Appendicitis

What the appendix is and why it gets inflamed

The appendix is a finger-shaped tube about 5 to 10 cm (2 to 4 inches) long attached to the start of the large intestine (the cecum). Its function is not fully understood; it may play a small role in immunity and gut bacteria. You can live normally without it.

Appendicitis usually starts when the opening of the appendix becomes blocked by:

• hardened stool (a fecalith)
• swollen lymph tissue, often after a viral infection
• rarely, a tumor, parasites or a foreign body

Mucus and bacteria build up behind the blockage, pressure rises, blood supply is cut off, and the wall becomes inflamed and infected. Without treatment, the wall can die and burst (perforate).

Symptoms of appendicitis

Classic pattern

1. Vague pain around the navel or upper belly, often mistaken for indigestion or gas
2. Loss of appetite, nausea and sometimes vomiting, usually after the pain starts
3. Over 12 to 24 hours, the pain moves to the lower right belly (a spot called McBurney's point, about a third of the way from the right hip bone to the navel) and becomes sharp and constant
4. Low-grade fever, typically 37.5 to 38.3 °C (99.5 to 101 °F)
5. Pain worse with walking, coughing, sneezing or bumps in the road

Other symptoms

• constipation, or mild diarrhea
• feeling the need to pass stool or gas that does not relieve the pain
• a swollen belly
• pain on urination, if the appendix lies near the bladder

Appendicitis pain location

Most people feel pain in the lower right abdomen. But the appendix can lie in different positions, so pain may be felt:

• in the lower back or right flank (appendix behind the bowel)
• low in the pelvis, causing bladder or rectal symptoms
• higher on the right side in pregnancy, as the growing womb pushes it upward

Appendicitis in children and older adults

Young children often cannot describe pain well. They may be irritable, refuse to eat, vomit, have a fever and walk bent over or not want to jump. Appendicitis is more likely to have ruptured by the time it is diagnosed in children under 5. Older adults may have milder pain, less fever and a slower, vaguer onset, which also delays diagnosis.

Appendicitis vs other causes of lower right belly pain

How appendicitis is diagnosed

There is no single test. Doctors combine:

• History and examination: tenderness at McBurney's point, pain on releasing pressure (rebound tenderness), guarding, and pain in the right lower belly when the left side is pressed (Rovsing's sign)
• Blood tests: raised white cell count and C-reactive protein
• Urine test: to rule out a urinary infection or kidney stone
• Pregnancy test in anyone who could be pregnant
• Imaging: - Ultrasound: first choice in children and pregnant women, as it avoids radiation - CT scan: the most accurate test in adults - MRI: in pregnancy when ultrasound is inconclusive

Scoring systems such as the Alvarado score or the Appendicitis Inflammatory Response score help decide who needs imaging or surgery.

Treatment

Appendectomy

Surgery to remove the appendix is the standard treatment.

• Laparoscopic (keyhole) appendectomy: done through 3 small cuts with a camera. Most people go home within 24 hours and return to normal activities in 1 to 2 weeks
• Open appendectomy: through a single larger cut, sometimes needed for a ruptured appendix or abscess

Antibiotics are given before surgery, and continued afterward if the appendix has burst.

Antibiotics instead of surgery

For uncomplicated appendicitis confirmed on CT (no rupture, abscess or appendicolith), antibiotics alone are a reasonable option for some adults. Studies such as the CODA trial found that about 7 in 10 people treated with antibiotics avoided surgery over the following months, but about 3 in 10 eventually needed an appendectomy. Discuss the trade-offs with your surgeon.

Ruptured appendix and abscess

A burst appendix causes peritonitis, infection spreading through the abdomen, or a walled-off abscess. Treatment includes IV antibiotics, drainage of any abscess with a needle under scan guidance, and surgery either immediately or several weeks later.

Complications

• Perforation (rupture): more likely after 48 to 72 hours of symptoms, and in young children and older adults
• Peritonitis: widespread infection of the abdominal lining, which can lead to sepsis
• Abscess
• After surgery: wound infection, bleeding, and rarely bowel blockage from adhesions later

Recovery after appendectomy

• Walk on the day of or day after surgery to speed recovery and prevent clots
• Use acetaminophen (paracetamol) or ibuprofen as advised for pain. Shoulder-tip pain after keyhole surgery comes from the gas used and fades in a day or two
• Avoid heavy lifting (more than about 10 lb or 4.5 kg) for 2 weeks after keyhole surgery, longer after open surgery
• Most people return to school or desk work in 1 to 2 weeks
• Call your surgeon for fever, worsening pain, redness or discharge from wounds, vomiting or inability to pass gas

Frequently asked questions

What are the early signs of appendicitis?

The earliest sign is usually a dull pain around the navel or upper belly, often with loss of appetite and nausea. Over the next 12 to 24 hours the pain moves to the lower right abdomen, becomes sharper and worsens with movement, and a low fever may develop.

Where is appendicitis pain located?

Typically in the lower right abdomen, about a third of the way between the right hip bone and the navel. It often starts near the navel first. In some people it is felt in the right flank, lower back or pelvis, and in pregnancy it can be higher on the right side.

How do I know if it is appendicitis or gas?

Gas pain is crampy, moves around and is relieved by passing gas or a bowel movement, and appetite is usually normal. Appendicitis pain becomes constant, settles in the lower right, gets worse with walking or coughing, and comes with loss of appetite and often fever. If unsure, get checked.

How long before an appendix bursts?

Rupture risk rises after about 48 to 72 hours from the start of symptoms, although it can happen sooner, especially in young children. This is why suspected appendicitis needs same-day assessment.

Can appendicitis be treated without surgery?

Some adults with uncomplicated appendicitis confirmed on a CT scan can be treated with antibiotics alone. About 3 in 10 later need surgery. Surgery remains standard for complicated appendicitis, and for most children and adults who prefer a definitive treatment.