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Appendicitis is an inflammation of the appendix, which is the worm-shaped pouch attached to the cecum, the beginning of the large intestine. The appendix has no known function in the body, but it can become diseased. Appendicitis is a medical emergency, and if it is left untreated the appendix may rupture and cause a potentially fatal infection.


Appendicitis is the most common abdominal emergency found in children and young adults. One person in 15 develops appendicitis in his or her lifetime. The incidence is highest among males aged 10-14, and among females aged 15-19. More males than females develop appendicitis between puberty and age 25. It is rare in the elderly and in children under the age of two.
The hallmark symptom of appendicitis is increasingly severe abdominal pain. Since many different conditions can cause abdominal pain, an accurate diagnosis of appendicitis can be difficult. A timely diagnosis is important, however, because a delay can result in perforation, or rupture, of the appendix. When this happens, the infected contents of the appendix spill into the abdomen, potentially causing a serious infection of the abdomen called peritonitis.
Other conditions can have similar symptoms, especially in women. These include pelvic inflammatory disease, ruptured ovarian follicles, ruptured ovarian cysts, tubal pregnancies, and endometriosis. Various forms of stomach upset and bowel inflammation may also mimic appendicitis.
The treatment for acute (sudden, severe) appendicitis is an appendectomy, surgery to remove the appendix. Because of the potential for a life-threatening ruptured appendix, persons suspected of having appendicitis are often taken to surgery before the diagnosis is certain.

Causes and symptoms

The causes of appendicitis are not well understood, but it is believed to occur as a result of one or more of these factors: an obstruction within the appendix, the development of an ulceration (an abnormal change in tissue accompanied by the death of cells) within the appendix, and the invasion of bacteria.
Under these conditions, bacteria may multiply within the appendix. The appendix may become swollen and filled with pus (a fluid formed in infected tissue, consisting of while blood cells and cellular debris), and may eventually rupture. Signs of rupture include the presence of symptoms for more than 24 hours, a fever, a high white blood cell count, and a fast heart rate. Very rarely, the inflammation and symptoms of appendicitis may disappear but recur again later.
The distinguishing symptom of appendicitis is pain beginning around or above the navel. The pain, which may be severe or only achy and uncomfortable, eventually moves into the right lower corner of the abdomen. There, it becomes more steady and more severe, and often increases with movement, coughing, and so forth. The abdomen often becomes rigid and tender to the touch. Increasing rigidity and tenderness indicates an increased likelihood of perforation and peritonitis.
Loss of appetite is very common. Nausea and vomiting may occur in about half of the cases and occasionally there may be constipation or diarrhea. The temperature may be normal or slightly elevated. The presence of a fever may indicate that the appendix has ruptured.


A careful examination is the best way to diagnose appendicitis. It is often difficult even for experienced physicians to distinguish the symptoms of appendicitis from those of other abdominal disorders. Therefore, very specific questioning and a thorough physical examination are crucial. The physician should ask questions, such as where the pain is centered, whether the pain has shifted, and where the pain began. The physician should press on the abdomen to judge the location of the pain and the degree of tenderness.
The typical sequence of symptoms is present in about 50% of cases. In the other half of cases, less typical patterns may be seen, especially in pregnant women, older patients, and infants. In pregnant women, appendicitis is easily masked by the frequent occurrence of mild abdominal pain and nausea from other causes. Elderly patients may feel less pain and tenderness than most patients, thereby delaying diagnosis and treatment, and leading to rupture in 30% of cases. Infants and young children often have diarrhea, vomiting, and fever in addition to pain.
While laboratory tests cannot establish the diagnosis, an increased white cell count may point to appendicitis. Urinalysis may help to rule out a urinary tract infection that can mimic appendicitis.

Key terms

Appendectomy (or appendicectomy) — Surgical removal of the appendix.
Appendix — The worm-shaped pouch attached to the cecum, the beginning of the large intestine.
Laparotomy — Surgical incision into the loin, between the ribs and the pelvis, which offers surgeons a view inside the abdominal cavity.
Peritonitis — Inflammation of the peritoneum, membranes lining the abdominal pelvic wall.
Patients whose symptoms and physical examination are compatible with a diagnosis of appendicitis are usually taken immediately to surgery, where a laparotomy (surgical exploration of the abdomen) is done to confirm the diagnosis. In cases with a questionable diagnosis, other tests, such as a computed tomography scan (CT) may be performed to avoid unnecessary surgery. An ultrasound examination of the abdomen may help to identify an inflamed appendix or other condition that would explain the symptoms. Abdominal x-rays are not of much value except when the appendix has ruptured.
Often, the diagnosis is not certain until an operation is done. To avoid a ruptured appendix, surgery may be recommended without delay if the symptoms point clearly to appendicitis. If the symptoms are not clear, surgery may be postponed until they progress enough to confirm a diagnosis.
When appendicitis is strongly suspected in a woman of child-bearing age, a diagnostic laparoscopy (an examination of the interior of the abdomen) is sometimes recommended before the appendectomy in order to be sure that a gynecological problem, such as a ruptured ovarian cyst, is not causing the pain. In this procedure, a lighted viewing tube is inserted into the abdomen through a small incision around the navel.
A normal appendix is discovered in about 10-20% of patients who undergo laparotomy, because of suspected appendicitis. Sometimes the surgeon will remove a normal appendix as a safeguard against appendicitis in the future. During the surgery, another specific cause for the pain and symptoms of appendicitis is found for about 30% of these patients.


The treatment of appendicitis is an immediate appendectomy. This may be done by opening the abdomen in the standard open appendectomy technique, or through laparoscopy. In laparoscopy, a smaller incision is made through the navel. Both methods can successfully accomplish the removal of the appendix. It is not certain that laparoscopy holds any advantage over open appendectomy. When the appendix has ruptured, patients undergoing a laparoscopic appendectomy may have to be switched to the open appendectomy procedure for the successful management of the rupture. If a ruptured appendix is left untreated, the condition is fatal.


Appendicitis is usually treated successfully by appendectomy. Unless there are complications, the patient should recover without further problems. The mortality rate in cases without complications is less than 0.1%. When an appendix has ruptured, or a severe infection has developed, the likelihood is higher for complications, with slower recovery, or death from disease. There are higher rates of perforation and mortality among children and the elderly.


Appendicitis is probably not preventable, although there is some indication that a diet high in green vegetables and tomatoes may help prevent appendicitis.



Van Der Meer, Antonia. "Do You Know the Warning Signs of Appendicitis?" Parents Magazine (April 1997): 49.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.


inflammation of the vermiform appendix, a serious disease that usually requires surgical removal (appendectomy). When performed early the operation is comparatively simple and safe. When the appendix becomes inflamed and infected, rupture may occur within a matter of hours. Rupture of the appendix leads to peritonitis, one of the most serious of all diseases, although its danger has been reduced by antibacterial agents.
Cause. If the tubelike appendix becomes plugged by a hard bit of fecal matter or by intestinal worms, or becomes inflamed from other causes, normal drainage cannot take place. Because the appendix is chiefly lymphatic tissue, an infection that produces enlarged lymph nodes elsewhere in the body also can increase the glandular tissue in the appendix and obstruct its lumen. Narrowing of the lumen makes the pouchlike organ more susceptible to bacterial infection. Escherichia coli and other types of bacteria multiply and cause inflammation and infection that spread to the peritoneal cavity unless the body's defenses are able to overcome the infection or the appendix is removed before it ruptures.
Symptoms. The classic symptoms of appendicitis are pain, nausea, vomiting, and low-grade fever in adults. Children tend to have higher fevers. The pain typically begins in the umbilical region and eventually localizes in the right lower quadrant of the abdomen over the site of the appendix. The pain is persistent and is aggravated by motion, causing the patient to bend over and tense the abdominal muscles (muscle guarding). Rebound pain occurs when the abdomen is deeply palpated and the hand is quickly removed from the abdomen. The patient also can feel pain in the area of the appendix when either a rectal or pelvic examination is done.

Other data that may support a diagnosis of appendicitis are obtained through a blood cell count. An elevated white cell count (leukocytosis) commonly accompanies appendicitis as it does other kinds of inflammation. Mild leukocytosis of 14,000 to 16,000 per mm3 is common. A white cell count higher than 20,000 per mm3 suggests a ruptured appendix and peritonitis.

Other diseases that can be mistaken for appendicitis are gallbladder attacks and kidney infection on the right side. The onset of pneumonia, rheumatic fever, or diabetic ketoacidosis can imitate appendicitis. In women, there is the possibility of a ruptured ectopic pregnancy, a twisted ovarian cyst, or a hemorrhaging ovarian follicle at the middle of the menstrual cycle.
Patient Care. When appendicitis is suspected because of symptoms exhibited by the patient, a health care provider should be notified immediately. The patient should lie down and remain as quiet as possible. It is best to give him nothing by mouth, and because of the danger of aggravating the condition and possibly causing rupture of the appendix, cathartics and laxatives are contraindicated. Applications of heat and the administration of laxatives or enemas are contraindicated for the same reasons. After the patient has been assessed and a diagnosis of appendicitis has been established, appendectomy will probably be performed as soon as possible.

During the preoperative phase it may be necessary to hydrate the patient with intravenous fluid therapy, especially when there has been prolonged nausea and vomiting. Decompression of the intestinal contents by suction via a nasogastric tube is also necessary in some cases.

Postoperative care is usually uneventful. The exception is when there has been a ruptured appendix; this serious condition warrants diligent and aggressive nursing care to overcome the effects of peritonitis with the resultant shifting of body fluids, hypovolemia (which can be life-threatening), and septic shock. Antibacterial drugs are administered to combat the infection. Gastric and intestinal decompression is maintained, and most surgeons advocate intraperitoneal draining by means of Penrose drains in order to prevent formation of abscesses and promote healing. The most common complications of appendectomy and peritonitis are (1) infection of the surgical wound, (2) paralytic ileus due to irritation of the small bowel, (3) abscesses, and (4) obstruction and adhesions.

Ongoing assessment of the patient includes observing the type and amount of drainage from the intestinal tract via the nasogastric tube and from the Penrose drain in the wound; appearance of the surgical incision; dressings applied and the frequency with which they are changed; evidence that bowel function is returning to normal, e.g., presence of bowel sounds, passing of flatus and fecal material; measurement of intake and output; tolerance of foods and liquids once the nasogastric tube is removed and decompression discontinued; and tolerance for physical activity, coughing and deep breathing, positioning, and postoperative exercises.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


Inflammation of the vermiform appendix.
[appendix + G. -itis, inflammation]
Farlex Partner Medical Dictionary © Farlex 2012


Inflammation of the vermiform appendix.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


Inflammation of the vermiform appendix, most common in children.
Clinical findings
Right lower quadrant pain of acute onset; rebound tenderness over McBurney’s point in right lower quadrant; fever, anorexia, constipation, diarrhoea, nausea, vomiting.
Increased WBCs, left shift of WBCs, increased ESR.
History, physical exam, ultrasound, CT.
Many cases eventually rupture; regression is rare.
Rupture, purulent peritonitis; if untreated, death.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.


Surgery Inflammation of the vermiform appendix which is most common in children Clinical Right lower quadrant pain of acute onset, rebound tenderness over McBurney's point in right hypogastrium, fever, anorexia, constipation, diarrhea, N&V Lab ↑ WBCs, left shift of WBCs, ↑ ESR Diagnosis Hx, PE, ultrasound, CT Management Appendectomy Complications Rupture, purulent peritonitis; untreated, death. See Appendix. Cf Left-sided appendicitis.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


Inflammation of the vermiform appendix.
[appendix + G. -itis, inflammation]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012


Acute inflammation of the blind-ended ‘vermiform’ APPENDIX. The condition usually starts with central abdominal pain and slight fever. Vomiting may occur. The pain then shifts to the lower right corner of the abdomen and increases in severity. It is made worse by movement or coughing. There is considerable local tenderness and either constipation or slight diarrhoea may occur. The main danger is rupture of an obstructed appendix, release of the contents into the abdominal cavity, and PERITONITIS. Treatment usually involves an operation to remove the inflamed appendix, but conservative management is sometimes appropriate. The diagnosis is not always easy. CT scanning has been found helpful.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005


Inflammation of the vermiform appendix.
[appendix + G. -itis, inflammation]
Medical Dictionary for the Dental Professions © Farlex 2012

Patient discussion about appendicitis

Q. How is Acute Appendicitis Diagnosed? My doctor sent me to the emergency room because he thought I might have acute appendicitis. What are the symptoms and how is it diagnosed?

A. The symptoms of acute appendicitis can be misleading at first, because they are very unspecific. Usually the patient arrives with abdominal pain, that is "classicaly" located in the lower right side of the abdomen. However, sometimes the pain can't be located at a certain location. The pain tends to increase within hours, and become intolerable, to a point where the patient seeks medical care. Other common symptoms are nausea, vomiting, lack of appetite and fever. The diagnosis is usually made clinically by physical examination. In some cases a CT-scan is performed as well.

Q. What Causes Acute Appendicitis? I've heard that appendicitis is a very common situation. What causes it to happen? Is there a way to avoid it?

A. Appendicitis is caused by an infection of the appendix, usually from bacterias that are already located in the abdomen. It is not a situation that can be avoided and can occur in a high prevalence in the population.

Q. What happens if you leave appendicitis alone? I have symptoms of appendicitis, but I don't want to go to the hospital. What should I do? and what could happen?

A. If you have symptoms of appendicitis you should see a doctor immediately, because the major complication of an untreated appendix is rupture and infection of the entire abdomen, that can lead to generalized sepsis.

More discussions about appendicitis
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References in periodicals archive ?
La torsion de la trompa, a pesar de ser menos frecuente que patologias como apendicitis, debe incluirse entre los diagnosticos diferenciales de dolor abdominal bajo, de aparicion aguda, con o sin masa anexial en mujeres independientemente de la edad.
Su biografa Petrement narra el inicio temprano de este problema, cuando a los 11 meses de nacida sufre apendicitis, como meses antes, su madre.
Asi, el protozoario ciliado Balantidium coli, aunque por lo general se presenta de manera asintomatica, en los seres humanos provoca diarrea con disenteria, peritonitis, apendicitis, hemorragia pulmonar e inclusive el deceso del individuo [28].