Appendicitis overview

# Overview
Appendicitis is a condition characterized by inflammation of the appendix and is the most common abdominal surgical emergency. Symptoms of appendicitis include a brief history of nausea, anorexia, and generalized abdominal pain with an eventual migration of the pain to the right lower quadrant. Fever (higher than 37.3C) is more often present in infants and young children. CT is considered the diagnostic imaging test of choice for suspected appendicitis. Perforation of an inflamed appendix is seen in 15% to 25% of all patients treated surgically, with the highest rates seen in young children and elderly patients. Treatment of appendicitis depends on whether the patient presents with simple inflammation of an intact appendix or with a perforated appendix with or without abscess. Definitive treatment for patients with appendicitis is an appendectomy. Nonoperative treatment with antibiotics and expectant observation is an option for pediatric patients. If left untreated, mortality is high mainly due to peritonitis and shock.

# Historical Perspective
Appendicitis was first officially described by Reginald J. Fitz of Harvard University in 1886. Since that time, the appendectomy has become one of the most common surgical procedures. The laparoscopic appendectomy was invented in 1980, and has led to reduced length of hospital stay, a decreased risk of infection, and a reduction in post-operative pain.

# Classification
Appendicitis may be classified at two levels. As appendicitis often results from appendiceal obstruction leading to necrosis and infection, it may be categorized based on the cause of the obstruction or on whether it is perforating or non-perforating.

# Pathophysiology
Appendicitis is caused by the obstruction of the tubular space inside the appendix.  This initial problem is compounded into a cascade of events that lead to the inflammation of the appendix, the obstruction of the blood vessels supplying it, and infection.  Once these blood vessels are obstructed, appendiceal tissue starts to die and leak out its cellular components. The appendix will rupture and can eventually lead to death if not treated.

# Causes
Appendicitis is mainly caused by the retention and obstruction of fecal matter, parasitic or bacterial infections of the appendix, and by physical damage to the appendix.

# Differentiating Appendicitis from other Diseases
Appendicitis presents with pain near the navel, specifically the right lower quadrant of the abdomen.  Because it is mainly characterized by different variants in type of abdominal pain, appendicitis must be differentiated from other diseases and disorders causing similar symptoms. Appendicitis should further be differentiated depending on the patient's age group.

# Epidemiology and Demographics
Appendicitis is a common disease in both Europe and America with about 100 people per 100,000 per year developing cases of appendicitis.  Younger people, in the age group of 10-19, have the highest rates of developing appendicitis.  Males are more likely than females to develop appendicitis.  Whites are more likely than nonwhites to develop appendicitis.

# Risk Factors
Anyone can get appendicitis, but it is more common among people 10 to 30 years old. Appendicitis leads to more emergency abdominal surgeries than any other cause.

# Natural History, Complications and Prognosis
If left untreated, appendicitis can lead to death if peritonitis develops from the rupturing of the appendix.  Acute appendicitis that is evaluated and treated early with an appendectomy generally leads to no further complications and to a full recovery of the patient.

# Diagnosis

## History and Symptoms
Patients with appendicitis commonly present with pain near the navel that eventually localizes to the right iliac fossa, loss of appetite, fever, nausea, and vomiting.

## Physical Examination
Physical examination will mostly be focused on abdominal findings. The patient may be ill appearing, in pain, with a fever and mild tachycardia. Even minimal pressure on the abdomen may elicit a marked response from the patient due to pain.

## Laboratory Findings
Common electrolyte and biomarker indicators of appendicitis include leukocytosis, and a shift to the left in the segmented neutrophils.

## Diagnostic Scoring
The Alvarado score is the most widely used scoring based system in making a diagnosis of appendicitis.

## CT
CT scans are the diagnostic test of choice for detecting appendicitis.  They can provide critical information regarding the size of the appendix. CT scans are preferred over ultrasounds for the detection of appendicitis.

## MRI
Magnetic resonance imaging (MRI) has become the common technique for diagnosing appendicitis in children and pregnant patients.

## Ultrasound
Ultrasounds are a useful tool for diagnosing appendicitis.  There are some limitations to the information provided by ultrasounds, such as sometimes ultrasonographic images of the iliac fossa show no abnormalities despite the presence of appendicitis.

## Other Imaging Findings
Tc-99m labeled anti-CD15 antibodies can be used in nuclear imaging to confirm appendicitis.

# Treatment

## Medical Therapy
In combination with surgery, antibiotics given intravenously such as cefuroxime and metronidazole may be administered early to help kill bacteria and thus reduce the spread of infection in the abdomen and postoperative complications in the abdomen or wound. Equivocal cases may become more difficult to assess with antibiotic treatment and benefit from serial examinations. Nonsurgical treatment may be used if surgery is not available, if a person is not well enough to undergo surgery, or if the diagnosis is unclear. Some research suggests that appendicitis can get better without surgery. Nonsurgical treatment includes antibiotics to treat infection and a liquid or soft diet until the infection subsides. A soft diet is low in fiber and easily breaks down in the gastrointestinal tract.

## Surgery
Surgery is the most effective therapy in treating appendicitis. Appendicectomy, or laproscopic removal of the appendix are the most effective therapies in treating appendicitis. Laproscopic surgery is the preferred method of surgery due to reduced complications and recovery time for the patient.

## Prevention

## Cost-effectiveness of therapy
In cases of abdominal pain suspected to be appendicitis, imaging diagnostic methods are more cost-effective than physical exams to make accurate diagnostic decisions.