Because gastrointestinal symptoms occur in 11 - 64% of COVID–19 patients[6–8], there have been early concerns during the current pandemic that the gastrointestinal system might be involved in the disease. Indeed, there is evidence that almost a third of all patients with COVID–19 and gastrointestinal complaints do not experience respiratory symptoms [7]. Early ex vivo experiments confirmed that SARS-CoV–2 can infect and replicate in enterocytes [4], and SARS-CoV–2 was demonstrated in stool specimen[3, 9]. In one study, SARS-CoV–2 was detected within enterocytes in biopsies taken from the esophagus, stomach, duodenum, and rectum of COVID–19 patients with severe disease [6] In another case report, SARS-CoV–2 was found in gastric, small intestinal, and rectal enterocytes of another COVID–19 patient with ARDS and bleeding from a gastric ulceration [9]. There is limited information regarding COVID–19 and acute appendicitis. While one report demonstrating SARS-CoV–2 in the peritoneal fluid of a patient with COVID–19 has been published[10], Ngaserin et al. reported recently that they could not detect SARS-CoV–2 in the peritoneal fluid of a COVID–19 patient with acute appendicitis[11]. Another case report recently described an appendectomy in a patient with COVID–19 but no investigations regarding the presence of SARS-CoV–2 in the appendix were performed [12].
Mechanistically, infection of gastrointestinal cells is most likely mediated by viral interaction with angiotensin converting enzyme 2 (ACE2), which serves as a functional receptor for SARS coronavirus [13] and which is expressed on gastrointestinal mucosal cells [14]. Currently, no evidence exists whether ACE2 is expressed in the vermiform appendix.
There are several caveats to our findings: first, our patient had only mild disease and it is likely that gastrointestinal involvement is more marked in severe cases and later stages of the disease course, as evidenced by the available studies involving gastrointestinal biopsies [6, 9]. Our patient had mild disease only, although we do not know with certainty if she was initially asymptomatic with regard to COVID–19. She had fever on presentation which we attributed to appendicitis, but it might also have been caused by COVID–19 even though respiratory symptoms were lacking. Like our patient, in a recent study most COVID–19 patients with fever had a body temperature in the range from 37.5°C—39.0°C[15]. Interestingly, there seems to be a significant number of patients who present with gastrointestinal symptoms only [6]. Two cases of COVID–19 patients with an appendicular syndrome as presenting complaint have been described, although appendicitis was not confirmed in either patient [16, 17]. In our case, however, appendicitis was confirmed laparoscopically and was certainly the cause for the gastrointestinal symptoms. As there are no reports of appendicitis caused by SARS-CoV–2 infection and since we did not find viral DNA in the appendectomy specimen, it seems unlikely that acute appendicitis could be part of the COVID–19 spectrum. Rather, our case highlights the concurrence of a common surgical emergency and COVID–19. In light of our data and of the recent failure to detect COVID–19 in the peritoneal fluid of a COVID–19 patient with acute appendicitis[11], we would consider the risk of infectious aerosol development during laparoscopic appendectomy in COVID–19 patients with mild symptoms to be relatively low. However, this is only one case report which clearly limits generalization and precautions such as appropriate personal protective equipment should be used whenever COVID–19 is suspected in a patient, especially as infection of operating personal might result from other sources such as the respiratory system.
In summary, we could not demonstrate SARS-CoV–2 in the appendectomy specimen of a COVID–19 patient with acute appendicitis. This finding adds to the scarcely available evidence that the risk for aerosol-transmitted COVID–19 infection during laparoscopic appendectomy is probably low, at least in patients with mild symptoms. Testing of additional appendectomy specimens of COVID–19 patients should be performed in the future to confirm our findings.