A 14-year-old Quarter Horse gelding presented for a 2-week history of increased respiratory rate, fever and weight loss. The referring veterinarian performed an ultrasonographic examination on the farm and considered a differential diagnosis of pleuritis and pleuropneumonia. On presentation, transtracheal wash showed suppurative septic inflammation with bacteria within macrophages. Thoracic ultrasonography showed increased hypoechoic fluid in the pleural and peritoneal cavities. Cytologic analysis of pleural and peritoneal fluids revealed lymphorrhagic effusion with atypical lymphocytes, suggestive of a lymphatic flow obstruction or lymphoma. Treatment consisted of drainage of the pleural fluid, anti-inflammatory agents, fluid therapy and antimicrobial therapy. Continued fluid accumulation in the thoracic cavity, tachypnoea, lack of response to pain medication and progressive lethargy resulted in the horse being subjected to euthanasia. At necropsy, bicavitary effusion was confirmed and histopathological diagnosis of multicentric lymphoma was made. Horses presenting with pleural effusion should also be evaluated for peritoneal effusion, as bicavitary effusion may indicate noninflammatory conditions such as neoplasia.

中文翻译：

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多中心淋巴瘤马的双腔积液

一头 14 岁的 Quarter Horse 阉马出现了 2 周呼吸频率增加、发烧和体重减轻的病史。转诊兽医在农场进行了超声检查，并考虑了胸膜炎和胸膜肺炎的鉴别诊断。就诊时，经气管冲洗显示巨噬细胞内有细菌的化脓性脓毒性炎症。胸部超声检查显示胸膜腔和腹膜腔中低回声液体增加。胸膜液和腹膜液的细胞学分析显示有非典型淋巴细胞的淋巴出血性渗出液，提示淋巴流动阻塞或淋巴瘤。治疗包括胸水引流、抗炎药、液体疗法和抗菌疗法。胸腔内持续积液、呼吸急促、对止痛药缺乏反应和逐渐嗜睡导致马被实施安乐死。尸检证实双腔积液，并作出多中心淋巴瘤的组织病理学诊断。出现胸腔积液的马也应评估腹腔积液，因为双腔积液可能表明非炎症性疾病，如瘤形成。