# Eosinophilic Gastroenteritis with Appendix Involvement: Role of Intestinal Ultrasound
###### Abstract  
Eosinophilic gastroenteritis (EG) is a rare condition characterized by patchy eosinophilic inflammation of one or more layers of the gastrointestinal tract with no secondary causes of eosinophil. EG is a treatable disease and, generally, patients show a positive response to steroid therapy. Sometimes the disease can present as acute abdomen, and appendicular involvement has seldom been described in the course of EG. In our case report we aimed to emphasize how useful gastrointestinal ultrasound is as a valuable tool for diagnosing and monitoring intestinal involvement during EG, avoiding invasive tests and unnecessary surgery. eosinophilic gastroenteritis; bowel ultrasound; appendicular involvement +
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the previous months, with no association with fever, vomiting, or diarrhea. Salmonellais (6 months earlier) was the only issue in his medical history. Neither drug assumption nor allergies were reported. The patient denied any recent travel abroad or raw food consumption. On admission, the patient's blood pressure, oxygen saturation, and heart and respiratory rate were normal. Physical examination revealed mild-severe abdominal tenderness in the lower and right quadrant. Blood tests showed an elevated white blood cell (WBC) count (19,000/mm\({}^{3}\)), with normal hemoglobin, coagulation indices, and liver and renal function. Differential leukocyte formula was unavailable on admission. An abdominal ultrasound was performed, with evidence of mild hepatosplenomegaly and an a-peristaltic, incompressible, dilated cecal appendix with wall thickness \(>\)6 mm with evidence of the \"target sign\". These ultrasound features were consistent with mild appendicitis involvement. Because of his refusal to be hospitalized, the patient was discharged with antibiotic therapy based on a 7-day amoxicillin/clavulanic-acid regimen. Two days later he came back to our emergency room with persistence of symptoms and onset of non-bloody diarrhea (5-6 bowel movements per day). Vital signs and physical examination were normal, as were ECG and abdomen X-ray. Blood tests revealed an elevated WBC count with absolute eosinophil (19,960/mm\({}^{3}\); EOS 10,470/mm\({}^{3}\)). An empiric antibiotic regimen with ciprofloxacin and metronidazolezo was prescribed. A few days later, because of the persistence of severe abdominal pain in the lower quadrant, a contrast-enhanced CT scan was performed, revealing multiple reactive lymph node enlargement and excluding acute appendicitis or abdominal masses. The patient was then admitted to a medical unit. Infectious enteritis being suspected, stool cultures for _Shigella, Salmonella, Campylobacter, C. difficile_ antigen, _E. coli O157:H7, Yersinia_ spp., _Giardia, Strongyloides, Toxcora, Cryptosporidium_ were carried out and tested negative. The test for serum _Schistosoma, Amoeba_ spp. and HIV antibodies was negative. Given the presence of multiple mesenteric lymphadenopathy in the CT scan, immunophenotyping by flow cytometry was performed on peripheral blood, revealing no phenotypic alterations of B/T-lymphocytes. Despite the patient always denying any upper respiratory tract symptoms, chest X-ray and ANCA (antineutrophil cytoplasmic antibodies) screening were carried out in order to rule out eosinophilic granulomatosis with polyangiitis, and they tested negative. A progressive reduction of bowel movements and normalization of the WBC count were observed during the antibiotic treatment, albeit the persistence of absolute eosinophil. Esophagostroduodenoscopy and colonoscopy were proposed, but the patient refused. He was then discharged with the indication to continue the diagnostic work-up as an outpatient and to have his blood monitored. The recurrence of abdominal discomfort in the right lower quadrant associated with a new rise of the eosinophilic count (WBC 12,800/mm\({}^{3}\), EOS 6200/mm\({}^{3}\)) was observed 8 weeks after the first admission. The patient was then admitted to our gastroenterology department.