Acute Appendicitis

BASIC INFORMATION
DEFINITION
Appendicitis is the acute inflammation of the appendix. In patients with abdominal pain acute appendicitis must always be considered in the differential diagnosis. In classical cases diagnosis is simple, but it may be very difficult in patients with atypical symptoms.
EPIDEMIOLOGY & DEMOGRAPHICS
• Appendicitis occurs in 10% of the population, most commonly between the ages of 10 and 30 yr.
• It is the most common abdominal surgical emergency.
• Incidence of appendicitis has declined over the past 35 yr.
• Male:female ratio is 3:2 until mid-20s; it equalizes after age 30 yr.
PHYSICAL FINDINGS & CLINICAL PRESENTATION
• Abdominal pain: initially the pain may be epigastric or periumbilical in nearly 50% of patients; it subsequently localizes to the RLQ within 12 to 18 hr. Pain can be found in back or right flank if appendix is retrocecal or in other abdominal locations if there is malrotation of the appendix.
• Pain with right thigh extension (psoas sign), low-grade fever: temperature may be >38° C if there is appendiceal perforation.
• Pain with internal rotation of the flexed right thigh (obturator sign) is present.
• RLQ pain on palpation of the LLQ (Rovsing’s sign): physical examination may reveal right-sided tenderness in patients with pelvic appendix.
• Point of maximum tenderness is in the RLQ (McBurney’s point).
• Nausea, vomiting, tachycardia, cutaneous hyperesthesias at the level of T12 can be present.
Clinical Features. The pain initially starts epigastrically and is only localized in the right lower quadrant after some hours. It is rarely very strong. The pressure point depends on the localization of the appendix, which can be very variable. The McBurney point (middle of a line drawn between the navel and anterior superior iliac spine) is most frequently sensitive to pressure. Another pain localization in the right lower quadrant or even the right epigastric region (with a highly displaced appendix) does not preclude appendicitis (consider situs inversus in rare cases). With a pelvic position of the appendix, rectal examination, which should always be part of the clinical examination for suspected appendicitis, is decisive. Rebound tenderness is always present, except in very early stages, and reflects the degree of peritoneal involvement.
ETIOLOGY
Obstruction of the appendiceal lumen with subsequent vascular congestion, inflammation, and edema; common causes of obstruction are:
• Fecaliths: 30% to 35% of cases (most common in adults)
• Foreign body: 4% (fruit seeds, pinworms, tapeworms, roundworms, calculi)
• Inflammation: 50% to 60% of cases (submucosal lymphoid hyperplasia [most common etiology in children, teens])
• Neoplasms: 1% (carcinoids, metastatic disease, carcinoma)

DIAGNOSIS
DIFFERENTIAL DIAGNOSIS
Leukocytosis is generally present. Nausea and vomiting are common. Fever is generally not high with the rectal temperature being significantly higher than the axillary temperature. Obstipation is generally present; diarrhea is rarely encountered initially. Sonography is frequently helpful.
• Intestinal: regional cecal enteritis, incarcerated hernia, cecal diverticulitis, intestinal obstruction, perforated ulcer, perforated cecum, Meckel’s diverticulitis
• Reproductive: ectopic pregnancy, ovarian cyst, torsion of ovarian cyst, salpingitis, tuboovarian abscess, Mittelschmerz endometriosis, seminal vesiculitis
• Renal: renal and ureteral calculi, neoplasms, pyelonephritis
• Vascular: leaking aortic aneurysm
• Psoas abscess
• Trauma
• Cholecystitis
• Mesenteric adenitis
WORKUP
• Patients presenting with RLQ pain, nausea, vomiting, anorexia, and RLQ rebound tenderness should undergo prompt clinical and laboratory evaluation. Imaging studies are generally not necessary in typical appendicitis. They are useful when the diagnosis is uncertain.
LABORATORY TESTS
• CBC with differential reveals leukocytosis with a left shift in 90% of patients with appendicitis. Total WBC count is generally lower than 20,000/mm3 . Higher counts may be indicative of perforation. Less than 4% have a normal WBC and differential. A low Hgb and Hct in an older patient should raise suspicion for carcinoma of the cecum.
• Microscopic hematuria and pyuria may occur in <20% of patients.
IMAGING STUDIES
• Appendiceal CT scan as a noninvasive diagnostic aid has an accuracy of more than 90%. It improves patient care and reduces the use of hospital resources.
• Ultrasound is useful, especially in younger women when diagnosis is unclear. Normal ultrasonographic findings should not deter surgery if the history and physical examination are indicative of appendicitis.

Ultrasound followed by CT with rectal contrast is more than 90% accurate in detecting acute appendicitis in children.
• Laparoscopy may be useful as both a diagnostic and a therapeutic modality.
TREATMENT
NONPHARMACOLOGIC THERAPY
The appendix is removed by open surgery or laparoscopically. If an appendix mass is present, the patient is usually treated conservatively with intravenous fluids and antibiotics. The pain subsides over a few days and the mass usually disappears over a few weeks. Interval appendicectomy is recommended at a later date to prevent further acute episodes.
• NPO
• Do not administer analgesics or antibiotics until the diagnosis is made (may mask signs of peritonitis).
ACUTE GENERAL Rx
• Urgent appendectomy (laparoscopic or open), correction of fluid and electrolyte imbalance with vigorous IV hydration and electrolyte replacement
• IV antibiotic prophylaxis to cover gram-negative bacilli and anaerobes (cefotetan, clindamycin and genta-micin, or metronidazole with gentamicin)
DISPOSITION
In general, prognosis is excellent. Mortality is <1% in young adults without complications; however, it exceeds 10% in elderly patients with ruptured appendix.