What You Need to Know About Acute Appendicitis

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Appendicitis is inflammation of the appendix, which is a small tube attached to the large intestine. Acute appendicitis is characterized by sudden pain in the lower right side of the abdomen. It is commonly treated with emergency surgery, known as an appendectomy.

This article discusses the symptoms and diagnosis of appendicitis, as well as treatment and recovery.

Appendicitis Symptoms

Laura Porter / Verywell

Is Acute Appendicitis a Severe Condition?

The appendix is a small, fingerlike tube attached to the large intestine in the lower right part of the abdomen. Experts still haven't determined the function of the appendix, as it is not required for typical body processes.

Appendicitis is inflammation of the appendix. It is the most common cause of acute abdominal pain for which people need surgery. Appendicitis most often occurs in people between the ages of 10 and 20 years old, but it can occur at any time. 

If appendicitis is caught early, it does not have to be a severe condition. However, if it is unrecognized, the inflammation will worsen. When this occurs, people can develop complications that can lead to severe consequences or death.

Symptoms

The most common symptom associated with appendicitis is abdominal pain. Classically, the pain begins near the belly button and then moves to the lower right part of the abdomen. This process can occur over a few hours to up to 48 hours.

However, not everyone has these classic symptoms. It is essential to recognize when a person has abdominal pain that feels different from any other abdominal pain they’ve had before.

The pain associated with appendicitis usually worsens over 24–48 hours. It's unusual for the pain to start suddenly and become severe within minutes.

Other symptoms of appendicitis are:

Children

The symptoms associated with acute appendicitis can be different in children. Up to half of children have vague symptoms and generalized abdominal pain.

Additionally, young children can be challenging to assess because they have difficulty describing and showing healthcare providers the location of their pain. They might not be able to describe the symptoms at all.

Pregnant People

Typically, people with appendicitis complain of lower right quadrant pain. However, the appendix might be moved upward by the enlarging uterus when a person is pregnant, so the pain is felt in the upper right abdomen rather than the lower abdomen.

Complications

As an inflamed appendix slowly grows larger, eventually it will rupture. Serious complications can occur if the appendix ruptures. The two most concerning complications associated with appendicitis are abscess development and peritonitis.

As part of the intestine, the appendix is filled with bacteria. When it ruptures, bacteria and other toxins spread to the abdominal cavity. This can lead to a severe infection of the entire abdomen called peritonitis.

Alternatively, the pus from the rupture might stay contained in a small area, leading to the development of an abscess. An abscess is often not as severe as peritonitis, but it still requires treatment.

What Causes Appendicitis?

Most of the time, the cause of appendicitis is not clear. Historically, it was thought that appendicitis develops because of a blockage at the opening of the appendix.

This blockage could be from:

  • A small tissue growth
  • An infection elsewhere in the digestive tract
  • Other bowel problems, like inflammatory bowel disease (IBD), namely Crohn's disease and ulcerative colitis
  • A hard piece of stool that is trapped at or near the appendix

Diagnosis

Diagnosing appendicitis involves reviewing symptoms and ordering:

  • A physical exam
  • Laboratory tests
  • Imaging studies

Healthcare providers will assess a patient’s symptoms and the location of abdominal tenderness on a physical exam to determine the likelihood of having appendicitis. Not all patients with abdominal pain need to have laboratory or imaging studies performed if the physical exam does not suggest acute appendicitis or another concerning abdominal problem.

Sometimes providers will use a scoring system called the Alvarado score to help them determine the likelihood of appendicitis in a particular patient.

On examination, patients with classic symptoms such as lower right abdominal pain, loss of appetite, nausea or vomiting, and fever, are considered likely to have appendicitis. Laboratory and imaging studies merely help to confirm the diagnosis. Conversely, patients who do not have any nausea, vomiting, or abdominal tenderness and have normal laboratory tests are unlikely to have appendicitis.

Specific laboratory tests that help a healthcare provider determine the likelihood of abdominal infection vs. an alternative diagnosis include:

Patients with a high white blood cell count are likely to have appendicitis.

Imaging tests used to diagnose appendicitis include:

A CT scan is most often used to diagnose appendicitis. However, this test exposes patients to low radiation levels, so CT imaging should be used sparingly in children and pregnant patients.

An abdominal ultrasound is not as reliable to diagnose appendicitis, but it is often the first imaging test used in children. If the ultrasound is inconclusive, then CT imaging will be performed.

MRI is very effective at diagnosing appendicitis. It is often used in pregnant patients. However, it is expensive, time-consuming, and not always available. MRI can also be used in children, but young children may not sit still for the test.

How Much Radiation Is in a CT of the Abdomen and Pelvis?

The amount of radiation a person is exposed to from one CT scan of the abdomen and pelvis is approximately 10 millisieverts (mSv), which equals about three to four years of background radiation that an American is exposed to over one year.

Treatment

The typical treatment for patients with appendicitis is intravenous (IV) antibiotics and removal of the appendix. It is best to treat appendicitis early to avoid complications, such as abscess development and peritonitis.

Generally, surgery is performed 12–24 hours after a patient is diagnosed with appendicitis.

Can Antibiotics Alone Treat Appendicitis?

There has been increasing research into the use of antibiotics alone to treat appendicitis, but at this time, isolated antibiotic therapy is less effective overall than adding surgical treatment.

Appendectomy

Surgeons can remove the appendix in two ways:

  • Open appendectomy: The surgeon creates a small incision on the abdomen to access the appendix.
  • Laparoscopic appendectomy: The surgeon creates one hole in the abdomen to use a laparoscope (a tiny camera and light) and one or two other small holes to insert tools to remove the appendix.

The type of surgery performed depends on the individual patient, the severity of appendicitis, and the surgeon performing the procedure. Laparoscopic surgery is becoming more common because the recovery time is shorter, and it often has fewer postoperative complications.

When a Normal Appendix Is Present

Sometimes during surgery, the surgeon finds a normal appendix. The surgeon will still remove the appendix so that a person doesn’t develop appendicitis at a later time. 

If a person develops an abscess around the appendix, healthcare providers typically drain the pus to allow it to heal before removing the appendix later. However, patients who are incredibly ill from appendicitis require immediate surgery even if an abscess is present. Patients with an abscess will also be treated with intravenous antibiotics.

People with appendicitis and peritonitis are typically very ill and may require care in an intensive care unit (ICU). These patients also need an emergency appendectomy and a washout of the abdominal cavity.

Recovery

Usually, people do very well recovering after an appendectomy. Surgeons generally limit physical activity for three to five days after laparoscopic surgery and 10 to 14 days after open appendectomy. A few days after surgery, a person can resume their regular diet and lifestyle.

Some people can develop complications from the surgery itself. The complications include:

These complications do not happen often and are more common in people who have severe, complicated appendicitis.

Summary

Appendicitis is inflammation of a small piece of the large intestine called the appendix. Symptoms of appendicitis include pain on the lower right side of the abdomen accompanied by fever, vomiting, and loss of appetite. Healthcare providers diagnose acute appendicitis in a hospital setting based on a patient’s physical exam, laboratory tests, and imaging studies. Treatment involves intravenous antibiotics and surgery.

If caught early, appendicitis is easily treatable and not a severe disease. However, it can lead to complications such as abscess development and peritonitis when left untreated.

A Word From Verywell

Appendicitis causes significant pain and requires surgery, but it does not have to be a severe illness. If you develop persistent pain on the lower right side of your abdomen that is different from abdominal pain you have had before, seek care at a hospital or emergency department.

Frequently Asked Questions

  • What side is the appendix on?

    The appendix is on the lower right side of your abdominal area. Most people have pain in that area when they have appendicitis, but sometimes the pain is in other parts of the abdomen or even in the back.

  • Is acute appendicitis curable?

    Appendicitis is curable with intravenous antibiotics and removal of the appendix.

  • Is acute appendicitis the same as appendicitis?

    The terms "acute appendicitis" and "appendicitis" are used interchangeably. "Acute" means that the infection happens over a short time. Chronic appendicitis is when the appendix is inflamed for days or weeks. Chronic appendicitis is rare.

  • How long does appendicitis last?

    Acute appendicitis is generally recognized within a few hours to a few days. Once treatment is initiated with antibiotics and surgery, people typically heal within approximately one week. There are rare instances of people with chronic or recurrent appendicitis who have abdominal pain for days to weeks before seeing a healthcare provider.

  • Can food cause appendicitis?

    Food is not a typical cause of appendicitis. There have been sporadic case reports of undigested plants and fruit seeds found inside removed appendices. However, these cases are so rare that they are not considered a regular cause of appendicitis.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  6. Poprom N, Numthavaj P, Wilasrusmee C, et al. The efficacy of antibiotic treatment versus surgical treatment of uncomplicated acute appendicitis: Systematic review and network meta-analysis of randomized controlled trial. Am J Surg. 2019;218(1):192-200. doi:10.1016/j.amjsurg.2018.10.009

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By Christine Zink, MD
Dr. Christine Zink, MD, is a board-certified emergency medicine with expertise in the wilderness and global medicine. She completed her medical training at Weill Cornell Medical College and residency in emergency medicine at New York-Presbyterian Hospital. She utilizes 15-years of clinical experience in her medical writing.