Abstract
BACKGROUND: Among coagulation disorders, primary fibrinogen deficiency is very rare in dogs. It is divided into hypofibrinogenemia, afibrinogenemia and dysfibrinogenemia. Afibrinogenemia has been described in three dogs. There are, however, no published case reports of primary hypofibrinogenemia in dogs. CASE PRESENTATION: A 1.5 year-old male German Pointer dog was evaluated for a locked-jaw syndrome associated with eye protrusion which appeared after a minor head trauma. Three months before the trauma, a persistent increase in coagulation times was detected by the referring veterinarian after a strong suspicion of snake envenomation. Apart for the primary complaint, physical examination was normal. A complete hemostatic profile revealed a moderately increased prothrombin time, activated partial thromboplastin times and a dramatically decreased fibrinogen concentration (0.34 g/L, reference interval [1.3-4.8 g/L]). Platelet count, plasma D-dimers and antithrombin, were all within the reference intervals and not consistent with a disseminated intravascular coagulation. Other possible causes of hypofibrinogenemia such as chronic hemorrhage and liver failure were excluded by laboratory work-up and imaging studies. Finally, antifibrinogen circulating anticoagulants were excluded using a dilution of citrated plasma from the pooled plasma of healthy dogs. These results supported a diagnosis of congenital fibrinogen deficiency and secondary retrobulbar hematoma and/or cellulitis. The dog's condition improved rapidly after symptomatic treatment with corticosteroids and antibiotics. At the 1 year follow-up, the dog was clinically normal but a persistent hypofibrinogenemia (≤ 0.8 g/L) remained. CONCLUSIONS: Various clinical presentations may occur in canine primary hypofibrinogenemia which should be included in the list of coagulation disorders. Diagnosis should include fibrinogen determination by coagulometric and non-coagulometric methods to differentiate from dysfibrinogenemia. There is no specific treatment but care should be taken to prevent bleeding and trauma. Emergency management of bleeding episodes with cryoprecipitate is the treatment of choice.