establishing a definitive diagnosis of the hereditary deficiency. Differentiation between afibrino- ... definitif de deficience hereditaire. Les taux de fibrinogene ...
Dysfibrinogenemia or afibrinogenemia in a Border Leicester lamb Gilles Fecteau, Joseph G. Zinkl, Bradford P. Smith, Sharon O'Neil, Steven Smith, Susan Klopfer Abstract Hereditary fibrinogen deficiency is a rare condition in all species. Measurement of plasma fibrinogen should indicate low levels. Specific factor assays and pedigree analysis are essential in establishing a definitive diagnosis of the hereditary deficiency. Differentiation between afibrinogenemia, hypofibrinogenemia, and dysfibrinogenemia requires sophisticated techniques and assistance from a specialized laboratory.
Resume - Dysfibrinogenemie ou afibrinogenemie chez un agneau Border Leicester. La deficience hereditaire en fibrinogene est une condition rare chez toutes les especes. Des dosages des facteurs specifiques et une analyse genealogique sont essentiels 'a l'etablissement d'un diagnostic definitif de deficience hereditaire. Les taux de fibrinogene plasmatique devraient etre bas. Le diagnostic differentiel entre I'afibrinogenemie, 1'hypofibrinogenemie et la dysfibrinogenemie necessite l'usage de techniques d'avant-garde et l'aide d'un laboratoire specialise. (Traduit par doc teur Andre Blouin) Can Vet J 1997; 38: 443-444
A7-week-old, female, Border Leicester lamb was referred to the Veterinary Medical Teaching Hospital, University of California, Davis, with a history of chronic swelling and bleeding of the umbilicus, recurrent periorbital swelling, and chronic infection of the ear tag wound. The lamb originated from a flock of 35 head. The referring veterinarian was concerned that inbreeding may have led to expression of an inherited hemostatic disorder. On physical examination, the animal appeared within the normal range of size for its age. It was bright and alert with normal appetite. The rectal temperature was 39.1 °C. Heart rate was rapid (>180 beats/min) with a normal rhythm. No murmur was noticed. Respiratory rate was rapid (>100 breaths/min), but lung sounds were normal. A firm swelling could be palpated over the left shoulder. There was chronic inflammation around the umbilicus and at the ear tag wound. On the day of presentation, the eyes appeared normal. The scleral and the vulvar mucosa were pale. All other physical parameters were normal. Initial laboratory evaluation included hematology and a chemistry panel. Abnormal hematologic findings included low total protein (49 g/L; reference range, 60 to 75 g/L), packed cell volume (0.15 L/L; reference range, 0.27 to 0.45 L/L), hemoglobin (43 g/L; reference range, 90 to 150 g/L), red blood cells (4.39 X 1012/L; reference range, 9.0 to 15.0 x 1012/L), and high reticulocyte count (246 X 109 cells/L; reference range, 0). Examination of the blood smear revealed marked anisocytosis,
Departement de sciences cliniques, Faculte de medecine v'terinaire, Universite de Montreal, C.P. 5000, Saint-Hyacinthe (Quebec) J2S 7C6 (Fecteau); Veterinary Medical Teaching Hospital University of California Davis, Davis, California 95616 USA (Zinkl, Smith, Smith, O'Neil); Aquajito Veterinary Hospital, 1221 10th Street, Monterey, California 93940 USA (Klopfer). Can V.t 38, July July 1997 Vet J Volume 38,
moderate polychromasia, poikilocytosis, and basophilic stippling. The total and differential white blood cell counts were within reference ranges on the initial blood sample. Heat precipitable fibrinogen concentration was 1 g/L (reference range, 1 to 5 g/L). Serum biochemical profile revealed slightly elevated alkaline phosphatase activity (322 U/L; reference range, 50 to 300 U/L) and increased total bilirubin (10.26 umol/L; reference range, 1.71 to 3.42 umol/L). Further investigation of hemostatic capacity included the following laboratory evaluations: platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT), proteins induced by vitamin K antagonism (PIVKA), Russell's viper venom time, thrombin time (TT), clottable fibrinogen, heat precipitable fibrinogen, and fibrin and fibrinogen degradation products (FDPs). Coagulation factors II, V, VII, VIII, IX, X, XI, and XII were also evaluated. The platelet count was higher than normal (911 X 106 platelets/L; reference range, 250 to 750 X 106 platelets/L). Other results are presented in Tables 1 and 2. Interpretation of these results led us to the conclusion that a fibrinogen defect existed. However, the presence of a thrombin inhibitor could not be ruled out. No immunological assay to detect fibrinogen was performed, because antibody to sheep fibrinogen was not available. However, crossimmuno reactivities among vertebrate fibrinogens could have justified the use of antibody from another species (1). Also, alternative methods of fibrinogen measurement, such as chemical methods (adding thrombin to plasma and weighting the fibrin clot produced), could have been used. Any of these methods would have been useful to enable us to differentiate congenital afibrinogenemia from the production of an abnormal fibrinogen (dysfibrinogenemia). Because heat precipitable fibrinogen was present at low concentration (1 g/L) and clottable fibrinogen was below the limits of detection (
