[Toxic megacolon]

[Endoscopy on the surgical intensive care unit]

Endoscopy is most frequently performed in intensive care units (ICU) for gastrointestinal bleeding; however, there are other indications for performing an endoscopy on the ICU. This article shows the indications for this, the background and the peri-interventional and postinterventional management. The endoscopic placement of a postpyloric feeding tube is a well-established procedure. For anastomotic leakage in the esophagus and rectum, the endoscopic vacuum therapy is the treatment of choice. Gastrointestinal motility disorders are a frequent phenomenon in critically ill patients and are associated with increased mortality. With a cecal diameter > 9-12 mm, endoscopic decompression can be performed; however, this is associated with an increased risk of perforation and should only be carried out after the failure of conservative treatment.

Gastrointestinal toxicities associated with immune checkpoint inhibitors: a disproportionality analysis leveraging VigiBase, the WHO Adverse Drug Reaction Database

With the improvement of people's living standards, gastrointestinal adverse reactions caused by various adverse factors have attracted more and more people's attention. A recent study has indicated that coronavirus disease 2019 (COVID-19) could also invade the gastrointestinal tract, leading to gastrointestinal adverse reactions (Song et al., 2020). In recent years, immunotherapy has provided certain effects for some patients with advanced malignant tumors. A microencapsulation of immunoglobulin Y (IgY) was reported to provide an effective way to preserve IgY and improve its performance in the gastrointestinal tract (Zhang J et al., 2020). Immune checkpoint inhibitors (ICIs) can significantly improve the survival of some advanced malignant tumors, especially metastatic malignant melanoma and lung cancer (Afzal et al., 2018; Madden and Kasler, 2019). They include anti-cytotoxic T lymphocyte-associated antigen-4 (anti-CTLA-4) antibodies (ipilimumab and tremelimumab), anti-programmed cell death protein 1 (anti-PD-1) antibodies (nivolumab and pembrolizumab), and anti-programmed death-ligand 1 (anti-PD-L1) antibodies (atezolizumab, avelumab, and durvalumab) (Baxi et al., 2018). Previous studies have shown that ICI combination therapy, such as nivolumab plus ipilimumab, has particular efficacy in lung cancer, renal cell carcinoma, and malignant melanoma (Wolchok et al., 2017; Derosa et al., 2018; Doroshow et al., 2019). However, ICIs may also lead to many immune-related adverse events (irAEs), even causing severe complications in certain cases. The most well-established toxicities from ICI therapy are gastrointestinal irAEs, including enteritis, enterocolitis, microscopic colitis, and gastritis, which have attracted public attention in recent years; reports of such events associated with ICI therapy also have increased (Tandon et al., 2018; de Malet et al., 2019). These gastrointestinal irAEs may generally respond well to corticosteroids and infliximab (Haanen et al., 2017). Although most of these irAEs are low-grade, a lack of detection and timely treatment may incur severe or fatal complications.

Gastrointestinal Motility Problems in Critically Ill Patients

Gastrointestinal (GI) motility problems are common complications in critical care patients. GI problems contribute to an increased risk of morbidity and mortality. Toxic megacolon (TM) is a type of acquired megacolon categorized as a medical emergency and includes severe inflammation affecting all layers of the colon wall. The high incidence of GI complications in critically ill patients requires the critical care nurse to provide close monitoring of patients at risk and an acute awareness of the causation, signs and symptoms, and treatment of various GI motility disorders, including gastroparesis, ileus, and TM.

[Acute colonic pseudo-obstruction: Ogilvie syndrome]

Acute colonic pseudo-obstruction (ACPO) is characterized by marked colonic dilatation which develops over several days. ACPO is due to a motility disorder and is not caused by colonic obstruction and occurs in patients with severe, often acute underlying diseases or postoperatively. It is associated with a 25-30% mortality overall that increases to up to 50% in patients who develop complications (e.g. colonic ischemia and perforation). The pathogenesis of the disorder has not yet been clarified and clinical symptoms and signs are relatively unspecific. In particular, ACPO has to be differentiated from colonic obstruction and toxic megacolon. For this blood tests and radiological tests are required, e.g. plain abdominal radiograph, abdominal computed tomography (CT) and water soluble contrast enema, which are also required for detection of complications. Patients with ACPO should generally receive supportive therapy for decompression of the gastrointestinal tract (e.g. gastric and rectal tubes) and to minimize predisposing factors. In most uncomplicated cases this leads to resolution of colonic dilatation. Clinical and radiological controls at close intervals are required until the condition is resolved. If patients do not respond within 1-2 days or if ACPO has already reached a critical duration (>3-4 days) or extent (i.e. cecal diameter ≥12 cm), neostigmine should be administered and leads to durable success in approximately 3 out of 4 patients. Patients who are still refractory to treatment should receive endoscopic decompression. More invasive therapeutic options, such as cecostomy or (segmental) colonic resection should only be considered for patients who still do not respond to treatment or present with the abovementioned complications.