Appendicitis Clinical Presentation

Variations in the position of the appendix, age of the patient, and degree of inflammation make the clinical presentation of appendicitis notoriously inconsistent. Statistics report that 1 of 5 cases of appendicitis is misdiagnosed; however, a normal appendix is found in 15-40% of patients who have an emergency appendectomy.

Niwa et al reported an interesting case of a young woman with recurrent pain in who was referred for appendicitis, treated with antibiotics, and was found to have an appendiceal diverticulitis associated with a rare pelvic pseudocyst at laparotomy after 12 months.^[2] Her condition was probably due to diverticular perforation of the pseudocyst.

Symptoms

The classic history of anorexia and periumbilical pain followed by nausea, right lower quadrant (RLQ) pain, and vomiting occurs in only 50% of cases. Nausea is present in 61-92% of patients; anorexia is present in 74-78% of patients. Neither finding is statistically different from findings in patients who present to the emergency department with other etiologies of abdominal pain. In addition, when vomiting occurs, it nearly always follows the onset of pain. Vomiting that precedes pain is suggestive of intestinal obstruction, and the diagnosis of appendicitis should be reconsidered. Diarrhea or constipation is noted in as many as 18% of patients and should not be used to discard the possibility of appendicitis.

The most common symptom of appendicitis is abdominal pain. Typically, symptoms begin as periumbilical or epigastric pain migrating to the right lower quadrant (RLQ) of the abdomen. This pain migration is the most discriminating feature of the patient's history, with a sensitivity and specificity of approximately 80%, a positive likelihood ratio of 3.18, and a negative likelihood ratio of 0.5.^[3] Patients usually lie down, flex their hips, and draw their knees up to reduce movements and to avoid worsening their pain. Later, a worsening progressive pain along with vomiting, nausea, and anorexia are described by the patient. Usually, a fever is not present at this stage.

The duration of symptoms is less than 48 hours in approximately 80% of adults but tends to be longer in elderly persons and in those with perforation. Approximately 2% of patients report duration of pain in excess of 2 weeks. A history of similar pain is reported in as many as 23% of cases, but this history of similar pain, in and of itself, should not be used to rule out the possibility of appendicitis.

In addition to recording the history of the abdominal pain, obtain a complete summary of the recent personal history surrounding gastroenterologic, genitourinary, and pneumologic conditions, as well as consider gynecologic history in female patients. An inflamed appendix near the urinary bladder or ureter can cause irritative voiding symptoms and hematuria or pyuria. Cystitis in male patients is rare in the absence of instrumentation. Consider the possibility of an inflamed pelvic appendix in male patients with apparent cystitis. Also consider the possibility of appendicitis in pediatric or adult patients who present with acute urinary retention.^[4]

It is important to remember that the position of the appendix is variable. Of 100 patients undergoing 3-dimensional (3-D) multidetector computed tomography (MDCT) scanning, the base of the appendix was located at the McBurney point in only 4% of patients; in 36%, the base was within 3 cm of the point; in 28%, it was 3-5 cm from that point; and, in 36% of patients, the base of the appendix was more than 5 cm from the McBurney point.^[5]

The most specific physical findings in appendicitis are rebound tenderness, pain on percussion, rigidity, and guarding. Although RLQ tenderness is present in 96% of patients, this is a nonspecific finding. Rarely, left lower quadrant (LLQ) tenderness has been the major manifestation in patients with situs inversus or in patients with a lengthy appendix that extends into the LLQ. Tenderness on palpation in the RLQ over the McBurney point is the most important sign in these patients.

A careful physical examination, not limited to the abdomen, must be performed in any patient with suspected appendicitis. Gastrointestinal (GI), genitourinary, and pulmonary systems must be studied. Male infants and children occasionally present with an inflamed hemiscrotum due to migration of an inflamed appendix or pus through a patent processus vaginalis. This is often initially misdiagnosed as acute testicular torsion. In addition, perform a rectal examination in any patient with an unclear clinical picture, and perform a pelvic examination in all women with abdominal pain.

According to the American College of Emergency Physicians (ACEP) 2010 clinical policy update, clinical signs and symptoms should be used to stratify patient risk and to choose next steps for testing and management.^{[6, 7]}

Accessory signs

In a minority of patients with acute appendicitis, some other signs may be noted. However, their absence never should be used to rule out appendiceal inflammation. The Rovsing sign (RLQ pain with palpation of the LLQ) suggests peritoneal irritation in the RLQ precipitated by palpation at a remote location. The obturator sign (RLQ pain with internal and external rotation of the flexed right hip) suggests that the inflamed appendix is located deep in the right hemipelvis. The psoas sign (RLQ pain with extension of the right hip or with flexion of the right hip against resistance) suggests that an inflamed appendix is located along the course of the right psoas muscle.

The Dunphy sign (sharp pain in the RLQ elicited by a voluntary cough) may be helpful in making the clinical diagnosis of localized peritonitis. Similarly, RLQ pain in response to percussion of a remote quadrant of the abdomen, or to firm percussion of the patient's heel, suggests peritoneal inflammation.

The Markle sign, pain elicited in a certain area of the abdomen when the standing patient drops from standing on toes to the heels with a jarring landing, was studied in 190 patients undergoing appendectomy and found to have a sensitivity of 74%.^[8]

Rectal examination

There is no evidence in the medical literature that the digital rectal examination (DRE) provides useful information in the evaluation of patients with suspected appendicitis; however, failure to perform a rectal examination is frequently cited in successful malpractice claims. In 2008, Sedlak et al studied 577 patients who underwent DRE as part of an evaluation for suspected appendicitis and found no value as a means of distinguishing patients with and without appendicitis.^[9]

The incidence of appendicitis is unchanged in pregnancy relative to the general population, but the clinical presentation is more variable than at other times.

During pregnancy, the appendix migrates in a counterclockwise direction toward the right kidney, rising above the iliac crest at about 4.5 months' gestation. RLQ pain and tenderness dominate in the first trimester, but in the latter half of pregnancy, right upper quadrant (RUQ) or right flank pain must be considered a possible sign of appendiceal inflammation.

Nausea, vomiting, and anorexia are common in uncomplicated first trimester pregnancies, but their reappearance later in gestation should be viewed with suspicion.

Several investigators have created diagnostic scoring systems to predict the likelihood of acute appendicitis. In these systems, a finite number of clinical variables is elicited from the patient and each is given a numeric value; then, the sum of these values is used.

The best known of these scoring systems is the MANTRELS score, which tabulates migration of pain, anorexia, nausea and/or vomiting, tenderness in the RLQ, rebound tenderness, elevated temperature, leukocytosis, and shift to the left (see Table 1).^[10]

Table 1. MANTRELS Score (Open Table in a new window)

Clinical scoring systems are attractive because of their simplicity; however, none has been shown prospectively to improve on the clinician's judgment in the subset of patients evaluated in the emergency department (ED) for abdominal pain suggestive of appendicitis. The MANTRELS score, in fact, was based on a population of patients hospitalized for suspected appendicitis, which differs markedly from the population seen in the ED.

In reviewing the records of 150 ED patients who underwent abdominopelvic computed tomography (CT) scanning to rule out appendicitis, McKay and Shepherd suggested that patients with an MANTRELS score of 0-3 could be discharged without imaging, that those with scores of 7 or above receive surgical consultation, and those with scores of 4-6 undergo CT evaluation.^[11] The investigators found that patients with a MANTRELS score of 3 or lower had a 3.6% incidence of appendicitis, patients with scores of 4-6 had a 32% incidence of appendicitis, and patients with scores of 7-10 had a 78% incidence of appendicitis.^[11]

In another study, Schneider et al concluded that the MANTRELS score was not sufficiently accurate to be used as the sole method for determining the need for appendectomy in the pediatric population.^[12] These investigators, studied 588 patients aged 3-21 years and found that a MANTRELS score of 7 or greater had a positive predictive value of 65% and a negative predictive value of 85%.

Scoring systems and computer-aided diagnosis

Computer-aided diagnosis consists of using retrospective data of clinical features of patients with appendicitis and other causes of abdominal pain and then prospectively assessing the risk of appendicitis. Computer-aided diagnosis can achieve a sensitivity greater than 90% while reducing rates of perforation and negative laparotomy by as much as 50%.

However, the principle disadvantages to this method are that each institution must generate its own database to reflect characteristics of its local population, and specialized equipment and significant initiation time are required. In addition, computer-aided diagnosis is not widely available in US EDs.

The stages of appendicitis can be divided into early, suppurative, gangrenous, perforated, phlegmonous, spontaneous resolving, recurrent, and chronic.

Early stage appendicitis

In the early stage of appendicitis, obstruction of the appendiceal lumen leads to mucosal edema, mucosal ulceration, bacterial diapedesis, appendiceal distention due to accumulated fluid, and increasing intraluminal pressure. The visceral afferent nerve fibers are stimulated, and the patient perceives mild visceral periumbilical or epigastric pain, which usually lasts 4-6 hours.

Suppurative appendicitis

Increasing intraluminal pressures eventually exceed capillary perfusion pressure, which is associated with obstructed lymphatic and venous drainage and allows bacterial and inflammatory fluid invasion of the tense appendiceal wall. Transmural spread of bacteria causes acute suppurative appendicitis. When the inflamed serosa of the appendix comes in contact with the parietal peritoneum, patients typically experience the classic shift of pain from the periumbilicus to the right lower abdominal quadrant (RLQ), which is continuous and more severe than the early visceral pain.

Gangrenous appendicitis

Intramural venous and arterial thromboses ensue, resulting in gangrenous appendicitis.

Perforated appendicitis

Persisting tissue ischemia results in appendiceal infarction and perforation. Perforation can cause localized or generalized peritonitis.

Phlegmonous appendicitis or abscess

An inflamed or perforated appendix can be walled off by the adjacent greater omentum or small-bowel loops, resulting in phlegmonous appendicitis or focal abscess.

Spontaneously resolving appendicitis

If the obstruction of the appendiceal lumen is relieved, acute appendicitis may resolve spontaneously.^{[13, 14]} This occurs if the cause of the symptoms is lymphoid hyperplasia or when a fecalith is expelled from the lumen.

Recurrent appendicitis

The incidence of recurrent appendicitis is 10%. The diagnosis is accepted as such if the patient underwent similar occurrences of RLQ pain at different times that, after appendectomy, were histopathologically proven to be the result of an inflamed appendix.

Chronic appendicitis

Chronic appendicitis occurs with an incidence of 1% and is defined by the following: (1) the patient has a history of RLQ pain of at least 3 weeks’ duration without an alternative diagnosis; (2) after appendectomy, the patient experiences complete relief of symptoms; (3) histopathologically, the symptoms were proven to be the result of chronic active inflammation of the appendiceal wall or fibrosis of the appendix.