What Is Acute Appendicitis?

Woman with abdominal pain

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Acute means sudden (i.e., sudden onset of symptoms). The causes of acute appendicitis are said to involve factors causing a blockage. This blockage creates bacteria collection in the appendix, resulting in inflammation, infection, and/or severe pain in your lower right abdomen area. Untreated, acute appendicitis can cause the appendix to burst or rupture, causing bacteria to spill into your bloodstream, which can cause sepsis and even death. For this reason, acute appendicitis should always be treated as a medical emergency.

Read on to learn the difference between acute appendicitis and chronic appendicitis, including symptoms of acute appendicitis to watch for in adults and children, what causes appendicitis, how to get a diagnosis and treatment for appendicitis, the link between pregnancy and appendicitis, and what to expect in terms of recovery from appendicitis. 

Acute Appendicitis vs. Chronic Appendicitis

Acute appendicitis is the sudden onset of appendicitis. It comes on quickly, progresses to an emergency quickly, and is cause for immediate medical care. Acute appendicitis is cited as the most common abdominal surgical emergency in the world, with an annual incidence of 96.5 to 100 cases per 100,000 adults or 1 in 1,000 adults.

Chronic appendicitis symptoms of abdominal pain are the same but are said to be milder than acute appendicitis. These symptoms can come and go over weeks, months, and years.

Although chronic appendicitis is not seen as an immediate medical emergency, it’s important to see your healthcare provider about abdominal pain as it can lead to acute appendicitis. 

Acute Appendicitis Symptoms

The most common symptom of acute appendicitis is abdominal pain in the lower right abdomen area where your appendix is located. Symptoms tend to come on quickly and worsen quickly, too. 

Symptoms in Adults vs. Children

It was previously thought that classic symptoms of acute appendicitis were less present in cases of appendicitis in children than in adults and that children generally had a delayed presentation of symptoms compared to adults.

One study examined symptoms in 210 children and 744 adults and found that contrary to traditional teaching, diagnosing acute appendicitis in children and adults is more similar than not. Specifically, researchers didn’t find delayed presentation of symptoms in children.

Common symptoms of acute appendicitis and burst appendix include:

  • Abdominal pain that worsens when you breathe, move, sneeze, or cough
  • Swollen abdomen (particularly the lower right side which is tender to the touch)
  • Constipation or diarrhea
  • Additional digestive discomfort from not being able to pass gas
  • Loss of appetite 
  • Nausea or vomiting
  • Low-grade fever or fever between 100° F to 101° F (37.7° C to 38.3° C) 

What Causes Acute Appendicitis

Acute appendicitis is caused by a blockage inside it or outside it between the appendix and the large intestine. Inside the appendix, blockages can be caused by bacteria, viruses, or parasites like intestinal worms. Outside the appendix, the blockage can be caused by hard stools (severe constipation) or tumor growth.

Blockage can begin to cut off blood flow to the appendix; without treatment, it can burst or lose all functionality (i.e., die). If acute appendicitis leads to rupture, stool, mucus, and infection can spread to the bloodstream. Risk of a serious infection known as peritonitis increases.

How Common Is Acute Appendicitis? 

Specifically in the US, acute appendicitis carries a lifetime risk of 8.6% in males and 6.7% in females.

How Serious Is Acute Appendicitis?

Acute appendicitis is always a serious and immediate medical emergency and should be responded to as such. Someone with acute appendicitis is at risk of their appendix bursting, leading to serious infection, health complications, and even death. With acute appendicitis, the appendix can rupture or tear within as little as 48 to 72 hours after you first experience symptoms. This is why seeking immediate care from your healthcare provider or emergency department is critical.

Diagnosis & Treatment of Acute Appendicitis

The sudden onset of severe abdominal pain (the kind that wakes you from sleep) is a telltale sign to see a healthcare provider for an accurate diagnosis. 

Acute appendicitis is diagnosed based on a:

  • Physical exam, which includes pressing on the lower right side of your abdomen to test for your reaction
  • Health history involving questions about any previous abdominal pains or digestive disorders
  • Basic blood panel to test for infection 
  • C-reactive protein blood test to check for other causes of inflammation
  • Urine test analysis to test for infection or pregnancy 

Additionally, your healthcare provider may request the following further diagnostic tests:

  • Abdominal ultrasound to check for noticeable blockage and how blood is flowing
  • Computerized tomography (CT) scan to check surrounding bones, muscles, fats, and organs
  • Magnetic resonance imaging (MRI) scan instead of CT if you have a pregnancy 

Treatment of acute appendicitis typically requires surgically removing the appendix (i.e., an appendectomy). This remains the same whether or not your appendix bursts. The surgeons will remove your appendix anyways to prevent future cases of appendicitis.


The main complication from acute appendicitis is a ruptured or burst appendix. If your appendix bursts, it opens a path for infection to spread.  

Other complications include:

  • Abscess or pus-filled pockets resulting from infection
  • Sepsis if bacteria gets into bloodstream 
  • Peritonitis (severe abdominal infection)

Both sepsis and peritonitis are serious medical emergencies that can result in death if not treated promptly. 

There is no known way to prevent acute appendicitis or appendix rupture, but getting to the emergency room as soon as you detect symptoms is the best way to help reduce the risk of complications associated with acute appendicitis.

Acute Appendicitis and Pregnancy

Acute appendicitis is the most common surgical problem experienced in pregnancy. The diagnosis, though, is complicated by pregnancy symptoms which cause abdominal and digestive discomfort. It’s also been suggested that pregnant persons experience less pain from acute appendicitis, and the area is less tender than in other people.

Delayed diagnosis may be behind the high incidence of burst appendixes in the third trimester in this population. If you are pregnant and experiencing abdominal pain, be sure not to assume the symptoms are associated and seek medical attention.

What Is the Difference Between Appendicitis and Acute Appendicitis?

The main difference between appendicitis and acute appendicitis is the onset time of symptoms. When experiencing any acute form of an illness, the symptoms will come on quickly and intensely. You won’t be able to ignore the pain as a nagging or discomforting sensation; it will be unlike other abdominal pains.

Appendicitis typically refers to chronic appendicitis or appendicitis that is milder but with ongoing and fluctuating symptoms that can progress to acute appendicitis and medical emergencies. 


The outlook for people with acute appendicitis who seek immediate medical care is excellent. You can live a healthy life without your appendix. If your appendix bursts, though, recovering from acute appendicitis will take a little longer, and treating for potential infection with antibiotics may be necessary.


Acute appendicitis is a sudden onset of severe abdominal pain and symptoms of infection caused by a blockage. The appendix may be blocked by bacteria, viruses, or parasites or be obstructed by stool, or, less likely, a tumor. Acute appendicitis is always a medical emergency because it progresses quickly and can lead to appendix rupture. If your appendix bursts, it can cause serious infections and be fatal. Therefore, immediate treatment, which involves surgical removal of the appendix, and may include antibiotic treatment to remedy or prevent infection, is critical to avoid complications.

9 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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By Michelle Pugle
Michelle Pugle, BA, MA, is an expert health writer with nearly a decade of contributing accurate and accessible health news and information to authority websites and print magazines. Her work focuses on lifestyle management, chronic illness, and mental health. Michelle is the author of Ana, Mia & Me: A Memoir From an Anorexic Teen Mind.