Table of contents
Expand All Topics
Acute appendicitis
Background
Overview
Definition
Acute appendicitis is a disease resulting from acute inflammation of the vermiform appendix.
1
Pathophysiology
Acute appendicitis is initiated by a process that causes obstruction of the appendiceal lumen, such as fecaliths, lymphoid hyperplasia, parasites, Crohn's disease, foreign bodies, or neoplasms.
2
Epidemiology
The incidence of acute appendicitis is estimated at 110 per 100,000 person-years in the US, with a male predominance.
3
Disease course
Progressive luminal obstruction is associated with inflammation and distension of the appendix, leading to suppurative transmural inflammation, ischemia, infarction, and perforation. Perforated appendicitis progresses to generalized peritonitis and intra-abdominal abscess formation.
4
Prognosis and risk of recurrence
The mortality rate associated with non-perforated appendicitis is 0.8 per 1,000 individuals, whereas, for perforated appendicitis, it increases to 5.1 per 1,000 individuals. The risk of recurrent appendicitis after interval appendicectomy is about 20% within a year. Recurrent appendicitis may also occur in the setting of previous appendicectomy in patients with a long appendiceal stump.
4
5
Guidelines
Key sources
The following summarized guidelines for the evaluation and management of acute appendicitis are prepared by our editorial team based on guidelines from the American Academy of Family Physicians (AAFP 2024,2018), the Infectious Diseases Society of America (IDSA 2024), the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES 2024), the Surgical Infection Society (SIS 2024), the American College of Radiology (ACR ...
Show more
Classification and risk stratification
Risk stratification: as per IDSA 2024 guidelines, assess disease severity for risk stratification in patients with complicated intra-abdominal infections. Consider using the APACHE II as the preferred severity of illness score for risk stratification within 24 hours of hospital or ICU admission in adult patients with complicated intra-abdominal infection, if a severity of illness score is used.
B
Diagnostic investigations
Abdominal ultrasound: as per WSES 2020 guidelines, obtain diagnostic imaging in patients with suspected appendicitis after an initial assessment and risk stratification using clinical scores.
B
Show 3 more
More topics in this section
CT and MRI
Blood cultures
Diagnostic procedures
Explorative laparoscopy
As per WSES 2020 guidelines:
Perform explorative laparoscopy in patients with negative imaging but progressive or persistent pain to establish/exclude the diagnosis of acute appendicitis or alternative diagnoses.
A
Avoid obtaining cross-sectional imaging (CT) in < 40 years old high-risk patients with AIR score 9-12, Alvarado score 9-10 and AAS ≥ 16 before proceeding to diagnostic and/or therapeutic laparoscopy.
D
More topics in this section
Histopathology
Medical management
Nonoperative management, uncomplicated disease: as per EAST 2019 guidelines, insufficient evidence to recommend for or against antibiotics-first therapy versus surgery in patients with acute uncomplicated appendicitis.
I
More topics in this section
Nonoperative management (complicated disease)
Analgesic therapy
Perioperative care
Preoperative antibiotics: as per WSES 2020 guidelines, administer a single preoperative dose of broad spectrum antibiotics in patients with acute appendicitis undergoing appendectomy.
A
More topics in this section
Intraoperative grading systems
Postoperative antibiotics (uncomplicated disease)
Postoperative antibiotics (complicated disease)
Postoperative antibiotics (chronic disease)
Postoperative nasogastric tube
Postoperative diet
Surgical interventions
Timing of surgery
As per WSES 2020 guidelines:
Plan laparoscopic appendectomy for the next available operating list within 24 hours in patients with uncomplicated acute appendicitis, minimizing the delay wherever possible.
B
Do not delay appendectomy in patients with acute appendicitis requiring surgery beyond 24 hours from the admission.
D
More topics in this section
Laparoscopic appendectomy
Technical considerations for surgery
Intra-abdominal cultures
Specific circumstances
Pediatric patients, diagnostic imaging: as per AAFP 2024 guidelines, obtain ultrasound as the preferred initial imaging modality in pediatric patients with acute abdominal pain.
B
Show 2 more
More topics in this section
Pediatric patients (laboratory tests)
Pediatric patients (management)
Pregnant patients (diagnostic imaging)
Pregnant patients (laboratory tests)
Pregnant patients (management)
Elderly patients
Patients with obesity
Patients with immunosuppression