with bilateral choanal atresia but do not have difficulty swallowing air. The VACTERL association refers to vertebral anomalies, imperforate anus, cardiac defects, tracheoesophageal fistula, radial and renal malformation, and limb defects.
Answer
B
29 A 3000-g infant is born with esophageal atresia and a distal tracheoesophageal fistula. If the infant does not exhibit respiratory distress and associated anomalies are not present, which of the following is the preferred treatment?
A Gastrostomy, cervical esophagostomy, and delayed repair
B Gastrostomy, sump tube drainage of the proximal pouch, and delayed repair
C Fistula ligation and delayed esophageal repair
D Division of the fistula with primary esophageal anastomosis
E Primary repair with colonic interposition
Ref.: 1-3
Comments
The timing and type of surgical intervention for esophageal atresia and tracheoesophageal fistula depend on the maturity of the infant and associated cardiorespiratory problems or other congenital anomalies that have an impact on the mortality associated with primary repair. Medically stable infants weighing more than 2500 g are treated by primary repair with fistula division, closure of its tracheal end, and end-to-end anastomosis of the esophageal segments. Unstable infants with respiratory problems can be treated by gastrostomy and sump drainage of the blind proximal pouch. Because loss of ventilatory pressure can occur through the open tracheoesophageal fistula or retrograde aspiration of gastric contents into the lungs can exacerbate the pulmonary symptoms, some infants may benefit from primary fistula ligation without esophageal repair, with or without gastrostomy placement. The final esophageal repair is accomplished after the complicating cardiorespiratory problems have been addressed.
Answer
D
30 Common complications following repair of esophageal atresia and tracheoesophageal fistula include all of the following except:
A Esophageal strictures
B Anastomotic leak
C Tracheomalacia
D Recurrent fistula
E Gastroesophageal reflux
Ref.: 1-3
Comments
Gastroesophageal reflux and tracheomalacia are commonly associated with esophageal atresia and tracheoesophageal fistula in infants. Gastroesophageal reflux is believed to be related to the underlying esophageal dysmotility and perhaps to dysfunction of the lower esophageal sphincter, which frequently requires fundoplication. Anastomotic leakage, stricture, and recurrent fistula formation are known operative complications.
Answer
C
31 Which of the following statements concerning necrotizing enterocolitis (NEC) is true?
A The initial insult in NEC is to the intestinal mucosa.
B The jejunum is the most frequently involved site.
C Operative intervention is indicated after resuscitation.
D Progression of NEC is halted after surgical therapy.
E The cecum is frequently not involved.
Ref.: 1, 2
Comments
Necrotizing enterocolitis is a disease that affects the intestinal tract of neonates. Clinical and experimental data have shown that the cause of NEC is multifactorial, with risk factors including perinatal stress, maternal cocaine use, and prematurity. The initial injury with NEC is observed in the intestinal mucosa. The spectrum of severity ranges from isolated mucosal injury to transmural bowel necrosis. Although the terminal ileum and right colon are the most commonly affected sites, the disease can be segmental or affect the entire gastrointestinal tract. The initial treatment of infants with NEC is nonsurgical and consists of nasogastric decompression, bowel rest, broad-spectrum antibiotics, optimal fluid management, and parental nutrition. Operative intervention, such as bowel resection with proximal enterostomy, is indicated to treat the acute complications of NEC, which include intestinal perforation, necrosis, persistent bleeding, or obstruction. Operative intervention, however, does not prevent progression of the disease, which can continue after resection and may require additional surgical therapy.
Answer
A
32 A premature infant with a history of neonatal respiratory distress requiring ventilatory support is being fed oral formula. Abdominal distention develops, and blood-streaked stool is passed. Appropriate management includes which of the following?
A Anoscopy for a probable neonatal fissure
B Barium enema to rule out intussusception
C Restriction of oral intake to clear liquid to prevent mucosal injury
D Antibiotic-directed treatment of specific pathogens cultured from the stool
E Cessation of oral feeding, institution of nasogastric drainage, intravenous antibiotics, total parenteral nutrition, and serial abdominal examinations and radiographic studies
Ref.: 1-3
Comments
See Question 33.
Answer
E
33 Which of the following are indications for surgery in an infant with NEC?
A Pneumatosis intestinalis
B Portal venous gas
C Pneumoperitoneum
D Bloody stools
E All of the above
Ref.: 1-3
Comments
Necrotizing enterocolitis affects premature infants with a history of neonatal stress who received oral feedings. The pathophysiologic processes involve mucosal ischemia, bowel necrosis, perforation, peritonitis, and sepsis. Clinical manifestations are initial intolerance of formula, abdominal distention, blood-streaked stool with progression to systemic sepsis, metabolic acidosis, and thrombocytopenia. The initial treatment is directed at prevention of further mucosal injury and septic complications. Oral feedings are stopped, nasogastric tube decompression is instituted, broad-spectrum antibiotics are administered, and fluid and electrolyte support is provided. Close monitoring with physical examination, serial radiographs, and biochemical assessment for signs of deterioration is mandatory. Pneumatosis intestinalis is a pathognomonic radiographic finding of NEC that is caused by invasion of the bowel wall by gas-forming organisms. Portal venous gas indicates the presence of gas-forming organisms translocated to the portal circulation. Neither of these radiographic findings is an absolute indication for surgery, however. Indications for surgical intervention are perforation, persistent necrosis as evidenced by progressive clinical deterioration such as worsening metabolic acidosis, thrombocytopenia, and hemodynamic instability. During surgery, the necrotic bowel is resected, and the ends of the retained bowel are brought out as enterostomies. Bowel preservation is a high priority during surgery to avoid complications associated with short bowel syndrome. A second-look operation in 24 hours can be performed if bowel viability is questionable at the first operation.
Answer
C
34 Which of the following statement concerning the physiology of the newborn is true?
A Perfusion is best monitored clinically by distal pulses.
B Newborns preferentially breathe through their mouths rather than their noses.
C Cardiac output in the newborn period is primarily rate dependent.
D Newborns have normal levels but are functionally deficient in immunoglobulins and C3b complement.
E Adequate capillary refill is less than 5 seconds.
Ref.: 1
Comments:
Capillary refill is the best way to clinically monitor cardiac perfusion in a newborn. Adequate capillary refill is less than 1 second. Unlike adults and older children, cardiac output in the newborn is directly related to the child’s heart rate, and the child’s ability to increase cardiac output depends on the increase in heart rate and not stroke volume. Newborns are obligate nose breeders. Respiratory distress in the newborn is heralded by nasal flaring, grunting, and intercostal and substernal retractions. Newborns are immunodeficient from low immunoglobin and C3b levels.
Answer
C
35 A newborn is evaluated for respiratory distress because of severe hypoxia several hours after birth. The patient appears dyspneic, tachypneic, and cyanotic. The abdomen is noted to be scaphoid. Which of the following is true of this newborn?
A This condition can be diagnosed prenatally with fetal ultrasound.
B An upper gastrointestinal contrast-enhanced study is required to diagnose this condition.
C The survival rate is extremely low.
D Emergency surgical intervention is required within hours of birth.
E Emergency placement of a chest tube is required.
Ref.: 1
Comments
This patient most likely has congenital diaphragmatic hernia. The incidence of congenital diaphragmatic hernia is reported to be the range of 1 in 2000 to 5000 live births. The most common diaphragmatic defect is in a posterolateral location and is known as a Bochdalek hernia. A less common site for the defect is anteromedial (retrosternal), in which case it is known as a Morgagni hernia. Congenital diaphragmatic hernias can be diagnosed on prenatal ultrasound. A plain chest radiograph demonstrating an intrathoracic location of the gastric air bubbles, nasogastric tube, or intestines is diagnostic. Rarely is an upper gastrointestinal study needed. Before it was understood that pulmonary hypoplasia and pulmonary hypertension are the causes of morbidity and mortality in infants with congenital diaphragmatic hernia, emergency repair was recommended. However, because emergency repair does not improve the outcome, pediatric surgeons will wait between 24 and 72 hours for cardiorespiratory stabilization before proceeding to surgical repair. The survival rate of infants with congenital diaphragmatic hernia is in the range of 70% to 90%. A chest tube may be needed in situations in which a tension pneumothorax could occur following the institution of high-pressure ventilation.
Answer
A
36 During treatment of an infant with congenital diaphragmatic hernia, all of the following may be required except:
A Chest tube insertion
B ECMO
C High-frequency oscillatory ventilation
D Immediate surgery
E Nitric oxide
Ref.: 1
Comments:
The primary physiologic disturbance in infants with respiratory distress caused by congenital posterolateral diaphragmatic hernia is related to pulmonary hypoplasia and high pulmonary vasculature resistance (pulmonary hypertension) because of pulmonary arteriolar vasoconstriction. The initial resuscitation must include prompt correction of hypoxia, metabolic acidosis, and hypothermia to relieve the pulmonary vasoconstriction. High pulmonary vascular resistance produces right-to-left shunting via the patent ductus arteriosus, thus further compromising the infant’s cardiopulmonary status. Initial treatment involves endotracheal intubation for respiratory distress, placement of an orogastric tube, and maintenance of adequate vascular volume. Infants intubated with high-pressure ventilation are prone to the development of pneumothorax, and tube thoracostomy may be required. Treatment consists of gentle ventilation to recruit alveoli and avoid barotrauma with the use of high-frequency oscillatory ventilation or the addition of a pulmonary vascular dilator such as inhaled nitric oxide. Extracorporeal membrane oxygenationmay salvage infants who remained critically ill despite conventional support. Surgical repair is performed after resuscitation and stabilization of the infant’s cardiopulmonary status. Definitive surgical repair is usually carried out via an abdominal approach. Biomesh or synthetic material may be used if primary approximation of the diaphragmatic defect is not possible.
Answer
D
37 All of the following are true of bronchopulmonary malformations except:
A Associated anomalies are extremely rare in patients with pulmonary sequestration.
B CT, magnetic resonance imaging (MRI), or both are indicated before surgical intervention in those with pulmonary sequestration.
C Congenital lobar emphysema occurs in a histologically normal lung and is caused by air trapping secondary to abnormal cartilaginous support of the feeding bronchus.
D A congenital cystic adenomatoid malformation typically has a bronchial communication and receives its blood supply from the normal pulmonary circulation.
E Pulmonary sequestrations are associated with congenital cardiac defects.
Ref.: 1
Comments
Pulmonary sequestrations are either intralobar or extralobar and are associated with congenital cardiac defects. The vascular supply and drainage of pulmonary sequestrations frequently include anomalous systemic and pulmonary vessels, such as the aorta and azygous veins, which can complicate surgical excision. CT angiography, magnetic resonance imaging, or both are therefore important for mapping the blood supply before removal of the pulmonary sequestrations. Both types may be complicated by a large intravascular shunt leading to cardiac insufficiency, and intralobar sequestrations are commonly complicated by infections and bleeding. Congenital lobar emphysema is caused by overdistention of histologically normal lung because of air trapping as a result of abnormal cartilaginous support of the feeding bronchus. Congenital cystic adenomatoid malformations, unlike pulmonary sequestrations, typically have bronchial communications and normal blood supply. Because of the high risk for infection and the potential for malignant degeneration, resection is recommended for all these lesions.
Answer
A
38 With regard to defects of the abdominal wall, which statement is correct?
A In gastroschisis, the herniated bowel contents are covered by a membrane.
B Gastroschisis is frequently associated with cardiac malformations.
C Chromosomal abnormalities are often present with omphalocele.
D Treatment of abdominal wall defects is immediate surgical closure of the fascial defect.
E In omphalocele, a silo bag is placed to cover the exposed intestine.
Ref.: 1
Comments
Both omphalocele and gastroschisis are neonatal abdominal wall defects. In omphalocele, the umbilical cord arises from the layers of peritoneum and amnion covering the abdominal wall contents. In contrast, in gastroschisis, the abdominal wall defect is to the right of the umbilical ring and is complete with herniation of the intestines. Approximately 50% of infants born with omphalocele have other malformations, including cardiac and chromosomal abnormalities. Anomalies associated with gastroschisis are rare, with the major exception being intestinal atresia. The initial management of abdominal wall defects consists of nasogastric decompression, intravenous fluids, broad-spectrum antibiotics, and protection of the abdominal wall contents. In omphalocele, the sac is covered with a sterile occlusive dressing, and a work- up for associated anomalies should be initiated. In gastroschisis, a silo bag is placed to cover the exposed intestines. Complete medical evaluation and resuscitation of the infant with protection of the abdominal contents take precedence over surgical closure.
Answer
C
39 An asymptomatic 3-year-old boy is found to have a palpable abdominal mass on routine examination. Which of the following is true regarding the most likely diagnosis in this child?
A The current overall survival rate of these patients is about 50%.
B The hereditary form of this tumor is more aggressive and more common.
C Common metastatic foci are in the lungs and liver.
D There is no role for preoperative chemotherapy in the treatment of this childhood tumor.
E Measurement of serotonin metabolites in the urine aids in the diagnosis and in monitoring the course of the disease.
Ref.: 1
Comments
The differential diagnosis for this mass is Wilms tumor and neuroblastoma. This patient has a Wilms tumor. Neuroblastoma is the third most common pediatric malignancy. More than 80% of cases are seen before the age of 4 years. They arise from neural crest cells, and the tumor originates most frequently in the adrenal glands. Two thirds of these tumors are first noticed as an asymptomatic mass. The use of preoperative chemotherapy is based on the stage of the tumor. Determination of serum catecholamines or their metabolites (or both) is used to aid in diagnosis and monitoring of the disease. The patient should be evaluated with abdominal CT, which usually shows displacement of an intact kidney. Bone metastasis, proptosis, and periorbital ecchymosis may develop. Spontaneous regression of neuroblastoma in infants has been well described, especially in tumors with a nearly triploid number of chromosomes that also lack N-myc amplification and loss of chromosome 1p. Wilms tumor is an embryonal tumor of renal origin and the most common primary malignant kidney tumor in childhood. It is commonly manifested as an asymptomatic abdominal mass. Abdominal and thoracic CT, MRI, or both are used preoperatively to distinguish Wilms tumor from neuroblastoma and assess for bilateral Wilms tumor, liver or lung metastasis, and vascular invasion such as tumor thrombus within the inferior vena cava. Urine examination for vanillylmandelic acid (VMA) also helps distinguish Wilms tumor from neuroblastoma. VMA will be produced and levels elevated in children with neuroblastoma, whereas it will not be produced and levels will be normal in those with Wilms tumor. The most common germline mutation is the Wilms tumor gene-1. Hereditary Wilms tumor is uncommon. Wilms tumor is associated with Denys-Drash syndrome, WAGR syndrome (Wilms tumor, aniridia, genitourinary abnormalities, and mental retardation), and Beckwith-Wiedemann syndrome; thus, patients with these syndromes need to be screened for Wilms tumor. Preoperative chemotherapy is indicated for the treatment of invasive Wilms tumor. The current overall survival rate after surgical resection exceeds 85%.
Answer
C
40 A 6-month-old infant has a history of an acute onset of crampy abdominal pain and leg withdrawal of 12 hours’ duration. Rectal examination shows guaiac-positive stool. Which of the following is the most likely diagnosis?
A Bleeding Meckel diverticulum
B Acute appendicitis
C Kidney stone
D Infected urachal cyst
E Intussusception
Ref.: 2, 3
Comments
Ileocolic intussusception should be strongly suspected in a child between the ages of 3 and 18 months with colicky abdominal pain and guaiac-positive stools. Acute appendicitis, infected urachal cyst, and nephrolithiasis can occur in this age group but are not accompanied by bloody stools. A bleeding Meckel diverticulum is usually painless, and frank bloody stool is seen.
Answer
E
41 Cystic hygromas are most commonly complicated by which of the following?
A Infection
B Hemorrhage
C Respiratory distress
D Malignancy
E All of the above
Ref.: 1-3
Comments
Cystic hygroma is a congenital lymphangiomatous malformation that commonly occurs in the posterior region of the neck, the axilla, the groin, or the mediastinum. These lesions can attain a large size, and all of the complications mentioned have been described. Malignant degeneration is rare. Infection, however, is the most common complication.
Answer
A
42 Progressive abdominal distention and bilious vomiting develop in a newborn. Radiographic studies reveal distended bowel loops of various size with air-fluid levels and a “soap suds” appearance in the right lower quadrant. Which of the following procedures should be performed next?
A Laparotomy
B Paracentesis
C Gastrografin lower gastrointestinal radiographic studies
D Gastrografin upper intestinal radiographic studies
E Sweat chloride test
Ref.: 1-3
Comments
Postnatal distal intestinal obstruction with the classic radiographic findings of “soap bubbles” suggests the diagnosis of meconium ileus. Nearly all affected infants have cystic fibrosis. Abnormalities in salt and water exchange across the intestinal lumen lead to a thick inspissated meconium plug causing distal ileal obstruction. With uncomplicated meconium ileus, a Gastrografin enema may be both diagnostic and therapeutic. The detergent and hyperosmolar effects of the contrast material may loosen the thick meconium and relieve the obstruction. Surgery is indicated if the obstruction does not respond to the Gastrografin enema or if complications such as peritonitis or perforation are present. The usual operative treatment includes exteriorization of the intestines to allow postoperative irrigation of the inspissated meconium with a water-soluble agent or N-acetylcysteine. A positive sweat chloride test is diagnostic of cystic fibrosis and can be performed electively. Paracentesis and lavage have no role in the work-up or treatment of meconium ileus.
Answer
C
43 Select the true statement regarding the operative management of intussusception.
A Resection should be performed without an attempt at intraoperative manual reduction.
B Primary ileocolic anastomosis may be performed if bowel resection is necessary.
C After successful reduction by barium enema in a 1-year-old child, delayed surgery should be performed because of the risk for recurrence.
D After successful reduction by barium enema, exploration is indicated to rule out associated pathologic processes.
E Appendectomy should never be performed after successful operative manual reduction.
Ref.: 1
Comments
See Question 43.
Answer
B
44 Contraindications to attempted reduction of an intussusception via air/barium enema in a child include which of the following?
A Pneumoperitoneum
B Initial evaluation after 48 hours of symptoms
C Recurrence after hydrostatic reduction
D Age older than 5 years
E Recurrent symptoms in the immediate postoperative period
Ref.: 1
Comments
Ileocolic intussusception should be strongly suspected in a child between the ages of 3 and 18 months with colicky abdominal pain and guaiac-positive stools. A barium or preferably an air enema should be performed promptly for diagnosis and reduction of the intussusception via hydrostatic or pneumatic pressure. In approximately 80% of children, successful radiologic reduction is the only therapy needed. An attempt at nonoperative reduction is contraindicated in children with perforation or peritonitis. In such cases, prompt surgery is required. When nonviable bowel is encountered at the time of exploration, resection is carried out without an attempt at reduction. Otherwise, reduction by gentle digital pressure on the intussusceptum is attempted. Resection is performed if the intussusception is not manually reducible. Primary anastomosis can be performed. After successful operative manual reduction, an appendectomy is usually performed. Recurrence is not considered to be an absolute indication for surgery, and a second and third attempt may be successful. A 1-year-old child most likely has “idiopathic” intussusception with no anatomic leading point. Children older than 5 years are more likely to have surgical lead points such as an intestinal polyp, Meckel diverticulum, or tumor (lymphoma). Further work-up and appropriate surgery to prevent recurrences are needed. Intussusception recurs in 5% to 10% of patients regardless of whether the intussusception has been reduced radiographically or operatively. Treatment involves repeated air enema, which is successful in most cases.
Answer
A
45 The “double-bubble” sign seen on abdominal radiographs of neonates is suggestive of all of the following conditions except:
A Duodenal atresia
B Normal newborn radiographic finding at delivery
C Malrotation of the midgut
D Meconium ileus
E Duodenal stenosis
Ref.: 1-3
Comments
The radiographic double-bubble sign usually signifies duodenal obstruction (Figure 32-2). It has been believed to be pathognomonic of duodenal atresia. Infants are born with a gasless abdomen. After taking the first few breaths, they start swallowing air. This column of air usually takes 6 to 12 hours to reach the distal end of the colon. Therefore, an abdominal film taken a few minutes after delivery might show a double bubble and yet be normal in the absence of other clinical signs of intestinal obstruction such as bilious emesis. The double-bubble sign can also be seen in infants with malrotation and midgut volvulus, but air is present in the distal intestines. This is an operative emergency to avoid progression to vascular necrosis of the entire midgut. Immediate diagnostic upper gastrointestinal study and operative treatment are essential. Both ileal atresia and meconium ileus are manifested as distal small bowel obstruction. The radiographic findings of ileal atresia and meconium ileus are multiple dilated loops of intestine with air-fluid levels, along with the presence of “soap suds” for meconium ileus.
Figure 32-2 The classic double-bubble sign (arrows) seen on a radiograph.
(Reprinted with permission from Kimura K, Loening-Baucke V: Radiologic decision making: bilious vomiting in the newborn: rapid diagnosis of intestinal obstruction, Am Fam Physician 61:2791, 2000.
Answer
D
46 The treatment of choice for duodenal atresia is which of the following?
A Duodenojejunostomy
B Duodenoduodenostomy
C Duodenostomy with delayed repair
D Gastrojejunostomy
E Roux-en-Y enterostomy
Ref.: 1
Comments
Once the diagnosis is made, surgery can be deferred until after medical stabilization and work-up for associated anomalies. Duodenoduodenostomy is the preferred operation because it provides physiologic continuity to the gastrointestinal tract. An intraluminal duodenal windsock diaphragm or partial webs should be sought intraoperatively by passing a Foley catheter into the distal part of the duodenum. If no resistance is encountered on withdrawal of the Foley catheter from the duodenum, continuity is ensured; otherwise, the obstruction is untreated.
Answer
B
47 Which of the following is the most reliable test for establishing the diagnosis of gastroesophageal reflux in pediatric patients?
A Esophagography
B Esophagoscopy with biopsy
C Upper gastrointestinal contrast-enhanced study
D Monitoring of the pH of the esophagus for 12 to 24 hours
E Nuclear scanning after the ingestion of radioactive milk
Ref.: 1-3
Comments
All of the studies listed are useful in documenting the presence of gastroesophageal reflux, but an abnormal finding on a 12- to 24-hour esophageal pH study is most sensitive and specific for gastroesophageal reflux as the cause of the symptoms.
Answer
D
48 Which of the following is false regarding teratomas in the pediatric population?
A Sacrococcygeal teratomas are treated by excision of the tumor alone and by addition of coccygectomy as needed.
B The sacrococcygeal site is the most common location for the tumor in neonates.
C Most neonatal sacrococcygeal teratomas are benign.
D Elevations in the α-fetoprotein level confirm the diagnosis.
E Evidence of hydrops and a large teratoma carries a poor prognosis.
Ref.: 1
Comments
Teratomas are tumors arising from more than one of the three embryonic germ layers and contain tissue that is foreign to the anatomic site in which they are found. The sacrococcygeal region is the most common site for neonatal teratomas. In adolescents, the gonads are a more common site for teratomas. Most neonatal sacrococcygeal teratomas are benign. Without coccygectomy, complete tumor extirpation is associated with a higher rate of recurrence. Patients must be monitored carefully after surgical intervention because recurrence can be seen even with benign tumor. Levels of α-fetoprotein markers are always elevated at birth because of components of maternal origin. Levels are expected to continue to decrease and normalize after excision with subsequent follow-up and should be monitored to detect incomplete resection or tumor recurrence. Prenatal intervention is advocated for fetuses with evidence of hydrops and a large sacrococcygeal teratoma because the prognosis is poor in these cases.
Answer
D
49 Hepatoblastomas in children are characterized by all of the following except:
A Usually occur in children younger than 3 years
B Associated with Beckwith-Wiedemann syndrome
C Often extensively invasive and multifocal
D Better response to preoperative chemotherapy
E Elevated α-fetoprotein levels
Ref.: 1
Comments
Hepatoblastomas usually occur before 3 years of age, whereas hepatocellular carcinoma may be found in children and adults. Hepatoblastoma is most often unifocal, whereas hepatocellular carcinoma is often invasive and multicentric. Hepatoblastoma is associated with hemihypertrophy, very low birth weight, familial adenomatous polyposis, and Beckwith-Wiedemann syndrome, whereas hepatocellular carcinoma is associated with underlying chronic liver injury such as occurs with perinatally acquired infection with hepatitis B and C viruses, mutations in c-met, tyrosinemia, biliary cirrhosis, and α1-antitrypsin deficiency. α-Fetoprotein levels parallel disease activity in both hepatoblastoma and hepatocellular carcinoma. The overall survival rate is 70% for hepatoblastoma and 25% for hepatocellular carcinoma. Chemotherapy is more effective for hepatoblastoma than for hepatocellular carcinoma.
Answer
C
50 A 2-year-old boy is seen in your office with a midline neck mass that has been present for 2 months. On examination, the mass is 2 cm in size, is not tender or pulsatile, and moves with protrusion of his tongue. Ultrasound of the neck demonstrates a midline cystic lesion sitting deep to the strap muscles with no surrounding lymphadenopathy or other pathology. The thyroid gland is noted in the normal location. Findings on thyroid function studies are normal. Which of the following statements is true regarding this mass?
A Simple excision of the mass is sufficient.
B This mass most likely represents ectopic thyroid tissue.
C The rate of recurrence is very high after appropriate therapy.
D These lesions can be found along the base of tongue and hyoid bone.
E Most lesions are associated with a draining cutaneous fistula tract.
Ref.: 4-6
Comments
The most likely diagnosis is a thyroglossal duct cyst. The differential diagnosis for a midline neck mass in a child would also include a dermoid cyst, lymphadenopathy, ectopic thyroid, thymic cyst, or a ranula. Thyroglossal duct cysts arise from remnants of the thyroid gland that descended from the foramen cecum at the tongue base down to its anatomic position in the neck. The hyoid bone is a common location to find the cyst. Most do not have a draining fistula tract, as with branchial cleft remnants. Ultrasound and thyroid function tests should be performed to be certain that there is thyroid tissue in the normal anatomic location so that the patient is not rendered hypothyroid in the postoperative period. Surgical treatment involves removal of the cyst tract along with the central hyoid bone—the Sistrunk procedure. Simple cyst excision alone results in high rates of recurrence, whereas a Sistrunk procedure has reported recurrence rates of less than 5%.
Answer
D
References
1 Warner BW. Pediatric surgery. In Townsend CM, Beauchamp RD, Evers BM, et al, editors: Sabiston textbook of surgery: the biological basis of modern surgical practice, ed 18, Philadelphia: WB Saunders, 2008.
2 Hackman D, Grikscheit TC, Wang KS, et al. Pediatric surgery. In Brunicardi FC, Andersen DK, Billiar TR, et al, editors: Schwartz’s principles of surgery, ed 9, New York: McGraw-Hill, 2010.
3 Rowe MI, O’Neill IA, Grosfied IL, et al, editors. Essentials of pediatric surgery. St. Louis: CV Mosby, 1995.
4 Lorenz RR, Netterville JL, Burkey BB. Head and neck. In Townsend CM, Beauchamp RD, Evers BM, et al, editors: Sabiston textbook of surgery: the biological basis of modern surgical practice, ed 18, Philadelphia: WB Saunders, 2008.
5 Bailey BJ, Johnson JT, Newlands SD. Head and neck surgery—otolaryngology, ed 4. Philadelphia: Lippincott Williams & Wilkins; 2006.
6 Cummings CW, Haughey BH, Thomas JR, et al. Cummings otolaryngology: head and neck surgery, ed 4. Philadelphia: CV Mosby; 2005.