What is Appendicitis?

What is Appendicitis?

Appendicitis is a condition in which the appendix becomes infected or inflamed. This causes pain in the lower right part of the abdomen. Sometimes, the pain begins near the navel (belly button) and then moves. Appendicitis is the most common cause of acute abdominal pain.

This condition can affect anyone, but it most frequently occurs in people aged 10 to 30. It’s important to seek treatment quickly if you suspect you have appendicitis, as the appendix can rupture as soon as 48 to 72 hours after symptoms begin.

What is the Appendix?

The appendix is a small, finger-like tube that projects from the colon on the lower right side of the abdomen. In young children, it forms a part of the immune system, which helps the body fight infection and protect cells.

When you get older, the appendix ceases its immune function, and other parts of the body take on this function instead. Some professionals think the appendix stores probiotics (good bacteria), helping to “reboot” the digestive system after diarrheal illnesses. Other professionals theorize the appendix serves no purpose in adults and is simply left over from our evolutionary past.

Types of Appendicitis


Appendicitis (inflammation of the appendix) can be either acute or chronic:

  • Acute appendicitis develops quickly, typically within a few hours to a few days. It may also become infected and requires immediate medical attention. Surgery may be required to remove the appendix. About 8.6% of biologically male people and 6.7% of biologically female people in the United States are diagnosed with appendicitis in their lifetimes.
  • Chronic appendicitis refers to inflammation of the appendix that lasts for an extended period of time. This is a rare condition and can be difficult to diagnose because symptoms may be mild or come and go.

Signs & Symptoms of Appendicitis


There are several typical signs and symptoms of appendicitis:

  • Abdominal pain is usually the first appendicitis symptom. In some people, the pain begins around the navel, then moves to the lower right part of the abdomen. In other people, the pain begins by the navel and travels to the lower right of the abdomen. The pain usually gets worse over time, becoming severe as inflammation increases. Pain can vary depending on the exact position of your appendix. The pain may seem to be in the upper abdomen during pregnancy, as the appendix is higher.
  • Pain that gets worse when moving. Pain during coughing, walking, sneezing, or inhaling deeply can point to appendicitis.
  • Diarrhea, especially when severe, can be an initial manifestation of appendicitis. Sometimes diarrhea will occur with gas.
  • Constipation or difficulty passing gas are common symptoms and don’t necessarily mean you have appendicitis, but they can be initial symptoms. If you feel you’re having trouble passing gas, this can be a symptom of a total or partially obstructed bowel, which can be a sign of appendicitis. Sometimes constipation can occur with gas.
  • Nausea, vomiting, or loss of appetite can all occur in people with appendicitis. You may feel as though you can’t eat. Loss of appetite can be one of the first symptoms of appendicitis, often progressing into nausea and vomiting.
  • Fever and chills can be symptoms of appendicitis. A fever higher than 101 degrees Fahrenheit and an increased heart rate can be signs that appendicitis is worsening, and the appendix may burst. Mild fever and abdominal pain are common signs of appendicitis in children.
  • Peritonitis. Redness and inflammation of the lining of the abdomen, called the peritoneum, may occur in elderly patients, who may not present with the usual conclusive signs of acute appendicitis. Signs of peritonitis may include abdominal distention (swelling beyond its normal size), severe tenderness, reduced abdominal wall movement (reduced movement of abdomen moving inward and outward while breathing), and guarding (voluntary or involuntary tensing of abdominal muscles).

What Causes Appendicitis?


Appendicitis occurs when the inside of your appendix becomes infected or inflamed. This can be caused by blockages or infections.

  • Blockages, or obstructions, in the lining of the appendix, are thought to be the root cause of appendicitis often. Such blockages trigger infection, which in turn causes inflammation. The cause of such blockages is not always clear, but various situations and conditions may trigger them, including:
    • Fecal impaction
    • Intestinal worms or parasites
    • Irritation and ulcers in the gastrointestinal (GI) tract resulting from chronic disorders, such as Crohn’s disease, ulcerative colitis, or irritable bowel syndrome (IBS)
    • Benign or malignant tumors
    • Abdominal trauma or injury
    • Foreign objects
    • Enlarged lymph tissue of the appendix wall (usually the result of GI infections)
  • Infections, whether viral, bacterial, or fungal, can also cause appendicitis. These infections may be caused by:
    • Measles. This highly contagious respiratory virus spreads via the air (such as through sneezing and coughing) and human contact. Most of the population has been vaccinated against measles, but unvaccinated people are at risk during outbreaks.
    • E. coli. These bacteria are found in the environment, foods, and the intestines of humans and animals. Eating contaminated food is the most common cause of E. coli infections.
    • Adenovirus. There are several types of adenoviruses. This group of viruses can cause infections leading to bronchitis, diarrhea, colds, pneumonia, sore throat, bladder infections, pink eye, and more.
    • Salmonella bacteria. This common bacteria infects the GI tract. It typically lives in animal and human intestines and is shed through the stool. Humans are usually exposed to it through contaminated food or water. While some people have no symptoms, most people experience fever and abdominal cramps.
    • Shigella bacteria. This bacteria results in shigellosis, a very contagious infection caused by food poisoning that can lead to diarrhea. It’s one of the leading causes of diarrhea worldwide.

Other fungal, bacterial, viral, and parasitic infections can cause appendicitis as well. While contaminated food and water can lead to a serious infection that causes appendicitis, it is not caused by any one type of food.

Risk Factors

Risk Factors

Although anyone can get appendicitis, there are a few appendicitis risk factors that may increase your chances:

  • Having a family history of appendicitis may mean you’re more likely to get it yourself
  • Being biologically male slightly increases your chance of developing appendicitis
  • Having cystic fibrosis as a child can also raise your risk
  • Being pregnant may increase the risk of appendicitis, especially during the first and second trimesters (zero to 26 weeks)
  • Being in your teens and 20s means you are at higher risk, but people can get appendicitis at any age
  • Having a chronic GI disorder, such as IBS, may raise your chance of developing appendicitis



There are several serious complications that can occur because of appendicitis:

  • Burst appendix can occur if one’s appendix is not removed quickly enough
  • Peritonitis, a serious condition that causes redness and inflammation of the lining of the abdomen (called the peritoneum), can occur after one’s appendix bursts, letting bacteria into the peritoneum through a hole in the digestive tract. This can be life-threatening and requires immediate surgical removal of the ruptured appendix.
  • Abdominal infections can occur because of the abscesses that may form after one’s appendix has burst
  • Sepsis, a life-threatening bodily response to infection that can lead to organ failure, tissue damage, and even death, can occur if appendicitis is not treated quickly enough, allowing infection to spread in the abdomen



There is no way to prevent appendicitis, but maintaining a high-fiber diet can help with appendicitis prevention by preventing infections that may lead to appendicitis.

Get Care

Trust NewYork-Presbyterian for Appendicitis Care

The experts at NewYork-Presbyterian have experience with chronic and acute appendicitis and other digestive and kidney diseases. Our team will work with you to address your symptoms quickly, including any severe pain you may be experiencing, and ensure you receive the care and treatment you need. Contact us today to make an appointment.

If you think you are experiencing symptoms of appendicitis, seek care at a medical emergency department or call 911 immediately.