Causes and Outcome of Systemic Inflammatory Response Syndrome in Dogs: An Observational Study of 172 Cases.

OBJECTIVE: To evaluate the clinical characteristics, underlying diseases, organ dysfunctions, and survival of dogs with systemic inflammatory response syndrome (SIRS) or sepsis. DESIGN: Prospective observational study from January to December, 2023. SETTING: Single-center, veterinary university teaching hospital. ANIMALS: One hundred sixty-six dogs; six dogs with distinct cases of SIRS were included twice (172 cases). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Dogs were included if they met two or more of the four SIRS criteria (hypothermia or fever; tachycardia; tachypnea; leukocytosis, leukopenia, or left shift) and had a disease causing systemic inflammation. Cases were categorized into groups (G) "nonseptic SIRS" (G1: n = 73), "sepsis" (G2: n = 92), "sepsis without organ dysfunction" (G2a: n = 25), "severe sepsis" (G2b: n = 59; dysfunction of one or more organ systems), "septic shock" (G2c: n = 8; hypotension despite adequate fluid resuscitation), and "SIRS of unclear origin" (G3: n = 7). The most common causes of SIRS/sepsis were gastrointestinal diseases (n = 61 [35.5%]), vector-borne diseases (n = 28 [16.3%]), and neoplasia (n = 22 [12.8%]). There was dysfunction of one or more organs in 114 cases (66.3%). The coagulation system was most frequently affected (n = 78 [45.3%]), followed by the cardiovascular system (n = 47 [27.3%]), respiratory tract (n = 14 [8.1%]), kidney (n = 13 [7.6%]), and liver (n = 6 [3.5%]). Overall, 128 of 165 cases (77.6%) survived until discharge (short-term), and 116 of 159 (73%) survived ≥4 weeks after discharge (long-term). Differences in outcome were found between G1 and G2 (short-term: p = 0.046, long-term: p = 0.015), with dogs in G2 having better survival. Short-term mortality was higher in cases with one or more organ dysfunctions than in cases without (p = 0.031). CONCLUSIONS: SIRS can be triggered by a variety of diseases in dogs. Strict and regular monitoring is important for early detection of organ dysfunction.