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The answer is d. Umbilical hernias occur in about 7% to 8% of the population, with an equal male:female ratio. There is a marked preponderance in the African-American
population. The defect results from incomplete closure of the umbilical ring. This natural process normally occurs shortly before or at the time of birth. Children in whom the umbilical ring does not close completely, will be left with an umbilical bulge. In 80% of these children, the defect will close spontaneously by the time they are 3 to 4 years of age. Thus, waiting until that time to see if the defect will close is the best practice. There are no manipulation maneuvers of the defect, such as daily reduction, use of a compressive patch, placement of a constricting coin or truss type of apparatus that will cause it to close spontaneously; either the defect will close or it will not. If the defect has not closed by the time the child is of preschool age, the recommendation is to perform elective closure of the defect. The choice of nontreatment will result only in persistence of the hernia, which will usually worsen as the patient gets older. Females will have a significant issue with protrusion, enlargement, and often pain once they begin childbearing.

For those patients that have at baseline a significantly increased intra-abdominal pressure, from entities such as ventriculoperitoneal shunt, ascites or peritoneal dialysis, the defect often will not close and may result with a progressive increase in size. There is also a higher incidence of recurrence if repaired. Under normal circumstances, <1% of patients experience recurrence. However patients with risk factors for increased intra-abdominal pressure have a higher incidence of recurrence after repair.

Patients who experience incarceration or develop recurrent episodes of localized periumbilical abdominal pain secondary to the defect, should undergo repair of the defect regardless of age. Giant defects (>4 cm), will not close spontaneously and often will show some signs of enlargement as the child is getting older. Skin breakdown may occur with larger defects because of constant irritation of the thin umbilical skin and may lead to early repair. If the large defects are uncomplicated, one can explain to the parents that these defects will not close spontaneously but undergo elective repair once the patients are 18 to 24 months of age. If they are repaired prior to that, they have a higher incidence of recurrence. Incarceration is unlikely in these giant, easily reducible umbilical hernias.

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The answer is d. About 7% of the population will develop appendicitis at some point during their lifetime. The peak incidence is between 14 to 20 years of age. Fifty percent of patients <7 to 10 years of age will present with perforation of the appendix.

The diagnosis of appendicitis is usually made with a combination of history and physical examination findings. Most often, the physical examination tends to be the most reliable, especially with younger patients. Right lower quadrant tenderness is the most consistent feature. Younger patients often demonstrate atypical symptoms or quite often have a very rapid progression of their symptoms, during which they may perforate within 24 to 48 hours of the onset of the symptoms. It is unclear if this is because of a difference in the progression of the disease or because the patient may be less communicative and unable to really voice concerns until he or she becomes very ill. Thus, the abdominal tenderness and often right lower quadrant tenderness may be the only significant and consistent physical finding.

Ultrasonography, which is a reliable tool for experienced radiologist, can be used to assist in making the diagnosis of appendicitis. Those individuals who are comfortable using compressive grading for diagnosis of appendicitis with ultrasound tend to be quite accurate. However, consistent experience with this modality is mandatory for it to be helpful. It is the gold standard for ruling out ovarian pathology, which lends itself to being very complimentary to other modalities and the physical examination in the female patient. Computed tomography (CT) scanning is very reliable in making the diagnosis of appendicitis for all age groups; it is >90% to 95% accurate. The use of CT for the diagnosis of appendicitis is usually performed with oral, rectal, and intravenous contrast.

Once the diagnosis of appendicitis is made, an appendectomy is performed through an open versus a laparoscopic appendectomy. If the diagnosis is certain, the vast majority of the pediatric population at this point has their appendix removed laparoscopically. This has been the progressive trend over the last decade. At one time the decision was based on body habitus; the larger children doing best with a laparoscopic appendectomy versus the very thin, small child having the appendix to be removed through a small, right lower quadrant incision. Now parents actually request and expect that the procedure will be done laparoscopically. Data demonstrate that there is a slight improvement in recovery as
well as decreased hospital length of stay for those who undergo laparoscopic appendectomy.

Patients who present with perforation and significant intra-abdominal soiling with gross peritonitis often require an exploratory laparotomy to control the intra-abdominal infection. There are patients who present with a localized phlegmon and/or abscess that can be treated conservatively with antibiotics, plus or minus percutaneous drainage. If successfully treated, they return in 8 to 12 weeks for an interval appendectomy. There are studies that state that the interval appendectomy may not be necessary and that the risk of recurrence of appendicitis is no higher than appendicitis for the general population once they have been adequately treated conservatively. The author recommends and takes all patients for interval appendectomies if the parents agree.

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The answer is e. The classic triad for appendicitis is right lower quadrant tenderness, fever, and leukocytosis. However, of all patients who have appendicitis, only 30% present with that classic triad; thus, the majority of patients do not present with the typical or classic symptoms of appendicitis. This is especially true in the younger population.

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The answer is c. The incidence of intussusception is 1 to 4 cases per 1000 live births. The peak incidence occurs between 6 to 18 months of age. The most common type is ileal colic intussusception. The lead point is most often enlarged mesenteric lymph nodes, which is why there tends to have been a subclinical or clinical prodrome of a viral illness at some point in the recent past. A polyp, a Meckel’s diverticulum, or a tumor can be the lead point, but these are much less common. The clinical presentation is the most important factor in making the diagnosis: crampy, debilitating intermittent abdominal pain with intervening periods of normalcy.

In the words of the senior pediatric surgeon Michael Klein, “Intussusception is a diagnosis made with the ears (i.e., by history) versus appendicitis, which is a diagnosis made with your hands (i.e., on physical examination-RLQ tenderness).” The crampy intermittent abdominal pain should increase the suspicion of intussusception. Quite often, the physical examination is unremarkable, as are plain abdominal films. Thus, having a negative x-ray or exam does not rule out intussusception. Other findings, such as the presence of a right upper quadrant mass or currant jelly stools, may be a part of the classic presentation but usually begin to occur when the intussusception has been ongoing for an extended period. Lethargy is part of the presentation in about 10% of cases.

Both diagnosis and treatment are achieved with a contrast enema. Air contrast enema is most commonly used today in place of radiopaque material. This is the case because of a decreased risk of significant intra-abdominal contamination in case of perforation. Quite often, many patients undergo a screening ultrasound, which, in experienced hands, can determine the presence of an intussusception by demonstrating the presence of a “target sign.” If the ultrasound is negative, then the patient can be treated expectantly. If the ultrasound is positive, then they can move on to some type of enema. Gaining in popularity is the use of saline enemas under ultrasound guidance to determine reduction of the intussusception. This obviously avoids the use of any x-ray, thus avoiding the child’s exposure to radiation.

These methods of reduction are somewhere between 85% and 95% successful. If they are unsuccessful in demonstrating complete reduction, the patient will require operative intervention and a manual reduction of the intussusception. This can be performed via open versus laparoscopic reduction. A small percentage of patients with intussusception that are not able to be reduced require resection of the ileum and cecum with a primary anastomosis as definitive treatment. This is also potentially performed in patients who have had multiple recurrences. There has been some description of the use of delayed enema studies once the patients has had an attempted reduction but cannot demonstrate reflux into the terminal ileum. In this situation, the patient is admitted to the hospital if he or she is clinically stable and returned to the radiology suite 8 to 12 hours after some of the edema has had a chance to resolve. The contrast enema is repeated to demonstrate reflux into the terminal ileum.

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The answer is e. Hypertrophic pyloric stenosis, which leads to persistent vomiting, dehydration, and electrolyte abnormalities, is a medical emergency. The classic presentation is a patient who has a hypochloremic, hypokalemic, contraction, and metabolic alkalosis with paradoxical aciduria. This electrolyte defect comes from significant emesis with the loss of potassium and hydrogen ions. The patient also becomes profoundly dehydrated. The renal tubules conserve sodium with the exchange of potassium for sodium so that intravascular hydration status can be maintained with conservation of fluids. Once the potassium has been depleted, another positive ion is required for exchange for the sodium. Thus, the body chooses volume status over acid-base status and then begins to release hydrogen ions in exchange for the sodium ions. Although the patient is already alkalotic, acid will be released, resulting in acidic urine in the presence of metabolic alkalosis (i.e., paradoxical aciduria).