Appendicitis

Acute appendicitis is one of the most common causes of abdominal pain in childhood. This diagnosis must be considered in all age groups but is more common between the ages of 4 and 15 years. The function of the appendix is unknown. However, in rabbits and other animals the cecum is similar in shape to the appendix and plays a role in digestion of food. The middle, inside portion of the appendix may be irregular and somewhat narrow because of the presence of lymph nodes in the wall of the appendix.

In most patients the appendix is located in the right lower area of the abdomen. However, since the appendix is a fingerlike projection, it may be in various locations in the right upper area of the abdomen under the gallbladder, in the pelvis, across the top of the bladder, and behind the large intestine. (Figure 1).

Figure 1: McBurney's point is located one third of the distance along a line from the front of the right pelvic bone and the belly button.

Appendicitis most often results from blockage by feces which has formed a stone (a fecalith) or, less commonly, from enlarged lymph nodes caused by a viral infection. Once a blockage occurs, bacteria located within the appendix grow. The pressure in the appendix increases and the appendix becomes swollen. Eventually the blood vessels to the appendix close and the appendix dies. Subsequent perforation will occur. (Figure 2).

Figure 2: An appendix which has died, but is not yet ruptured is shown during a laparoscopic appendectomy. Note the enlarged, swollen appendix (white arrow) with a relatively normal appendix where it attaches to the large intestine (black arrow).

CLINICAL PRESENTATION
Acute appendicitis usually begins with pain, frequently localized to the area around the belly button. This is commonly followed by loss of appetite: most children with appendicitis show no interest in their favorite foods. Nausea and vomiting usually are seen next. In time the pain eventually shifts to the right lower area of the abdomen. In some patients, the appendix lies behind the first part of the large intestine and in those patients the shift of pain to the right lower area of the abdomen may be absent. The pain in appendicitis is continuous and generally does not get better. The pain is usually present even when the patient is lying still. Occasionally a child complains of right lower abdominal pain while walking, or refuses to stand up or walk. Obtaining accurate information from an infant or a very young child (<3 years old) may be a problem because communication is difficult in this younger age group which leads to a high rate of perforated appendicitis among these children. Most children with appendicitis have a low-grade fever of 38° to 39° C. However, it is unusual for patients with appendicitis to present with a temperature above 39° C. When the temperature is this high, an illness due to a virus should be considered.

PHYSICAL EXAMINATION
The examination must include a careful abdominal and rectal examination. A youngster who is ill and in pain is often frightened by an unfamiliar environment such as an emergency room. Examination under these circumstances can be extremely difficult. Observation of the child will often detect signs suggestive of appendicitis: the patient usually lies quietly on the side with the knees drawn up. The patient with appendicitis moves slowly and carefully, avoiding any sudden movements: sudden movement causes the appendix to irritate the inside of the abdomen and to cause pain. The abdominal examination should be initiated anywhere but the right lower quadrant with that area left for last. Potentially unpleasant parts of the examination such as evaluation of the throat with the use of a tongue blade or looking at the tympanic membranes with an otoscope or performing a rectal examination should be left for last. Careful examination of the neck, throat and chest are important to identify other potential causes of abdominal pain other than appendicitis.

The child can be asked to &##8220;point with one finger at the spot where it hurts the most" which is usually found in the right lower area of the abdomen at McBurney's point. (Figure 3). Gentle pushing on the abdomen may identify tenderness in the right lower area of the abdomen which is suggestive of appendicitis. Talking to children about pets, siblings, or school while examining the abdomen may distract them and allow a better examination. The stethoscope may be used to push on the abdomen in young patients that believe that the stethoscope is being used for listening. By watching for changes in the patient's facial expression one may get an idea of how much the abdomen hurts. Having a patient raise the hips and buttocks off of and then drop them onto the examining table may elicit pain consistent with appendicitis. A patient with appendicitis will rarely get off the examining room table and jump up and down more than once and will have pain when doing so. Holding a hand above a child's head and challenging him or her to jump and touch it is irresistible to most children except those in whom pain is produced. As mentioned previously, watching how the patient moves on and off the examining table is also helpful.

Figure 3: The appendix is a finger-like projection that can extend down, toward the middle, upwards toward the liver, or behind the first portion of the large intestine which is called the cecum.

A rectal examination should be performed in most patients unless the diagnosis is clear. The rectal examination may identify constipation, which may be a cause of abdominal pain. A tender area or a mass to the right on rectal examination suggests appendicitis. In most teenage girls, a routine pelvic examination is not necessary. Instead, the uterus, cervix, and even the ovaries can be partially assessed during the rectal examination.

LABORATORY TESTS
Laboratory tests are not especially helpful in the diagnosis of early appendicitis. Approximately 90% of the patients with appendicitis will have a white blood cell count that is high (between 10,000 to 15,000 per cubic millimeter); looking at the urine may be of importance to identify a bladder infection or the presence of blood in the urine which may be caused by a kidney stone. However, an abnormal urine may also be observed in patients with appendicitis if the appendix is near the bladder or ureter (tube which runs between the kidney and bladder). In teenage female patients a urine pregnancy test should be obtained.

DIAGNOSTIC TESTS
A chest x-ray should be performed if there is a concern for pneumonia. An abdominal x-ray might show the presence of an appendix stone (fecalith) in the right lower area of the abdomen that suggests that appendicitis may be present. Unfortunately, a fecalith is only seen on x-ray in a few patients (15%). Ultrasound examination is especially useful in teenage girls in whom gynecology conditions such as an ovarian cyst are being considered. The typical finding of appendicitis on ultrasound is a round, tender, stiff, blind-ending structure that is greater than 6mm (quarter inch) in diameter and sitting next to the first part of the large intestine which is called the cecum. Computed tomographic (CT) scans play a role in the diagnosis of appendicitis. Contrast (dye) is administered by mouth or through the rectum such that it fills the cecum and, hopefully, the appendix. One advantage of giving the contrast by the rectum rather than by mouth is that the test can be performed much more rapidly. The CT may show an enlarged, swollen appendix which often presents as a "target sign&##8221; (See Figure 4) A reaction in the area surrounding the appendix may also be seen. CT evaluation appears to increase the physician&##8217;s ability to diagnose appendicitis. However, there are a group of patients that clearly have appendicitis in whom a CT scan may be wasteful and expose the child unnecessarily to radiation. As such, the scan is most useful in patients in whom the diagnosis of appendicitis is unclear.

Figure 4a: CT scan showing appendicitis. The typical &##8220;target sign&##8221; of the appendix is shown in the right lower abdomen of the upper scan (black arrow).

Figure 4b:  An enlarged, swollen appendix is shown by the white arrow in the lower scan.

Performing an operation by placing a scope into the abdomen (laparoscopy), looking at the appendix, and doing an appendectomy is the final diagnostic test in the patient with continuing pain and concern for appendicitis.

DIFFERENTIAL DIAGNOSIS
Although appendicitis is a common childhood condition, arriving at the diagnosis may be difficult in up to half of the patients, especially in infants, very young children, mentally retarded children, patients initially hospitalized for other conditions, and teen-age girls in whom various gynecologic problems may also present with lower abdominal pain. One third to one half of patients with ruptured appendicitis have already been seen in a physician's office or an emergency room and are sent home with an incorrect diagnosis. A careful menstrual cycle history often yields important diagnostic clues. In addition, observation of a discharge from the vagina, tenderness of the uterus or cervix, and lower abdominal pain on both sides while pressing on the abdomen may suggest infection of the ovaries and fallopian tubes. Twisting (torsion) of either a normal ovary, an ovarian cyst, an ovary with a tumor, or a pregnancy in the fallopian tube are also diagnostic considerations. In addition, mid-monthly cycle ovulation may be a cause of concern because of the pain (&##8220;mittelschmerz&##8221;). Infections of the intestines due to a virus (gastroenteritis) with vomiting, watery diarrhea, and high fever is a frequent cause of abdominal pain in young children.

Other conditions that may cause abdominal pain in childhood include Crohn's disease, intestinal bacterial infection, pancreatitis, perforated ulcer, gallstone or gallbladder problems. Abdominal pain may also be caused by constipation, urinary infection, kidney stones, and a number of other conditions (Table 1).

In children less than 3 years of age, viral illnesses and ileocolic intussusception (where the last part of the small intestine moves up into the large intestine) are two of the more common conditions which can be confused with appendicitis. In children in whom the immune system is decreased (often patients with leukemia) the right colon may get sick and swollen as a result of bacteria invading the intestinal wall (typhlitis) and may be the cause of severe right lower abdominal pain which may be difficult to distinguish from appendicitis. The CT scan in patients with typhlitis may demonstrate thickening of the right side of the large intestine.

Table 1: Other causes of abdominal pain which may be confused with appendicitis

TREATMENT
Children with appendicitis usually fit into one of three groups. The first are patients who present with an obvious case of appendicitis. The second group of patients are those who clearly do not have appendicitis. Finally, the third and most perplexing group are those children with abdominal pain in whom the diagnosis is unclear. Here tests including ultrasonography or CT may be required. In most patients a decision as to whether appendicitis is likely or unlikely can be made based on the symptoms, the examination, and if required, an ultrasound or CT. If appendicitis is likely, an operation is typically performed. If it is not likely, then most children can be followed closely from home. Occasionally admission for observation and serial examination is required.

The time interval between onset of symptoms and rupture of the appendix can be shorter or longer, but in general appears to be about 36 to 48 hours. Ruptured appendicitis occurs in about one out of three patients admitted to most children's hospitals. Patients with ruptured appendicitis may be treated with antibiotics followed by an appendectomy approximately 6 weeks later. Patients with ruptured appendicitis tend to appear more ill, more often have fevers, have a higher white blood cell count, have tenderness over most of the abdomen, and have a longer period of symptoms. However, even a combination of these symptoms does not help a lot to tell the difference between ruptured and non-ruptured appendicitis. CT may help to tell whether the appendix is ruptured or non-ruptured, but the CT is not always correct. The surgeon must simply make a judgment as to whether the child has &##8220;ruptured” or &##8220;non-ruptured&##8221; appendicitis.

In instances of early appendicitis, the child should receive intravenous fluids, antibiotics, and medication for pain relief. Once antibiotics are administered, there is often a reduction in pain and tenderness in many children. As such, in most instances, antibiotics and pain medications should not be given until the diagnosis of appendicitis has been made. Once antibiotics are given, the infection in the appendix usually begins to get better so that the need for immediate operation is also removed. As a result, most appendectomy cases can wait until the daylight hours.

Appendectomy is accomplished at many centers via a laparoscopic approach. The costs of the operation are greater with laparoscopy than with an open operation, but the hospital stay is shorter such that the overall costs are about the same. A laparoscopic oepration can be performed in the same time that it takes to perform an open appendectomy. One benefit, other than that the scar is smaller, is the ability to completely see the other structures inside the abdomen should the appendix appear normal. The laparoscopic operation can be performed through using three or two &##8220;ports&##8221; (Figure 5). With a three port operation, ports are placed through the belly button, the left lower abdomen and the right mid-abdomen. A space is created between the appendix and the blood vessels going to the appendix (the mesentery) near where the appendix joins the large intestine. A stapler which divides and seals is first fired across the blood vessels and then across the appendix itself. The appendix is then removed. With the two port technique a port is placed through the belly button and through the right lower abdomen. The appendix is grasped and brought up through the port site as the port is removed. An appendectomy is then performed outside of the body as the blood vessels and the appendix are tied off with sutures. The appendix is then removed. This technique is best used when an early appendicitis is present or a normal appendix is found.

Figure 5: Laparoscopic appendectomy demonstrating A) dividing the blood vessels going to the appendix using a stapler followed by B) removal of the appendix using a stapler.

In some cases, an open appendectomy is performed through a longer right lower abdomen incision (Figure 6). Antibiotics are continued after the operation only in patients with ruptured appendicitis. Patients can usually start eating following the operation and, in most cases of non-ruptured appendicitis, are discharged in the first 24 hours.

Figure 6: (A), An incision is made in the right lower abdomen. (B) , The muscle is opened. (C), The transverse the first part of the large intestine, the cecum, is identified. (D), The swollen appendix is seen and the blood vessels going to the appendix are tied off. (E), A suture is placed in the cecum around the bottom of the appendix. (F), The bottom of the appendix is crushed tied off. The appendix is removed and (G) the remaining portion of the appendix is dunked down into the cecum using the suture tied in &##8220;E&##8221;.

When the appendix has ruptured, antibiotics should be given to treat infection. Pain medication is administered. When ready, the patient may be taken to the operating room for appendectomy. However, in many cases of ruptured appendicitis, the approach of interval appendectomy is applied: patients are first treated with antibiotics to allow the infection to go away. Abscesses (pus pockets) are drained out using the CT to guide placement of a needle into the abscess (Figure 7) Antibiotics are continued until the infection is gone. A peripherally-inserted central catheter (PICC) may be placed into a vein and the patient sent home on intravenous (IV) antibiotics once the child is eating a diet and pain is controlled on medication taken by mouth. Nutrition given into the IV may be necessary until adequate nutrition can be taken by mouth. Appendectomy is then performed after 6 to 8 weeks. The complications appear to be less with this approach of waiting before doing the appendectomy when the appendix has ruptured.

Figure 7: CT scan demonstrating the findings of a pus pocket (abscess, see arrow) in the right lower abdomen of a child with perforated appendicitis.

DEATHS AND COMPLICATIONS
The number of cases where children have died from appendicitis has decreased over the past 3 decades to the point where it is now almost never the cause of death. The availability of excellent antibiotics along with the availability of CT scans have made deaths from appendicitis almost unheard of and the incidence certainly <1%. Infection of the incision after an appendectomy is a fairly rare complication (3%). Abscesses (pus pockets) are also fairly uncommon (<5%) and can usually be managed by draining the pus with a needle placed while watching the CT, drainage through the rectum, or continued antibiotic administration in the case of multiple, small pus pockets. There is a 3% to 5% risk of small bowel obstruction (blockage) after appendicitis and appendectomy. Currently, >90% of children operated upon for appendicitis indeed have the disease.

CHRONIC (LONG TERM) APPENDICITIS
Although whether chronic appendicitis exists is controversial, most surgeons have managed patients with chronic abdominal pain that resolved with appendectomy. In some cases, patients have noted intermittent right lower abdominal pain and, in fact, the appendix which is subsequently removed has chronic changes consistent with bouts of appendicitis. Some surgeons have suggested that when the appendix does not fill or only partially fills with barium during a barium enema or when barium does not drain from the appendix after a few days following a barium enema, suggests that chronic appendicitis may be present. Laparoscopy with appendectomy has provided a means for evaluating the appendix in the child with persistent lower abdominal pain.

Articles and graphics adapted from O'Neill: Principles of Pediatric Surgery. © 2003, Elsevier.