Coagulation status in dogs with naturally occurring Angiostrongylus vasorum infection

Abstract

OBJECTIVES Angiostrongylus vasorum infection is associated with bleeding tendencies in approximately one‐third of clinical cases. The cause of the coagulopathy is poorly understood but may be related to disseminated intravascular coagulation. Thromboelastography is a global evaluation of coagulation and has not been described in a cohort of dogs with this disease. MATERIALS AND METHODS Thromboelastography in association with other measures of coagulation including prothrombin and activated partial thromboplastin times, antithrombin percentage activity and D‐dimer and von Willebrand factor concentrations was evaluated in a group of 30 dogs with A. varosum infection. RESULTS A total of 18 dogs had signs of bleeding on physical examination. Thromboelastography was consistent with hypocoagulation in 17 of these dogs. There was no association between any of the other measures and hypocoagulation on thromboelastography. Abnormal coagulation times were not significantly associated with bleeding. Only fibrinogen concentration was significantly lower in dogs that were bleeding compared with those that were not (P = 0 · 026). D‐dimer concentrations were increased in 22/25 cases in the study; however, other coagulation parameters were more variable. CLINICAL SIGNIFICANCE Although the changes identified in this study were not consistent, there is activation of coagulation within this population, possibly consistent with an intravascular disseminated coagulopathy.

Unexplained bleeding as primary clinical complaint in dogs infected with Angiostrongylus vasorum

“…So far, hyperfibrinolysis has been described in one dog with A. vasorum infection using thromboelastography (TEG) (Schmitz and Moritz, 2009). A recent study reported TEG results in 30 dogs, however, this study did not conclusively prove the presence of hyperfibrinolysis (Adamantos et al, 2015). At any rate, in view of quite variable results of platelet numbers, coagulation times, fibrinogen and D-Dimer concentrations in dogs bleeding due to A. vasorum infection, various mechanisms, including iatrogenic actions, probably play a pathogenetic role.…”

“…Furthermore, coagulation times are usually normal, in experimentally as well as naturally infected dogs , Borgeat et al, 2015Matos et al, 2016). In contrast, another subgroup of dogs mainly presents with clinical signs dominated by bleeding and, like in our case series, abnormal coagulation tests are usually present (Chapman et al, 2004, Adamantos et al, 2015.…”

“…Disseminated thrombosis, i.e. disseminated intravascular coagulation (DIC), was proposed as possible cause (Ramsey et al, 1996;Schmitz and Moritz, 2009;Adamantos et al, 2015). Disseminated intravascular coagulation is a dynamic process, and overt bleeding is typically observed in the acute phase.…”

“…On the other side of the hemostasis spectrum, bleeding is an important part of the pathophysiologic changes in many dogs. It is found (upon necropsy) in the lungs as well as the CNS and eyes, depending on the localization of the primary disease process in the individual dog (Adamantos et al, 2015). We have seen several dogs where unexplained bleeding was the primary presenting complaint, in which A. vasorum infection was not considered initially.…”

“…Some dogs may have ophthalmologic abnormalities (Rosenlund et al, 1991;King et al, 1994). Finally, a few dogs present with polyuria/ polydipsia due to hypercalcemia, thought to be caused by excessive vitamin D production associated with granulomatous disease (Boag et al, 2005;Adamantos et al, 2015).…”