Abstract: Objective To analyze the clinical and imaging characteristics of Mpox with HIV-positive or HIV-negative patients, so as to provide reference for clinical diagnosis and treatment. Method The clinical and imaging data of 36 confirmed Mpox patients admitted to Beijing You'an Hospital of Capital Medical University from June 1 to November 30, 2023, were retrospectively analyzed. The patients were divided into HIV-positive and HIV-negative groups based on whether they were co-infected with HIV. The clinical and imaging characteristics of the two groups were observed and compared. Result All 36 cases were from the male population who have sex with men (MSM), with an average age of (31.5±6.4) years. There were 28 cases in the positive group and 8 cases in the negative group. The most common features were skin lesions, fever, and lymph node enlargement. The rash first appeared on the genitals and anus in 24 cases (66.7%) and was predominantly distributed in those areas in 30 cases (83.3%), with papules and pustules being the most common. There were 14 cases (38.9%, 14/36) of comorbidities with other sexually transmitted diseases. Additionally, there were 21 cases (58.3%,21/36)of comorbid bacterial infections, mainly soft tissue skin infections and perianal infections. Patients with abnormal imaging findings were in the HIV-positive group. CT findings four cases of bacterial pneumonia were characterized by ground-glass opacities, consolidations, and multiple nodules. Two cases were complicated by intestinal obstruction, and the imaging features were dominated by dilatation of the gastrointestinal tract. In one case, proctitis was manifested as thickening of the rectal wall. There were no statistically significant differences found between the epidemiological data, clinical characteristics, distribution and nature of the rash, and laboratory test results of the two groups (P>0.05). Conclusion Mpox patients in Beijing are mostly young MSM and are often HIV-positive. The rash typically appears first and most often in the genital and perianal areas. Ulcerative rashes are only observed in individuals who are HIV-positive. Mild cases have a good prognosis, while severe cases can be complicated by bacterial infections, intestinal obstruction, and proctitis. CT in patients with pneumonia shows solid and ground-glass density shadows and multiple, randomly distributed solid nodules in both lungs.

Key words: Mpox, Human immunodeficiency virus, Clinical Characteristic, Image, Rash