Evaluation of hemostatic derangements associated with canine anaphylaxis and the relationship to syndrome severity

Abstract

ObjectiveTo describe hemostatic derangements associated with canine anaphylaxis and to assess for association with syndrome severity.DesignProspective observational study.SettingUniversity teaching hospital.AnimalsTwenty‐seven client‐owned dogs, recruited from November 2018 to January 2022, diagnosed with anaphylaxis of varying severity were included. Study inclusion required presentation <6 hours after initiation of clinical signs, no medications or history of illness within the prior 2 weeks, lack of comorbidities expected to affect hemostasis, and lack of a disease state that could alternatively explain the clinical presentation.InterventionsBlood samples were collected within the first hour of presentation for CBC, serum biochemistry, prothrombin time (PT), activated partial thromboplastin time (aPTT), and viscoelastic coagulation testing for use with a cartridge‐based point‐of‐care device.Measurements and main resultsClotting time and clot formation time were prolonged, alpha angle and maximum clot firmness were decreased, PT and aPTT were prolonged, and platelet counts were lower in severe cases compared to mild and moderate cases. There were no differences for any parameter between mild and moderate cases. The presence or absence of abdominal effusion was not associated with hemostatic status.ConclusionsGlobal hemostatic derangements consistent with hypocoagulability are a prominent feature of severe anaphylaxis in dogs and should be considered for routine evaluation.

Acute hepatic rupture causing hemoperitoneum in a dog with anaphylaxis

“…Hemoperitoneum associated with canine anaphylaxis has been documented in multiple case reports and case series to date, though no definitive mechanism has been identified to explain the source of the acute haemorrhage. (Caldwell et al, 2018;Hnatusko et al, 2021;Smith et al, 2020Smith et al, , 2023Summers et al, 2021) In the case presented in this report, acute hepatic parenchymal rupture was noted on necropsy, which likely explains the severity and progressive nature of the hemoperitoneum seen clinically. The cause of the hepatic rupture, however, could not be definitively determined.…”

“…Haemostatic system derangements, such as consumption of coagulation factors, widespread platelet activation, dysfibrinogenolysis and fibrinolysis, have been demonstrated in anaphylaxis (Guilarte et al., 2017 ). Prolonged clotting times, thrombocytopenia and generalized hypocoagulable viscoelastic coagulation tracings have been documented to occur in canine anaphylaxis cases and have been postulated as a mechanism for the development of AAH (Hnatusko et al., 2021 ; Smith et al., 2023 , 2020 ). Other proposed mechanisms include vascular leakage due to vasoactive mediator release and vessel rupture due to acute hepatic congestion and portal hypertension (Hnatusko et al., 2021 ; Summers et al., 2021 ).…”