A case of factor X deficiency in a Chihuahua dog.

A juvenile Chihuahua dog developed hemoperitoneum after routine ovariohysterectomy. She was managed with packed red blood cell and fresh frozen plasma transfusions as well as an exploratory laparotomy to verify ligature sites. No recurrence of hemorrhage occurred. Factor X deficiency was diagnosed and confirmed with repeat analysis including during times of health.

Cas de carence du facteur X chez une chienne Chihuahua. Une jeune chienne Chihuahua a développé un hémopéritoine après une ovariohystérectomie de routine. Elle a été gérée à l'aide de concentrés de globules rouges et de transfusions de plasma frais congelé ainsi que d'une laparotomie exploratoire pour vérifier les sites de ligature. Aucune récurrence d'hémorragie ne s'est produite. La carence du facteur X a été diagnostiquée et confirmée par une analyse répétée durant des périodes de santé.(Traduit par Isabelle Vallières).

Hereditary deficiency of vitamin-K-dependent coagulation factors in Rambouillet sheep.

A flock of Rambouillet sheep experienced unexpected lamb mortality associated with excessive bleeding at the time of parturition. Most lambs died of blood loss through the umbilicus or into subcutaneous tissues. Subsequently, nine ewes which had previously delivered lambs that bled to death were bred to the suspected sire of the previous bleeding lambs. Fifteen lambs were born alive the following Spring, and three males and one female bled clinically. These lambs had markedly decreased factor IX (< 16%) and factor X (< 4%) activities, with variably decreased factor II (11-36%) and factor VII (20-37%) activities. Protein C chromogenic activity was also markedly decreased (< 1%) in these lambs. The results from crossed immunoelectrophoresis and 'protein-induced-in-vitamin-K-absence' determination of the plasma of affected lambs, with antiserum directed against coagulation factor X, protein C or proteins S, suggested that these proteins were not carboxylated normally. Examination of liver from one lamb in the first batch and the four subsequent lambs did not reveal a known vitamin K antagonist. The breeding data suggested that the coagulopathy in these sheep was inherited as an autosomal recessive trait. The genetic or molecular defect that exists in these lambs is unknown, but possibilities include abnormal gamma-glutamyl carboxylase activity or abnormal metabolism of vitamin K.

Factor X deficiency in a cat.

Severe congenital deficiency of factor X was diagnosed in a 3-year-old castrated male domestic shorthair cat with clinical signs of generalized seizures and prolonged bleeding after venipuncture. Heritability of factor X deficiency was suspected because of a prolonged Russell's viper venom time in the dam and reductions in factor X activity in the dam and 1 sibling. To our knowledge, factor X deficiency in cats has not been reported previously. Definitive diagnosis for animals with clinical signs of coagulopathy may require repetition of coagulation screening tests using different assay methods or specific coagulation factor analyses.

Optimization of prothrombin time measurements in canine plasma.

OBJECTIVE: To optimize a prothrombin time (PT) method designed for human plasma for use with canine plasma. SAMPLE POPULATION: 100 plasma samples from healthy dogs and 50 plasma samples with reduced activity of the single factors II, V, VII or X. PROCEDURE: Canine plasma samples with various coagulation activity values (100, 75, 50, 25 and 10%: prepared by dilution from a plasma pool [n = 100]) were assayed at various sample dilutions and dilutions of the thromboplastin component of 3 commercial calcium thromboplastin reagents. The sc-named optimized PT test was compared with the standard test with respect to its sensitivity and correlation with the sum of the activity decreases of single factors II, V, VII, and X in relation to the respective reference range. RESULTS: The time intervals between various coagulation activity values, which were small by use of the standard test, could be increased by diluting the sample and substituting fibrinogen, but not by diluting the tissue thromboplastin component of PT reagent. On the basis of 50 abnormal plasma samples, the optimized test had high sensitivity (0.90 to 1.00, dependent on reagent and sample dilution) in contrast to the standard test, which had low sensitivity (0.24 to 0.58, dependent on reagent). Also, correlation with the sum of the activity decreases was closer by use of the optimized (0.90 to 0.93) than the standard (0.58 to 0.84) test. CONCLUSIONS: In contrast to the standard test, an optimized test is suitable as a sensitive screening test of the extrinsic coagulation system in dogs. CLINICAL RELEVANCE: The optimized PT method is easy to perform and, therefore, should be in general use for assay of canine plasma.

[Applicability of activated partial thromboplastin time (APTT) as a screening test of milk to medium deficiencies of coagulation factors in cats]. / Eignung der aktivierten partiellen Thromboplastinzeit (aPTT) als Screeningtest für gering- bis mittelgradige Gerinnungsfaktorverminderungen bei der Katze.

The present investigation examined if the aPTT shows sufficient sensitivity for single factor activities also in cats when measured with the test optimized for humans using a commercial reagent. Comparative measurements were done with different modifications of the aPTT (sample predilution, addition of fibrinogen). Measurements of the aPTT using different methods and the activity of the coagulation factors II, V, X, VIII, IX, XI, and XII were performed in 42 healthy cats in order to determine the reference ranges. The same measurements were done on 21 cat plasmas where at least one of the coagulation factors was diminished in relation to the corresponding reference range. The conventional aPTT reflected the decrease in coagulation factor activity in each of the 21 plasmas by prolongation above the reference range (14.6-24.4 s). The test thus possesses high sensitivity and is a suitable screening test also for the cat. In contrast, in tests with sample predilution the sensitivity was lower (3-4 false negative results). This was probably caused by the distinct increase of the range of the reference values.

Vitamin K-dependent multifactor coagulopathy in Devon Rex cats.

A coagulopathy attributable to a deficiency of vitamin K-dependent clotting factors (II, VII, IX, and X) was diagnosed in 3 Devon Rex cats. There was no evidence for exposure to vitamin-antagonist-related rodenticides. The cats did not have evidence of hepatic disease, gastrointestinal disease, or fat malassimilation. Oral treatment with vitamin K1 resulted in normalization of clotting factor concentrations. However, when treatment was discontinued in 2 cats, prothrombin and activated partial thromboplastin values became prolonged again, although the cats did not have clinical signs of a bleeding disorder.

Inherited coagulation disorders.

Inherited coagulation disorders have been diagnosed in many breeds of dogs as well as in mongrels and cats. This article presents the different coagulation factor deficiencies that are known to exist in small animals. A description is given of each coagulation factor along with the relevant clinical signs, inheritance, and the breeds affected. Suggestions are also given for the diagnosis and therapy of these deficiencies.

Acquired coagulation factor X activity deficiency connected with Hymenoxys odorata DC (Compositae), bitterweed poisoning in sheep.

An acquired coagulation factor X activity deficiency was demonstrated in sheep fed Hymenoxys odorata, bitterweed plant. All coagulation tests were normal before the sheep were given the plant material. All tests involving the function of factor X, including a specific factor assay, became abnormal after the sheep were given bitterweed. Other specific factors remained within normal limits. The presence of an inhibitory activity could not be shown.