North American Veterinary Licensing Examination (NAVLE) Practice Test

What is the typical cause of a severe increase in bleeding times and low platelet counts in dogs?

1. Aortic thromboembolism

2. Hyperadrenocorticism

3. Disseminated intravascular coagulation (DIC)

4. Immune-mediated thrombocytopenia

The correct answer is: Disseminated intravascular coagulation (DIC)

A severe increase in bleeding times combined with low platelet counts in dogs is typically caused by disseminated intravascular coagulation (DIC). In DIC, there is an inappropriate activation of the coagulation cascade, leading to widespread formation of small blood clots throughout the blood vessels. This process consumes clotting factors and platelets, resulting in a paradoxical increased risk of bleeding due to the depletion of these components. As a result, dogs can present with multiple organ dysfunction and severe bleeding episodes, alongside laboratory findings that show prolonged bleeding times and low platelet counts. While other conditions like immune-mediated thrombocytopenia can lead to low platelet counts and bleeding tendencies, the systemic nature and acute onset of DIC, alongside marked changes in coagulation parameters, are distinct. DIC is frequently secondary to underlying conditions such as infections, trauma, or neoplasia, which can contribute to the severity and complexity of the clinical picture compared to the other options presented.