Appendicitis is either infection or inflammation of the appendix, a pinkie-sized organ at the junction of the small and large intestines, whose function is unclear.

Acute appendicitis is the most common surgical emergency in children and adolescents. Overall, there are about 250,000 cases of appendicitis in the United States annually, and the majority occurs in children 6- to 10-years-old. Appendicitis affects males more often than females (M:F ratio is 3:2) and the lifetime risk for each group is 8.6% and 6.7%, respectively. Caucasians are affected more commonly than other racial groups. Acute appendicitis occurs more frequently during the summer months.

What Causes Appendicitis?

The infection or inflammation occurs when the opening of the tube becomes obstructed by very hard fecal matter (stool), thick dried mucus or, in rare cases, parasites or tumors. The most common cause of obstruction is hard stool.

How Is Appendicitis Diagnosed?

A good history and physical examination is the best way to begin diagnosis. Follow-up examinations by the same person are perhaps the most accurate diagnostic tool.

Blood tests may be very helpful. A white blood cell count of more than 10,000 is found in more than 90% of children with acute appendicitis. A urinalysis may also be helpful to differentiate the problem from a urinary tract issue.

An abdominal ultrasound uses high-frequency sound waves to show images of blood vessels, organs and tissues may be helpful to pinpoint inflammation or perforation, and a computed tomography (CT), a combination of x-rays and computer technology, may also be useful. This is especially true in situations when the diagnosis is unclear, such as in severely obese patients and patients presenting late and suspected of having abscesses.

What Are the Symptoms of Appendicitis?

Appendicitis can affect any age group. Although exceptionally rare in newborns and infants, acute appendicitis does occasionally occur at that young age, and diagnosis may be extremely difficult and delayed. In slightly older children, the first signs and symptoms are variable, sometimes making it difficult to diagnose. Loss of appetite is usually the first symptom. Then the child frequently reports a dull, vague pain in the belly button area that may gradually migrate to the right lower abdomen. Children typically report a gradual increase in the pain.

If the appendix is located in a place other than where it is usually found, the pain may likewise vary in location. For example, if the inflamed appendix is near the ureter or bladder, the child may have urinary tract symptoms such as having to urinate frequently and/or painful urination.

Nausea and mild vomiting usually develop within a few hours after the pain appears. Diarrhea may also occur. Severe gastrointestinal (GI) symptoms that develop prior to the onset of pain usually indicate a diagnosis other than acute appendicitis. However, mild GI complaints such as indigestion or change in bowel habits may sometime precede the pain. 

Typically, patients with uncomplicated appendicitis have low-grade fever. Temperatures above 101.5°F suggest that the appendix may have already burst. Children with appendicitis avoid movement and tend to lie still in bed. Frequently, they lie quietly on their sides or with their knees flexed. They sometimes walk with a limp, favoring the right leg.

Left untreated, the tissues of the blocked appendix soon begin to die (gangrene) and will perforate (burst), causing peritonitis, a serious, potentially deadly infection in the child's abdomen.

What Is the Treatment for Appendicitis?

Although spontaneous resolution can sometimes occur, surgical removal of the appendix is still the best treatment for patients suspected of having acute appendicitis. In uncomplicated situations, the child typically receives preoperative and postoperative antibiotics for only 24 hours and is usually discharged from the hospital in 24–48 hours. Most children resume normal activity and may return to school in as little as 4–5 days.

For children who are brought for examination several days or weeks after symptoms have begun, treatment is more complex and less standard. Some may have immediate surgery while others are better served by receiving 2–3 weeks of intravenous antibiotic therapy and/or CT-guided abscess drainage. If surgery is not done initially, an elective interval appendectomy is usually performed 4–6 weeks later, but may not be necessary.

For perforated or gangrenous appendicitis, a five-day course of antibiotics is often recommended; however, many surgeons stop postoperative antibiotics when the recovering patient is free of fever and has a normal white blood cell count.

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