Bowel inflammatory presentations on computed tomography in adult patients with severe aplastic anemia during flared inflammatory episodes

Abstract

BACKGROUND Patients with severe aplastic anemia (SAA) frequently present with inflammatory episodes, and during flared inflammatory episodes, hematopoietic function is further exacerbated. The gastrointestinal tract is the most common site for infectious and inflammatory diseases, and its structural and functional features confer on it the most potent capacity to affect hematopoietic and immune functions. Computed tomography (CT) is a readily accessible approach to provide highly useful information in detecting morphological changes and guiding further work-ups. AIM To explore CT imaging presentations of gut inflammatory damage in adult SAA patients during inflammatory episodes. METHODS We retrospectively evaluated the abdominal CT imaging presentations of 17 hospitalized adult patients with SAA in search of the inflammatory niche when they presented with systemic inflammatory stress and exacerbated hematopoietic function. In this descriptive manuscript, the characteristic images that suggested the presence of gastrointestinal inflammatory damage and related imaging presentations of individual patients were enumerated, analyzed and described. RESULTS All eligible patients with SAA had CT imaging abnormalities that suggested the presence of an impaired intestinal barrier and increased epithelial permeability. The inflammatory damages were concurrently present in the small intestine, the ileocecal region and the large intestines. Some readily identified imaging signs, such as bowel wall thickening with mural stratification (“water holo sign”, “fat holo sign”, intramural gas and subserosal pneumatosis) and mesenteric fat proliferation (fat stranding and “creeping fat sign”), fibrotic bowel wall thickening, “balloon sign”, rugged colonic configuration, heterogeneity in the bowel wall texture, and adhered and clustered small bowel loop (including various patterns of “abdominal cocoon”), occurred at a high incidence, which suggested that the damaged gastrointestinal tract is a common inflammatory niche responsible for the systemic inflammatory stresses and the exacerbated hematopoietic failure in patients with SAA. Particularly, the “fat holo sign” was present in 7 patients, a rugged colonic configuration was present in 10 patients, the adhesive bowel loop was present in 15 patients, and extraintestinal manifestations suggestive of tuberculosis infections were present in 5 patients. According to the imaging features, a suggestive diagnosis of Crohn’s disease was made in 5 patients, ulcerative colitis in 1 patient, chronic periappendiceal abscess in 1 patient, and tuberculosis infection in 5 patients. Other patients were diagnosed with chronic enteroclolitis with acutely aggravated inflammatory damage. CONCLUSION Patients with SAA had CT imaging patterns that suggested the presence of active chronic inflammatory conditions and aggravated inflammatory damage during flared inflammatory episo...

Tuberculosis-induced aplastic crisis and atypical lymphocyte expansion in advanced myelodysplastic syndrome: A case report and review of literature

“…The gastrointestinal tract is an organ that hosts the most abundant lymphatic tissues and microbial community and therefore can provide sufficient activated immune cells and continuously supply exogenous antigens from both pathogenic and commensal microbes to initiate and perpetuate deranged autoimmunity in the context of increased epithelial permeability and gut inflammatory conditions[ 30 - 33 ], leading to autoimmune hematopoietic failure[ 34 - 37 ]. In our retrospective study to explore the inflammatory conditions of SAA patients during inflammatory flare-ups, 5 of 17 recruited patients exhibited imaging abnormalities suggestive of tuberculosis infection, all involving the gastrointestinal tract and suggesting a high frequency of tuberculosis infection in autoimmune hematopoietic failure[ 38 ]. Gut inflammatory conditions in the sustenance of autoimmune responses have been demonstrated by the fact that the onset of an autoimmune disease cannot occur in a germ-free state[ 39 - 41 ].…”

Leukemic transformation during anti-tuberculosis treatment in aplastic anemia-paroxysmal nocturnal hemoglobinuria syndrome: A case report and review of literature

“…In our investigation of inflammatory niches in SAA patients during inflammatory episodes, 5 of 17 recruited patients had imaging abnormalities suggestive of tuberculosis reactivation, all involving the gastrointestinal tract[ 47 ]. Gastrointestinal infections can induce inflammatory lesions in both infected and noninfected segments through induction of gut dysbiosis[ 48 - 50 ].…”

When inflammatory stressors dramatically change, disease phenotypes may transform between autoimmune hematopoietic failure and myeloid neoplasms

“…The contribution of the gut microbiome to sustaining the pathogenesis of graft-versus-host disease after allogeneic hematopoietic stem cell transplantation, a pathogenic mechanism similar to that of AA and frequently used to study AHF pathogenesis in animal models, was reported several decades ago ( 161 ). In our retrospective study, all patients with SAA had imaging abnormalities that reflected the existence of chronic inflammatory lesions and acutely aggravated inflammatory damage in the gastrointestinal tract during inflammatory episodes and exacerbated cytopenia ( 349 ). Similar to non-hematological AIDs ( 156 – 160 ), growing evidence demonstrates that the gastrointestinal tract is the most common inflammatory nidus that sustains AHF pathogenesis in patients with a background of an inflamed BME ( 89 , 90 ).…”

“…Disseminated tuberculosis ( 368 – 371 ) or even disseminated BCG vaccination ( 372 ) can induce BM hypoplasia and peripheral cytopenia. The fact that tuberculosis-induced AHF occurs only in disseminated tuberculosis instead of in isolated pulmonary tuberculosis suggests that tuberculosis can infect hematopoietic tissues ( 373 ) or the gastrointestinal tract ( 34 , 35 , 181 , 349 ). Gut involvement and subsequent dysbiosis ( 181 ) likely play more important roles in inducing systemic inflammatory disorders ( 374 , 375 ).…”

“…Gut involvement and subsequent dysbiosis ( 181 ) likely play more important roles in inducing systemic inflammatory disorders ( 374 , 375 ). In our retrospective study investigating infectious niduses during flared inflammatory episodes and accelerated cytopenia, five of 17 recruited SAA patients had imaging abnormalities suggestive of tuberculosis reactivation, all of which involved inflammatory diseases in the gastrointestinal tract ( 349 ). The incidence of tuberculosis reactivation may be even greater in advanced MN patients ( 376 – 378 ).…”