Appendicitis seems to develop when the appendix becomes blocked either by hard fecal material (called a fecalith) or swollen lymph nodes in the intestine that can occur with various infections.
Pain typically starts around the bellybutton (umbilicus) and then moves to the right lower abdomen but it may also be widespread and it may make children irritable or listless.
Diagnosis is challenging and may require blood tests, ultrasonography, computed tomography, magnetic resonance imaging, or laparoscopy.
An inflamed appendix is usually removed surgically.
(For adults, see Appendicitis Appendicitis Appendicitis is inflammation and infection of the appendix. Often a blockage inside the appendix causes the appendix to become inflamed and infected. Abdominal pain, nausea, and fever are common... read more .)
The appendix is a small finger-length portion of intestine that does not clearly have any essential bodily function. However, appendicitis is a medical emergency that requires surgery. This disorder is rare in children younger than 1 year but becomes more common as children grow older and is most common among adolescents and adults in their 20s.
Appendicitis seems to develop when the appendix becomes blocked either by hard fecal material (fecalith) or swollen lymph nodes in the intestine, which can occur with various infections. In either case, the appendix swells, and bacteria in it grow. Rarely, swallowed foreign objects Bezoars Bezoars are tightly packed collections of partially digested or undigested material that can become stuck in the stomach or intestines. Masses of undigestible materials can get stuck in the... read more 
and infections with certain parasitic worms (such as strongyloidiasis Strongyloidiasis Strongyloidiasis is infection caused by the roundworm Strongyloides stercoralis, which enters the body when bare skin comes in contact with soil contaminated with the worm. Usually, people... read more 
) can also cause appendicitis.
Complications of appendicitis
If appendicitis is unrecognized or untreated, the appendix can rupture, creating a pocket of infection outside the intestine (abscess Abdominal Abscesses An abscess is a pocket of pus, usually caused by a bacterial infection. Most people have constant abdominal pain and a fever. Computed tomography or another imaging test can distinguish an abscess... read more ) or spilling contents of the intestines into the abdominal cavity, causing a serious infection (peritonitis Peritonitis Abdominal pain is common and often minor. Severe abdominal pain that comes on quickly, however, almost always indicates a significant problem. The pain may be the only sign of the need for surgery... read more ). The likelihood of the appendix rupturing depends on the child's age. Ruptures of the appendix occur in about 65% of children who are under 5 years of age and in up to 90% of children who are under 2 years of age.
Symptoms of Appendicitis
In children who are over 2 to 3 years of age, the order in which symptoms appear is more important than any one symptom itself. The first symptom to develop is pain. Appendicitis almost always causes pain. The pain may start in the middle of the abdomen around the bellybutton and then move to the lower right area of the abdomen. However pain, particularly in infants and children, may be widespread rather than confined to the right lower portion of the abdomen. Younger children may be less able to identify a specific location for the pain and may be very irritable or listless.
After the pain has begun, many children develop nausea or vomiting and do not want to eat. Then the abdomen is tender when the doctor pushes on it, usually in the area over the appendix. A low-grade fever (100 to 101° F [37.7 to 38.3° C]) develops next and is a common symptom. Lastly, fever is followed by laboratory test results that show infection, such as a high white blood cell count. This order of symptoms is different from that in children who have viral gastroenteritis Gastroenteritis in Children Gastroenteritis is inflammation of the digestive tract that results in vomiting, diarrhea, or both and is sometimes accompanied by fever or abdominal cramps. Gastroenteritis is usually caused... read more , in whom vomiting typically occurs first, and pain and diarrhea develop later. Significant diarrhea is not common among children who have appendicitis.
Diagnosis of Appendicitis
Ultrasonography
Sometimes other imaging tests
Sometimes laparoscopy
The diagnosis of appendicitis in children can be challenging for many reasons. Many disorders can cause similar symptoms, including viral gastroenteritis Gastroenteritis in Children Gastroenteritis is inflammation of the digestive tract that results in vomiting, diarrhea, or both and is sometimes accompanied by fever or abdominal cramps. Gastroenteritis is usually caused... read more , Meckel diverticulum Meckel Diverticulum A Meckel diverticulum is a saclike outpouching of the wall of the small intestine that is present in some children at birth. Most children do not have symptoms, but sometimes painless rectal... read more , intussusception Intussusception Intussusception is a disorder in which one segment of the intestine slides into another, much like the parts of a telescope. The affected segments block the bowel and block blood flow. The cause... read more , and Crohn disease Crohn Disease Crohn disease is an inflammatory bowel disease where chronic inflammation typically involves the lower part of the small intestine, the large intestine, or both and may affect any part of the... read more 
. Often, children, particularly younger children, do not have typical symptoms and physical examination findings, particularly when the appendix is not in its usual position in the right lower part of the abdomen. This lack of typical symptoms can be deceptive.
Most often, doctors do ultrasonography Ultrasound Scanning (Ultrasonography) of the Abdomen Ultrasound scanning uses sound waves to produce pictures of internal organs (see also Ultrasonography). An ultrasound scan can show the size and shape of many organs, such as the liver and pancreas... read more 
, which does not expose the child to radiation. If the diagnosis is not clear, doctors may do computed tomography Computed Tomography (CT) In computed tomography (CT), which used to be called computed axial tomography (CAT), an x-ray source and x-ray detector rotate around a person. In modern scanners, the x-ray detector usually... read more 
(CT) or magnetic resonance imaging Magnetic Resonance Imaging (MRI) In magnetic resonance imaging (MRI), a strong magnetic field and very high frequency radio waves are used to produce highly detailed images. MRI does not use x-rays and is usually very safe... read more 
(MRI). Doctors who suspect appendicitis usually give fluids and antibiotics by vein while waiting for results of blood, urine, and imaging tests.
If the diagnosis is not clear, doctors may do laparoscopy Laparoscopy Laparoscopy is an examination of the abdominal cavity using a fiberoptic instrument inserted through the abdominal wall. This is a surgical procedure done in an operating room. People are given... read more , in which a small viewing scope is put through the wall of the abdomen to look inside. If appendicitis is found during laparoscopy, doctors can remove the appendix using the laparoscope. Alternatively, especially in children whose symptoms and examination findings are not typical of appendicitis, doctors may simply do repeated physical examinations. Seeing whether the symptoms and tenderness are getting worse or better with time may help doctors decide whether appendicitis is present. Doctors also note the order in which the symptoms appear.
Prognosis for Appendicitis
With early treatment, the overall prognosis for children who have appendicitis is very good. Less than 0.1% (one in a thousand) of children die. About 3% of children develop complications even if their appendix did not rupture.
If children are not treated until the appendix has ruptured, which occurs most commonly in children under 2 years of age, the prognosis is worse. About 10 to 15% of children who have surgery for a ruptured appendix have complications.
If children are not treated, appendicitis rarely can go away on its own. Usually, however, untreated appendicitis progresses and causes peritonitis, an abdominal abscess, and sometimes death.
Treatment of Appendicitis
Appendectomy
Antibiotics by vein
The best treatment for appendicitis is surgical removal of the inflamed appendix (appendectomy). Before surgery, doctors give antibiotics by vein, which decreases the risk of complications. Doctors have recently found that appendicitis can sometimes be treated successfully with only antibiotics. If the antibiotic treatment is unsuccessful, surgery is done. Even if antibiotic treatment is successful, children sometimes develop appendicitis again. Surgical removal of the appendix is still generally the recommended treatment for appendicitis.
Appendectomy is fairly simple and safe, requiring a hospital stay of 2 to 3 days in children who have no complications, such as a ruptured appendix. If the appendix has ruptured, the doctor removes it and may wash out the abdomen with fluid, give antibiotics for several days, and watch for complications, such as infection and bowel blockage. Children who have a ruptured appendix typically need to stay longer in the hospital.
About 10% of the time, surgeons discover a normal appendix while doing an appendectomy. This finding is not considered a medical error because the consequences of delaying surgery when appendicitis is suspected are serious. When the appendix is found to be normal, the surgeon looks in the abdomen for another cause of the pain. The doctor usually removes a normal appendix so that the child never develops appendicitis.
