RETROPERITONEAL EFFUSION IN DOGS AND CATS

Although cases of retroperitoneal effusion associated with adrenal gland neoplasia have been reported in the veterinary literature, these clinical reports have been largely anecdotal. To our knowledge, no comprehensive evaluation of the causes or clinical indications of effusion (RPE) in the retroperitoneal space exists. In this retrospective study, we evaluated the causes, presenting signs, clinical findings and outcomes associated with RPE. The records of 23 cats and 44 dogs presenting to the Tufts University School of Veterinary Medicine between 1996 and 2003 and having been identified with RPE were reviewed. The presence of RPE was identified using abdominal ultrasonography. All of the cats and 84% (n=38) of dogs in this study presented through the Emergency Service. Diagnoses for RPE were categorized as follows: (Group 1) 14 dogs and 3 cats with acute renal failure associated with infection; (Group 2) 5 dogs and 6 cats with acute renal failure of unknown etiology; (Group 3) 3 cats with acute renal failure due to urinary tract obstruction; (Group 4) 8 dogs with adrenal gland neoplasia; (Group 5) 7 dogs and 1 cat with non-adrenal gland neoplasia; (Group 6) 5 dogs and 4 cats with other renal disease, and (Group 7) 5 dogs and 6 cats with RPF due to other causes. The most frequent presenting complaints in all categories except for those in Group 4 included anorexia, lethargy and vomiting. Physical examination findings were very similar for all categories except for those in Group 4 and included abdominal pain, dehydration, mental depression, lethargy and weakness. For those in Group 4, the most common complaints were collapse or marked weakness, anorexia, lethargy, and discomfort. The physical examination findings for dogs in Group 4 also included collapse or marked weakness, and abdominal distension. Percent mortality for dogs was 39% and, for cats, 43%. In each category, the percent mortalities are as follows (euthanized=e, died=d): Group 1: dogs: 14% (e n=1, d n=1), and cats: 33% (e n=1); Group 2: dogs: 100% (e n=4, d n=1) and cats 67% (e n=4).; Group 3: cats: 100% (e n=2, d n=1); Group 4: dogs: 32% (e n=3); Group 5: dogs: 71% (e n=5) and cats: 0%;. Group 6: dogs: 0% and cats: 25% (e n=1), and Group 7: dogs: 40% (e n=2) and cats: 17% (e n=1). Retroperitoneal effusion, regardless of cause, is associated with significant disease. In people, another category of disease associated with RPE is trauma. Although this category is not included in this study, abdominal ultrasonography of trauma victims may identify a veterinary population with RPE.