Acute Appendicitis

This common presentation requires quick action to avoid complications

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Appendicitis is one of the most prevalent acute abdominal conditions, and it requires immediate medical attention. Patients with appendicitis often present with diffuse abdominal complaints, therefore it is important that NPs and PAs recognize the signs and symptoms of acute appendicitis, establish an appropriate diagnosis and refer the patient appropriately.


The appendix is a small worm-shaped projection at the junction of the small intestine and large intestine. Its exact function is unknown and its removal has no adverse health effects. The appendix may become obstructed and/or infected, leading to inflammation and ultimately appendicitis.1

Appendicitis may occur at any age, but it is most prevalent in the 10- to 19-year-old age group.2 In recent years, the number of cases in patients ages 30 to 69 has increased 6.3%.3 An increase in cases also has been documented in ethnic minorities, but this is likely due to changing demographics and enhanced census reporting.3 Men have a higher rate of appendicitis than women.2,3


Appendicitis is caused by a change in the normal flora of the appendix. It begins with a dilated appendix, which becomes obstructed by hardened feces, growths, the inflammatory process of other diseases, or trauma. The appendix continues to secret mucus, which becomes trapped as a result of the obstruction. This mucus production causes the normal flora in the appendix to multiply, resulting in an infection. The appendix continues to dilate and can impede blood flow, causing necrosis to the tissue. Or it may rupture, resulting in the spread of infection throughout the peritoneum.1,4


The diagnosis of appendicitis is based largely on the patient history and the results of the physical examination. The patient initially complains of an acute onset of mild to severe pain in the epigastric or periumbilical area of the abdomen. Within the first 24 hours, the pain shifts to the right lower quadrant (RLQ); this is the pain presentation classically associated with appendicitis. The patient often complains that the pain is worse with coughing or walking. Nausea and anorexia are common complaints after the onset of pain, and the patient may or may not experience associated vomiting.

A patient with severe chills or rigor and RLQ pain should raise clinical suspicion for appendix rupture and should be immediately transferred to the emergency department (ED). A patient with abrupt cessation of pain should also be treated as a medical emergency and transferred to the ED.

Very young and very old patients, as well as women of childbearing age, may have atypical or nonspecific presentations.1 In the aging population these symptoms can include indigestion, flatulence, bowel irregularity, diarrhea, abdominal distention, weakness and generalized malaise.1,5

In terms of objective evidence, the patient may or may not have hypertension and tachycardia; these are related to the degree of pain or fever experienced.1 Several tests can be performed in the office to facilitate a diagnosis of appendicitis. The sensitivity and specificity of these diagnostic maneuvers may be directly related to the experience of the practitioner.

The Rovsing sign is considered positive when deep palpation applied to the left lower quadrant results in increased RLQ pain upon release of the pressure. The Psoas sign is considered positive if increased pain is experienced in the RLQ when the patient raises the right leg against mild pressure from the practitioner. The obturator sign is positive if RLQ pain increases when the practitioner flexes the right knee and hip and then internally rotates the right leg in this position. McBurney sign is positive if the patient experiences pain when pressure is applied between the anterior superior spine of the ilium and the umbilicus.1,5 Table 1 shows the sensitivity and specificity for each of these signs.

Differential Diagnosis

A wide range of differential diagnoses can be included when considering appendicitis. These include, but are not limited to, the following:

  • urinary tract infection
  • Crohn disease
  • diverticulitis
  • cholelithiasis
  • pancreatitis
  • mesenteric adenitis
  • gastroenteritis
  • sexually transmitted diseases.

For women the differential diagnoses may also include:

  • pelvic inflammatory disease
  • ectopic pregnancy
  • ovarian cyst.

Diagnostic Testing

Histopathology is the only means of obtaining a definitive diagnosis of appendicitis. As a result, the rate of negative appendectomy (nonincidental removal of a normal appendix) continues to range between 20% and 40% worldwide.6 A number of scoring methods are available to assist in the diagnosis of appendicitis. Scoring can assist in discriminating between acute appendicitis and non-specific abdominal pain.7

The Alvarado Scoring System is based on three symptoms in the history, three signs in the physical assessment and two simple laboratory tests (Table 2). A score of 4 or less means the patient is at low risk of acute appendicitis. A score of 5 or 6 places the patient at a moderate risk and implies the need to be hospitalized for observation. A score of 7 or higher places the patient at high risk and requires a referral to a surgeon or ED for surgical intervention.6,7

Scoring systems are most useful in adults, but can be used for children with slight modifications to the testing parameters. Changes include a decrease in the score for leukocytosis and an increase in the score for rebound tenderness at the iliac fossa, which is elicited in children by having them hop or cough.8

If questions about the final diagnosis remain after a complete history and physical, lab testing and radiographic studies are required to rule out competing diagnoses. Although this type of testing generally occurs in the hospital, it is important for office-based NPs and PAs to have a working knowledge of the tests and the potential benefits and drawbacks.

According to Doria et al, the benefits of ultrasound over computed tomography (CT) are lower cost, lack of potentially harmful radiation, and no required preparation time. The advantages of CT over ultrasound include less operator reliance and better visualization regardless of disease or patient circumstance.9 The main disadvantage associated with the use of CT in children is exposure to radiation at a young age. Table 3 shows the ranges for the sensitivity and specificity of ultrasound and CT.


Once the diagnosis of appendicitis is made, the treatment is surgery.1 Timely referral is key. For most NPs and PAs in an outpatient setting, this will mean getting the patient to the ED. A phone call to the ED attending physician once the patient has left the office or clinic can provide him or her with vital information and expedite the triage procedure. Rupture of the appendix occurs in 17% to 40% of patients with appendicitis, and it can result in higher rates of mortality.1


After surgery the patient is usually discharged from the hospital the same day, provided no complications arise. If the appendix ruptured, the patient will be required to stay in the hospital for further treatment. Follow-up occurs with the surgeon, and the patient should return to have sutures removed 5 to 7 days after surgery. Education for the patient should include no heavy lifting for at least 2 weeks (possibly longer); signs of infection at the suture site; signs of complications; when to return to the hospital; instructions for early ambulation; and timing of return to a normal diet.1  


1. Thomas DJ. Abdominal Problems. In: Dunphy LM, et al, eds. Primary Care. The Art and Science of Advanced Practice Nursing. 3rd ed. Philadelphia, PA: FA Davis Company; 2011:555-557.

2. Partrick DA, et al. Increased CT scan utilization does not improve the diagnostic accuracy of appendicitis in children. J Pediatr Surg. 2003;38(5):659-662.

3. Buckius MT, et al. Changing epidemiology of acute appendicitis in the United States: study period 1993-2008. J Surg Res. 2012;175(2):185-190.

4. National Digestive Diseases Information Clearinghouse. Appendicitis. http://digestive.niddk.nih.gov/ddiseases/pubs/appendicitis/appendicitis.pdf

5. Black CE, et al. Acute appendicitis in adults: clinical manifestations and diagnosis. Available with subscription. UpToDate, 2012.

6. Dey S, et al. Alvarado scoring in acute appendicitis-a clinicopathological correlation. Indian J Surg. 2010;72(4):290-293.

7. Singh K, et al. Application of Alvarado scoring system in diagnosis of acute appendicitis. JK Science. 2008;10(2):84-86.

8. Shera AH, et al. Clinical scoring system for diagnosis of acute appendicitis in children. Indian J Pediatr. 2011;78(3):287-290.

9. Doria AS, et al. US or CT for diagnosis of appendicitis in children and adults? A meta-analysis. Radiology. 2006;241(1):83-94.

Erin McDonald is a family nurse practitioner. She has completed a disclosure statement and reports no relationships related to this article.


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