What are the diagnostic criteria and management strategies for acute appendicitis (inflammation of the appendix)?

From the Guidelines

Appendicitis should be suspected in patients with right lower quadrant abdominal pain, especially when accompanied by nausea, vomiting, fever, and anorexia, and managed promptly with surgical intervention or non-operative approaches as recommended by the 2020 update of the WSES Jerusalem guidelines 1. The diagnostic criteria for acute appendicitis involve clinical evaluation using scoring systems, laboratory tests, and imaging studies. Key points to consider in diagnosis include:

• Clinical presentation with right lower quadrant abdominal pain, nausea, vomiting, fever, and anorexia
• Use of clinical scores such as the Alvarado score to assess the likelihood of appendicitis
• Laboratory tests showing elevated white blood cell count and C-reactive protein
• Imaging studies such as ultrasound or CT scan to confirm the diagnosis Management strategies for acute appendicitis include:
• Surgical intervention through appendectomy, which can be performed laparoscopically or as an open procedure, as the primary treatment for confirmed appendicitis
• Non-operative approach with antibiotics in select cases of uncomplicated appendicitis, using regimens such as intravenous piperacillin-tazobactam or ceftriaxone plus metronidazole, followed by oral antibiotics like amoxicillin-clavulanate or ciprofloxacin plus metronidazole
• Close monitoring for clinical deterioration in patients managed non-operatively, with awareness of the 20-30% risk of recurrence within one year
• Aggressive management with surgical intervention and longer courses of antibiotics for complicated appendicitis with perforation or abscess formation, as recommended by the 2020 update of the WSES Jerusalem guidelines 1. It is crucial to prioritize prompt diagnosis and treatment to minimize the risk of perforation, which significantly increases morbidity and mortality rates.

From the FDA Drug Label

1.1 Intra-abdominal Infections Piperacillin and tazobactam for injection is indicated in adults and pediatric patients (2 months of age and older) for the treatment of appendicitis (complicated by rupture or abscess) and peritonitis caused by beta-lactamase producing isolates of Escherichia coli or the following members of the Bacteroides fragilis group: B. fragilis, B. ovatus, B. thetaiotaomicron, or B. vulgatus.

The diagnostic criteria for acute appendicitis are not explicitly stated in the provided drug labels. Management strategies for acute appendicitis include treatment with piperacillin and tazobactam for injection for complicated appendicitis, as indicated in the drug label 2. Key points:

• Piperacillin and tazobactam for injection is indicated for the treatment of appendicitis (complicated by rupture or abscess)
• The treatment should be used in patients with infections caused by beta-lactamase producing isolates of certain bacteria, including Escherichia coli and members of the Bacteroides fragilis group.

From the Research

Diagnostic Criteria for Acute Appendicitis

• The clinical diagnosis of acute appendicitis is based on history and physical, laboratory evaluation, and imaging 3
• Classic symptoms of appendicitis include:
  • Vague periumbilical pain
  • Anorexia/nausea/intermittent vomiting
  • Migration of pain to the right lower quadrant
  • Low-grade fever
• The diagnosis of acute appendicitis is made in approximately 90% of patients presenting with these symptoms 3

Management Strategies for Acute Appendicitis

• Laparoscopic appendectomy remains the most common treatment 3
• Increasing evidence suggests that broad-spectrum antibiotics successfully treat uncomplicated acute appendicitis in approximately 70% of patients 3
• Specific imaging findings on computed tomography (CT) can identify patients for whom an antibiotics-first management strategy is more likely to fail 3
• CT findings of appendicolith, mass effect, and a dilated appendix greater than 13 mm are associated with higher risk of treatment failure of an antibiotics-first approach 3
• Surgical management should be recommended in patients with CT findings of appendicolith, mass effect, or a dilated appendix who are fit for surgery 3
• In patients without high-risk CT findings, either appendectomy or antibiotics can be considered as first-line therapy 3
• In unfit patients without these high-risk CT findings, the antibiotics-first approach is recommended, and surgery may be considered if antibiotic treatment fails 3
• Approximately 90% of patients treated with antibiotics are able to avoid surgery during the initial admission, while the other 10% that fail to respond to antibiotics require a rescue appendectomy 4
• Recurrence rates of non-operated patients within 1 year are as high as 20-30% 4

Antibiotic Management

• Preoperative broad-spectrum antibiotics are often used in clinical practice to decrease surgical site infections after appendectomy for acute appendicitis 5
• However, this treatment strategy has come under scrutiny because of increasing rates of antibiotic-resistant infections 5
• A quality improvement study found that updating electronic health record orders to encourage preoperative administration of narrow-spectrum antibiotics and educating surgeons and emergency department clinicians about selecting appropriate antibiotic therapy for acute appendicitis can decrease the treatment of uncomplicated acute appendicitis with piperacillin-tazobactam without increasing the rate of surgical site infections 5