Anatomic site and etiology of hemorrhage in small versus large dogs with spontaneous hemoperitoneum.

OBJECTIVE: To compare anatomic sources and underlying etiology of hemorrhage in small vs large dogs with spontaneous hemoperitoneum (SH).

STUDY DESIGN: Retrospective cross-sectional study.

ANIMALS: Client-owned dogs with SH at 2 academic institutions.

METHODS: Medical records were reviewed for age, breed, sex, weight, and results of imaging, surgery, necropsy, cytology, and histopathology. Dogs were divided according to body weight (≤ 20 kg = small, > 20 kg = large). Confidence intervals were calculated to estimate rates of splenic and hepatic hemorrhage in small and large dog SH populations. Multivariable regression was used to compare prevalence of anatomic sources of hemorrhage and etiology in small vs large dogs.

RESULTS: We identified 742 dogs with SH, including 637 in which the anatomic site of hemorrhage was investigated. Splenic hemorrhage was diagnosed in 43.2% (95% CI, 34.3-52.4) of small dogs and 61.3% (95% CI, 57.0-65.6) of large dogs. Small dogs had lower prevalence of splenic hemorrhage (prevalence ratio, 0.70; 95% CI, 0.58-0.87; P < .001) and higher prevalence of hemorrhage from liver (prevalence ratio, 1.72; 95% CI, 1.20-2.47; P = .003) or from another location such as retroperitoneal mass, kidney, or adrenal (prevalence ratio, 2.73; 95% CI, 1.66-4.47; P < .001) vs large dogs. Hemangiosarcoma was associated with splenic hemorrhage and occurred more frequently in large vs small dogs (P = .011).

CONCLUSION: Small dogs had a lower rate of splenic hemorrhage and higher rates of hemorrhage from liver and other sites compared to large dogs. Etiologies other than splenic hemangiosarcoma were common, particularly among dogs weighing ≤ 20 kg.

CLINICAL SIGNIFICANCE: Clinicians should perform diagnostics and consider body size before making presumptive diagnoses in dogs with SH.