Reply to the comments on "Coffee bean sign, steel pan sign and whirl sign in sigmoid volvulus".

We thank Prof. Atamanalp and colleagues for their interest and valuable comments on our article. The authors have highlighted important considerations in the diagnosis of sigmoid volvulus (SV). We would like to respond to their comments. Firstly, although we agree with their opinion that CT, MRI, and endoscopy are more reliable diagnostic tools than plain radiography, we still emphasize that diagnostic imaging for SV is initially based on plain radiography, as recommended by the WSES consensus guidelines. Since SV is the third most common cause of colonic obstruction worldwide, the accessibility of plain radiography is crucial. Among the many plain radiographic signs of SV, Levsky et al. reported that the most sensitive signs were absence of rectal gas, followed by inverted-U appearance and coffee bean sign. Understanding these signs may lead to early detection of SV and further CT evaluation for ischemia or perforation. Despite the high value of plain radiography, there is a global tend to use CT instead from the outset. Secondly, we agree with their opinion that endoscopy is not only a therapeutic, but also a diagnostic procedure to assess mucosal viability. In addition, we believe that endoscopy is also useful in ruling out other obstructive lesions, including colorectal neoplasia and complicated sigmoid diverticular disease. In the clinical setting, endoscopy is performed after the diagnosis of SV by plain radiography or CT and serves as the first line of decompression of SV when ischemia or perforation is not suspected. Finally, we congratulate Prof. Atamanalp and colleagues for their dedicated contribution to the large-scale SV studies in Eastern Anatolia, Turkey, where SV is endemic.

Hyperbaric oxygen therapy for perianal Crohn's disease.

I read with great interest the letter by Calderón et al., who clearly described effectiveness of hyperbaric oxygen therapy (HBOT) for refractory ischemic ulcer at the ileorectal anastomosis in Crohn's disease (CD). I congratulate them on their efforts in achieving a favorable long-term outcome. I would like to share my experience of HBOT for perianal CD (PCD). In addition, I discuss recent trials of HBOT for PCD.

Rapid formation of aortoesophageal fistula complicated by mycotic thoracic aortic aneurysm secondary to infective endocarditis.

A 73-year-old man was admitted with four weeks of intermittent fever. He had a history of total aortic arch replacement for aortic arch aneurysm four years prior. CT scans showed no abnormalities before admission. Repeated blood cultures yielded Streptococcus anginosus and Prevotella melaninogenica, suggesting infective endocarditis (IE). Transesophageal echocardiography revealed a vegetation on the aortic valve, confirming IE. He suddenly presented with massive hematemesis and hypotension. Endoscopy revealed an elevated lesion with a laceration but no active bleeding in the esophagus. CT scans showed a thoracic aneurysm involving the esophagus. A diagnosis of aortoesophageal fistula (AEF) complicated by mycotic thoracic aortic aneurysm (MTAA) was made, and he underwent stent graft interpolation followed by minimally invasive esophagectomy. MTAAs are more prone to rupture than arteriosclerotic aneurysms as they are usually not true but pseudoaneurysms. Antecedent infection, including endocarditis, sepsis, predisposes to MTAA. AEF is a rare but life-threatening cause of gastrointestinal bleeding characterized by Chiari's triad. There have been no reports of such rapid formation of AEF after the graft replacement, as shown here. A recent article reported a rapid formation (16 days) of AEF after thoracic endovascular aortic repair, emphasizing prosthetic infection as the most important risk factor. Our case underscores the importance of suspecting AEF and conducting repeated appropriate examinations even if initial examinations do not reveal any aneurysms.

Strongyloides stercoralis hyperinfection presenting pneumatosis intestinalis and acute respiratory distress syndrome after treatment for COVID-19.

A 91-year-old man was admitted with vomiting and abdominal pain. He had had COVID-19 pneumonia a month before and the treatment had consisted of remdesivir, dexamethasone and baricitinib. CT scans showed pneumatosis intestinalis. His respiratory condition rapidly deteriorated and chest CT scans showed ground-glass opacity and Strongyloides stercoralis was identified in the sputum, making a diagnosis of hyperinfection syndrome associated acute respiratory distress syndrome. Treatment of ivermectin was not achieved in time and he died of multiple organ failure. S. stercoralis is a soil-transmitted helminth endemic to tropical and subtropical areas. Immunosuppressive conditions can cause hyperinfection syndrome and life-threatening conditions. Our case highlights the importance of assessing for untreated chronic strongyloidiasis in COVID-19 patients requiring steroid treatment in endemic areas.

Endoscopic findings of radiation ileitis.

I herein report a case of radiation ileitis. Ileocolonoscopy disclosed villous edema and multiple patchy lymphangiectasias in the terminal ileum. While observing, active bleeding occurred from the numerous telangiectasias and friable atrophic mucosa. Clinical manifestations of radiation ileitis are briefly discussed.

Ulcerative colitis exacerbated by strongyloidiasis.

We herein report a case of ulcerative colitis (UC) exacerbated by strongyloidiasis. Parasites including Strongyloides stercoralis and Entamoeba histolytica can cause chronic gastrointestinal inflammation and long-lasting symptoms resembling UC. On the other hand, it is not well-known that such organisms can trigger the exacerbation of pre-existing UC. We would like to highlight the importance of recognition of strongyloidiasis in the management of UC patients who have lived in or migrated from endemic regions, such as Asia, Africa, and South America.

Duodenal nodularity with villous flattening in common variable immunodeficiency.

We herein report a case of common variable immunodeficiency (CVID). Endoscopy with biopsies disclosed duodenal nodularity with villous flattening associated with CVID. CVID-associated enteropathy is briefly discussed.

Chinese dragon sign of ulcerative colitis.

We present a case of a 17-year-old woman with ulcerative colitis (UC) presented with abdominal pain and hematochezia. A CT scan showed active bowel inflammation, presenting the Chinese dragon sign. A diagnosis of exacerbation of UC was made. This sign refers to tortuous thick-walled sigmoid colon and rectum with narrow lumen resembles the body of the dragon and hypervascularity of the involved mesenteric vessels as bright dots next to the outer wall resemble the legs and skin spikes. Although this sign is nonspecific and may appear in ischemic colitis, ischemic colitis usually does not have rectal involvement and can be differentiated from typical UC.

Comb sign in Crohn's disease.

We present a case of a 13-year-old boy with Crohn's disease (CD) who presented with abdominal pain and diarrhea. On examination, there was tenderness on the lower abdomen. Laboratory examinations showed elevated inflammatory parameters. A CT scan showed active inflammation of the ileum and rectosigmoid colon with the comb sign. A diagnosis of exacerbation of CD was made. The comb sign refers to hypervascularity of the mesentery with vascular dilatation, tortuosity, and wide spacing of the vasa recta that are aligned as the teeth of a comb. This sign is not always pathognomonic for CD; however, it may help identification of acute exacerbation in known CD and differentiating active CD from hypovascular disease such as lymphoma. The comb sign can be highly correlated with the endoscopic severity rather than mural thickening in CD.

Jejunal lymphangioma.

We herein report a case of jejunal lymphangioma. A CT scan showed non-enhancing cystic masses in the jejunum. Enteroscopy revealed multiple cystic swelling with whitish carpet-like villi. Histopathology disclosed dilated lymphatic channels, lined by a single layer of endothelial cells, which were positive for the lymphatic endothelial marker by the immunohistochemical staining. Clinical manifestations of intestinal lymphangioma are briefly discussed.

Transparent cap-assisted endoscopic retrieval of a sharp foreign body in the esophagus.

We herein report an 80-year-old woman who accidentally ingested a sharp foreign body. Transparent cap-assisted endoscopy disclosed an impacted press-through package (PTP) in the upper esophagus. The PTP was grasped by the forceps, inserted into the cap, and removed carefully without complication. Ingestion of sharp-pointed foreign bodies has serious risks of gastrointestinal perforation and hemorrhage; therefore, emergent endoscopic removal has been recommended. Transparent cap-assisted endoscopy is a simple, safe, and effective method with a shorter procedure time and clearer visual field compared with conventional endoscopy. We wish to emphasize that this method has advantages and a potential to be used for endoscopic retrieval of small sharp foreign bodies.