Appendicitis is swelling (or inflammation) of the appendix, a narrow, tube-shaped organ attached to the large intestine on the lower right side of the abdomen. The condition may cause the appendix to rupture, a complication that can be life-threatening.
Appendicitis is the leading cause of emergency abdominal operations in the United States, according to the National Institutes of Health. Anyone can develop the condition, but most people who get appendicitis are 10 to 30 years old. More than 5 percent of the U.S. population develops appendicitis at some point in their lives, the NIH says.
Abdominal pain is the most common symptom of acute appendicitis. The pain typically begins near the belly button, and then moves to the lower right side of the abdomen, usually over a period of 12 to 24 hours, according to the NIH. The pain often gets worse if the patient moves around, takes deep breaths, coughs, or sneezes.
People who experience persistent abdominal pain should see their health care provider right away, said Dr. Robert Glatter, an emergency physician at Lenox Hill Hospital in New York City. "The longer you wait the more concerning the risk of complication," Glatter said.
Other symptoms of appendicitis include:
- loss of appetite
- nausea or vomiting
- constipation or diarrhea
- low-grade fever
- abdominal swelling/bloating
Although loss of appetite and fever are common symptoms of appendicitis, not all patients will have these symptoms, Glatter said.
Appendicitis can be harder to diagnose in the elderly, because they may not have physical symptoms that younger people have, such as tenderness in the abdomen, Glatter said.
In pregnant women, appendicitis pain may be in the upper right hand side of the abdomen, because the appendix migrates upward during pregnancy, Glatter said.
A blockage of the appendix — by feces, a foreign object, or in some rare cases, a tumor — is the most common cause of appendicitis, according to the NIH. When the appendix is blocked,the normal bacteria in the organ multiply, causing swelling and infection.
Appendicitis is most common in people in their teens and twenties, but it can happen at any age. There is no evidence that certain diets can prevent appendicitis, the NIH says.
Appendicitis can run in families, so having a family history of appendicitis can increase a person's risk of the condition, Glatter said.
To diagnose appendicitis, doctors can perform the following tests: A physical exam that applies gentle pressure to the abdomen, blood tests to check for infection, urine tests to test for kidney problems, and imaging tests, including a CT scan or ultrasound, according to the Mayo Clinic.
Doctors typically preform a CT scan for adults, and an ultrasound for children, Glatter said.
In the United States, appendicitis is typically treated with surgery to remove the appendix, called an appendectomy. Prompt surgery decreases the chances that the appendix will burst, the NIH says.
However, in Europe there has been a shift towards treating mild cases of appendicitis with antibiotics alone, Glatter said. A 2012 study in the United Kingdom found that patients with mild appendicitis who were treated with antibiotics were about 30 percent less likely to experience complications, such as wound infection, compared to those who underwent surgery. In these cases, people treated with antibiotics may not need surgery at all, or they may have their appendix removed at a later date, Glatter said.
In the United States, it is less common to treat appendicitis with antibiotics alone, but some academic centers are considering it, Glatter said.
Most people with appendicitis recover quickly after surgery, and don't need to make any changes to their lifestyle. Patients who've had their appendix burst may take longer to recover, the NIH says.
If an inflamed appendix isn’t removed quickly, it can rupture. When the appendix ruptures, it can spill the infection throughout the abdomen, leading to a potentially dangerous condition called peritonitis, in which the lining of the abdominal cavity is infected. The condition can lead to sepsis, or a serious infection of the bloodstream.
People who have a rupture appendix may feel less pain for a short time, but the pain will soon become worse than before and likely cause sickness.
In most cases of peritonitis, the appendix is removed immediately with surgery. This is usually done through a laparotomy (a single incision). When the infection and inflammation are under control (usually after about six to eight weeks), surgeons remove what is left of the burst appendix.
In some cases, an abscess forms around the burst appendix. Surgeons typically drain the pus from the abscess before surgery using a tube placed through the abdominal wall. After surgery, the drainage tube is left in for around two weeks, while the patient takes antibiotics.
The appendix is a thin tube, about 4 inches long, which lies at the junction of the small intestine and the large intestine on the right side of the abdomen. It produces mucus that travels into the large intestine.
The appendix is often thought of as a "useless" organ that serves no function in humans, but was left over from a human ancestor. However, in recent years, some scientists have hypothesized that the appendix does indeed have a purpose. One theory is that the appendix may be a storage unit for good bacteria, which can help reboot the digestive system after a bacterial infection. A 2013 study in the journal Comptes Rendus Palevol found that an appendix-like organ has evolved independently 32 times in different mammal species, suggesting that the organ may play a role in mammalian health.
Jessie Szalay contributed to this article.