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Make the Diagnosis: Appendicitis, Adult

Prior Probability

The incidence of appendicitis among emergency patients with abdominal pain is up to 25% for patients younger than 60 years. For those older than 60 years, the incidence is up to 5%.

Populations for Whom Appendicitis Should be Considered

  • All patients with abdominal pain.

Detecting the Likelihood of Appendicitis Among Emergency Patients With Abdominal Pain in the RLQ

The Alvarado1 model is recommended as the most user-friendly while being among the most powerful. The details of the clinical decision rule are displayed in Table 5-6. Note that the MANTRELS mnemonic is helpful in that it is easy to remember and is organized according to medical history, physical examination, and laboratory data.

Table 5-6Operating Characteristics of the Alvarado Model

Reference Standard

Histologically proven diagnosis or no surgery after adequate follow-up (which allows the inference that appendicitis was not present).

Original Article: Does This Adult Patient Have Appendicitis?

Clinical Scenario

A 29-year-old patient presents to your office with abdominal pain and a fever. The patient was well until 1 day ago and had never experienced abdominal pain. A vague periumbilical pain awoke him from sleep 12 hours previously, and he soon developed anorexia, nausea, and vomiting. His wife consulted their family medical reference guide and then brought him to the office, concerned that his symptoms matched a description of appendicitis. The pain then migrated to the right lower quadrant (RLQ) and was much worse while he was riding in the car to the physician's office.

The patient's oral temperature is 37.8°C; the pulse rate and blood pressure are normal. He has RLQ tenderness, guarding but not rigidity, and rebound tenderness in the RLQ. A rectal examination reveals no tenderness, and he does not exhibit the psoas or obturator signs. Rovsing sign is positive.

Why Is This an Important Question to Answer With a Clinical Examination?

In western countries, appendicitis represents a common cause of acute abdominal pain. According to National Center for Health Statistics data, approximately 500 000 patients underwent appendectomies from 1979 to 1984. Individuals carry a 7% lifetime risk of developing appendicitis.1 The incidence of appendicitis causing abdominal pain depends on the clinical setting. In series from emergency departments or surgical services, 25% of patients younger than 60 years and evaluated for acute abdominal pain have acute appendicitis, whereas the incidence in those ...

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