Appendicitis is an inflammation of the appendix, a small finger-shaped sac of tissue attached to the large intestine in the lower right part of the abdomen. The infection may cause the appendix to become inflamed, causing the tissue to swell or stool to harden.
The appendix performs no known function in the body, but if it becomes inflamed, the consequences can be serious. This is why proper diagnosis of appendicitis is important. Timely diagnosis means timely treatment. If appendicitis is not treated, the appendix can burst, causing a dangerous infection within the abdomen.
Because the initial symptoms of appendicitis are similar to many other diseases, including abdominal pain and swelling, nausea, vomiting, fever, diarrhea, constipation, and difficult drainage, appendicitis may not be diagnosed based on symptoms alone. Your healthcare provider will likely perform other diagnostic steps as well.
To identify appendicitis, health care providers rely on a medical history evaluation, physical examination, blood tests, urinalysis, and imaging. Your primary care provider, emergency room doctor, or radiologist will do this.
To help diagnose appendicitis, health care providers rely on certain criteria to assess the severity of the case. The modified Alvarado scoring system is the most commonly used diagnostic criterion in clinical practice. Dr. Alfred Alvarado originally developed the system in 1986 for use in pregnant people. This soon gained attention for all cases of suspected appendicitis and remains the standard approach.
The modified Alvarado scoring system relies on assessment of current symptoms and clinical test results. Your health care provider calculates your score on a scale of 0 to 9, with a score of 7 or higher meaning you are more likely to have appendicitis.
The system awards 2 points each for an elevated white blood cell count (blood test results) and pain or tenderness in the lower right abdomen. Suppliers also add 1 point for each of the following:
- Migratory abdominal pain (pain that moves)
- Recurring tenderness in the abdomen
- Fever
- nausea or vomiting
- loss of appetite
The first step in diagnosing appendicitis is assessing your symptoms and overall health. Your health care provider will ask you about your history of medical conditions, treatments, and alcohol or drug use, as well as any medications or supplements you are taking and any dietary concerns you may have. They may also ask about your family history of digestive problems.
They will also ask you about your symptoms. In particular, you need to know when the pain started, how severe it is, and where in the abdomen it is located. They may also inquire about any other signs or concerns you may have.
Your healthcare provider will also want to evaluate your abdomen. These may include:
- Apply gentle pressure or shake to the affected area and the area around the abdomen.
- Press into your right knee as you lift your leg.
- To assess pain, you are asked to lie on your left side and move and rotate your leg.
- Use a stethoscope to listen to the inside of the abdomen.
Depending on other conditions suspected, your provider may also do a visual and physical examination of the pelvis in people assigned female at birth. A digital rectal examination may also be performed, which involves physically assessing a man's prostate or a woman's rectum using a gloved hand.
Blood and urine tests help your healthcare provider rule out other potential causes of your symptoms and may indicate signs of appendicitis. These clinical tests may include:
- White blood cell count (high levels indicate infection)
- C-reactive protein (CRP) test; Elevated levels of this liver protein indicate infection.
- A urine sample is tested for signs of kidney stones or bladder infection.
- Pregnancy Test, Pregnancy May Cause Abdominal Symptoms
Although a physical examination and clinical examination are sufficient to diagnose appendicitis, imaging of the appendix and inside the abdomen can help your healthcare provider assess the extent of inflammation and infection. They may also screen for complications by looking for blockages such as an abscess (a pocket of pus) or a ruptured appendix (a ruptured appendix can spread the infection).
The most commonly used imaging modalities include computed tomography (CT), ultrasound, and magnetic resonance imaging (MRI).
Computed tomography (CT)
A CT scan uses multiple X-rays to create a three-dimensional image of the appendix. This is done while lying down. In some cases, contrast dye may need to be swallowed, injected, or given in an enema (given through the rectum). This substance helps the radiologist better visualize inflammation or infection in the area when viewing images.
CT scans are very accurate, but they are not right for everyone. Because of the risk of exposure to radiation to the fetus, people who may become pregnant should take a pregnancy test before a CT scan. Meanwhile, other options must be used first to limit radiation exposure to children.
Magnetic resonance imaging (MRI)
Abdominal MRI is another form of imaging that uses X-rays to create images of the appendix and abdomen. This type produces very accurate and reliable images, but is not widely used and requires a trained professional.
Because MRIs do not emit radiation, your radiologist may consider them if you are pregnant.
abdominal ultrasound
With ultrasound, images are created using directed sound waves within the abdomen. The procedure is performed while lying down. Providers use portable devices that transfer images to the screen. Ultrasound is safer for children and pregnant women because it does not rely on radiation.
A variety of conditions can cause symptoms similar to appendicitis. Therefore, a big part of diagnosis involves ruling out other conditions that share symptoms. This is primarily done by evaluating imaging results.
Additionally, certain bacterial or viral infections can cause symptoms similar to appendicitis, so blood tests may be needed to rule out these other underlying causes.
Conditions that cause symptoms similar to appendicitis include:
- Abdominal adhesions: Scar-like bands of tissue between abdominal organs
- inflammatory bowel disease (IBD): A series of chronic bowel diseases, including Crohn's disease and ulcerative colitis
- ileus: Partial or complete blockage of the intestines
- Pelvic Inflammatory Disease (PID): Infections and scarring of the uterus, ovaries, or other female reproductive organs
- Kidney stones: Development of solid calcium deposits in the kidneys
- Ectopic Pregnancy: If the fetus implants outside the uterus
- Ovarian torsion: When blood supply to the ovaries is cut off
- Testicular torsion: When the spermatic cord that supplies blood to the testicles is twisted and the blood supply is blocked
Appendicitis is a disease in which the appendix becomes inflamed, causing symptoms such as pain and fever. Because inflammation can cause serious complications, appendicitis is considered a medical emergency that may require surgery. Therefore, accurate and timely diagnosis of appendicitis is very important.
To diagnose appendicitis, health care providers (often primary care providers or emergency physicians) rely primarily on a physical examination, medical history evaluation, and clinical testing. Imaging methods such as a CT scan, MRI, or ultrasound may also be performed. Doing so can rule out other potential causes of appendicitis-like symptoms, including abdominal scarring, inflammatory bowel disease, and kidney stones.