Management of Acute Appendicitis
Acute appendicitis (AA) is not, as long assumed, a linear inflammation of the appendix that inevitably leads to perforation, peritonitis with subsequent sepsis, and possibly death without medical intervention. Rather, AA is a significantly more heterogeneous and complex disease.
There is a distinction between uncomplicated appendicitis (UA; inflammatory thickening of the appendix) and complicated appendicitis (CA), which occurs in about 20% of cases, defined by the presence of gangrene or perforation of the appendix or a perityphlitic abscess. However, these are no longer understood as two consecutive stages of a disease but as two different disease entities in most cases [1]. This understanding is based on epidemiological data showing that the incidences of both forms develop independently of each other [2, 3].
Diagnostics
In addition to medical history, a clinical examination considering various appendicitis signs (McBurney, Lanz, Blumberg, Rovsing, Psoas) and a blood test are mandatory [4]. A shift of pain from the epigastrium to the right lower abdomen is often indicative of AA in the medical history [5].
Leukocytosis and elevated CRP are nonspecific inflammatory parameters [6]. The presence of two or more variables makes the presence of AA more likely, while the absence of all variables makes it unlikely [7]. In routine diagnostics, procalcitonin has no relevant significance, but high procalcitonin levels in combination with high CRP levels correlate with CA [8,9].
Increased body temperature and fever are nonspecific symptoms but correlate with advanced AA, so temperature measurement should be routinely performed [6]. According to a meta-analysis, a rectal-digital examination is not necessarily required [10].
A urinalysis (dipstick test) and a pregnancy test in young women of childbearing age should be regularly performed [4].
Appendicitis Scores
Various scores have been developed to better assess the likelihood of AA: Alvarado (MANTRELS) Score, Appendicitis Inflammatory Response (AIR or Andersson’s) Score, Pediatric Appendicitis Score (PAS), Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) Score, and Adult Appendicitis Score (AAI) [11-14]. These can facilitate decision-making [15], but are rarely used in clinical practice in Germany.
Imaging Diagnostics
With sonography (specificity 71-94%, sensitivity 81-98%), AA can be reliably confirmed with appropriate expertise, but it is not sufficiently reliable to definitively exclude it [16, 17, 18]. An abdominal CT (sensitivity 76-100%, specificity 83-100%) is superior to ultrasound for excluding or confirming the diagnosis of AA [16]. However, radiation exposure, especially in children, adolescents, and pregnant women, should not be underestimated [11]. Here, MRI (sensitivity 97%, specificity 95%) offers a safe alternative to CT without radiation exposure [16].
In the USA, imaging is performed in over 80% of patients (mostly CT), while in Europe, about 1/3 and in Australia about 3/4 of patients with suspected appendicitis do not undergo imaging [15]. Dutch guidelines consider imaging indispensable in appendicitis diagnostics [19].
Therapy of Acute Appendicitis - Surgical
Currently, there is no guideline from Germany for the therapy of appendicitis. Internationally, there are the "Guidelines for Laparoscopic Appendectomy" from the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES). More recent guidelines have been published by the European Association of Endoscopic Surgery as part of a consensus conference (EAES) and by the World Society of Emergency Surgery (WSES) [11, 16, 20]. The guidelines largely agree in recommending laparoscopic appendectomy as the first-choice treatment method.
In laparoscopic appendectomy, there is a reported increased rate of intra-abdominal abscesses, especially in CA, while the open technique has a higher rate of wound infections and passage disorders [21, 22, 23].
In AA, the perioperative administration of a broad-spectrum antibiotic (single-shot) reduces the occurrence of wound infections and abscesses. In UA, continuing antibiotics postoperatively is not sensible, while in CA, it should be continued for 3 to 5 days considering clinical and laboratory values [11].
Timing of Surgery in Acute Appendicitis
In cases of imaging suspicion of UA, an appendectomy can be postponed by 12-24 hours after immediate initiation of antibiotic therapy without increasing morbidity. In patients ≥ 65 years or with comorbidities, the procedure should be performed ≤ 12 hours from diagnosis. An appendectomy ≥ 48 hours is associated with a higher rate of surgical infections [11, 24, 25, 25a, 25b].
In CA with phlegmon or abscess, no safe recommendation on the timing of surgery can be made based on current data. The urgency depends on the severity of the clinical findings and comorbidities. In perforated appendicitis with free air, there is undoubtedly an urgent indication for surgery [26].
Conservative Therapy in Uncomplicated Appendicitis
Primary conservative therapy of a mostly CT-confirmed UA with antibiotics is effective in about 86% of patients. If conservative therapy fails (14% of cases with persistent or worsening symptoms), a prompt appendectomy should be performed [27]. In patients with an initial response to antibiotics, an appendectomy can be avoided in nearly 80% of cases in the first year, but at least 22.5% experience recurrent appendicitis in the first year [28]. In a study with a 5-year follow-up, the incidence of recurrent appendicitis was 27% in the first year, 34% after 2 years, 35.5% after 4 years, and 39% after 5 years [29]. A review from 2019 indicates that up to 37% of patients initially treated conservatively require appendectomy within a year [29a]. A meta-analysis from 2019 found no statistically significant increase in perforation rate with imaging-confirmed UA under conservative therapy, but the effectiveness of surgical therapy for AA is higher [28, 30].
Therapy of Complicated Appendicitis
There is currently no internationally standardized evidence-based concept for the treatment of CA.
Some retrospective studies and meta-analyses show low morbidity for conservative or interventional management of CA compared to immediate appendectomy [31, 32]. Other studies demonstrate the advantage of surgical therapy for CA [33, 34, 35]. A meta-analysis from 2019 compares two patient groups: laparoscopic group (appendectomy or lavage with drainage) and conservative group (only antibiotics or antibiotics with interventional drainage). The laparoscopic group showed higher rates of complication-free courses, shorter hospital stays, and lower incidence of abscess recurrences or residues. The meta-analysis clearly favors laparoscopic management of CA [34].
Laparoscopic interval appendectomies 4 to 6 months after CA should only be performed in selected patients (e.g., with existing symptoms), as they have a higher conversion rate, significantly more intraoperative complications, and intra-abdominal infections compared to immediate appendectomy [36, 37].
Even though conservative therapy is gaining importance, various publications indicate that the current data is insufficient to deviate from the primary surgical approach in acute appendicitis [38-41]. The main criticism is the lack of randomized placebo-controlled blinded studies to clarify long-term outcomes regarding the adverse effects of conservative therapy.